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中野 直樹医学部附属病院 リハビリテーション部助教
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■ 論文- PURPOSE: The aim of this study was to compare total perioperative blood loss in patients undergoing total knee arthroplasty (TKA) in different ABO blood types. METHODS: This study was approved by the Institutional Review Board of our hospital (IRB No. 1510) on 2 February 2015. A total of 260 knees undergoing unilateral primary cemented cruciate-retaining TKA for knee osteoarthritis were retrospectively registered. Perioperative total blood loss was calculated for each blood types based on the change in hematocrit from pre- to postoperative day 7, preoperative height and weight. Differences in blood loss among the four ABO blood types were assessed. The association between blood type (O versus others) and total blood loss was further evaluated after adjusting for baseline characteristics through inverse probability of treatment weighting (IPTW). RESULTS: The study population was divided based on the ABO blood type: type O, 87; type A, 82; type B, 54; and type AB, 37. The mean total blood loss was 829 ± 370 ml for type O, 702 ± 384 ml for type A, 574 ± 361 ml for type B, and 528 ± 282 ml for type AB. Patients with blood Type O had significantly higher blood loss than all other blood types. After IPTW adjustment, mean total blood loss remained higher in type O (790 ± 370 ml) compared to other blood types (613 ± 364 ml). CONCLUSION: These findings suggest that blood type O may be associated with increased perioperative blood loss in TKA.2025年07月, Knee surgery & related research, 37(1) (1), 32 - 32, 英語, 国際誌研究論文（学術雑誌）
- This study examined the impact of preoperative coronal plane alignment of the knee (CPAK) classification on intraoperative soft tissue balance and postoperative clinical outcomes in patients undergoing modified kinematically aligned (mKA) and mechanically aligned (MA) total knee arthroplasty (TKA). A total of 90 knees treated with mKA-TKA and 63 knees treated with MA-TKA were classified based on CPAK. After adjusting for confounding factors, intraoperative soft tissue balance, including varus/valgus balance and joint component gap, range of motion (ROM), and the 2011 Knee Society score (KSS), were compared 1 year postoperatively using one-way ANOVA. The analysis included 69 knees classified as type I and 18 type II in the mKA group, and 52 type I and 11 type II in the MA group. Varus balance at 30 and 60 degrees flexion was significantly larger in mKA type I and MA type I compared to mKA type II (p < 0.001, 0.005, <0.001, 0.008). At 90 degrees, mKA type I showed a larger varus balance than both MA type I and mKA type II (p = 0.008, 0.002), while at 120 degrees, mKA type I demonstrated a larger varus balance than MA type I (p < 0.001). The improved ROM in mKA type I was greater than in MA type I (p = 0.04). Improvement in the objective indicator of the 2011 KSS was better in mKA type I than in mKA type II, and patient satisfaction was significantly better in mKA type I compared to both mKA type II and MA type I (p = 0.01, <0.001, 0.03). mKA type I preserved lateral laxity in mid- and deep flexion compared to both mKA type II and MA type I, potentially contributing to improved ROM and clinical outcomes.2025年07月, The journal of knee surgery, 38(9) (9), 440 - 447, 英語, 国際誌研究論文（学術雑誌）
- OBJECTIVES: This multicentre, retrospective study aimed to evaluate differences in drug continuation rates and efficacy between first- and second-line use of biological DMARDs (bDMARDs) and Janus kinase inhibitors (JAKi) after failure of the initial therapy in real-world RA settings. METHODS: Data from an observational multicentre registry of patients with RA in Japan were analysed, encompassing 5900 treatment courses (4046 bDMARD/JAKi-naïve cases and 1854 second-line cases). Gray's tests were used to compare the cumulative incidence function (CIF) for drug discontinuation, considering discontinuation due to remission as a competing risk. Competing risk analysis using Fine-Gray model was conducted to analyse the hazard ratios after adjusting for potential confounders. Changes in the Clinical Disease Activity Index (ΔCDAI) and disease activity score (ΔDAS28-CRP) were assessed at each time point compared with baseline using a linear mixed model with covariate adjustments. RESULTS: Among the TNF inhibitors, IL-6 inhibitors, Cytotoxic T-lymphocyte associated protein 4 (CTLA4) and JAKi, only JAKi showed no significant difference in CIF of first- and second-line treatments. Competing risk analysis showed that consistent with the CIF analysis, second-line treatment influenced the drug continuation rates for all drugs except for JAKi. In analysing CDAI and DAS28-CRP trends using a linear mixed model, JAKi demonstrated similar efficacy as first- and second-line therapy, unlike other drugs. CONCLUSIONS: JAKi maintained continuation rates and efficacy in second-line treatment compared with first-line treatment, which is potentially advantageous over bDMARDs for patients with RA who require a change in initial therapy.2025年07月, Rheumatology (Oxford, England), 64(7) (7), 4207 - 4217, 英語, 国際誌研究論文（学術雑誌）
- BACKGROUND: The purpose of this study was to divide patients with borderline developmental dysplasia of the hip (BDDH) into two groups according to the presence of Cam lesions, and compare radiographs related to bone morphology between them. METHODS: We retrospectively analyzed consecutive patients with BDDH who underwent hip arthroscopy (HA) or periacetabular osteotomy (PAO) at our institution between October 2013 and October 2019. The patients were classified into two groups according to the presence of Cam lesions. Radiographic measurements including lateral center-edge angle (LCEA), acetabular roof obliquity (ARO), cliff sign, femoral epiphyseal acetabular roof (FEAR) index, vertical center anterior angle (VCA), and Sourcil Index were compared between the two groups. The cutoff values were calculated using a receiver operating characteristic curve. RESULTS: Sixty-nine hips were analyzed in this study (Cam+: 34, Cam-: 35). The ARO and FEAR index were significantly higher in the Cam-group (P < 0.001, P < 0.001). The LCEA, VCA, and Sourcil Index was significantly lower in the Cam-group than that in the Cam + group (P < 0.001, P < 0.001, P < 0.001). The cutoff values were 21.0° for LCEA, 15.1° for the ARO, 22.5° for the VCA angle, -2.2° for the FEAR index, and 49.5° for the Sourcil Index. CONCLUSION: Patients with BDDH exhibited significant differences in bone morphology depending on the presence of Cam lesions. Moreover, those without Cam lesions displayed similarities to patients with DDH.2025年07月, Asia-Pacific journal of sports medicine, arthroscopy, rehabilitation and technology, 41, 14 - 19, 英語, 国際誌研究論文（学術雑誌）
- AIMS: Evaluating plantar pressure distribution and coronal lower limb alignment, including the hindfoot, using the hip-to-calcaneus axis, known as the ground mechanical axis (GA), is valuable in total knee arthroplasty (TKA). This study aimed to compare postoperative changes in plantar pressure distribution and lower limb alignment between mechanically aligned TKA (MA-TKA) and ground kinematically aligned TKA (gKA-TKA), targeting neutral GA. METHODS: After 1:1 propensity score matching, 35 pairs of patients with end-stage osteoarthritis of the knee, who underwent gKA-TKA and MA-TKA with similar preoperative disability between September 2019 and March 2022, were compared. Plantar pressure distribution during walking and unipedal stance was measured preoperatively and one year postoperatively using a pressure plate. The hip-knee-calcaneus angle (HKC) (positive values = valgus) and the percentage of the GA passing position at the knee joint (%GA; medial edge, 0%; lateral edge, 100%) were assessed on long-leg radiographs in unipedal stance. RESULTS: MA-TKA showed a medial loading pattern in the hindfoot. gKA-TKA exhibited a nearly equal pressure distribution in the coronal plane of the hindfoot. Postoperative centre-of-pressure path length during unipedal stance was significantly better for gKA-TKA than MA-TKA (p = 0.043). Furthermore, mean HKC angle and mean %GA of the MA-TKA were 2.0° (SD 2.4°) and 54.2% (SD 9.0%), respectively; those of the gKA-TKA were -0.2° (SD 1.0°) and 49.6% (SD 5.0%), respectively. Significant correlations were observed between the HKC angle (r = 0.391 (95% CI 0.172 to 0.573)) or %GA (r = 0.343 (95% CI 0.117 to 0.535)) and the hindfoot plantar pressure pattern in the coronal plane, indicating that postoperative lower limb valgus deformity in the hip-to-calcaneus axis results in a medial loading pattern. CONCLUSION: gKA-TKA can provide more neutral weightbearing in the GA, more equal coronal hindfoot pressure during walking, and improved stability in unipedal stance compared with MA-TKA.2025年06月, The bone & joint journal, 107-B(6) (6), 604 - 614, 英語, 国際誌研究論文（学術雑誌）
- INTRODUCTION: The amount of change in coronal alignment by unicompartmental knee arthroplasty (UKA) is important when considering its long-term results. This study investigated whether the amount of change in mechanical hip-knee-ankle (mHKA) angle by medial fixed-bearing UKA can be predicted based on the arithmetic hip-knee-ankle (aHKA) angle, an indicator of bony nature that is independent of soft tissue balance. MATERIALS AND METHODS: The research involved 101 patients (125 knees) who underwent medial fixed-bearing UKA with the spacer-block technique. Pre- and postoperative mHKA angles, aHKA angle (180°- lateral distal femoral angle + medial proximal tibial angle), insert thickness, and the amount of bone cuts were measured. The component gap in extension was measured using a UKA tensor, and the pre-osteotomy gap was calculated. The correlation between aHKA angle minus preoperative mHKA angle and changes in mHKA angle, as well as the pre-osteotomy gap, were analysed. Additionally, changes in mHKA angle and total osteotomy volume were compared based on insert thickness. RESULTS: A positive correlation was found between aHKA angle minus preoperative mHKA angle and the change in mHKA angle. The pre-osteotomy gap was also positively correlated with aHKA angle minus preoperative HKA angle. Greater changes in mHKA angle occurred in cases with inserts ≥ 9 mm compared to 8 mm inserts, though osteotomy volume did not significantly differ between the groups. CONCLUSIONS: In fixed-bearing UKA, postoperative changes in mHKA angle are likely to be more pronounced when there is a significant difference between aHKA angle and preoperative mHKA angle. Surgical planning should account for this factor to optimise outcomes.2025年04月, Archives of orthopaedic and trauma surgery, 145(1) (1), 271 - 271, 英語, 国際誌研究論文（学術雑誌）
- PURPOSE: In unicompartmental knee arthroplasty (UKA), the tibial component tends to be placed in a mildly varus position because of the expected improvement in stress distribution and load transfer across the tibia. With the spacer block technique in UKA, if a tibial osteotomy is performed in the varus position, the femoral component is placed in the valgus position. Therefore, this study aimed to evaluate the impact of valgus positioning of the femoral component on the short-term postoperative clinical outcomes in fixed-bearing UKA using the spacer block technique. METHODS: We analyzed 77 knees of 70 patients who underwent fixed-bearing UKA using the spacer block technique for medial compartment osteoarthritis and spontaneous osteonecrosis of the knee. Patients were categorized based on femoral component alignment: the neutral group (-3° to + 3°, mean 0.5° ± 1.7° valgus) and the valgus group (> 3°, mean 5.7° ± 1.7° valgus). Postoperative outcomes, including the femorotibial angle (FTA), component sagittal alignment, knee range of motion, and 2011 Knee Society Score (KSS), were compared between the two groups. RESULTS: No significant differences were found between the neutral and valgus groups regarding the postoperative FTA, component sagittal alignment, knee range of motion (neutral vs. valgus group; extension,°: - 1.9 ± 2.9 vs. - 1.6 ± 2.9; flexion,°: 133.0 ± 6.9 vs. 131.3 ± 7.9), or 2011 KSS (objective knee indicators: 95.0 ± 8.9 vs. 96.8 ± 3.5; functional activities: 78.9 ± 15.3 vs. 78.2 ± 12.9). CONCLUSION: These findings support the safety of valgus positioning in fixed-bearing UKA, offering flexibility in component placement without compromising short-term clinical outcomes.2025年04月, European journal of orthopaedic surgery & traumatology : orthopedie traumatologie, 35(1) (1), 165 - 165, 英語, 国際誌研究論文（学術雑誌）
- Rheumatoid arthritis (RA) involves synovial tissue proliferation, inflammation, and angiogenesis, and contributes to joint destruction. Angiogenesis is a key therapeutic target for the treatment of RA, and Janus kinase (JAK) inhibitors have emerged as a promising therapy. In this study, we compared the inhibitory effects of five JAK inhibitors, including tofacitinib (TOF), baricitinib, peficitinib, upadacitinib, and filgotinib, on interleukin (IL)-6-induced inflammation in RA synovial tissues. All five inhibitors effectively suppressed IL-6-induced inflammatory and angiogenic factors, including vascular endothelial growth factor, intercellular adhesion molecule-1, and vascular cell adhesion molecule-1, by inhibiting the phosphorylation of signal transducer and activator of transcription (STAT)1 and STAT3. Overall, the results suggest that while all five JAK inhibitors are effective in reducing IL-6-induced inflammatory and angiogenic factors, their efficacy may differ owing to specific molecular mechanisms and pharmacological properties.2025年03月, Scientific reports, 15(1) (1), 9736 - 9736, 英語, 国際誌研究論文（学術雑誌）
- AIMS: Bone marrow mononuclear cells (BM-MNCs) are a rich source of hematopoietic stem cells that have been widely used in experimental therapies for patients with various diseases, including fractures. Activation of angiogenesis is believed to be one of the major modes of action of BM-MNCs; however, the essential mechanism by which BM-MNCs activate angiogenesis remains elusive. This study aimed to demonstrate that BM-MNCs promote bone healing by enhancing angiogenesis through direct cell-to-cell interactions via gap junctions, in addition to a previously reported method. METHODS: Using a murine fracture model, we aimed to elucidate the relationship between gap junction-mediated cell-to-cell interactions and enhanced fracture healing after BM-MNC transplantation. We evaluated the transfer of substances from BM-MNCs to vascular endothelial cells and osteoblasts in the tissues surrounding the fracture site and assessed the effects of BM-MNC transplantation on bone healing, angiogenesis, and osteogenesis. RESULTS: Bone marrow mononuclear cells transferred substances to vascular endothelial cells and osteoblasts in the tissues surrounding the fracture site. Moreover, BM-MNC transplantation promoted bone healing via gap junction-mediated cell-to-cell interactions, accelerating both angiogenesis and osteogenesis. CONCLUSIONS: Our findings provide a novel understanding of fracture healing mechanisms and suggest that BM-MNC transplantation enhances bone healing through gap junction-mediated cell-to-cell interactions, contributing to the development of regenerative medicine strategies targeting bone repair.2025年03月, Stem cells (Dayton, Ohio), 43(3) (3), 英語, 国際誌研究論文（学術雑誌）
- PURPOSE: The study aimed to determine the impact of intraoperative lateral laxity at extension on clinical and functional outcomes 1 year after posterior-stabilised total knee arthroplasty (PS-TKA). METHODS: In total, 91 varus-type osteoarthritic knees that underwent PS-TKA using the medial preservation gap technique were included. After the femoral trial component placement and patellofemoral joint reduction, the soft-tissue balance was assessed using an offset-type tensor with a 40-lb joint-distraction force. Patients were divided into the following three groups according to the intraoperative lateral laxity at extension (i.e., varus ligament balance) using the mean ± 1 standard deviation: Groups A, ≤0°; B, 0-4°; and C, >4°. The 2011 Knee Society Score (KSS) and 3-m timed up-and-go test (TUG) time 1-year postoperatively, and their improvements were compared among the groups. RESULTS: While significant improvements were observed in all subscales of the 2011 KSS and TUG post-TKA (p < 0.05), the improvement of functional activities and TUG time were significantly lower in Group C than in Group B (p < 0.05). However, no significant differences were observed in symptom improvement, patient satisfaction or patient expectation scores among the groups. CONCLUSION: An excessive lateral laxity (varus angle) >4° at extension was associated with lower improvement in functional ability 1-year postoperatively. Therefore, excessive intraoperative lateral laxity should be avoided in PS-TKA. LEVEL OF EVIDENCE: Level IV.2025年01月, Knee surgery, sports traumatology, arthroscopy : official journal of the ESSKA, 33(1) (1), 296 - 307, 英語, 国際誌研究論文（学術雑誌）
- OBJECTIVE: The role of Krüppel-like zinc finger transcription factor 15 (KLF15) in endochondral ossification during fracture healing remains unexplored. In this study, we aimed to elucidate the impact of KLF15 in a mouse model of tibial transverse fracture. METHODS: We created tamoxifen-inducible, cartilage-specific KLF15 knockout mice (KLF15 KO). KLF15 fl/fl Col2-CreERT mice from the same litters as the KLF15 KO mice, but not treated with 4-hydroxytamoxifen, were used as controls (CT). At 10 weeks, male KLF15 KO and CT mice underwent tibial fracture followed by intramedullary nailing. Both groups were administered tamoxifen at days 0, 3, and 7 after surgery. The tibiae were harvested on post-surgery days 7, 10, and 14 for radiological assessment using micro-computed tomography. Histological staining (Safranin-O) and immunohistochemistry for KLF15, SOX9, Indian hedgehog (IHH), RUNX2, and Osterix were performed. Additionally, cartilage from mouse fetus was cultured for qRT-PCR and western blot analyses of KLF15, SOX9, IHH, Col2, RUNX2, Osterix, TGF-β, SMAD3, and phosphor-SMAD3. RESULTS: The radiological assessment revealed that immature callus formation was delayed in KLF15 KO, compared with that in CT, peaking on day 14 compared with that on day 10 in CT. KLF15 KO mice exhibited delayed fracture healing and reduced Safranin-O staining at days 7 and 10 post-surgery. The ratio of cells positive for KLF15 and SOX9 was significantly lower in KLF15 KO than in CT, whereas the ratios for IHH, RUNX2, and Osterix showed no significant difference. RT-PCR revealed reduced expression of KLF15, SOX9, and COL2, with no significant changes in IHH, Osterix, RUNX2, TGF-β, and SMAD3. Western blot analysis indicated decreased SMAD3 phosphorylation in KLF15 KO mice. CONCLUSION: KLF15 regulates SOX9 via the TGF-β-SMAD3-SOX9 pathway, independent of IHH, in endochondral ossification. The KLF15 deficiency decreases SOX9 expression through reduced SMAD3 phosphorylation, subsequently delaying fracture healing.2025年01月, Bone, 190, 117302 - 117302, 英語, 国際誌研究論文（学術雑誌）
- INTRODUCTION: The purpose of this study was to compare leg length discrepancies (LLD) between simultaneous and staged bilateral total hip arthroplasty (BTHA). MATERIALS AND METHODS: This retrospective cohort study included 150 consecutive patients who underwent BTHA (60 simultaneous and 90 staged BTHA). To adjust for preoperative patient characteristics between groups, 1:1 propensity score matching was performed based on age, sex, body mass index, American Society of Anesthesiologists Physical Status, Tönnis classification, Crowe classification, preoperative range of motion (flexion and abduction), LLD, and Harris Hip Score (HHS). Finally, 66 patients (33 pairs) with comparable preoperative backgrounds were analyzed. Postoperative LLD and clinical outcomes, including HHS, range of motion (flexion and abduction), operative time, intraoperative blood loss, and complications, were compared between the simultaneous and staged BTHA groups. RESULTS: The LLD in the simultaneous BTHA group was significantly smaller than that in the staged BTHA group (simultaneous BTHA, 3.5 ± 3.2 mm; staged BTHA, 6.2 ± 4.5 mm, p < 0.001). The rate of LLD ≤ 7 mm was significantly higher in simultaneous BTHA (84.8%) compared to staged BTHA (57.6%) (p = 0.028). Other outcomes, including the HHS, range of motion (flexion and abduction), operative time, intraoperative blood loss, and complication rates were similar between the groups. CONCLUSION: Simultaneous BTHA has the potential to provide smaller LLD than staged BTHA because simultaneous surgery enables intraoperative comparison of bilateral leg lengths based on both extra- and intra-articular measurements. This approach may be advantageous for postoperative patient satisfaction.2024年12月, Archives of orthopaedic and trauma surgery, 145(1) (1), 12 - 12, 英語, 国際誌研究論文（学術雑誌）
- OBJECTIVE: This study aimed to analyze the clinical efficacy of JAK inhibitors in difficult-to-treat rheumatoid arthritis (D2TRA) and non-D2TRA patients and evaluate the factors influencing their efficacy using real-world data. METHOD: Here, 159 JAK inhibitor-treated patients with rheumatoid arthritis were categorized into D2TRA and non-D2TRA groups. Data including the Clinical Disease Activity Index (CDAI) at initiation and 6 months after drug administration, drug retention months, and reason for discontinuation due to toxic adverse events were collected. RESULTS: The retention rates at 6 months were 64.0% (D2TRA) and 78.4% (non-D2TRA) and were significantly different between the two groups (p = 0.030). The discontinuation rate owing to toxic adverse events significantly differed between the two groups (p = 0.030). The CDAI-low disease activity (LDA) rates differed significantly between the two groups (non-D2TRA, 62.3%; D2TRA, 34%; p < 0.001). CDAI-LDA achievement at 6 months after drug introduction was significantly associated with the number of times that biologic and/or targeted synthetic disease-modifying anti-rheumatic drugs were previously used and the CDAI at baseline in all patients treated with JAK inhibitors. However, no predictive factors were identified for D2TRA patients treated with JAK inhibitors. CONCLUSION: Compared to non-D2TRA patients, D2TRA patients demonstrated significantly lower drug retention rates, CDAI-LDA achievement rates, and safety of JAK inhibitors. No significant predictive factor for CDAI-LDA achievement 6 months after drug introduction was detected in D2TRA patients. Key Points • The retention of JAK inhibitors were significantly lower for the treatment of D2TRA patients in comparison with non-D2TRA patients. • The efficacy and safety of JAK inhibitors were significantly lower for the treatment of D2TRA patients. • Number of previous uses of b/tsDMARDs and CDAI at baseline were identified as the predictive factors for resistance to CDAI-LDA achievement to JAK inhibitor treatment. • No significant predictive factor for CDAI-LDA achievement 6 months after drug introduction was detected in D2TRA patients.2024年11月, Clinical rheumatology, 43(11) (11), 3285 - 3292, 英語, 国際誌研究論文（学術雑誌）
- INTRODUCTION: Many patients who have undergone a periacetabular osteotomy (PAO) for developmental dysplasia of the hip (DDH) have had jobs preoperatively. Postoperative return to work and work productivity are important for livelihood security and the social economy. However, there is a lack of evidence on work productivity after PAOs. Therefore, this study investigated the return to work rates and influence of workload, clinical, and radiographic parameters on work productivity after a curved PAO. MATERIALS AND METHODS: In this study, the data of 68 hip joints among 48 participants who underwent curved PAO for symptomatic DDH were analyzed. Correlations between postoperative work productivity and clinical, radiographic, and workload parameters were assessed. Work productivity was evaluated using the Work Productivity and Activity Impairment (WPAI) questionnaire. Clinical factors were assessed using the modified Harris Hip Scores (mHHS) and University of California, Los Angeles Activity scores. Preoperative and postoperative radiographic parameters were compared with postoperative work productivity. The workload was categorized using the Reichsausschuß für Arbeitszeitermittlung (REFA)-classification system. RESULTS: Of the participants, 98% returned to work and 87.5% returned to their original jobs. Work productivity was significantly improved in all workload categories at the 1-year postoperative follow-up. Multivariate analysis demonstrated that preoperative Tönnis and REFA classification grades were significantly associated with the postoperative WPAI. CONCLUSION: Curved PAOs can improve postoperative work productivity and return to work rates. Preoperative progression of osteoarthritis and heavy workload affect postoperative work productivity.2024年11月, Archives of orthopaedic and trauma surgery, 144(11) (11), 5005 - 5012, 英語, 国際誌研究論文（学術雑誌）
- BACKGROUND: The uncultured adipose-derived stromal vascular fraction (SVF), consisting of adipose-derived stromal cells (ADSCs), M2 macrophages (M2Φ) and others, has shown therapeutic potential against osteoarthritis (OA), however, the mechanisms underlying its therapeutic effects remain unclear. Therefore, this study investigated the effects of the SVF on OA in a human-immunodeficient rat xenotransplantation model. METHODS: OA model was induced in the knees of female immunodeficient rats by destabilization of the medial meniscus. Immediately after the surgery, human SVF (1 × 105), ADSCs (1 × 104), or phosphate buffered saline as a control group were transplanted into the knees. At 4 and 8 weeks postoperatively, OA progression and synovitis were analyzed by macroscopic and histological analyses, and the expression of collagen II, SOX9, MMP-13, ADAMTS-5, F4/80, CD86 (M1), CD163 (M2), and human nuclear antigen (hNA) were evaluated immunohistochemically. In vitro, flow cytometry was performed to collect CD163-positive cells as M2Φ from the SVF. Chondrocyte pellets (1 × 105) were co-cultured with SVF (1 × 105), M2Φ (1 × 104), and ADSCs (1 × 104) or alone as a control group, and the pellet size was compared. TGF-β, IL-10 and MMP-13 concentrations in the medium were evaluated using enzyme-linked immunosorbent assay. RESULTS: In comparison with the control and ADSC groups, the SVF group showed significantly slower OA progression and less synovitis with higher expression of collagen II and SOX9, lower expression of MMP-13 and ADAMTS-5, and lower F4/80 and M1/M2 ratio in the synovium. Only the SVF group showed partial expression of hNA-, CD163-, and F4/80-positive cells in the rat synovium. In vitro, the SVF, M2Φ, ADSC and control groups, in that order, showed larger pellet sizes, higher TGF-β and IL-10, and lower MMP-13 concentrations. CONCLUSIONS: The M2Φ in the transplanted SVF directly affected recipient tissue, enhancing the secretion of growth factors and chondrocyte-protecting cytokines, and partially improving chondrocytes and joint homeostasis. These findings indicate that the SVF is as an effective option for regenerative therapy for OA, with mechanisms different from those of ADSCs.2024年09月, Stem cell research & therapy, 15(1) (1), 325 - 325, 英語, 国際誌研究論文（学術雑誌）
- INTRODUCTION: This study aimed to evaluate differences in the pattern of fixation with a rectangular tapered short stem (Fitmore stem) due to proximal femoral medullary cavity morphology based on periprosthetic bone mineral density (BMD) and radiological findings. MATERIALS AND METHODS: We analyzed 105 consecutive patients (Dorr type A, 18; Dorr type B, 66; Dorr type C, 21) who underwent total hip arthroplasty using a Fitmore stem. Periprosthetic BMD was measured using dual-energy X-ray absorptiometry from 1 to 24 months postoperatively and radiological analysis was performed. Clinical outcomes were evaluated using the Harris hip score (HHS) and the University of California Los Angeles (UCLA) activity score preoperatively and 24 months postoperatively. RESULTS: At 24 months postoperatively, Dorr type C had significantly decreased BMD changes in Gruen zones 2, 6, and 7 compared to Dorr types A and B, and conversely, significantly increased BMD changes in zone 4 (p < 0.05). Dorr type C had significantly greater subsidence than the other types (p < 0.01) and significantly higher cortical hypertrophy in zone 3 (p < 0.01). Stress shielding was not significantly different between Dorr types. The preoperative and postoperative HHS and UCLA activity scores showed no significant differences between the Dorr types. CONCLUSIONS: In Dorr type C, BMD significantly decreased in the proximal femur with a rectangular tapered short stem, suggesting that the stem was fixed at the distal part. Careful observation of this prosthesis over time is needed in patients with Dorr type C.2024年08月, Archives of orthopaedic and trauma surgery, 144(8) (8), 3857 - 3864, 英語, 国際誌研究論文（学術雑誌）
- BACKGROUND: Both kinematically-aligned (KA) total knee arthroplasty (TKA) and bicruciate stabilized (BCS) TKA aim to reproduce the physiological knee kinematics. In this study, we compared the femoro-tibial component rotational mismatch between patients who underwent modified KA-TKA and those who received guided-motion BCS-TKA, and its influence on the clinical outcomes. METHODS: In this retrospective study, 77 consecutive patients were included and divided into two groups: subjects who underwent modified KA-TKA with Persona (KA Group; n = 42) and those who received BCS-TKA with JOURNEY II (BCS group; n = 35). Range of motion, the 2011 Knee Society Score (KSS), the rotational alignment of the femoral and tibial components, and the correlations between the rotational mismatch and the 2011 KSS subscales were examined. RESULTS: The postoperative objective knee indicators (P = 0.0157), patient satisfaction (P = 0.0039) and functional activity scores (P = 0.0013) in the KA group were significantly superior to those in the BCS group 1 year postoperatively. There was no significant difference between the two groups observed in the rotational mismatch. In the BCS group, significant negative correlations were identified between the rotational mismatch and objective indicators, patient satisfaction, and functional activity scores but not in the KA group. CONCLUSIONS: The short-term clinical results following KA-TKA showed superior objective knee indicators, patient satisfaction and functional activity scores. A negative correlation was observed between component rotational mismatch and the 2011 KSS subscales in the BCS group, compared to no relationship found between the two in the KA group. These findings suggested that KA-TKA has a relatively higher tolerance for rotational mismatch than BCS-TKA.2024年07月, Arthroplasty (London, England), 6(1) (1), 40 - 40, 英語, 国際誌研究論文（学術雑誌）
- INTRODUCTION: Postoperative osteoarthritis (OA) progression is a major determinant of failure after curved periacetabular osteotomy (CPO). A large postoperative combination angle, i.e., the combination of computed tomography-based anterior center edge and alpha angles, is associated with femoroacetabular impingement after CPO, but its association with postoperative OA progression is unclear. We aimed to identify the anatomical parameters that can lead to OA progression after CPO and the impact of the combination angle on the same. MATERIALS AND METHODS: We included 90 hips that were subjected to CPO at our center between March 2013 and March 2018. Seventeen hips showed OA progression with an increase in the Tönnis classification after surgery; 73 hips showed no progression. Radiographic anatomical parameters, including the lateral and anterior center edge angles, femoral and acetabular anteversion, and combination angle, and clinical outcomes, including modified Harris Hip Scores (mHHSs), postoperative anterior impingement, and range of motion, were compared between the two groups. Statistical significance was set at P < 0.05. RESULTS: Postoperative OA progression was significantly affected by preoperative OA evidence (P = 0.017), acetabular anteversion < 5.0° (P = 0.003), and a combination angle > 107.0° (P = 0.025). Patients with radiographic OA progression were associated with poor mHHSs (P = 0.017) and high frequencies of anterior impingement with a limited hip flexion and internal rotation angle. CONCLUSIONS: OA progression after CPO may be associated with preoperative evidence of OA and postoperative acetabular retroversion as well as a large combination angle. Surgeons should focus on the potential effects of preoperative OA grades, postoperative reduction in acetabular anteversion, and postoperative combination angle.2024年07月, Archives of orthopaedic and trauma surgery, 144(7) (7), 3083 - 3090, 英語, 国際誌研究論文（学術雑誌）
- INTRODUCTION: Bone maintenance after total hip arthroplasty (THA) is important for implant success. This study aimed to investigate the relationship between patient characteristics and periprosthetic bone maintenance after THA for better implant selection. MATERIALS AND METHODS: This retrospective cohort study enrolled 112 consecutive patients who underwent THA using full hydroxyapatite (HA) compaction with short (n = 55) or short-tapered wedge (n = 61) stems. Periprosthetic bone mineral density (BMD) was compared between the two groups after propensity score matching, and the relationship between periprosthetic BMD changes and patient background was analyzed. RESULTS: Both groups showed similar periprosthetic BMD changes after adjusting for patient background using propensity score matching. Canal flare index > 3.7 in patients that underwent THA using tapered-wedge stem (odds ratio (OR), 3.2; 95% confidence interval (CI), 1.3-7.9, p = 0.013) and baseline zone 1 BMD > 0.65 in patients that received with short HA compaction stems (OR, 430.0; 95% CI 1.3-1420, p = 0.040) were associated with proximal periprosthetic bone maintenance after THA. CONCLUSION: Considering their predictive value, canal flare index and zone 1 BMD assessment might be useful strategies for implant selection during THA.2024年06月, Archives of orthopaedic and trauma surgery, 144(6) (6), 2881 - 2887, 英語, 国際誌研究論文（学術雑誌）
- We report two cases wherein rotating hinge knee (RHK) arthroplasty was performed for Charcot joints that developed secondary to Charcot-Marie-Tooth disease (CMT). Case 1 was of a 74-year-old woman with CMT. She presented with muscle weakness and sensory disturbances of the distal lower limbs, deformity, and significant medial instability of the bilateral knees. She was then diagnosed with Charcot joints of the knees secondary to CMT, which were treated with RHK arthroplasty. Five years postoperatively, there was no instability, and she was able to stand unassisted without pain. Case 2 was a 90-year-old woman with CMT who presented with muscle weakness and sensory disturbances of the distal lower limbs, deformity, and significant medial instability of the bilateral knees. She was then diagnosed with Charcot joints of the knees secondary to CMT, which were also treated with RHK arthroplasty. One year postoperatively, there was no instability, and she was able to walk smoothly using a walker. These clinical cases indicate that RHK arthroplasty can be a good therapeutic option for Charcot joints of the knees in patients with CMT.2024年06月, Cureus, 16(6) (6), e63154, 英語, 国際誌研究論文（学術雑誌）
- The alignment philosophy in total knee arthroplasty (TKA) has tended to shift from the gold standard of mechanically aligned technique to personalized alignment, such as the kinematically aligned (KA) technique. However, the influences of different surgical techniques on lower limb alignment relative to the ground are not fully investigated. This study investigated the influence of the ankle and hindlimb alignment change after mechanically aligned TKA and KA-TKA. The varus osteoarthritic patients who underwent TKAs were divided into a mechanically aligned TKA group (group M, n = 50) and a KA-TKA group (group K, n = 50). Radiographic parameters (hip-knee-calcaneus [HKC] angle, hip-knee-ankle [HKA] angle, talar tilt angle [TTA], and tibiocalcaneal angle [TCA]) were investigated using full-length standing radiographs. The deviation angle (ΔTA; angle between the tibial mechanical axis [TMA] and the ground tibial mechanical axis [gTMA]) and the change of ΔTA (cΔTA) were also assessed. These parameters were compared between the two groups, along with the correlation between the preoperative HKA angle and other parameters. ΔTA, TTA, and TCA showed no differences between the groups pre- and postoperatively, and no significant changes were observed postoperatively. The preoperative HKA angle showed a significant negative correlation with cΔTA in both groups (group M: r = -0.33, p = 0.02; group K: r = -0.29, p = 0.04) although no correlation was observed the with preoperative TTA and TCA. Despite no change in ΔTA after surgery, the preoperative varus deformity was associated with a change in the deviation between gTMA and TMA after surgery. A severely varus knee may be inappropriate for ground KA-TKA.2024年05月, The journal of knee surgery, 37(6) (6), 409 - 415, 英語, 国際誌研究論文（学術雑誌）
- PURPOSE: The indication for unicompartmental knee arthroplasty (UKA) has been extended to cases with some degree of preoperative knee flexion contracture recently. The purpose of this study was to clarify the effect of flexion contracture on component angles. MATERIALS AND METHODS: Thirty-five fixed-bearing UKAs using the spacer block technique with preoperative flexion contracture (Group FC) and 35 UKAs using the same technique without preoperative flexion contracture (Group NC) were included. Using radiographs, the coronal femoral component angle, coronal tibial component angle, sagittal femoral component angle, and sagittal tibial component angle were determined. Also, extension and flexion angles of the knee as well as coronal Hip-Knee-Ankle (HKA) angles in long-leg standing radiographs were measured. The data about the thickness of the selected insert were also collected. The above results were compared between the two groups. RESULTS: The femoral component tended to be placed in a more varus and flexed position in Group FC, while no significant difference was found about the tibial component angles. While there was no significant difference in pre- and postoperative knee flexion angles between the two groups, flexion contracture remained postoperatively in Group FC. Preoperative HKA angle was greater in Group FC while the difference was no longer significant postoperatively. Regarding the thickness of the selected insert, thicker inserts tended to be used in Group FC. CONCLUSIONS: In fixed-bearing UKA with the spacer block technique, the femoral component tended to be placed in a flexed and varus position in the knees with preoperative flexion contracture.2024年05月, European journal of orthopaedic surgery & traumatology : orthopedie traumatologie, 34(4) (4), 2185 - 2191, 英語, 国際誌研究論文（学術雑誌）
- INTRODUCTION: Correct cup placement in total hip arthroplasty (THA) for patients with developmental dysplasia of the hip (DDH) is considerably difficult. This study aimed to analyze the orientation accuracy of cup insertion during THA using a portable navigation system in patients with DDH. MATERIALS AND METHODS: In this retrospective cohort study, we analyzed data from 64 patients who underwent THA using infrared stereo camera-matching portable navigation. Patients underwent THA via the anterolateral approach in the lateral decubitus position. Navigation records for intraoperative cup angles, postoperative cup angles measured on computed tomography (CT) images, and cup angle measurement differences were measured and compared between patients with non-DDH/mild DDH and severe DDH. Furthermore, the predictive factors for outliers of accurate acetabular cup placement were analyzed. RESULTS: The average measurement absolute abduction differences (postoperative CT-navigation record) were 3.9 ± 3.5° (severe DDH) and 3.3 ± 2.6° (non-DDH/ mild DDH), and the anteversion differences were 4.7 ± 3.4° (severe DDH) and 2.3 ± 2.1° (non-DDH/ mild DDH). The anteversion difference was different between the two groups. Multivariate analysis showed that the navigation difference (absolute difference in anteversion between postoperative CT and navigation records of > 5°) was significantly associated with severe DDH (odds ratio [OR]: 3.3; p = 0.049, 95% confidence interval [CI]: 1.0-11.1) and posterior pelvic tilt (OR: 1.1; p = 0.042, 95% CI: 1.0-1.27). CONCLUSIONS: In patients with severe DDH, it is important to pay close attention during THA using portable navigation. However, the average difference was < 5º even in patients with severe DDH, and the accuracy may be acceptable in a clinical setting when the cost is considered.2024年05月, Archives of orthopaedic and trauma surgery, 144(5) (5), 2429 - 2435, 英語, 国際誌研究論文（学術雑誌）
- PURPOSE: Only a few reports have been published so far on factors that predict postoperative coronal alignment after unicompartmental knee arthroplasty (UKA). The purpose of this study is to clarify the relationship between the arithmetic hip-knee-ankle angle (aHKA) and postoperative coronal alignment after medial fixed-bearing UKA. METHODS: One hundred and one consecutive patients (125 knees) who underwent medial fixed-bearing UKA were assessed. Pre- and postoperative coronal HKA angles, lateral distal femoral angle (LDFA), medial proximal tibial angle (MPTA), and the thickness of the tibial and femoral bone cut were measured. aHKA was calculated as 180° - LDFA + MPTA. Correlations between postoperative HKA angle and aHKA, LDFA, and MPTA were investigated by single regression analysis. After the patients were divided into three groups according to the postoperative HKA angle, i.e., HKA angle > 180°, 175° < HKA angle ≤ 180°, and HKA angle ≤ 175°, aHKA, LDFA, MPTA, preoperative HKA angle, and the thickness of the distal femoral as well as tibial bone cut were compared among the three groups. RESULTS: aHKA and MPTA were positively correlated with postoperative HKA angle, while no correlation was found between postoperative HKA angle and LDFA. Among the three groups classified by postoperative HKA angle, significant differences were found in aHKA, MPTA, and preoperative HKA angle, while no significant difference was found in LDFA and the amount of distal femoral and tibial osteotomies. CONCLUSIONS: aHKA was correlated with postoperative HKA angle after medial fixed-bearing UKA, which was probably due to the influence of MPTA.2024年04月, International orthopaedics, 48(4) (4), 889 - 897, 英語, 国際誌研究論文（学術雑誌）
- BACKGROUND: Total knee arthroplasty (TKA) for Charcot arthropathy of the knee is considered controversial because of its higher complication rate compared with that of TKA for osteoarthritis. In this study, we investigated the clinical outcomes, survival rates, and complications of primary TKA for Charcot arthropathy. METHODS: We conducted a retrospective analysis of nine patients (12 knees) with Charcot arthropathy who underwent TKA. The mean age of the patients was 63.9 ± 9.4 years (range, 52-83 years). The most frequent causative disease was diabetes mellitus (three patients). Patients' clinical outcomes, including the 2011 Knee Society Score and the range of motion, were compared between preoperative and the most recent postoperative data. The 5- and 10-year survival rates for aseptic revision, revision due to infection, and complications were examined. The mean follow-up period was 7.3 ± 3.9 years (range, 3-14 years). RESULTS: The 2011 Knee Society Score and the knee flexion angle significantly improved after TKA surgery (P < 0.05). The 5-year survival rates for aseptic revision, revision due to infection, and complications were 100%, 91.7%, and 83.3%, respectively; the 10-year survival rates for these parameters were the same. One patient underwent revision for insert replacement due to periprosthetic infection, and the other patient had varus/valgus instability due to soft tissue loosening. CONCLUSIONS: The mid- to long-term results of TKA for Charcot arthropathy were generally favorable. Our findings indicate that TKA may be a viable treatment option for Charcot arthropathy.2024年03月, Indian journal of orthopaedics, 58(3) (3), 308 - 315, 英語, 国際誌研究論文（学術雑誌）
- BACKGROUND: The relationship between the severity of preoperative varus deformity and the amount of its correction in unicompartmental knee arthroplasty (UKA) as well as the thickness of the insert has not been well known. METHODS: One hundred and three patients who underwent medial fixed-bearing UKA with the use of the spacer block method were assessed. After the component gap in extension was measured using a UKA tensor, the pre-osteotomy gap was calculated from the thickness of the bone cuts. The relationship between the preoperative hip-knee-ankle (HKA) angle as well as the pre-osteotomy gap and the amount of change in HKA angle were analysed. Also, preoperative HKA angle and the thickness of the bone cuts were compared among groups by the insert thickness. RESULTS: The mean preoperative HKA angle was 7.7 ± 3.1° varus. Patients with more varus deformity and those with a wider pre-osteotomy gap showed a more valgus change in HKA angle. As for the thickness of the insert, the preoperative HKA angle of the patients with the thinnest insert was significantly smaller (less varus) than that of those with the thicker insert while no statistically significant difference was found among the insert groups regarding the amount of the bone cuts. CONCLUSIONS: The severity of the preoperative varus deformity as well as the intraoperative pre-osteotomy gap related to the amount of change in HKA angle. As thick inserts tended to be used in severe varus knees, the tibial bone cut can be reduced in such cases.2024年01月, Journal of orthopaedic science : official journal of the Japanese Orthopaedic Association, 29(1) (1), 183 - 187, 英語, 国内誌研究論文（学術雑誌）
- OBJECTIVE: Krüppel-like zinc finger transcription factors (KLFs) play diverse roles in mammalian cell differentiation and development. In this study, we investigated the function of KLF15 in the progression of osteoarthritis (OA). METHODS: 0Destabilization of the medial meniscus (DMM) surgery was performed in 10-week-old male wild-type control (WT) mice and cartilage-specific KLF15 knockout (KO) mice. Histological analysis, immunohistochemistry, and terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick-end labeling staining were performed. Morphological changes were measured using microcomputed tomography. Six mice from each group were analyzed (total number of mice analyzed: 60). In vitro, immunofluorescence, quantitative reverse transcription-polymerase chain reaction, and western blot analyses were performed. RESULTS: KLF15 KO DMM mice exhibited significant cartilage degradation compared to WT mice. According to the Osteoarthritis Research Society International cartilage OA-histopathology scoring system, the mean sum score in KLF15 KO mice was significantly higher than that in WT mice at 8 weeks after surgery. Immunohistochemistry results revealed KLF15 KO mice exhibited reduced peroxisome proliferator-activated receptor gamma (PPARγ) expression, increased pIKKα/β, a disintegrin-like and metalloproteinase with thrombospondin motifs (ADAMTS) 5, and Matrix metalloproteinases (MMP13) expression, and reduced Forkhead box O (FOXO1) and Light chain 3B (LC3B) expression. Inhibition of PPARγ phosphorylation accelerated the effects of interleukin (IL) 1β-treatment in both KLF15 KO and WT chondrocytes, and activation of PPARγ expression canceled the IL1β-induced catabolic effects. CONCLUSION: Our results indicated that the OA phenotype of KLF15 KO DMM mice was influenced by reduced PPARγ expression, including enhanced pIKKα/β, ADAMTS5, and MMP13 expression, reduced autophagy, and increased apoptosis. KLF15 regulation may constitute a possible therapeutic strategy for the treating OA.2024年01月, Osteoarthritis and cartilage, 32(1) (1), 28 - 40, 英語, 国際誌研究論文（学術雑誌）
- INTRODUCTION: The aim of this study is to compare the accuracy of acetabular cup positioning between the accelerometer-based navigation system and the augmented reality-based navigation system during THA in the supine position. MATERIALS AND METHODS: This retrospective study included 66 patients (70 hips) who underwent THA using two types of portable navigation system, Hip Align or AR-Hip, in the spine position. The absolute difference between the intraoperative navigation record and postoperative measurement using computed tomography data was evaluated. Preoperative clinical factors that decreased the accuracy of cup positioning by ≥ 3° were analyzed via multiple logistic regression analyses. RESULTS: The average absolute error of inclination was 2.8 ± 2.6° in Hip Align and 2.7 ± 1.8° in AR-Hip, and absolute anteversion error was 2.5 ± 2.0° in Hip Align and 2.6 ± 2.2° in AR-Hip, and there was no significantly different between the two navigation systems. There was a significant association between the absolute measurement error (≥ 3°) of cup inclination and patients' BMI in the Hip Align group [odds ratio (OR) 1.350; 95% confidence interval (CI) 1.035-1.760; p = 0.027], but not in the AR-Hip group. CONCLUSIONS: The accuracy of the acetabular cup positioning between the Hip Align and AR-Hip showed no difference during THA in the spine position. The high BMI could have negative influence on the accuracy of cup positioning in THA using Hip Align, thus AR-Hip could be designable for obesity patients.2023年12月, Archives of orthopaedic and trauma surgery, 143(12) (12), 7229 - 7235, 英語, 国際誌研究論文（学術雑誌）
- BACKGROUND Distal femoral and proximal tibial fractures often lead to nonunion and post-traumatic osteoarthritis, and total knee arthroplasty (TKA) has emerged as an effective alternative for older patients. This report includes 3 cases of successful TKA treatment. The cases involve a 42-year-old man and a 62-year-old man with Hoffa coronal fractures of the distal femur, and a 50-year-old man with a proximal tibial fracture. These patients underwent multiple osteosynthesis procedures before receiving TKA. CASE REPORT Case 1: A 42-year-old man with a displaced Hoffa's fracture had persistent knee pain. Nonunion post-initial fixation led to reoperation with iliac bone grafting and plate fixation. TKA using a Posterior Stabilized (PS)-type implant resulted in improved motion and function after 3 years. Case 2: A 62-year-old man suffered lateral condyle and ligament injuries from a displaced Hoffa's fracture. Despite plate fixation, dislocation occurred, requiring conversion. TKA with long-stem hinge-type implant, using augmentation block, led to enhanced stability and outcomes at 2 years. Case 3: A 50-year-old man's tibial nonunion, treated with plate fixation, resulted in infection and bone fusion. TKA using a constrained PS-type implant insert addressed the lateral tibial adhesions via iliotibial band (ITB) release and treated severe tibial plateau damage. Positive results were seen at 1 year. CONCLUSIONS The challenges of pseudarthrosis, like bone defects and compromised tissue, highlight the need for precise implant selection based on evaluations of bone quality, defects, knee stability, and hyperextension, rather than resorting to overly-constrained implants.2023年11月, The American journal of case reports, 24, e941187, 英語, 国際誌研究論文（学術雑誌）
- The aim of the study is to explore and compare the differences in trochlear shape and knee anatomy between four types of prostheses and preoperative native knee matched with preoperative computed tomography (CT). Thirty patients were scheduled for primary kinematically aligned total knee arthroplasty (TKA) for varus knee osteoarthritis at our hospital and the region between their pelvis to ankle joint was simulated using a CT-based three-dimensional planning software. The axial plane containing the transepicondylar axis was set as Slice A, and the 10-mm distal plane from Slice A was set as Slice B. The distances to the deepest trochlear groove between the native knee and each prosthesis and the medial and lateral facet heights were compared among the four groups. The deepest femoral trochlear groove of the prostheses was located 1.6 to 3.0 mm more medial than that of the native knee, and in the Persona group, it was significantly more medial than in the e-motion or Triathlon groups on both Slices A and B. The native knee and the medial and lateral facet heights of the four prostheses on both Slices A and B were significantly lower than those of preoperative native knees when femoral prostheses were set in the kinematically aligned (KA)-TKA position. The deepest point of the trochlear groove of the Persona group was the most medial among the four prostheses studied, and the deepest points differed depending on the prosthesis design in KA-TKA. Thus, surgeons should carefully select the type of prostheses used in KA-TKA.2023年11月, The journal of knee surgery, 36(13) (13), 1316 - 1322, 英語, 国際誌研究論文（学術雑誌）
- PURPOSE: The load-bearing pattern of periprosthetic bone may differ between patients who underwent simultaneous bilateral and unilateral total hip arthroplasty (THA). We investigated the differences in periprosthetic bone remodeling after simultaneous bilateral total hip arthroplasty and unilateral total hip arthroplasty. METHODS: This retrospective cohort study enrolled 154 consecutive patients undergoing THA using full hydroxyapatite (HA) compaction short stems. Patient characteristics including age, body mass index, University of California Los Angeles (UCLA) activity score, and bone shape of the proximal femur were adjusted by propensity score matching. Subsequently, periprosthetic bone mineral density changes were compared between simultaneous bilateral and unilateral THA. RESULTS: We found that bone mineral density loss in the simultaneous bilateral THA group was significantly higher in zones 6 and 7 at 24 months after THA (zone 6, p = 0.019; zone 7, p = 0.041). Periprosthetic bone mineral density loss was not associated with clinical factors, including age, body mass index, and daily activity. Additionally, we demonstrated that periprosthetic bone mineral density loss was higher in zones 1, 4, 6, and 7 of patients with a normal hip on the contralateral side after unilateral THA (zone 1, p = 0.041; zone 4, p = 0.041; zone 6, p = 0.037; zone7, p = 0.019). CONCLUSIONS: The postoperative periprosthetic bone remodeling was lower in patients who underwent simultaneous bilateral THA than in those who underwent unilateral THA, even though patient characteristics were adjusted by propensity matching. Further observation of periprosthetic bone mineral density loss is needed to clarify the differences between the groups.2023年11月, International orthopaedics, 47(11) (11), 2767 - 2772, 英語, 国際誌研究論文（学術雑誌）
- Charcot arthropathy is a rapidly progressive and destructive form of arthropathy caused by various neurological diseases. Total hip arthroplasty (THA) is usually contraindicated in patients with Charcot arthropathy; however, recent studies have reported good results following THA in this patient population. Herein, we report a case of Charcot arthropathy secondary to syphilis in a patient who was successfully treated with constrained THA, a new type of THA. A 56-year-old man was injured in a car accident, and a displaced acetabular fracture was revealed three weeks later. He was treated conservatively but soon developed greater displacement of the fracture and femoral head destruction. The patient was referred to our hospital for further treatment. The patient had pelvic pseudarthrosis secondary to Charcot arthropathy at the time of the first visit to our hospital. First, THA was performed with the acetabular reconstruction of the deficient bone. However, the acetabular implant was displaced one week postoperatively. THA revision was performed using a constrained cup. Postoperatively, the patient exhibited good hip stability without dislocation. However, displacement of the acetabular cup occurred one year after the second surgery. We performed a re-revision of THA using a new type of constrained cup that offers a high level of constraint to maintain range of motion (ROM) and prevent dislocations. The patient was able to walk with a T-cane one year postoperatively. Herein, we report a difficult case of revision THA in a patient with Charcot arthropathy concomitant with syphilis. THA is usually contraindicated in patients with Charcot arthropathy; however, we propose that THA using constrained cups that offer a wider ROM may be a useful therapeutic strategy for the treatment of Charcot arthropathy.2023年11月, Cureus, 15(11) (11), e48295, 英語, 国際誌研究論文（学術雑誌）
- The stromal-vascular fraction (SVF), comprising heterogeneous cell populations and adipose-derived stromal cells (ADSCs), has therapeutic potential against osteoarthritis (OA); however, the underlying mechanism remains elusive. This study aimed to investigate the therapeutic effects of heterogeneous cells in rabbit SVF on rabbit chondrocytes. Rabbit SVF and ADSCs were autografted into knees at OA onset. The SVF (1 × 105) and low-dose ADSCs (lADSC; 1 × 104) groups adjusted for their stromal cell content were compared. Animals were euthanized 8 and 12 weeks after OA onset for macroscopic and histological analyses of OA progression and synovitis. Immunohistochemical and real-time polymerase chain reaction assessments were conducted. In vitro, immune-fluorescent double staining was performed for SVF to stain macrophages with F4/80, CD86(M1), and CD163(M2). OA progression was markedly suppressed, and synovitis was reduced in the SVF groups (OARSI histological score 8 W: 6.8 ± 0.75 vs. 3.8 ± 0.75, p = 0.001; 12 W: 8.8 ± 0.4 vs. 5.4 ± 0.49, p = 0.0002). The SVF groups had higher expression of collagen II and SOX9 in cartilage and TGF-β and IL-10 in the synovium, lower expression of MMP-13, and lower macrophage M1/M2 ratio than the lADSC groups. Immunofluorescent double staining revealed a markedly higher number of M2 than that of M1 macrophages in the SVF. The therapeutic effects of SVF on chondrocytes were superior than those of lADSCs, with enhanced anabolic and inhibited catabolic factors. Heterogeneous cells, mainly M2 macrophages in the SVF, enhanced growth factor secretion and chondrocyte-protective cytokines, thus benefiting chondrocytes and knee joint homeostasis. Overall, the SVF is a safe, relatively simple, and a useful treatment option for OA.2023年10月, Stem cell reviews and reports, 19(7) (7), 2407 - 2419, 英語, 国際誌研究論文（学術雑誌）
- PURPOSE: Assessment of the conventional mechanical axis (MA) (hip-to-talus axis) is reported to result in constitutional varus in the native knee. However, the ground MA (hip-to-calcaneus axis), which is the line from the hip center to the bottom of the calcaneus, passes through the center of the knee joint in the native knee and is a possible alternative target for total knee arthroplasty (TKA) assessments. Therefore, this study aimed to present a "ground kinematically aligned (KA)-TKA." In this technique, the femoral component is placed on the cylindrical axis using the calipered technique and the tibial component is placed to give a neutral ground MA. Radiographical investigation was used to determine whether physiological alignment can be individually achieved with ground KA-TKA; this was compared with that of a tibia-restricted modified KA-TKA, referring to conventional MA (hip-to-talus axis) results. METHODS: As the primary endpoint, this prospective cohort study compared the ground MA ratios of the knee joints in 40 ground KA-TKAs (G group: Coronal Plain Alignment of the Knee (CPAK) 28 type I, 7 II, 1 IV, and 4 V) with those of the preceding 60 modified KA-TKAs (M group: CPAK 46 type I, 12 II, and 2 V) performed for patients with varus osteoarthritis (OA). The number of outliers differing over ± 5% from the neutral were compared between groups using the χ2-test. The Hip-knee-ankle (HKA) angle, coronal femoral/tibial component alignment (FCA/TCA), and joint line orientation angle (JLOA) were compared between the groups using non-paired t-tests. Statistical significance was set at p < 0.05. RESULTS: The G group had a higher ratio of the ground MA passing through the knee center than the M group did; outliers differing over ± 5% from the neutral of the ground MA were 2/40 cases in the G group and 20/60 cases in the M group, which was a significant difference (p = 0.001). The HKA angle, FCA/TCA, and JLOA were not significantly different between the groups. CONCLUSIONS: Targeting the ground MA in KA-TKA for patients with varus OA was feasible and has the potential to provide a physiological alignment more similar to the native knee in TKA than other kinematic alignment techniques. LEVEL OF EVIDENCE: Level III.2023年09月, Knee surgery, sports traumatology, arthroscopy : official journal of the ESSKA, 31(9) (9), 3880 - 3888, 英語, 国際誌研究論文（学術雑誌）
- PURPOSE: This study aimed to evaluate kinematically aligned total knee arthroplasty (KA-TKA) targeting the neutral ground mechanical axis (MA) (hip-to-calcaneus axis), the line from the hip centre to the bottom of the calcaneus, (ground KA-TKA) in terms of its comparison with tibia-restricted modified KA-TKA (modified KA-TKA). METHODS: This retrospective cohort study included 106 consecutive patients who underwent unilateral KA-TKA for varus osteoarthritis (OA) (60 modified KA-TKAs and 46 ground KA-TKAs). After 1:1 propensity score matching, 60 patients (30 pairs) were matched between the groups with comparable demographic data. The hip-knee-ankle (HKA) angle, coronal femoral component alignment (FCA), and coronal tibial component alignment (TCA) were compared between groups. Intraoperative soft tissue balance, including the joint component gap and varus/valgus balance, was also compared between the groups. One year postoperatively, the clinical outcomes, including the range of motion and 2011 Knee Society Score, were compared between groups. RESULTS: The HKA angle and FCA/TCA were not significantly different between groups. Whereas the varus/valgus balance showed no significant differences between groups, smaller joint component gaps were found throughout the range of motion in the ground KA-TKA group than in the modified KA-TKA group. Despite no difference in clinical scores between groups, a significantly deeper postoperative flexion angle was achieved in the ground KA-TKA group than in the modified KA-TKA group (p < 0.05). CONCLUSION: Targeting neutral ground MA in KA-TKA for patients with varus OA has the potential to provide a better flexion angle with stable intraoperative soft tissue balance.2023年09月, International orthopaedics, 47(9) (9), 2215 - 2223, 英語, 国際誌研究論文（学術雑誌）
- INTRODUCTION: Kinematically aligned total knee arthroplasty (KA-TKA) has gained interest for achieving more favorable clinical outcomes than mechanically aligned TKA. One of the advantages of KA-TKA is reported to be an easy acquisition of intraoperative soft-tissue balance without excessive medial release for varus osteoarthritis. However, we hypothesized that the prosthesis type affects intraoperative soft-tissue balance even in the KA-TKA. The present study aimed to compare intraoperative soft-tissue balance and clinical outcomes of KA-TKAs using single-radius (SR) or multiradius (MR) prostheses. MATERIALS: AND METHODS: Consecutive 70 cruciate-retaining modified KA-TKAs (31 SR and 39 MR) were performed in patients with varus-type osteoarthritis using a navigation system. Intraoperative soft-tissue balance including joint component gap and varus/valgus balance was measured with femoral component placement and patellofemoral joint reduction throughout the range of motion using offset-type tensor and compared between the two groups. Two years postoperatively, the range of motion and 2011 Knee Society Scores were compared between the two groups. RESULTS AND CONCLUSION: Joint component gaps showed no significant differences between the two groups from 0 to 30 degrees of flexion. However, during 60 to 120 degrees of flexion, joint component gaps of SR group showed significantly larger values than those of MR group (p < 0.05). There were no significant differences in varus/valgus balance throughout the range of motion between the two groups. The postoperative clinical outcomes showed no significant differences between the two groups. INTERPRETATION: Despite no difference in clinical outcomes, joint component gap showed different patterns due to the prosthesis type in modified KA-TKAs.2023年08月, The journal of knee surgery, 36(10) (10), 1013 - 1019, 英語, 国際誌研究論文（学術雑誌）
- INTRODUCTION: This study compared the accuracy of three dimensional (3D) mini-optical navigation and accelerometer-based portable navigation systems for cup positioning during a total hip arthroplasty (THA) in the supine position. MATERIALS AND METHODS: This retrospective cohort study assessed data for 77 hips using 3D mini-optical navigation (n = 37) and accelerometer-based portable navigation (n = 40). The patients underwent THA through the mini-anterolateral approach in the supine position using a portable navigation system. We assessed the preoperative target angles, recorded intraoperative cup angles, postoperative CT imaging angles, cup angle measurement errors, and other clinical parameters. RESULTS: The mean absolute differences in radiographic inclination were similar between 3D mini-optical navigation and accelerometer-based portable navigation systems during THA in the supine position (2.8° ± 1.7° vs 2.8° ± 1.9°, p = 0.637). The mean absolute differences in radiographic anteversion were also similar (2.6° ± 2.3° vs 2.5° ± 1.9°, p = 0.737). Cup malalignment (absolute difference of inclination or anteversion between postoperative CT and preoperative target angle of > 5°) was significantly associated with body mass index (BMI) in accelerometer-based portable navigation but not in 3D mini-optical navigation. CONCLUSIONS: This is the first study to compare the accuracy of cup positioning between 3D mini-optical and accelerometer-based navigations in THA in the supine position. Both portable navigation systems accurately identified the orientation of cup placement. The accuracy of 3D mini-optical navigation is not affected by high BMI and may be preferred over other options in such patients.2023年07月, Archives of orthopaedic and trauma surgery, 143(7) (7), 3759 - 3766, 英語, 国際誌研究論文（学術雑誌）
- PURPOSE: This study aimed to examine the prosthetic orientations, limb alignment, intraoperative soft tissue balance, and early clinical outcomes associated with the use of the relatively new handheld robot technique compared to those associated with the use of the conventional alignment guide for bi-cruciate stabilized total knee arthroplasty (TKA). METHODS: This retrospective cohort study compared the prosthetic orientation and limb alignment of 35 patients who underwent TKA using robotic assistance (robot group) with those of patients who underwent TKA using a conventional alignment guide (control group). The coronal femoral component alignment (FCA), coronal tibial component alignment (TCA), and the hip-knee-ankle (HKA) angle were compared between groups. Intraoperative soft tissue balance, including the joint component gap and varus/valgus balance assessed by an offset-type tensor, were also compared between groups. One year postoperatively, the clinical outcomes, including the range of motion and 2011 Knee Society Score (KSS), were compared between groups. RESULTS: The HKA angle and FCA were 0.1° varus and 0.1° varus, respectively, in the robot group and 1.3° varus and 1.3° varus, respectively, in the control group. The difference in the HKA angle and the FCA, but not the TCA, between groups was statistically significant (p < 0.05). The intraoperative soft tissue balance showed more stable joint component gaps and varus/valgus balances throughout the range of motion in the robot group than in the control group. Clinical outcomes of the robot group showed superior 2011 KSS subscales compared to those of the control group. CONCLUSION: The accuracy of the implantations and stable soft tissue balance in the robot group were superior to those of the control group. The robot group also had superior patient-reported scores for early clinical outcomes.2023年06月, International orthopaedics, 47(6) (6), 1473 - 1480, 英語, 国際誌研究論文（学術雑誌）
- BACKGROUND Periprosthetic joint infection is a difficult complication, especially in patients with rheumatoid arthritis. Life-threatening septic shock due to periprosthetic joint infection caused by group G streptococcus is rare, and there have been few reports about its treatment. We describe a successful case of sudden onset septic shock due to group G Streptococcus infection after revision total knee arthroplasty. CASE REPORT A 61-year-old woman with rheumatoid arthritis treated with biological disease-modifying antirheumatic drugs for about 12 years presented with acute right knee pain and shock 6 months after revision total knee arthroplasty. Periprosthetic joint infection caused by group G Streptococcus was diagnosed. She was admitted to the Intensive Care Unit, treated with respiratory support and dialysis, and underwent irrigation, debridement, and polyethylene liner exchange as the first surgery. At 9 days after the first surgery, she underwent the second surgery, consisting of implant removal and antibiotic spacer placement due to failure. It took approximately 7 weeks to normalize the levels of systemic markers of inflammation with intravenous antibiotics and then oral antibiotics for further 12 weeks, but re-revision total knee arthroplasty was successfully performed 1.5 years later. At a 1-year follow-up from the final surgery, she was able to walk with a cane and had no symptoms of infection. CONCLUSIONS In such cases with sudden onset of septic shock due to periprosthetic joint infection, appropriate and prompt surgical treatment should be performed to save the infected limb as well as the patient's life.2023年04月, The American journal of case reports, 24, e938905, 英語, 国際誌研究論文（学術雑誌）
- The purpose of this study was to determine whether the transplantation of human cells from a non-reattached injured anterior cruciate ligament (ACL) remnant could enhance tendon-bone healing. Human ACL remnant tissue was classified into two groups based on the morphologic pattern as per Crain's classification: (1) non-reattachment group (Crain Ⅳ) and (2) reattachment group (Crain Ⅰ-Ⅲ). Seventy-five 10-week-old immunodeficient rats underwent ACL reconstruction followed by intracapsular administration of one of the following: (1) ACL-derived cells from the non-reattached remnant (non-reattachment group) (n = 5), (2) ACL-derived cells from the reattached tissue (reattachment group) (n = 5), or (3) phosphate-buffered saline (PBS) only (PBS group) (n = 5). Histological (Weeks 2, 4, and 8), immunohistochemical (Week 2), radiographic (Weeks 0, 2, 4, and 8), and biomechanical (Week 8) assessments were performed. Histological evaluation showed high and early healing, induction of endochondral ossification-like integration, and mature bone ingrowth at Week 4 in the non-reattachment group. Microcomputed tomography at Week 4 showed that the tibial bone tunnels in the non-reattachment group were significantly reduced compared to those in the reattachment and PBS groups. Moreover, biomechanical testing showed that ultimate load-to-failure in the non-reattachment group tended to be larger than that in the reattachment group, though not statistically significant. The enhanced healing potential in the non-reattachment group was explained by the increase in intrinsic angiogenesis/osteogenesis. In the subacute phase, the ACL-derived cells with the non-reattached morphologic pattern showed greater and earlier tendon bone healing compared with the cells obtained from the reattached morphologic pattern.2023年03月, Journal of orthopaedic research : official publication of the Orthopaedic Research Society, 41(3) (3), 500 - 510, 英語, 国際誌研究論文（学術雑誌）
- INTRODUCTION AND IMPORTANCE: Knee osteoarthritis with femoral and/or tibial extra-articular deformities makes total knee arthroplasty (TKA) technically difficult to perform, especially using intramedullary-based instrumentation systems. The Athena Knee 3-dimensional (3-D) image matching software is effective for TKA with an extra-articular deformity, especially in case of using a long-stem prosthesis or not available computer-assisted navigation systems. CASE PRESENTATION: A 79-year-old woman presented with right knee pain secondary to a progressive valgus deformity and gait disturbance. She had experienced a supracondylar femoral fracture fifteen years ago, and a tibial shaft fracture ten years ago on the same side; both of fractures were treated surgically. She had a severe valgus knee deformity and extra-articular deformity of femur and tibia, and valgus stress test detected medial knee instability. The range of motion was 0° in extension and 75° in flexion. Severe medial knee laxity compelled us to use a constrained and long-stem prosthesis, resulting in the use of an intramedullary guided system. The 3-D software system helped us to determine the amount of bone to cut as well as the appropriate entry points for the intramedullary rods and mechanical axis restoration. At two years after surgery, knee range of motion improved to 90° in flexion, and walking ability had also advanced from the use of two crutches to that of a T cane. CONCLUSION: The 3-D image matching software system for preoperative planning was useful for TKA with extra-articular deformity, especially in the case of a long-stem prosthesis without using a navigation system.2023年02月, International journal of surgery case reports, 103, 107853 - 107853, 英語, 国際誌研究論文（学術雑誌）
- Novel medial preserving gap technique (MPGT) focuses on medial compartment stability and allows lateral physiological laxity. This study aimed to compare the MPGT with the measured resection technique (MRT) to determine which provides better postoperative knee stability after posterior-stabilized total knee arthroplasty (PS-TKA). Primary PS-TKA, using either MPGT (n = 65) or MRT (n = 65), was performed in 130 patients with varus knee osteoarthritis. Postoperative knee stabilities at extension and flexion were assessed using varus-valgus stress radiographs and stress epicondylar view, respectively (at 1 month, 6 months, 1 year, and 3 years postoperatively). The distance between the femoral prosthesis and polyethylene insert was measured on each medial and lateral side, defined as the medial joint opening (MJO) and lateral joint opening (LJO), respectively. Decreasing MJO or LJO translated to increasing postoperative stability. The femoral external rotation angle was compared between the two surgical techniques; postoperative knee stability was also compared between the medial and lateral compartments, as well as the surgical techniques. A significant difference was found in the femoral external rotation angle between MPGT (4.2 ± 0.2 degrees) and MRT (3.6 ± 0.1 degrees, p < 0.01). Postoperative MJOs both at extension and flexion were significantly smaller than LJOs using MPGT and MRT at all time points (p < 0.05). MJOs and LJOs at extension using MPGT were significantly smaller than those when using MRT, at 1 and 3 years postoperatively (p < 0.05). Furthermore, MJOs at flexion using MPGT were significantly smaller than those when using MRT at 6 months, 1 year, and 3 years postoperatively (p < 0.05). MPGT provided higher postoperative medial knee stability than MRT both at extension and flexion, even at 3 years after PS-TKA. This suggests that this newly developed surgical technique is a more feasible option than MRT for the preservation of postoperative medial knee stability.2023年01月, The journal of knee surgery, 36(1) (1), 95 - 104, 英語, 国際誌研究論文（学術雑誌）
- PURPOSE: Changes in bone mineral density (BMD) around the fully hydroxyapatite (HA)-coated compaction broached and triple-tapered stem, namely, Polarstem, after total hip arthroplasty (THA) are currently unknown. Therefore, the aims of this study were to investigate clinical outcomes of Polarstem, mainly postoperative temporal changes in BMD around the stem for 2 years, and to compare them with those of HA-coated and non-HA-coated tapered-wedge stems. METHODS: This retrospective cohort study enrolled 100 consecutive patients who underwent THA using Polarstem (n = 38), HA-coated Anthology (n = 31), and non-HA-coated Anthology (n = 31). BMD was evaluated using dual-energy X-ray absorptiometry in seven regions according to the Gruen zones. Postoperatively, BMD around the stem was assessed within 2 months (baseline BMD) and at 6, 12, and 24 months. A change in BMD was defined as the value calculated by dividing each postoperative BMD value at 6, 12, and 24 months by the baseline BMD value. Changes in BMD and radiographic parameters such as stress shielding and spot welds were compared among the three stems. RESULTS: The incidence rate of stress shielding in the Polarstem group was significantly lower than those in the other two groups (p = 0.007). The change in BMD in Zone 7 of Polarstem was significantly more than that of the other two groups at 12 and 24 months postoperatively (p = 0.030 and p = 0.009, respectively). CONCLUSION: Polarstem, a fully HA-coated compaction broached and triple-tapered stem, maintained BMD around the femoral calcar until 2 years postoperatively and could reduce the risk of stress shielding compared with tapered-wedge stems.2022年12月, Archives of orthopaedic and trauma surgery, 142(12) (12), 4087 - 4093, 英語, 国際誌研究論文（学術雑誌）
- INTRODUCTION: Endochondral ossification is a complex biological phenomenon involving a variety of factors and cells. Cyclin-dependent kinase inhibitor 1 (p21) inhibits cell cycle progression and is affected by external stress. We recently reported that embryonic endochondral ossification is unaffected by endogenous p21 deficiency. In this study, we evaluated whether p21 expression affects endochondral ossification during fracture healing. METHODS: Tibial fractures were introduced into p21 knockout (p21-/-) (n = 24) and wild-type C57BL/6 (p21+/+) (n = 24) mice at age 10 weeks. Fracture healing was evaluated using radiological, histological, and immunohistochemical (IHC) analyses. The effect of p21 small interfering RNA (siRNA) on ATDC5 cells was assessed in vitro. RESULTS: The Allen score for fracture healing was lower in p21-/- mice than in p21+/+ mice. In addition, p21-/- mice exhibited larger calluses and lower bone mineral density. IHC analyses showed that p21-/- mice exhibited delayed endochondral ossification via the Ihh-Runx2-Osterix pathway in vivo. Down-regulation of p21 expression in ATDC5 cells delayed endochondral ossification in vitro. CONCLUSIONS: p21 deficiency leads to delayed endochondral ossification by attenuating the Ihh-Runx2-Osterix pathway in vivo, and p21 deficiency in hypertrophic chondrocytes causes delayed differentiation of hypertrophic chondrocytes in vitro. p21 plays a role in endochondral ossification during fracture healing.2022年12月, Bone, 165, 116572 - 116572, 英語, 国際誌研究論文（学術雑誌）
- This study aimed to evaluate the relationship between the radiographical features of combination of the acetabular coverage and the femoral head-neck shape and the occurrence of femoroacetabular impingement (FAI). In this study, 114 patients who had FAI with or without labral tear and mild osteoarthritis were analyzed. Plain radiographs and computed tomography (CT) were taken for evaluation of acetabular coverage and femoral head-neck measurements. The relationship between the combination angle of acetabular coverage and femoral head-neck measurements and the occurrence of FAI was evaluated. The prevalence of FAI patients with the combination angle of CT-anterior CE + α angle ≥100° was 6.1% (7/114 patients). Receiver operator characteristic curve analysis demonstrated a higher area under the curve for combination of CT-anterior center edge angle (ACEA) with the α angle at 0.94 (CT-ACEA +α angle). A threshold for the occurrence of FAI was determined using the combination CT-ACEA + α angle at 100°. The frequency of FAI surgery was significantly higher in patients with a combination angle ≥100° than in those with a smaller angle. The average modified Harris hip score was significantly lower in patients with a combination angle ≥100° than in those with a smaller angle. We suggest that the combination of lateral center edge angle ≥40°, α angle ≥50° and combined angles of CT-ACEA and α angle ≥100° may help diagnosis of FAI. Level of evidence III: retrospective cohort study.2022年12月, Journal of hip preservation surgery, 9(4) (4), 252 - 258, 英語, 国際誌研究論文（学術雑誌）
- PURPOSE: We aimed to investigate the differences in peri-prosthetic bone remodelling between the full hydroxyapatite (HA)-collared compaction short stem and the short tapered-wedge stem. METHODS: This retrospective cohort study enrolled 159 consecutive patients (159 joints) undergoing total hip arthroplasty (THA) using the full HA compaction short (n = 64) and short tapered-wedge (n = 95) stems. Body mass index (BMI), peri-prosthetic bone mineral density (BMD), and clinical factors, including the Japanese Orthopaedic Association score and the University of California Los Angeles (UCLA) activity score were assessed and compared. RESULTS: Stem related complications were seen in three cases. Both groups showed similar peri-prosthetic BMD changes. Peri-prosthetic BMD was almost maintained in the distal femur and Gruen zone 6 with both type of stems, but significant BMD loss was found in zones 1 and 7 in both groups and in zone 2 of the full HA compaction stem group. No significant correlations were found between the proximal femoral BMD changes and the age, BMI, and UCLA score in both the full HA compaction and tapered-wedge stem groups. Femoral bone shape affected the peri-prosthetic BMD changes in the tapered-wedge stem group but not in the full HA compaction group. The stem collar of the full HA compaction stem did not affect peri-prosthetic BMD, but unique bone remodelling in the calcar region was observed in 27.6% cases. A significant difference in the peri-prosthetic BMD changes at Gruen zone 2 was found in patients with or without thigh pain. CONCLUSION: Peri-prosthetic bone remodelling remained unaffected by clinical and radiographic factors after THA with the new short full HA compaction stem. Therefore, this new stem may be useful in a variety of cases.2022年10月, Archives of orthopaedic and trauma surgery, 142(10) (10), 2903 - 2910, 英語, 国際誌研究論文（学術雑誌）
- INTRODUCTION: The presence of tibiofemoral subluxation (TFS) in patients with unicompartmental arthritis, a potential contraindication to unicompartmental knee arthroplasty (UKA), remains controversial and is not commonly discussed. This study aimed to determine the predictability of postoperative TFS before surgery and the effect of TFS on clinical outcomes after fixed-bearing UKA. MATERIALS AND METHODS: In total, 70 patients with anteromedial osteoarthritis and osteonecrosis of the knee who underwent fixed-bearing UKA from January 2015 to January 2017 were included. The preoperative TFS was assessed using plain anteroposterior and valgus stress radiographs. The patients were classified into three groups as follows: group A (acceptable TFS, n = 36) comprising patients with preoperative TFS less than 5.0 mm; group C (correctable TFS, n = 17) comprising patients with preoperative TFS of more than 5.0 mm but corrected to less than 5.0 mm under valgus stress; and group U (uncorrectable TFS, n = 17) comprising patients with preoperative TFS of more than 5.0 mm under valgus stress. Patient-derived clinical scores were assessed with the 2011 Knee Society Score preoperatively and 2 years postoperatively. The results were compared among the three groups using analysis of variance. RESULTS: Group U showed significantly higher postoperative TFS than groups A and C. Improvements in "symptoms" and "patient satisfaction" scores 2 years after surgery were significantly higher in groups A and C than in group U. CONCLUSION: Preoperative assessment of TFS under valgus stress could be a predictor of postoperative TFS. Furthermore, preoperative uncorrectable TFS could increase pain and decrease patient satisfaction 2 years after undergoing fixed-bearing UKA.2022年10月, Archives of orthopaedic and trauma surgery, 142(10) (10), 2865 - 2874, 英語, 国際誌研究論文（学術雑誌）
- The aim of this simulation study was to evaluate the relationship of elements of anterior acetabular coverage and femoral head-neck shape with the occurrence of postoperative anterior impingement after curved periacetabular osteotomy (PAO). Sixty-two patients with symptomatic developmental dysplasia of the hip who had undergone curved PAO were selected. The likelihood of developing postoperative anterior impingement was explored through simulations of the range of motion by collision detection of the pelvis and femur. Postoperative anterior impingement was defined as impingement that occurred during postoperative bone flexion <105° or postoperative internal rotation <20° at 90° flexion. The three-dimensional center-edge (CE) angles, acetabular and femoral versions, radiographic alpha angles of the femoral head, combination angles of anterior CE and alpha angles, and combined anteversions of acetabular and femoral versions were compared between patients with postoperative anterior impingement and nonimpingement. A receiver operator characteristic (ROC) analysis was conducted to determine thresholds of the examined radiographic parameters and calculate their accuracy for predicting postoperative anterior impingement. A multivariate analysis was performed to test whether combined anteversion, anterior CE angle, and combination angle are associated with excellent modified Harris Hip Scores (mHHSs). ROC analysis demonstrated a combination angle ≥108° was predictive of the occurrence of postoperative anterior impingement after curved PAO, which can lead to impaired clinical outcomes. Conversely, a combination angle <108° was significantly associated with mHHS ≥ 90 points. To avoid postoperative anterior impingement, osteochondroplasty of the femoral head or anterior CE angle control should be performed for patients with preoperative combination angles ≥90°.2022年10月, Journal of orthopaedic research : official publication of the Orthopaedic Research Society, 40(10) (10), 2440 - 2447, 英語, 国際誌研究論文（学術雑誌）
- BACKGROUND: JOURNEY II bi-cruciate stabilized (BCS) knee system, a guided motion total knee arthroplasty (TKA), has been reported to reproduce physiological knee kinematic motion with good clinical outcomes. However, this guided system may be sensitive to the femorotibial rotational alignment. METHOD: Forty-four patients (50 knees) who underwent JOURNEY II BCS TKA were included in this retrospective study. The 2011 Knee Society Score (KSS) and range of motion were assessed pre-operatively and one year postoperatively. The femoral component rotational angle relative to the surgical epicondylar axis and the tibial component rotational angle relative to Akagi's line were measured postoperatively. The absolute difference between the femoral and tibial component rotational angles was defined as femorotibial component rotational mismatch. The correlation between the parameters of these rotational alignments and postoperative clinical outcomes was evaluated. Additionally, receiver operating characteristic curve analysis was performed to determine the optimal cut-off point of the femorotibial component rotational mismatch. RESULTS: Mean femoral and tibial component rotational angles were 0.4° (internal rotation) and 0.7° (external rotation), respectively. The rotational mismatch of the femorotibial component was 3.2°. There were negative correlations between femorotibial rotational mismatch and clinical outcomes, including objective knee indicators, patient satisfaction, functional activities, and total 2011 KSS. The area under the curve of the femorotibial component rotational mismatch was 0.768 and the cut-off value identified by the Youden index was 2.8°. CONCLUSIONS: Excessive rotational mismatch between the femoral and tibial components can negatively influence the clinical outcomes of JOURNEY II BCS TKA.2022年10月, The Knee, 38, 69 - 75, 英語, 国際誌研究論文（学術雑誌）
- PURPOSE: Lateral compartment osteoarthritis progression (LOP) is a major complication after Oxford mobile-bearing unicompartmental knee arthroplasty (OUKA). This study aimed to identify the association between tibiofemoral subluxation (TFS) and LOP after OUKA. Patients whose TFS was uncorrectable according to preoperative stress radiographs were hypothesised to develop residual TFS even after surgery, and thought to be more likely to develop LOP. METHODS: The study included 201 patients who underwent medial OUKA. Fifteen patients showed increases in LOP of at least two Kellgren-Lawrence grades after surgery [progression (P) group], while the others had no progression (N group, n = 186). TFS was measured on preoperative full leg weight-bearing radiographs, valgus stress radiographs and postoperative plain radiographs. Valgus stress radiographs were obtained using a firm manual valgus force with the knee flexed at 20°. Leg alignment, Oxford knee score (OKS), and revision rates were assessed. RESULTS: The P group had significantly higher TFS values on preoperative valgus stress (6.8° ± 2.2° vs. 4.5° ± 2.0°; P < 0.001) and postoperative radiographs (6.6° ± 2.3° vs. 4.6° ± 2.9°; P < 0.001) than the N group. Patients with postoperative residual TFS and postoperative valgus alignment were more likely to have LOP, but 9 of the 15 LOP patients did not show postoperative valgus alignment. The P group had significantly poorer postoperative OKS (33.0 ± 10.2 vs. 37.4 ± 6.5, P = 0.017) and a higher rate of revision (6/15 vs 6/186; odds ratio = 19.16; 95% CI = 4.98-76.05, P < 0.001). CONCLUSION: OA progression in the lateral compartment after medial OUKA might be associated with postoperative residual TFS, but does not always coexist with postoperative valgus alignment. Preoperative assessment of TFS with valgus stress could be a potential predictor of postoperative residual TFS and LOP. LEVEL OF EVIDENCE: Level III.2022年09月, Knee surgery, sports traumatology, arthroscopy : official journal of the ESSKA, 30(9) (9), 3236 - 3243, 英語, 国際誌研究論文（学術雑誌）
- The adipose-derived stromal vascular fraction (SVF) is composed of a heterogeneous mix of adipose-derived stem cells (ADSCs), macrophages, pericytes, fibroblasts, blood, and other cells. Previous studies have found that the paracrine effects of SVF cells may be therapeutic, but their role in osteoarthritis treatment remains unclear. This study aimed to investigate the therapeutic effect of SVF cells on chondrocytes. Chondrocytes were seeded on culture plates alone (control) or cocultured with SVF or ADSCs on cell culture inserts. After 48 h of coculture, chondrocyte collagen II, tissue inhibitors of metalloproteinases-3 (TIMP-3), and matrix metalloproteinases-13 (MMP-13) messenger RNA (mRNA) expression levels were evaluated using reverse-transcription polymerase chain reaction, and the transforming growth factor-β (TGF-β) levels in the supernatant were measured using ELISA. Immunohistochemical staining and flow cytometry were used to evaluate the macrophages in the SVF. These macrophages were characterized according to phenotype using the F4/80, CD86, and CD163 markers. To determine whether the Smad2/3 signaling pathways were involved, the chondrocytes were pre-treated with a Smad2/3 phosphorylation inhibitor and stimulated with the SVF, and then Smad2/3 phosphorylation levels were analyzed using western blot. The mRNA expression levels of various paracrine factors and chondrocyte pellet size were also assessed. Collagen II and TIMP-3 expression were higher in the SVF group than in the ADSC group and controls, while MMP-13 expression was the highest in the ADSC group and the lowest in the controls. TGF-β levels in the SVF group were also elevated. Immunohistochemical staining and flow cytometry revealed that the macrophages in the SVF were of the anti-inflammatory phenotype. Western blot analysis showed that the SVF increased Smad2/3 phosphorylation, while Smad2/3 inhibitors decreased phosphorylation. Smad2/3 inhibitors also reduced the expression of various other paracrine factors and decreased chondrocyte pellet size. These findings suggested that the paracrine effect of heterogeneous cells, such as anti-inflammatory macrophages, in the SVF partly supports chondrocyte regeneration through TGF-β-induced Smad2/3 phosphorylation.2022年09月, Journal of cellular physiology, 237(9) (9), 3627 - 3639, 英語, 国際誌研究論文（学術雑誌）
- Kinematically aligned total knee arthroplasty (TKA) has gained interest for achieving more favorable clinical outcomes than mechanically aligned TKA. The present study aimed to compare the clinical outcomes of kinematically aligned TKAs using single-radius (SR) or multi-radius (MR) prostheses. Sixty modified kinematically aligned cruciate-retaining TKAs (30 SR and 30 MR type prostheses) were performed in patients with varus-type osteoarthritis using a navigation system. Intraoperative and postoperative patellar tracking were compared between the two groups. Trochlea shape was also compared between the prostheses and preoperative native anatomy using three-dimensional simulation software. Total 2 years postoperatively, the range of motion and 2011 Knee Society Scores (KSS) were compared between the two groups. There were no differences in patellar maltracking including patellar lateral shift and tilt between the two groups; however, the ratio of intraoperative lateral retinacular release for adjusting patellar tracking was significantly higher in the MR group than in the SR group. Lateral and medial facet heights in both prostheses were understuffed compared with native knee anatomy, while the deepest point of the trochlear groove was significantly more medial in the MR group. The postoperative clinical outcomes showed no significant differences between the two groups. In conclusion, modified kinematically aligned TKAs using a SR or MR prosthesis showed no significant differences in clinical outcomes or patellar tracking when appropriate lateral retinacular release was performed.2022年07月, The journal of knee surgery, 35(9) (9), 1004 - 1009, 英語, 国際誌研究論文（学術雑誌）
- The relationship between patellofemoral joint (PFJ) degeneration and clinical outcomes following lateral unicompartmental knee arthroplasty (UKA) has not been well described thus far. This study aimed to investigate the relationship between the preoperative PFJ condition and postoperative outcomes and the changes in lower-limb and PFJ alignment after lateral UKA. This was a retrospective study including 54 patients (mean age 72.9 years) who underwent lateral UKA for isolated lateral knee osteoarthritis at our institution between March 2013 and January 2019. The Oxford Knee Score (OKS), the Knee Society Score-Knee (KSSK), and Knee Society Score-Function (KSSF), the degree of degeneration, tilting angle and lateral shift of the PFJ, and the hip-knee-ankle angle (HKA) were evaluated pre- and postoperatively. The average follow-up period was 2.8 (range 1-6.1) years. There was a significant improvement in the OKS, KSSK, and KSSF after lateral UKA. Preoperative degeneration of the PFJ did not correlate with the recovery of clinical scores. The degeneration, tilting angle, and lateral shift of the PFJ did not significantly progress following lateral UKA. The HKA was improved after lateral UKA, and there was no correlation between the HKA change and PFJ condition. Postoperative severe valgus knee alignment was associated with a greater tilting angle. Preoperative degeneration of the PFJ did not have a negative impact on postoperative outcomes, and no short-term changes in the degeneration, tilting angle, and lateral shift of the PFJ were observed. Correction of knee-joint alignment did not have a negative impact on the condition of the PFJ.2022年06月, The journal of knee surgery, 35(7) (7), 810 - 815, 英語, 国際誌研究論文（学術雑誌）
- BACKGROUND Acute arterial occlusion after total knee arthroplasty (TKA) is a rare but occasionally limb-threatening complication. Successful outcomes of surgical treatment for acute arterial occlusion after TKA have been frequently reported in the literature; however, few reports have described conservative treatment. This case report describes the successful conservative treatment of popliteal artery occlusion after TKA. CASE REPORT We report 2 cases of popliteal artery occlusion after TKA that were managed with conservative treatment. In Case 1, a 68-year-old woman presented with a weak dorsalis pedis pulse in the foot and weakness to dorsiflexion of the toe on the operative side immediately after TKA. The operative lower extremity arterial ultrasonography and computed tomography angiography demonstrated the popliteal artery occlusion. In Case 2, a 79-year-old woman presented a cold right foot and lack of popliteal and dorsalis pedis pulse in the operated extremity immediately after TKA, and Doppler ultrasound did not reveal a flow for the dorsalis pedis artery. In both patients, urgent angiographies showed popliteal artery occlusion, and blood flow was observable in the anterior tibial, peroneal, and foot arteries collateral perfusion. Thus, conservative treatments were chosen, and anticoagulant and vasodilator therapies were undergone in both patients. At 6 months after surgery, they were able to walk without intermittent claudication. CONCLUSIONS Conservative treatment can be a good option for popliteal artery occlusion after TKA in cases of rich collateral circulation.2022年04月, The American journal of case reports, 23, e936295, 英語, 国際誌研究論文（学術雑誌）
- PURPOSE: Tibial plateau fractures are serious complications of Oxford mobile-bearing unicompartmental knee arthroplasty (OUKA). This study examined where the fracture lines arises and evaluated the keel-cortex distances (KCDs) using three-dimensional computed tomography (3D-CT) and the effects of technical error (assessed by tibial component positions) and proximal tibial morphology on the KCDs. METHODS: This retrospective study included 217 OUKAs with cementless tibial components. Fifteen patients had tibial fractures after surgery. Anterior and posterior KCDs and fracture line origins were assessed using 3D-CT postoperatively. Proximal tibial morphology was assessed using the medial eminence line (MEL), which runs parallel to the tibial axis and passes through the tip of the medial intercondylar eminence of the tibia on long-leg anteroposterior radiograph. Knees had overhanging medial tibial condyle if the MEL passed medially to the medial tibial cortex. KCDs were compared between patients with/without fractures. Tibial component positions were evaluated, considering effects of tibial morphologies and component positions on fracture prevalence and KCDs. RESULTS: Fracture lines were found between the keel and posterior cortex in 12/15 patients. Posterior KCDs were significantly shorter in patients with fractures than in patients without (2.7 ± 1.6 mm vs 5.2 ± 1.7 mm, P < 0.001). Patients with medial overhanging condyles were more likely to have fracture (10/51 vs 5/166, P < 0.001) and had significantly shorter posterior KCD than those without (3.6 ± 1.5 mm vs 5.5 ± 1.8 mm, P < 0.001). Patients with tibial component that was set too medial, low, and valgus had higher rates of fracture than those without (7/39 vs 8/178, P = 0.008). Medial (r = 0.30, P < 0.001), low (r = -0.33, P < 0.001), and valgus implantations (r = 0.35, P < 0.001) of tibial components were related to shorter posterior KCDs. CONCLUSION: Short posterior KCD after OUKA is a risk factor for postoperative tibial fracture. Patients with either malposition of the tibial component (too medial, low, and valgus) and/or a medial overhanging condyle exhibit a shorter distance of posterior KCD and higher rate of fracture. LEVEL OF EVIDENCE: Level III.2022年04月, Knee surgery, sports traumatology, arthroscopy : official journal of the ESSKA, 30(4) (4), 1220 - 1230, 英語, 国際誌研究論文（学術雑誌）
- BACKGROUND: To improve implant survival through accelerated early bone remodeling during total hip arthroplasty (THA), hydroxyapatite (HA) is widely used as a bioactive coating, which is believed to enhance initial fixation by osseointegration. We aimed to investigate the relationship between stem insertion alignment and postoperative bone mineral density (BMD) changes in patients with full hydroxyapatite-coated (HA) compaction short stem and short tapered-wedge stem. METHODS: This retrospective cohort study enrolled 115 consecutive patients (115 joints) undergoing THA using the full HA compaction short (n = 59) and short tapered-wedge (n = 56) stems. Stem alignment, including anteversion, valgus, and anterior tilt were measured by a three-dimensional template using computed tomography data. Post-operative peri-prosthetic BMD was measured by dual-energy X-ray absorptiometry. The relationship between stem alignment and BMD changes in the stems was analyzed. RESULTS: Patterns of peri-prosthetic BMD changes were similar in both groups. Stem insertion alignments of anteversion, valgus, and anterior tilt were different between the two stem types. Stem alignment of valgus and anterior tilt did not affect peri-prosthetic BMD in either of the stem type. An absolute anteversion difference between stem anteversion and original canal anteversion caused significant peri-prosthetic BMD loss in Gruen zones one and seven in the tapered-wedge stem. However, stem alignment of absolute anteversion difference did not affect BMD changes in the HA compaction stem. CONCLUSIONS: Peri-prosthetic bone remodeling remained unaffected by stem alignment after THA with the new short full HA compaction stem.2022年03月, Journal of orthopaedic surgery and research, 17(1) (1), 131 - 131, 英語, 国際誌研究論文（学術雑誌）
- PURPOSE: The aim of this study was to evaluate the association between labral length and radiographic parameters of lateral and anterior acetabular coverage and the femoro-epiphyseal acetabular roof (FEAR) index in patients with developmental dysplasia of the hip (DDH). METHODS: We retrospectively analyzed data from patients with DDH who visited our hip joint clinic for the first time due to hip symptoms. DDH presence was defined as a lateral center-edge angle (LCEA) of ≤25°. The labral lengths on the anterior and lateral sides were measured on central axial and central coronal slices of T1-weighted magnetic resonance imaging, respectively. The Pearson correlation coefficients (r) and simple linear regression analyses were performed to determine the association of the lateral and anterior labral lengths with the radiographic parameters, including the LCEA, acetabular roof obliquity, FEAR index, anterior wall index, and vertical center anterior angle. RESULTS: This study included 88 patients, with a mean age of 39.6 ± 11.8 years. There were 65 women and 23 men. The lateral and anterior labral lengths correlated with all parameters of dysplasia. Specifically, the lateral labral length had a strong positive correlation with the FEAR index (R = 0.65, P < .001). The anterior labral length had a strong negative correlation with the anterior wall index (R = -0.66, P < .001). CONCLUSIONS: The lateral labral length had a strong positive correlation with the FEAR index. Furthermore, the anterior labral length had a correlation with the anterior dysplasia. LEVEL OF EVIDENCE: Level III, retrospective cross-sectional study.2022年02月, Arthroscopy : the journal of arthroscopic & related surgery : official publication of the Arthroscopy Association of North America and the International Arthroscopy Association, 38(2) (2), 374 - 381, 英語, 国際誌研究論文（学術雑誌）
- PURPOSE: To evaluate the relationship between morphological differences in labral tears and clinical features of the hip joint in patients who underwent hip arthroscopy. MATERIALS AND METHODS: We retrospectively analyzed data from patients who underwent arthroscopic surgery for the treatment of labral tears. Hip labral tears were morphologically classified as longitudinal peripheral tears (group L), radial fibrillated tears (group FI), radial flaps (group FL), and an unstable labrum (group U). Radiographically, the center-edge angle, acetabular roof obliquity, vertical-center-anterior angle, alpha angle, femoral head-neck offset ratio, and crossover sign were evaluated and compared among the groups. The relationship between labral morphology and these radiographic findings, as well as clinical findings, such as age, gender, preoperative range of hip motion, and the clinical outcomes using modified Harris Hip Score (mHHS) were also examined. RESULTS: This study included fifty patients. Groups L and FI were often observed in late middle-aged patients with relatively shallow acetabular coverage. Group FL tears were frequently observed in young males with radiographic features, such as femoroacetabular impingement (FAI), compared to the other groups. Group U comprised mostly young females with relatively shallow acetabular coverage compared to the other groups. For the postoperative mHHS, group FL showed the best score among all groups, with a significant difference between groups FL and FI (p = 0.034). CONCLUSIONS: Our study revealed that morphologically, different labral tears were associated with different clinical features and radiological findings. Especially, our study can provide predictive findings for hip arthroscopists that younger males with FAI show better clinical outcomes when compared to middle-aged females with shallow acetabulum, which is indicative of degenerative hip labral tears. LEVEL OF EVIDENCE: IV case series.2022年02月, Indian journal of orthopaedics, 56(2) (2), 295 - 302, 英語, 国際誌研究論文（学術雑誌）
- BACKGROUND: This study aimed to examine the accuracy of the HipAlign® accelerometer-based portable navigation system by measuring the intraoperative leg length change of patients who underwent total hip arthroplasty (THA) and comparing the measured leg length discrepancy (LLD) determined by the navigation system and a freehand technique. METHODS: A total of 61 patients who underwent THA using the anterolateral approach in the supine position were included in this study and divided into two groups: those who underwent THA with navigation (Group N; N = 31) and with the freehand technique (Group F; N = 30). Statistical analyses were performed to compare the intraoperative leg length change, pre- and post-LLD, absolute values of post-LLD, and the number of patients with the postoperative LLD within 10 mm and 5 mm between the two groups. Additionally, we examined the correlation between the leg length change obtained through intraoperative navigation and measured from the radiographs. Moreover, to evaluate the navigation accuracy, we examined the correlation between the absolute error of leg length change and cup orientation. RESULTS: The postoperative LLD was significantly lower and the number of patients with the postoperative LLD within 5 mm was significantly higher in Group N, compared with Group F. Additionally, the amount of leg length change measured intraoperatively by the navigation system was strongly correlated with the values obtained by the postoperative radiographic measurement with a small absolute error and minimal wasted time. Moreover, a significant positive correlation was found between the absolute error of the leg length change and that of the cup inclination. CONCLUSIONS: Our study demonstrates that the accelerometer-based portable navigation system is useful for the intraoperative adjustment of leg length discrepancy during THA for patients in the supine position, as it provides good accuracy and minimizes required time for use.2022年01月, Journal of orthopaedic science : official journal of the Japanese Orthopaedic Association, 27(1) (1), 169 - 175, 英語, 国内誌研究論文（学術雑誌）
- BACKGROUND: It is generally believed that contraction of the soft tissue structures on the medial side may occur in the knee with severe varus deformity. However, the relationship between the severity of varus deformity of the knee and the intraoperative soft tissue balance in unicompartmental knee arthroplasty (UKA) has not been well reported thus far. METHODS: One hundred and three consecutive medial UKAs were enrolled. After the femoral trial prosthesis was placed, the component gap was measured at 10° (extension) and 120° (flexion) of flexion using a UKA tensor. The pre-osteotomy gap was then calculated from the thickness of the bone cut. Paired Student's t-test was used to compare the component gap, as well as the pre-osteotomy gap, in extension and those in flexion. The relationship between the preoperative Hip-Knee-Ankle (HKA) angle and the pre-osteotomy gap was analysed using Pearson's correlation coefficient and simple linear regression analysis. RESULTS: The component gap in extension was significantly smaller than that in flexion while the pre-osteotomy gap in extension was significantly wider than that in flexion. There was a positive correlation between the severity of varus deformation in preoperative knee and the pre-osteotomy gap in extension, while there was no correlation between the preoperative HKA angle and the pre-osteotomy gap in flexion. CONCLUSIONS: The tension of the medial tightness does not correlate with the degree of preoperative varus deformity in UKA.2021年10月, The Knee, 32, 90 - 96, 英語, 国際誌研究論文（学術雑誌）
- AIMS: This study aimed to evaluate the accuracy of implant placement with robotic-arm assisted total hip arthroplasty (THA) in patients with developmental dysplasia of the hip (DDH). METHODS: The study analyzed a consecutive series of 69 patients who underwent robotic-arm assisted THA between September 2018 and December 2019. Of these, 30 patients had DDH and were classified according to the Crowe type. Acetabular component alignment and 3D positions were measured using pre- and postoperative CT data. The absolute differences of cup alignment and 3D position were compared between DDH and non-DDH patients. Moreover, these differences were analyzed in relation to the severity of DDH. The discrepancy of leg length and combined offset compared with contralateral hip were measured. RESULTS: The mean values of absolute differences (postoperative CT-preoperative plan) were 1.7° (standard deviation (SD) 2.0) (inclination) and 2.5° (SD 2.1°) (anteversion) in DDH patients, and no significant differences were found between non-DDH and DDH patients. The mean absolute differences for 3D cup position were 1.1 mm (SD 1.0) (coronal plane) and 1.2 mm (SD 2.1) (axial plane) in DDH patients, and no significant differences were found between two groups. No significant difference was found either in cup alignment between postoperative CT and navigation record after cup screws or in the severity of DDH. Excellent restoration of leg length and combined offset were achieved in both groups. CONCLUSION: We demonstrated that robotic-assisted THA may achieve precise cup positioning in DDH patients, and may be useful in those with severe DDH. Cite this article: Bone Joint Res 2021;10(10):629-638.2021年10月, Bone & joint research, 10(10) (10), 629 - 638, 英語, 国際誌研究論文（学術雑誌）
- PURPOSE: Recent advances in diagnostic imaging techniques and soft tissue endoscopy now allow for precise diagnosis and management of extra-articular hip pathology. The aim of this scoping review is to present an evidence-based update of the relevant literature focussing only on the pathoanatomy, clinical assessment and the diagnosis of pathology in the peritrochanteric space. METHODS: A literature search was performed on PubMed to include articles which reported on the anatomy and diagnosis of greater trochanteric pain syndrome, trochanteric bursitis, gluteus medius tears and external snapping hip syndrome. RESULTS: A total of 542 studies were identified, of which 49 articles were included for full text analysis for the scoping review. Peritrochanteric space pathology can be broadly classified into (1) greater trochanteric pain syndrome (GTPS), (2) abductor tears and (3) external snapping hip syndrome. Anatomically, gluteus medius, gluteus minimus and tensor fascia lata work in conjunction to abduct and internally rotate the hip. The anterolateral part of the gluteus medius tendon is more prone to tears due to a thin tendinous portion. Increased acetabular anteversion has also been shown to be associated with gluteal and trochanteric bursitis. In terms of clinical examination, tests which were found to be most useful for assisting in the diagnoses of lateral hip pain were the single-leg stance, resisted external derotation of the hip, hip lag sign and the Trendelenburg's test. Dynamic ultrasound along with guided injections and MRI scan do assist in differentiating the pathology and confirming the diagnosis in patients presenting with lateral hip pain. Finally, the assessment of baseline psychological impairment is essential in this group of patients to ensure outcomes are optimised. CONCLUSION: Lateral hip pain used to be a poorly defined entity, but advances in imaging and interest in sports medicine have led to a better understanding of the pathology, presentation and management of this cohort of patients. A thorough appreciation of the anatomy of the abductor musculature, specific clinical signs and imaging findings will lead to an appropriate diagnosis being made and management plan instituted. LEVEL OF EVIDENCE: IV.2021年08月, Knee surgery, sports traumatology, arthroscopy : official journal of the ESSKA, 29(8) (8), 2408 - 2416, 英語, 国際誌研究論文（学術雑誌）
- BACKGROUND: Many factors have been reported to affect postoperative range of knee flexion after total knee arthroplasty (TKA); however, no study has reported the impact of preoperative range of motion of the hip to the postoperative flexion angle of the knee thus far. METHODS: Of 38 consecutive patients who underwent posterior-stabilized TKA, we assessed 21 patients after excluding 17 patients who met exclusion criteria. The range of motion of the knee and the hip, age, body-mass index, serum albumin level, HbA1c, Kellgren-Lawrence grade, knee extension strength and radiological femorotibial angle as well as postoperative knee flexion angle at three months were evaluated. The preoperative data and the knee flexion angle at three months after TKA were compared using Spearman's rank correlation coefficient. RESULTS: Knee flexion angle at three months after TKA was positively correlated with preoperative flexion (ρ = 0.616, p = 0.007) and external rotation angle (ρ = 0.576, p = 0.012) of the hip as well as preoperative knee flexion angle (ρ = 0.797, p = 0.001). There were no correlations between postoperative knee flexion angle and other preoperative data. CONCLUSIONS: Patients with restricted flexion and/or external rotation of the hip may have contractures of Gluteus maximus, Gluteus medius and Tensor fasciae latae, which can cause hypertension of iliotibial tract. It may cause decreased internal rotation of the tibia when the knee is flexed, which affects postoperative knee flexion angle, thus limited flexion and/or external rotation of the hip might restrict knee flexion angle following TKA.2021年08月, Indian journal of orthopaedics, 55(4) (4), 948 - 952, 英語, 国際誌研究論文（学術雑誌）
- We recently reported that cyclin-dependent kinase inhibitor 1 (p21) deficiency induces osteoarthritis susceptibility. Here, we determined the mechanism underlying the effect of p21 in synovial and cartilage tissues in RA. The knee joints of p21-knockout (p21-/-) (n = 16) and wild type C57BL/6 (p21+/+) mice (n = 16) served as in vivo models of collagen antibody-induced arthritis (CAIA). Arthritis severity was evaluated by immunological and histological analyses. The response of p21 small-interfering RNA (siRNA)-treated human RA FLSs (n = 5 per group) to interleukin (IL)-1β stimulation was determined in vitro. Arthritis scores were higher in p21-/- mice than in p21+/+ mice. More severe synovitis, earlier loss of Safranin-O staining, and cartilage destruction were observed in p21-/- mice compared to p21+/+ mice. p21-/- mice expressed higher levels of IL-1β, TNF-α, F4/80, CD86, p-IKKα/β, and matrix metalloproteinases (MMPs) in cartilage and synovial tissues via IL-1β-induced NF-kB signaling. IL-1β stimulation significantly increased IL-6, IL-8, and MMP expression, and enhanced IKKα/β and IκBα phosphorylation in human FLSs. p21-deficient CAIA mice are susceptible to RA phenotype alterations, including joint cartilage destruction and severe synovitis. Therefore, p21 may have a regulatory role in inflammatory cytokine production including IL-1β, IL-6, and TNF-α.2021年06月, Scientific reports, 11(1) (1), 12516 - 12516, 英語, 国際誌研究論文（学術雑誌）
- BACKGROUND: The relationship between the femoral component design in total knee arthroplasty (TKA) and the patellofemoral contact force, as well as the soft tissue balance, has not been well reported thus far. METHODS: Twenty-eight mobile-bearing posterior-stabilized (PS) TKAs using the traditional model (PFC Sigma) and 27 mobile-bearing PS TKAs using the latest model (Attune) were included. Surgeries were performed using the measured resection technique assisted with the computed tomography (CT)-based free-hand navigation system. After all the trial components were placed, patellar contact forces on the medial and lateral sides were measured using two uniaxial ultrathin force transducers with the knee at 0°, 10°, 30°, 60°, 90°, 120°, and 135° of flexion. The joint component gap and the varus ligament balance of the femorotibial joint were also measured. The non-paired Student's t-test was conducted to compare the values of the two groups. RESULTS: The medial patellar contact force was significantly lower for Attune group than for PFC Sigma group at 120° of knee flexion (P = 0.0058). The lateral patellar contact force was also significantly lower for Attune group than PFC Sigma group at 120° and 135° of knee flexion (P = 0.0068 and P = 0.036). The joint component gap, as well as the varus ligament balance, showed no statistically significant difference between the two groups. CONCLUSIONS: Reduced thickness and width of the anterior flange of the femoral component in the Attune may play a role in low patellar contact force.2021年06月, The Knee, 30, 1 - 8, 英語, 国際誌研究論文（学術雑誌）
- INTRODUCTION: The concept of anatomic restoration has garnered considerable interest in the form of kinematically aligned total knee arthroplasty (KA-TKA). KA-TKAs have been reported to reproduce natural alignment and kinematics. However, few randomized controlled trials (RCTs) have compared the biomechanical outcomes and the long-term clinical outcomes of KA-TKA with those of mechanically aligned TKA (MA-TKA). We aim to investigate the long-term clinical and biomechanical effects of KA-TKA and to determine whether KA-TKA or MA-TKA is more appropriate for primary TKA. METHODS: This trial will compare clinical and biomechanical outcomes of KA-TKA to those of MA-TKA. Two hundred patients will be enrolled in the RCT and randomized into KA-TKA or MA-TKA groups. Both the groups will be evaluated 1 week before the operation, on the day of the operation, 6 months after the operation, and 1, 5, and 10 years after the operation. The primary outcome is the difference between preoperative and 1-year postoperative functional activity scores of the 2011 Knee Society Score (2011 KSS) in both groups as well as the differences between the scores of both groups. The secondary outcomes will include differences in symptom, satisfaction, and expectation scores of the 2011 KSS, intraoperative kinematics evaluation, postoperative clinical outcomes and complications, pre- and postoperative gait analyses and radiograph evaluations between both KA-TKA and MA-TKA.2021年06月, Contemporary clinical trials communications, 22, 100775 - 100775, 英語, 国際誌研究論文（学術雑誌）
- Lower extremity alignment is very important after total knee arthroplasty (TKA). This study aimed to compare the plantar pressure distribution while walking and the overall limb alignment, including the hindfoot, between kinematically (KA) and mechanically aligned (MA) TKA. The plantar pressure distribution was investigated using a pressure plate during walking and one-leg standing among four groups: patients one year after KA-TKA (KA group; n = 25), patients one year after MA-TKA (MA group, n = 25), patients with osteoarthritis (OA) undergoing non-surgical care (OA group, n = 25), and healthy controls (Healthy group; n = 25). Conventional and true mechanical axes (the line from the femoral head to the lowest point of the calcaneus) were evaluated on unipedal standing long-leg radiographs in the KA, MA, and OA groups. Results were compared using analysis of variance. The OA group showed a lateral loading pattern in the mid- and rearfoot, while the MA group showed a medial rearfoot loading pattern during walking. On the contrary, the KA and Healthy groups showed an almost equal pressure distribution between the medial and lateral rearfoot. Moreover, although both mechanical axes in the KA group passed through the knee more medially, a more neutral alignment was achieved in the true mechanical axis compared to that in the MA group. KA-TKA results in more neutral weight-bearing through the true mechanical axis and allows patients to walk while maintaining medial and lateral rearfoot pressure more evenly than MA-TKA.2021年05月, Journal of biomechanics, 120, 110379 - 110379, 英語, 国際誌研究論文（学術雑誌）
- PURPOSE: The aim of this study was to systematically review the existing literature comparing the postoperative outcomes after following hip arthroscopy in obese and non-obese patients. METHODS: Studies comparing the outcomes following hip arthroscopy of obese and non-obese patients were systematically identified via a computer-assisted literature search of Pubmed (Medline), EMBASE, and Cochrane Library using the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. Studies comparing the outcome of hip arthroscopy in different body mass index (BMI) groups were included. Data including patient-reported outcome measures (PROMs), revision arthroscopy rate, conversion rate to total hip arthroplasty (THA), and complications were collected. The methodological index for non-randomized studies (MINORS) and Newcastle-Ottawa Scale (NOS) were used to assess the quality of each study quality. The effect of heterogeneity was quantified by calculating the I2 value. RESULTS: A total of eight studies were finally included in the qualitative analysis, and three studies of high quality involving 373 hips were included in the quantitative assessment. All the studies defined obesity as a BMI of ≥ 30 kg/m2. The modified Harris Hip Score and the Non-Arthritic Hip Score were 5.1 (95% CI 1.1-9.1) and 9.0 (95% CI 5.0-13.1) points lower, respectively, in the obese group than in the non-obese group. The pooled odds ratios were 1.2 (95% CI 0.5-2.7) for revision arthroscopy, 2.4 (95% CI 1.3-4.6) for conversion to THA, and 3.2 (95% CI 1.2-8.6 for complications in favor of the non-obese group. The heterogeneity was low in all outcome assessments (I2 0-18%). CONCLUSION: Obese patients had significantly lower PROMs than non-obese patients following hip arthroscopic surgery, and the THA conversion and complication rates were 2.4 times and 3.2 times higher, respectively. Understanding the effect of obesity on hip arthroscopy will allow appropriate surgical indications for surgery to be further refined and help obese patients to understand their individual risk profile. LEVEL OF EVIDENCE: Systematic review of Level III-IV studies, Level IV.2021年05月, Knee surgery, sports traumatology, arthroscopy : official journal of the ESSKA, 29(5) (5), 1483 - 1493, 英語, 国際誌研究論文（学術雑誌）
- This study aimed to investigate the accuracy of cup placement and determine the predictive risk factors for inaccurate cup positioning in robot-assisted total hip arthroplasty (THA). We retrospectively analyzed 115 patients who underwent robot-assisted THA between August 2018 and November 2019. Acetabular cup alignment and three-dimensional (3D) position were measured using pre- or postoperative computed tomography (CT) data. Absolute differences in cup inclination, anteversion, and 3D position were assessed, and their relation to preoperative factors was evaluated. The average measurement of the absolute differences was 1.8° ± 2.0° (inclination) and 1.9° ± 2.3° (anteversion). The average absolute difference in the 3D cup position was 1.1 ± 1.2 mm (coronal plane) and 0.9 ± 1.0 mm (axial plane). Multivariate analysis revealed that a posterior pelvic tilt [odds ratio (OR, 1.1; 95% confidence interval (CI), 1.00-1.23] and anterior surgical approach (OR, 5.1; 95% CI, 1.69-15.38) were predictive factors for inaccurate cup positioning with robot-assisted THA. This is the first study to demonstrate the predictive risk factors (posterior pelvic tilt and anterior surgical approach) for inaccurate cup position in robot-assisted THA.2021年04月, Scientific reports, 11(1) (1), 7578 - 7578, 英語, 国際誌研究論文（学術雑誌）
- BACKGROUND: Novel therapeutic strategies for the healing of nonunion, which has serious effects on the quality of life of patients, are needed. We evaluated the therapeutic effect of local transplantation of human stromal vascular fraction (SVF) cells on fracture healing in a rat non-healing fracture model and compared the effects between freshly isolated (F) and cryopreserved (C)-SVFs. METHODS: Non-healing fracture model was induced in the femur of female immunodeficient rats (F344/N Jcl rnu/rnu) with cauterizing periosteum. Immediately after the creation of non-healing fracture, rats received local transplantation of F and C-SVFs suspended in phosphate-buffered saline (PBS) or the same volume of PBS without cells using the same scaffold as a control group. During 8 weeks post-surgery, radiologic, histological, immunohistochemical, and biomechanical analyses were performed to evaluate fracture healing. The comparison of radiological results was performed with a chi-square test, and the multiple comparisons of immunohistochemical, histological, and biomechanical results among groups were made using a one-way analysis of variance. A probability value of 0.05 was considered to denote statistical significance. RESULTS: At week 8, in 60% of animals receiving F-SVF cells and in 50% of animals receiving C-SVF cells, the fracture radiologically healed with bone union whereas nonunion was observed in the control group. The healing potential was also confirmed by histological and biomechanical assessments. One of the mechanisms underlying healing involving intrinsic angiogenesis/osteogenesis was enhanced in F- and C-SVF groups compared with that in the control group. Human cell-derived vasculogenesis/osteogenesis, which was also confirmed in an in vitro differentiation assay, was also enhanced in the F- and C-SVF groups compared with that in the control groups and could be another mechanism for healing. CONCLUSIONS: SVF cells can enhance bone healing and cryopreserved cells have almost equal potential as fresh cells. SVF cells can be used for improving nonunion bone fracture healing as an alternative to other mesenchymal stem cells and the effect of SVF cells can be maintained under cryopreservation.2021年02月, Stem cell research & therapy, 12(1) (1), 110 - 110, 英語, 国際誌研究論文（学術雑誌）
- BACKGROUND: The effect of increased tibial slope on the bearing movement and clinical results in mobile-bearing unicompartmental knee arthroplasty has not been well discussed. We aimed to clarify the extent of in vivo sagittal bearing movement and bearing overhang using fluoroscopy and their relationship with the tibial posterior slopes and clinical results. METHODS: This retrospective study included 40 patients who underwent Oxford unicompartmental knee arthroplasty for anteromedial osteoarthritis or osteonecrosis of the knee. Intraoperative posterior translation and posterior overhang of the bearing were assessed during flexion. The tibial posterior slopes were evaluated before and 2 weeks after surgery, and its increment was recorded. Clinical evaluations were also performed preoperatively and at 2 years postoperatively (maximum flexion angle, Oxford Knee Score). Single linear regression analysis was performed to assess the correlation between the tibial posterior slopes and the posterior translation and the posterior overhang and determine if these could affect the clinical outcomes. FINDINGS: The average posterior translation was 10.7 ± 4.3 mm, and posterior overhang of the mobile bearing was found in 35% of overall patients. They were associated with increased tibial slope as well as poorer improvement in Oxford Knee Score at 2 years postoperatively. INTERPRETATION: In Oxford unicompartmental knee arthroplasty, mobile bearing can probably move posteriorly beyond the posterior margin of the tibial component during flexion when the tibial posterior slope increases more than the original magnitude. Additionally, the posterior translation and posterior overhang closely correlated with the poorer improvement in Oxford Knee Score at 2 years postoperatively.2020年12月, Clinical biomechanics (Bristol, Avon), 80, 105148 - 105148, 英語, 国際誌研究論文（学術雑誌）
- BACKGROUND: Although total knee replacement (TKR) is an effective intervention for end-stage arthritis of the knee, a significant number of patients remain dissatisfied following this procedure. Our aim was to identify and assess the factors affecting patient satisfaction following a TKR. MATERIALS AND METHODS: In accordance with the PRISMA guidelines, two reviewers searched the online databases for literature describing factors affecting patient satisfaction following a TKR. The research question and eligibility criteria were established a priori. Any clinical outcome study that described factors relating to overall satisfaction after primary TKR was included. Quality assessment for the included studies was performed by two accredited orthopaedic surgeons experienced in clinical research. RESULTS: The systematic review identified 181 relevant articles in total. A history of mental health problems was the most frequently reported factor affecting patient satisfaction (13 reportings). When the results of the quality assessment were taken into consideration, a negative history of mental health problems, use of a mobile-bearing insert, patellar resurfacing, severe pre-operative radiological degenerative change, negative history of low back pain, no/less post-operative pain, good post-operative physical function and pre-operative expectations being met were considered to be important factors leading to better patient satisfaction following a TKR. CONCLUSION: Surgeons performing a TKR should take these factors into consideration prior to deciding whether a patient is suitable for a TKR. Secondarily, a detailed explanation of these factors should form part of the process of informed consent to achieve better patient satisfaction following TKR. There is a great need for a unified approach to assessing satisfaction following a TKR and also the time at which satisfaction is assessed.2020年10月, International orthopaedics, 44(10) (10), 1971 - 2007, 英語, 国際誌研究論文（学術雑誌）
- PURPOSE: There has been relatively little information about the treatment for ischiofemoral impingement (IFI) because of its rarity as well as the uncertainty of diagnosis. The aim of this study was to provide the reader with the available treatment strategies and their related outcomes for IFI based on the best available evidence, whilst highlighting classically accepted ways of treatment as well as relatively new surgical and non-surgical techniques. METHODS: A systematic review of the literature from Medline, Embase, AMED, Cochrane and Google Scholar was undertaken since inception to December 2017 following the PRISMA guidelines. Clinical outcome studies, prospective/retrospective case series and case reports that described the treatment outcome for IFI were included. Animal or cadaveric studies, trial protocols, diagnostic studies without any description of treatments, technical notes without any results, and review articles were excluded. RESULTS: This systematic review found 17 relevant papers. No comparative studies were included in the final records for qualitative assessment, which means all the studies were case series and case reports. Eight studies (47.1%) utilised non-surgical treatment including injection and prolotherapy, followed by endoscopic surgery (5 studies, 29.4%) then open surgery (4 studies, 23.5%). Mean age of the participants was 41 years (11-72 years). The mean follow-up was 8.4 months distributed from 2 weeks to 2.3 years. No complications or adverse effects were found from the systematic review. CONCLUSION: Several treatment strategies have been reported for IFI, and most of them have good short- to medium-term outcomes with a low rate of complications. However, there are no comparative studies to assess the superiority of one technique over another, thus further research with randomised controlled trials is required in this arena. This study explores the wide variety and categories of different treatments used for IFI to guide physicians and shed light on what can be done for this challenging cohort of patients. LEVEL OF EVIDENCE: III.2020年09月, Knee surgery, sports traumatology, arthroscopy : official journal of the ESSKA, 28(9) (9), 2772 - 2787, 英語, 国際誌研究論文（学術雑誌）
- INTRODUCTION: Iliopsoas impingement occurs secondary to a tight iliopsoas tendon that causes impingement during movement. This review presents current aspects regarding the diagnosis of iliopsoas impingement and also exposes the readers to the possible anatomic and clinical variations together with the available treatment options. METHODS: We conducted a narrative literature review with regard to non-arthroplasty iliopsoas impingement. RESULTS: Iliopsoas impingement is characterised by a distinct pattern of labral pathology, with anteriorly localised labral damage, that does not extend to the anterosuperior portion of the acetabulum. Anterior groin pain and intermittent catching, snapping or popping of the hip are common symptoms. Non-specific focal tenderness is often found over the iliopsoas tendon at the level of the anterior aspect of the joint. The 'C-sign' and Impingment test are usually positive. Dynamic ultrasonography is also useful for confirming the diagnosis. Initial management of painful iliopsoas impingement should be conservative. When patients continue to have pain, an ultrasound-guided injection can provide relief and predict the response to the surgical release. For patients who have recurrent pain after local injection of steroids, arthroscopic release has shown to achieve effective results. CONCLUSIONS: Although different treatment options for iliopsoas impingement are emerging, the current standard of therapy is conservative followed by an arthroscopic tenotomy if necessary. Young adult hip surgeons should always keep this differential in mind in a patient presenting with groin pain and mechanical symptoms.2019年09月, Hip international : the journal of clinical and experimental research on hip pathology and therapy, 29(5) (5), 460 - 467, 英語, 国際誌研究論文（学術雑誌）
- BACKGROUND: Total knee replacements (TKR) aim to restore stability of the tibiofemoral and patella-femoral joints and provide relief of pain and improved quality of life for the patient. In recent years, computer-assisted navigation systems have been developed with the aim of reducing human error in joint alignment and improving patient outcomes. METHODS: We examined the current body of evidence surrounding the use of navigation systems and discussed their current and future role in TKR. RESULTS: The current body of evidence shows that the use of computer navigation systems for TKR significantly reduces outliers in the mechanical axis and coronal prosthetic position. Also, navigation systems offer an objective assessment of soft tissue balancing that had previously not been available. Although these benefits represent a technical superiority to conventional TKR techniques, there is limited evidence to show long-term clinical benefit with the use of navigation systems, with only a small number of studies showing improvement in outcome scores at short-term follow-up. Because of the increased costs and operative time associated with their use as well as the emergence of more affordable and patient-specific technologies, it is unlikely for navigation systems to become more widely used in the near future. CONCLUSIONS: Whilst this technology helps surgeons to achieve improved component positioning, it is important to consider the clinical and functional implications, as well as the added costs and potential learning curve associated with adopting new technology.2019年06月, International orthopaedics, 43(6) (6), 1337 - 1343, 英語, 国際誌研究論文（学術雑誌）
- Quadriceps strength is important for maintaining functional movement in patients with knee osteoarthritis (OA). We aimed to examine whether knee OA severity weakened the magnitude of the associations between leg muscle mass, quadriceps strength, and functional movement. Screening for People Suffering Sarcopenia in Orthopedic cohort of Kobe study (SPSS-OK) was a single-center cross-sectional study. We recruited 611 patients with knee OA. Leg muscle mass was determined by bioimpedance and used as a proxy for quadriceps muscle mass. Quadriceps strength and indices of functional movement (assessed by the functional activities category of the new Knee Society Score questionnaire [KSS] and the Timed Up and Go [TUG] test) were measured. Knee OA severity was determined by the Kellgren-Lawrence radiographic grade. A series of general linear models was fitted with adjustment for confounding variables. The increase in quadriceps strength per leg associated with a 1-kg increase in leg mass per leg was 7.29 Nm, 5.43 Nm, and 3.77 Nm among patients with knee OA grade 1/2, 3, and 4, respectively (P for interaction = 0.003). A 1-Nm increase in quadriceps strength per leg was associated with both a 0.14 point increase in KSS movement score and a 0.05 s decrease in TUG, regardless of knee OA severity (P for interaction 0.430 and 0.323). Severe knee OA may reduce efficiency in the exertion of quadriceps strength by leg muscle mass even when the amount of muscle mass remains unchanged.2019年03月, Clinical rheumatology, 38(3) (3), 719 - 725, 英語, 国際誌研究論文（学術雑誌）
- In the last 15 years, hip arthroscopy has become increasingly popular in addressing femoroacetabular impingement (FAI) because of its minimally invasive approach. However, assessing the adequacy of bone resection when correcting FAI can be difficult because visualisation and spatial awareness of the joint are poor. Recent advances in technology in the field of computer-assisted surgery and navigation and robotic surgery in orthopaedics as a resource for preoperative planning and intraoperative assistance have been widely reported. This technology is expected to upgrade surgical planning and operative techniques, decrease human error and improve patient outcomes by precisely defining the divergent anatomy and kinematics of the hip joint. This review attempts to bring the reader up-to-date with the current developments in the field of computer assisted hip arthroscopy, and discusses our experience with pre-operative planning, navigation and robotics and also provides a platform for future research in this arena.2018年12月, The international journal of medical robotics + computer assisted surgery : MRCAS, 14(6) (6), e1929, 英語, 国際誌研究論文（学術雑誌）
- The aim of this study was to evaluate the effect of symptomatic labral tears on the sex lives of women and the effect of surgical intervention on hip symptoms during sexual intercourse. One hundred and twenty consecutive women who had undergone hip arthroscopy under a single surgeon at a tertiary referral centre were identified. A specific questionnaire was designed and sent to each of the patients. Data were collected on the nature of symptoms, if they experienced any hip pain during sexual intercourse and if this had impacted on their sex lives and the degree of resolution of hip symptoms after the procedure, on a scale of 1-10. One hundred and four responses were available. Ninety-two women reported that they were sexually active. Of these, 87 (94%) reported pain during intercourse affecting their sex life. Eight women reported hip pain for a few days following intercourse and four stated that they are often not able to continue on account of the pain. Mean patient satisfaction with a resolution of symptoms during intercourse was 7.8 out of the 10. Seventy-seven women reported a post-operative improvement in the hip symptoms experienced during sex. Labral tears do have a significant effect on the sex life of women. Hip arthroscopy to address the labral tear as well as any underlying pathology relieves the pain experienced by women during intercourse with, a resultant improvement in their sex lives.2018年12月, Journal of hip preservation surgery, 5(4) (4), 357 - 361, 英語, 国際誌研究論文（学術雑誌）
- Unicompartmental knee arthroplasty (UKA) is a bone conserving and ligament-sparing procedure that reliably restores normal knee kinematics and function for arthritis limited either to the medial or the lateral compartment of the knee. Although there is enough evidence to demonstrate that the UKA offers good medium to long-term success given the correct patient selection, prosthesis design, and implantation technique, there are several reports to suggest inferior survival rates in comparison with the total knee arthroplasty (TKA). Furthermore, it is a specialized procedure which works well in the hands of the experienced operator and therefore different authors' tend to draw different conclusions based on the same evidence, and as a result, there is great variability in the usage of the UKA. The aim of this current concept's review is to present to the readers the history of the UKA especially with reference to implant design, discuss current controversies, and outline the future perspectives of this novel procedure.2018年11月, The journal of knee surgery, 31(10) (10), 992 - 998, 英語, 国際誌研究論文（学術雑誌）
- OBJECTIVE/PURPOSE: The aim of the study was to assess the options of treatment and their related outcomes for chondral injuries in the hip based on the available evidence whilst highlighting new and innovative techniques. METHODS: A systematic review of the literature from PubMed (Medline), EMBASE, Google Scholar, British Nursing Index (BNI), Cumulative Index to Nursing and Allied Health Literature (CINAHL) and Allied and Complementary Medicine Database (AMED) was undertaken from their inception to March 2017 using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Clinical outcome studies, prospective/retrospective case series and case reports that described the outcome of cartilage repair technique for the chondral injury in the hip were included. Studies on total hip replacement, animal studies, basic studies, trial protocols and review articles were excluded. RESULTS: The systematic review found 21 relevant papers with 596 hips. Over 80% of the included studies were published in or after 2010. Most studies were case series or case reports (18 studies, 85.7%). Arthroscopy was used in 11 studies (52.4%). The minimum follow-up period was six months. Mean age of the participants was 37.2 years; 93.5% of patients had cartilage injuries of the acetabulum and 6.5% of them had injuries of the femoral head. Amongst the 11 techniques described in the systematic review, autologous matrix-induced chondrogenesis, osteochondral autograft transplantation and microfracture were the three frequently reported techniques. CONCLUSION: Over ten different techniques are available for cartilage repair in the hip, and most of them have good short- to medium-term outcomes. However, there are no robust comparative studies to assess superiority of one technique over another, and further research is required in this arena.2018年10月, International orthopaedics, 42(10) (10), 2309 - 2322, 英語, 国際誌研究論文（学術雑誌）
- 2018年09月, The Physician and sportsmedicine, 46(3) (3), 270 - 272, 英語, 国際誌
- PURPOSE: Final tunnel location in the anterior cruciate ligament (ACL) reconstruction is unpredictable due to tunnel widening and/or transposition. The mechanical stress around the tunnel aperture seems to be a major factor but is not fully investigated. The purpose of this study was to measure the stress from the ACL graft around the tunnel aperture when the ACL graft tension reaches its peak. METHODS: Six cadaveric knees were used. Single-bundle ACL reconstruction was performed using a hamstrings graft. Both femoral and tibial tunnels were created at the centre of the original ACL footprint. A 7-mm-internal-diameter aluminium cylinder with pressure sensors was placed in the femoral tunnel. Hamstrings graft with a microtension sensor was inserted. After fixation, passive extension-flexion was performed while monitoring the tunnel aperture pressure and the graft tension simultaneously. The pressure on the femoral tunnel aperture when the ACL graft tension reach its peak was compared between four directions. RESULTS: The ACL graft tension peaked (67 ± 49 N) at full extension (-5.8 ± 4.1°). Pressure at the femoral tunnel aperture was different between different directions (p < 0.01). Distal part had significantly larger pressure (1.7 ± 1.3 MPa) than the other directions (p < 0.01). Second largest pressure was carried in the anterior part (0.6 ± 0.5 MPa), followed by proximal and posterior parts (0.4 ± 0.3, 0.2 ± 0.2 MPa respectively). CONCLUSION: The stress distribution at the femoral tunnel aperture is not equal in different directions, while the distal part dominantly bears the stress from the ACL graft. Surgeons should pay close attention to the distal edge of the femoral tunnel which should be inside the anatomic ACL footprint eventually.2018年04月, Knee surgery, sports traumatology, arthroscopy : official journal of the ESSKA, 26(4) (4), 1145 - 1151, 英語, 国際誌研究論文（学術雑誌）
- Subspine impingement is an extra-articular hip impingement syndrome that usually occurs when there is abnormal contact between an enlarged or malorientated anterior inferior iliac spine (AIIS) and the distal anterior femoral neck in straight flexion of the hip. We present the case of a 13-year-old boy with a history of left groin pain and loss of range of movement of the hip for over six months following an avulsion fracture of the AIIS during a game of rugby. He was diagnosed with subspine impingement secondary to a large lesion of heterotopic ossification in the rectus femoris; this was dissected and extracted from the muscle in toto arthroscopically. This case highlights the importance of heterotopic ossification after injury as an important cause for subspine impingement in the young adult hip. This is the first report and describes subspine impingement secondary to a large lesion of heterotopic ossification.2018年, SICOT-J, 4, 41 - 41, 英語, 国際誌研究論文（学術雑誌）
- Restricted hip movement along with femoroacetabular impingement (FAI) has been reported to be an important risk factor in anterior cruciate ligament (ACL) injury. We performed a literature review assessing the evidence that FAI, or restricted hip movement, contributes to the likelihood of sustaining an ACL injury to provide an evidence-based and comprehensive update on the relationship between these pathologies. Studies were divided into three categories: clinical studies, radiological studies and cadaveric studies. Clinical studies primarily assessed the limitations to hip movement in patients with ACL injury, and numerous studies of this kind have demonstrated a relationship between restricted movement and ACL injury. Radiological studies have been able to demonstrate a higher number of bony hip abnormalities in patients with ACL injury. However, due to variable results within these studies, it is unclear which kinds of bony abnormality are specifically associated with an increased risk of ACL injury. Cadaveric studies have demonstrated that peak ACL relative strain was inversely related to the range of internal rotation of the femur, thus providing a potential mechanism for this relationship. In conclusion, clinical and radiological studies have established a correlation between restricted hip and ACL injury, but have been unable to demonstrate an increased risk of future ACL injury in individuals with restricted hip movement. Future prospective cohort studies are necessary to confirm this. Additionally, these findings highlight the need for a thorough clinical assessment of the hip when assessing patients with an ACL injury.2018年, Journal of orthopaedic surgery (Hong Kong), 26(3) (3), 2309499018799520 - 2309499018799520, 英語, 国際誌研究論文（学術雑誌）
- OBJECTIVE: It is difficult to achieve proper alignment after total knee arthroplasty (TKA) in patients with extra-articular deformity (EAD) because of altered anatomical axis and distorted landmarks. As of this writing, only case series have been reported with regard to the usefulness of computer-assisted navigation systems for TKA with EAD. This study therefore compared outcomes in TKA with EAD, with and without navigation. METHODS: Fourteen osteoarthritis patients with EAD due to previous fracture malunion or operations were assessed. Seven TKAs were performed with navigation (navigation group) and another 7 were performed without navigation (manual group). Clinical and radiographic outcomes were compared before and two years after surgery. RESULTS: The mean postoperative Knee Society function score was significantly higher in the navigation group. No significant difference was found in postoperative range of motion and Knee Society knee score. The rate of outliers in radiographic outcomes tended to be lower in the navigation group. CONCLUSION: Better clinical outcomes were achieved in cases in which navigation was used. Computer-assisted navigation is useful in TKA for patients with EAD. Level of Evidence III; Case control study.2018年, Acta ortopedica brasileira, 26(3) (3), 170 - 174, 英語, 国際誌研究論文（学術雑誌）
- BACKGROUND: The main cause for revision hip arthroscopy surgery is incomplete bony resection of femoroacetabular impingement (FAI). This study aimed to compare the cam resection accuracy via the conventional hip arthroscopy technique with the navigation technique. METHODS: Two prospectively randomized groups were recruited: navigated (n = 15) and conventional (n = 14). A pre-operative CT and post-operative MRI scan were obtained in all cases to compare alpha angle, range of motion simulation and determine a pre-operative 3D surgical resection plan. RESULTS: Post-operatively, the mean maximal alpha angle improved significantly in the navigated group compared with the conventional group (55°vs.66°; P = 0.023), especially in the 12 o' clock position (45°vs.60°; P = 0.041). However, positioning time and radiation exposure were significantly longer in the navigated group. CONCLUSION: Navigated surgery is effective for patients with cam type FAI in helping restore normal anatomy, however, not without drawbacks. Larger studies will be required to validate our results.2017年12月, The international journal of medical robotics + computer assisted surgery : MRCAS, 13(4) (4), 英語, 国際誌研究論文（学術雑誌）
- PURPOSE: Postoperative neutral limb alignment [femorotibial mechanical axis (FTMA) 180° ± 3°] is generally considered to be one of the prerequisites for successful total knee arthroplasty (TKA). However, the influence of residual malalignment on clinical and functional outcomes after TKA is unknown. Therefore, the purpose of this study was to investigate the relationship between postoperative limb alignment and clinical outcomes in Asian patients who underwent primary TKA. METHODS: The study included 220 knees with a mean age of 73.5 years who underwent primary TKA for varus-type osteoarthritis; the mean follow-up period was 3.6 years. Patients were divided into four groups based on postoperative FTMA: severe varus (FTMA < 174°, n = 15), mild varus (FTMA >177°and ≤174°, n = 61), neutral (FTMA 180° ± 3°, n = 128), and valgus (FTMA > 183°, n = 16). Knee Society Knee Score (KSKS) and Knee Society Functional Score (KSFS) were compared among the 4 groups. RESULTS: KSKS and KSFS showed significant improvement in all groups. There were no statistically significant differences for postoperative KSKS among the four groups. For KSFS, however, the severe varus and valgus groups exhibited significantly lower values compared with the mild varus and neutral groups. CONCLUSION: Postoperative mild varus alignment as well as neutral mechanical alignment of the lower limb led to excellent functional outcomes. For the clinical relevance, postoperative mild varus alignment of the lower limb is acceptable following TKA for varus-type osteoarthritis. LEVEL OF EVIDENCE: IV.2017年11月, Knee surgery, sports traumatology, arthroscopy : official journal of the ESSKA, 25(11) (11), 3488 - 3494, 英語, 国際誌研究論文（学術雑誌）
- BACKGROUND & PURPOSE: Increasing our appreciation of the historical foundations of hip arthroscopy offers greater insight and understanding of the field's current and future applications. This article offers a broad history of the progress of hip arthroscopy. METHODS: Hip arthroscopy's development from the early technologies of endoscopy to the present day is described through a review of the available literature. RESULTS: Endoscopic science begins with the Lichtleiter, developed by Phillip Bozzini (1779-1809) in 1806, but endoscopes were not applied to joints until 1912, as presented by Severin Nordentoft (1866-1922). The work of Kenji Takagi (1888-1963), especially, was instrumental in the arthroscope's development, allowing Michael Burman (1901-75) to perform the first recorded hip arthroscopy, detailed in a 1931 paper after extensive cadaveric research. Although World War II stalled further development, a renewed application of fibre optics following post-war innovations in glass manufacture heralded the modern arthroscope's invention. During the 1970s hip arthroscopy was first mobilized for diagnosis and exploration, leading to its later adoption for therapeutic surgical interventions. Modern hip arthroscopy has been facilitated by international research into optimum distraction, portals of entry, positioning of patients, and the technology of arthroscopic instruments. In 2008, the International Society for Hip Arthroscopy (ISHA) was founded to represent this international expert community. CONCLUSIONS: Technology, communication and evidence-based medicine have jointly facilitated the development of this young but promising corner of Orthopaedics.2017年10月, International orthopaedics, 41(10) (10), 1983 - 1994, 英語, 国際誌研究論文（学術雑誌）
- PURPOSE: Extra-articular hip impingement syndromes encompass a group of conditions that have previously been an unrecognised source of pain in the hip and on occasion been associated with intra-articular hip impingement as well. As arthroscopic techniques for the hip continue to evolve, the importance of these conditions has been recognised recently and now form an important part of the differential of an individual presenting with hip pain. The aim of this article, therefore, is to provide the reader with an evidence-based and comprehensive update of these syndromes. METHODS: By reviewing past literature, the anatomy, pathophysiology, clinical features and the management of the five common extra-articular hip impingement syndromes were described. RESULTS: The common extra-articular impingement syndromes are: 1) Ischiofemoral impingement: quadratus femoris muscle becomes compressed between the lesser trochanter and the ischial tuberosity. 2) Subspine impingement: mechanical conflict occurs between an enlarged or malorientated anterior inferior iliac spine and the distal anterior femoral neck. 3) Iliopsoas impingement: mechanical conflict occurs between the iliopsoas muscle and the labrum, resulting in distinct anterior labral pathology. 4) Deep gluteal syndrome: pain occurs in the buttock due to the entrapment of the sciatic nerve in the deep gluteal space. 5) Pectineofoveal impingement: pain occurs when the medial synovial fold impinges against overlying soft tissue, primarily the zona orbicularis. Knowledge for these syndromes still remains limited for reasons mostly relating to their low prevalence and their co-existence with typical femoro-acetabular impingement. CONCLUSIONS: The knowledge of extra-articular hip impingement syndromes is essential and should form a part of the differential diagnoses alongside intra-articular pathology including femoro-acetabular impingement particularly in the younger patient with a non-arthritic hip.2017年07月, International orthopaedics, 41(7) (7), 1321 - 1328, 英語, 国際誌研究論文（学術雑誌）
- BACKGROUND: Vascular CD34+ cells in anterior cruciate ligament (ACL) tissue have the potential for high proliferation and multilineage differentiation that can accelerate tendon-bone healing. While patient characteristics, such as age, can affect tendon-bone healing, the influence of elapsed time after injury on the healing process is unclear. HYPOTHESIS: Cells obtained during the early phase after injury will exhibit a greater tendon-bone healing potential compared with chronic phase counterparts when applied to an immunodeficient rat model of ACL reconstruction. STUDY DESIGN: Controlled laboratory study. METHODS: Adult human ACL-ruptured tissue was harvested from patients undergoing arthroscopic primary ACL reconstruction and classified into 2 groups based on the time elapsed between injury and surgery: (1) early group (≤3 months from injury) and (2) chronic group (>3 months from injury). In addition, 76 ten-week-old female immunodeficient rats underwent ACL reconstruction, followed by intracapsular administration of one of the following: (1) ACL-derived cells from the early group (n = 5), (2) ACL-derived cells from the chronic group (n = 5), or (3) phosphate-buffered saline (PBS) only (n = 5). During the 8 weeks after surgery, histological (weeks 2, 4, 8), immunohistochemical (week 2), radiographic (weeks 0, 2, 4, 8), and biomechanical (week 8) analyses were performed to evaluate tendon-bone healing. RESULTS: In the early group, the histological evaluation showed early healing, induction of endochondral ossification-like integration, and mature bone ingrowth. Micro-computed tomography showed that the tibial bone tunnels at week 4 and week 8 were significantly reduced in the early group compared with those in the chronic group and PBS group ( P < .05). Moreover, biomechanical tensile strength was significantly greater in the early group than in the other groups ( P < .05). An accelerated healing potential in the early group was further demonstrated by the enhancement of intrinsic angiogenesis/osteogenesis and human-derived vasculogenesis/osteogenesis. CONCLUSION: Compared with human ACL-derived cells obtained during the chronic phase, cells obtained during the early phase after injury have a greater tendon-bone healing potential when used in an immunodeficient rat model of ACL reconstruction. CLINICAL RELEVANCE: During ACL reconstruction surgery, transplanting ACL remnant tissue in the early phase after injury could accelerate and enhance tendon-bone healing.2017年05月, The American journal of sports medicine, 45(6) (6), 1359 - 1369, 英語, 国際誌研究論文（学術雑誌）
- Treatment of painful internal snapping hip via arthroscopic release of the iliopsoas tendon is becoming the preferred option over open techniques because of the benefits of minimal dissection and fewer complications. However, complications do occur with arthroscopic techniques as well. We present the case of a 33-year-old woman who presented with painful internal snapping of her right hip and underwent arthroscopic release of the iliopsoas tendon. Following the procedure she continued to complain of pain in her groin and was therefore investigated further with a magnetic resonance imaging (MRI) which revealed a swelling near the femoral circumflex vessels. A computed tomography (CT) angiogram revealed a 15 mm pseudoaneurysm of the femoral circumflex artery, which was successfully treated by selective catheterisation and embolisation. Hip arthroscopists should be sufficiently familiar with the vascular anatomy around the hip and keep this complication in mind when releasing the iliopsoas tendon arthroscopically especially in revision cases with adhesions.2017年, SICOT-J, 3, 26 - 26, 英語, 国際誌研究論文（学術雑誌）
- Pectineofoveal impingement is a relatively rare condition, which can cause hip or groin pain along with mechanical symptoms of clicking in the young adult. We present the case of a 13-year-old girl who was referred to us with left hip pain, which had been affecting her for over six months along with mechanical symptoms of clicking. Following appropriate clinical examination and investigations the patient underwent arthroscopic surgery of her hip. At arthroscopy, a cyst was identified on the medial synovial fold, which was abutting against the zona orbicularis leading to pectineofoveal impingement. The cyst was decompressed and the synovial fold excised arthroscopically. Following arthroscopic intervention, the patient did extremely well and remains asymptomatic at the last follow-up (7 months following the procedure). The case highlights the importance of the medial synovial fold pathology as an important cause for pain and mechanical symptoms in the young adult hip.2017年01月, Journal of hip preservation surgery, 4(1) (1), 93 - 96, 英語, 国際誌研究論文（学術雑誌）
- Despite the initial promise of metal-on-metal (MoM) implants as the ideal bearing surface for hip replacements and resurfacings, high short term failure rates due to an adverse reaction to metal debris (ARMD) have led to a dramatic reduction in the number of MoM implants used in the modern era. With over one million patients worldwide having undergone hip operations utilizing a MoM bearing surface, the long term outcomes for such patients remains unknown, and there is much debate as to the most effective management of these patients. Although several regulatory bodies have released guidelines on the management of patients with MoM hips, these recommendations remain open to interpretation, and the most effective management for these patients remains unclear. The aim of this review is to compare the current guidelines for managing patients with MoM hips and also to discuss established ARMD risk factors, evidence regarding the optimum management for patients with MoM hips, and the indications for revision surgery. Furthermore, although specialized laboratory tests and imaging can be used to facilitate clinical decision making, over-reliance on any single tool should be avoided in the decision making process, and surgeons should carefully consider all findings when determining the most appropriate course of action.2017年, Indian journal of orthopaedics, 51(4) (4), 414 - 420, 英語, 国際誌研究論文（学術雑誌）
- PURPOSE: Given the knee kinematics and soft tissue balance in unicompartmental knee arthroplasty (UKA), it was hypothesised that intraoperative medial compartment stability will result in good functional outcome. The purpose of this study was to test the influence of soft tissue balance on post-operative knee flexion in UKA. METHODS: The influence of soft tissue balance on post-operative knee flexion in UKA was first examined retrospectively by using a newly developed tensor device in 30 consecutive patients diagnosed with either isolated medial compartmental osteoarthritis or idiopathic necrosis. The intraoperative component gap of the medial compartment was measured by using the tensor while applying a 20-lb joint distraction force at 0°, 10°, 30°, 45°, 60°, 90°, 120°, and 135° of knee flexion, with calculation of the joint looseness. Correlations between the soft tissue parameters and post-operative knee flexion angles were analysed 1 year after surgery. RESULTS: The post-operative knee flexion angle was negatively correlated with the component gap at 45°, 60°, and 90° of flexion (R = -0.41, P < 0.05; R = -0.44, P < 0.05; and R = -0.44, P < 0.05, respectively). Furthermore, the post-operative knee flexion angle was negatively correlated with joint looseness at 45°, 60°, and 90° of flexion (R = -0.40, P < 0.05; R = -0.41, P < 0.05; and R = -0.36, P < 0.05, respectively). CONCLUSIONS: The intraoperative medial compartment stability of knee flexion in midrange resulted in increasing post-operative knee flexion angle in UKA. Medial soft tissue release should be minimised, and assessment of soft tissue balance using a tensor can be performed to predict the post-operative knee flexion angle during surgery for UKA. LEVEL OF EVIDENCE: III.2017年01月, Knee surgery, sports traumatology, arthroscopy : official journal of the ESSKA, 25(1) (1), 272 - 276, 英語, 国際誌研究論文（学術雑誌）
- INTRODUCTION: There are few specific reports of late medial instability after total knee arthroplasty (TKA). We described two cases of late medial instability of the knee due to hip disease with osteoarthritis or rheumatoid arthritis after TKA, which required revision TKA. PRESENTATION OF CASES: An 82-year-old woman experienced right femoral neck fracture due to a fall that required conservative treatment at age 77 years and underwent left TKA at age 80 years. A 68-year-old woman underwent left TKA at age 54 years, right TKA at age 64 years, and left THA at age 67 years. Both cases required revision TKA with constrained knee prostheses due to the severe medial instability. Hip-knee-ankle (HKA) angle, range of motion (ROM), Knee Society score (KSS) and functional score (FS) were evaluated pre- and postoperatively. Their respective HKA angle improved from 134° and 155° preoperatively to 184° and 179° postoperatively. KSS improved from -4 and 53 points to 59 and 100 points, respectively. FS improved from -10 and 58 points to 25 and 90 points, respectively. In the 82-year-old woman, ROM did not improve from -10-90° to -20-90°. On the other hand, in the 68-year-old woman, ROM improved from 0-110° to 0-125°. The late medial instability in the current case report was partly due to a similar mechanism underlying the long leg arthropathy and coxitis knee caused by hip joint degeneration. CONCLUSIONS: Constrained prostheses were applied for both patients, providing moderately good short-term results.2017年, International journal of surgery case reports, 37, 200 - 204, 英語, 国際誌研究論文（学術雑誌）
- PURPOSE: To evaluate quantitatively the biomechanical function of anterior cruciate ligament (ACL) remnants in patients with ACL injuries. Anterior tibial translation (ATT) with KT-1000 and during the Lachman test with an electromagnetic measurement system (EMS) and tibial acceleration during the pivot shift test with EMS were measured. METHODS: A total of 121 unilateral ACL injuries were examined. ACL remnants were morphologically classified as being attached to the posterior cruciate ligament (PCL group), to the roof of the intercondylar notch (RIN group), to the lateral wall of the intercondylar notch (LWIN group), or as having no substantial remnants (NONE group). Partial ACL tears were excluded. ATT was measured using KT-1000. ATT during the Lachman test and tibial acceleration during the pivot shift test were measured using EMS. RESULTS: ACL remnant patterns were as follows: PCL group, 27 knees; RIN group, 34 knees; LWIN group, 27 knees; and NONE group, 33 knees. The ATT side-to-side difference in LWIN group (3.4 ± 0.7 mm) by KT-1000 was significantly smaller than the RIN (5.7 ± 1.0 mm) and NONE groups (5.9 ± 1.0 mm) (P < .05). The ATT side-to-side difference during the Lachman test was significantly smaller in the LWIN group (5.3 ± 1.2 mm) than the PCL (8.6 ± 1.4 mm), RIN (8.5 ± 1.2 mm), and NONE groups (7.6 ± 1.0 mm) (P < .05). Tibial accelerations were 2.0 ± 0.4, 1.7 ± 0.2, 1.9 ± 0.2, and 1.8 ± 0.3 m/s(2) in the PCL, RIN, LWIN, and NONE groups, respectively. There were no significant differences among groups. CONCLUSIONS: ACL remnants attached to the lateral wall of the intercondylar notch partially contributed to anterior-posterior stability but did not contribute to dynamic knee stability. These findings suggest that ACL remnants attached to nonanatomic insertion sites do not contribute significantly to knee stabilization. LEVEL OF EVIDENCE: Level III, diagnostic study of nonconsecutive patients.2016年07月, Arthroscopy : the journal of arthroscopic & related surgery : official publication of the Arthroscopy Association of North America and the International Arthroscopy Association, 32(7) (7), 1359 - 66, 英語, 国際誌研究論文（学術雑誌）
- BACKGROUND: This study aimed to resolve uncertainty regarding sex differences in alignment changes with age. METHODS: We measured various parameters of weight-bearing long leg radiographs of 797 legs without osteoarthritic changes, which were classified according to sex and age (young [15-39 years], middle-aged [40-54 years], aged [55-69 years], and elderly [≥70 years]), and performed morphological analysis of the lower extremities. The mean measurements in each group were calculated and compared among the groups. RESULTS: In the young and middle-aged populations, the femorotibial angle was significantly more varus in male than in female participants (p<0.001). In addition, medial femoral bowing was seen both in male and female participants, but it was more significant in male participants (p<0.005). This was due to greater femoral condylar orientation (p<0.01) and tibial plateau inclination (p<0.01) in male participants compared to female participants with nearly identical joint space narrowing. In aged and elderly populations, on the contrary, lateral femoral bowing was seen in both male and female participants, and there were no differences in any measured values, including the femorotibial angle, between male and female participants. CONCLUSIONS: In relatively young Japanese individuals, male participants' femorotibial angles were more varus and had more medial femoral bowing than female participants, while there was no difference in any measured values between male and female participants in older adults by a radiographic analysis on the alignment of the lower extremities. LEVEL OF EVIDENCE: Level 2.2016年03月, The Knee, 23(2) (2), 209 - 13, 英語, 国際誌研究論文（学術雑誌）
- BACKGROUND: Although many studies have reported that postoperative knee flexion is influenced by preoperative conditions, the factors which affect postoperative knee flexion have not been fully elucidated. We tried to investigate the influence of intraoperative soft tissue balance on postoperative knee flexion angle after cruciate-retaining (CR) total knee arthroplasty (TKA) using a navigation and an offset-type tensor. METHODS: We retrospectively analyzed 55 patients with osteoarthritis who underwent TKA using e.motion-CR (B. Braun Aesculap, Germany) whose knee flexion angle could be measured at 2 years after operation. The exclusion criteria included valgus deformity, severe bony defect, infection, and bilateral TKA. Intraoperative varus ligament balance and joint component gap were measured with the navigation (Orthopilot 4.2; B. Braun Aesculap) while applying 40-lb joint distraction force at 0° to 120° of knee flexion using an offset-type tensor. Correlations between the soft tissue parameters and postoperative knee flexion angle were analyzed using simple linear regression models. RESULTS: Varus ligament balance at 90° of flexion (R = 0.56; P < .001) and lateral compartment gap at 90° of flexion (R = 0.51; P < .001) were positively correlated with postoperative knee flexion angle. In addition, as with past studies, joint component gap at 90° of flexion (R = 0.30; P < .05) and preoperative knee flexion angle (R = 0.63; P < .001) were correlated with postoperative knee flexion angle. CONCLUSION: Lateral laxity as well as joint component gap at 90° of flexion is one of the most important factors affecting postoperative knee flexion angle in CR-TKA.2016年02月, The Journal of arthroplasty, 31(2) (2), 401 - 5, 英語, 国際誌研究論文（学術雑誌）
- BACKGROUND: Recent developments in hip arthroscopic techniques and technology have made it possible in many cases to avoid open surgical dislocation for treating a variety of pathology in the hip. Although early reports suggest favourable results' using hip arthroscopy and it has been shown to be a relatively safe procedure, complications do exist and can sometimes lead to significant morbidity. METHODS: This is a review article. The aim of this manuscript is to present the most frequent and/or serious complications that could occur at or following hip arthroscopy and some guidelines to avoid these complications. CONCLUSION: Most complications of hip arthroscopy are minor or transient but serious complications can occur as well. A lot of complication e.g. acetabular labral puncture go unreported. Appropriate education and training, precise and meticulous surgical technique with correct instrumentation, the right indication in the right patient and adherence to advice from mentors and experienced colleagues are all essential factors for a successful outcome. Level of evidence: V.2016年, Muscles, ligaments and tendons journal, 6(3) (3), 402 - 409, 英語, 国際誌研究論文（学術雑誌）
- OBJECTIVE: To determine whether the second-generation constrained condylar prosthesis provided satisfactory results in revision total knee arthroplasty. METHODS: A series of 41 cases of revision total knee arthroplasty using the second-generation constrained condylar knee prosthesis was reviewed. The series comprised 7 men and 34 women with a mean age of 73.2 years. The original diagnosis was predominantly osteoarthritis. The most common reason for revision surgery was aseptic loosening. The mean interval between the primary and revision surgeries was 66.4 months. The mean follow-up period was 49.4 months. RESULTS: The mean Knee Society knee score improved from 43.8 to 82.9 after revision surgery, the mean Knee Society function score improved from 37.1 to 79.2; the range of motion improved from 95.6° to 105.6° and the radiological femorotibial alignment improved from 181.4° (varus 6.4°) to 174.9° (valgus 0.1°), on average (p<0.001 at all items). CONCLUSION: Revision total knee arthroplasty with the use of the second-generation constrained condylar knee prosthesis yielded reproducible clinical success. Level of Evidence IV, Case series.2016年, Acta ortopedica brasileira, 24(6) (6), 304 - 308, 英語, 国際誌研究論文（学術雑誌）
- BACKGROUND: No study has examined the possible factors associated with different characteristics of stem-like cells derived from anterior cruciate ligament (ACL) remnants. And the purpose of the study is to elucidate whether demographic factors are associated with healing potential of stem-like cells derived from the ACL remnants tissue. METHODS: Thirty-six ACL remnants were harvested from patients who received primary arthroscopic ACL reconstruction. Interval from injury to surgery, age, sex, and combined meniscal or chondral injuries were analyzed. Cells were isolated from remnant tissues and their healing potential was evaluated by: 1) characterization of surface markers (CD34, CD44, CD45, CD146, CD29, and Stro-1), 2) cell expansion, 3) osteogenic differentiation, and 4) endothelial differentiation. Finally, using multivariable logistic regression to evaluate the relation between demographic factors and healing potential parameters. Adjusted odds ratios (OR) were calculated, and the significant difference was set at p < 0.05. RESULTS: ACL remnant tissue harvested less than 90 days after injury predicted higher fractions of stem-like cells [CD34+ (OR = 6.043, p = 0.025), CD44 + (OR = 8.440, p = 0.011), CD45+ (OR = 16.144, p = 0.015), and CD146+ (OR = 9.246, p = 0.015)] and higher expansion potential (passage 3: OR = 9.755, p = 0.034; passage 10: OR = 33.245, p = 0.003). Regarding osteogenic differentiation, higher gene expression of Osteocalcin (OR = 22.579, p = 0.009), Alkaline phosphatase (OR = 6.527, p = 0.022), and Runt-related transcription factor 2 (OR = 5.247, p = 0.047) can also be predicted. Younger age predicted higher CD34+ levels (20 ≤ age < 30 years, OR = 2.020, p = 0.027) and higher expansion potential at passage 10 (10 ≤ age < 20 years, OR = 25.141, p = 0.026). There was no significant relation found between meniscal or chondral injuries and ACL healing potential. CONCLUSION: Our results indicated that the ACL remnant tissue harvested within 3-months after injury yields higher healing potential, suggesting early surgical intervention may achieve better clinical results.2015年12月, BMC musculoskeletal disorders, 16, 390 - 390, 英語, 国際誌研究論文（学術雑誌）
- BACKGROUND: Whereas clinical studies have revealed a number of important risk factors for postoperative infection following total knee arthroplasty (TKA), it is unclear which factor influences clinical results. A multicenter study was therefore performed by reviewing 51 patients with deep infection after TKA and seeking for the factors related to clinical outcomes. METHODS: Fifty-one deep infections after TKA were treated from 2000 to 2011 at the multicenter including a university or three arthroplasty centers. Among them, two clinical outcome measures including retention of prosthesis at initial treatment and functional prosthetic knee were assessed for several factors such as age, sex, primary diagnosis, onset time after primary TKA, type of hospital where the primary TKA was performed and the organism's resistance to methicillin using the logistic regression analysis model. RESULTS: Among the factors, type of hospital where the primary TKA was performed and onset time after primary TKA had higher multivariable-adjusted odds ratios (ORs) for retention of primary prosthesis (ORs 35.21 and 11.69, respectively.). The cases which primary surgery were performed in arthroplasty centers had higher multivariable-adjusted ORs for functional prosthetic knee (OR 4.9). Thirty-one infection cases with non-methicillin-resistant organisms were all able to keep functional prosthetic knee after the operation, whereas 13 out of 20 infection cases with methicillin-resistant organisms lost their knee function after the operation. CONCLUSIONS: Onset time after primary TKA, type of hospital where the primary surgery was performed and the organism's resistance to methicillin are important factors influencing the clinical outcomes after infected TKA. LEVEL OF EVIDENCE: Level 3. Retrospective comparative study.2015年09月, The Knee, 22(4) (4), 328 - 32, 英語, 国際誌研究論文（学術雑誌）
- BACKGROUND: The anterior cruciate ligament (ACL) does not heal spontaneously after injury, and ACL patients of different ages respond differently to treatment. Although ACL-derived CD34-positive cells contribute to bone-tendon healing after ACL reconstruction, the relationship between the healing potential of ACL-derived cells and a patient's age is unknown. HYPOTHESIS: ACL-derived cells from young patients will have a greater effect on the maturation of bone-tendon integration in an immunodeficient rat model of ACL reconstruction compared with cells derived from older patients. STUDY DESIGN: Controlled laboratory study. METHODS: Sixty 10-week-old female immunodeficient rats underwent ACL reconstruction (using the autologous flexor digitorum longus tendon as a graft) followed by intracapsular administration of ACL-derived cells from patients aged 10 to 19 years (younger group) or patients aged 30 to 39 years (older group), or they were given phosphate-buffered saline (PBS; PBS group). Histologic, radiographic, and biomechanical examinations were performed 2 to 8 weeks after surgery. In addition, intrinsic and human cell-derived angiogenesis and osteogenesis were examined by immunohistochemistry. RESULTS: In the younger group, histologic assessment demonstrated early bone-tendon healing, which induced endochondral ossification-like integration. Micro-computed tomography showed a statistically significant reduction in the area of tibial bone tunnel in the younger group (week 4, 20.0% ± 11.2% reduction; week 8, 25.7% ± 5.6% reduction) compared with the older group (week 4, 1.8% ± 3.0% reduction; week 8, 4.0% ± 5.9% reduction) and the PBS group (week 4, -0.5% ± 3.2% reduction; week 8, 3.3% ± 5.2% reduction) (week 4, P < .05; week 8, P < .01). Failure loads during tensile testing demonstrated a significantly higher ultimate load to failure in the younger group (17.52 ± 4.01 N) compared with the older (8.05 ± 2.91 N) and PBS (7.01 ± 3.16 N) groups (P < .05), and isolectin B4 and rat osteocalcin immunostaining indicated enhanced intrinsic angiogenesis and osteogenesis in the younger group. There was no statistically significant difference in the results of radiographic and biomechanical examinations between the older and PBS groups. Double immunohistochemistry for human-specific endothelial cell and osteoblast markers demonstrated a greater ability of differentiation into endothelial cells and osteoblasts in the younger group. CONCLUSION: ACL-derived cells from younger patients enhanced early bone-tendon healing in an immunodeficient rat model of ACL reconstruction. CLINICAL RELEVANCE: Surgeons should consider a patient's age when performing ACL reconstruction with remnant preservation or ruptured tissue incorporation, as this can predict healing ability.2015年03月, The American journal of sports medicine, 43(3) (3), 700 - 8, 英語, 国際誌研究論文（学術雑誌）
- The present study aimed to examine the results of total knee arthroplasty (TKA) with the NexGen Legacy posterior-stabilized (LPS)-Flex system for osteoarthritis in the valgus knee. Between 2003 and 2011, 27 valgus knees in 26 patients who underwent TKA with the NexGen LPS-Flex implant were clinically and radiologically evaluated after a minimum follow-up of 2 years. The original diagnosis was osteoarthritis. Knee Society Knee Score (KSKS), Knee Society Function Score (KSFS), maximum flexion angle, maximum extension angle, and radiological femorotibial angle (FTA) were evaluated pre- and postoperatively. The mean KSKS improved from 42.6 before surgery to 82.2 by the final follow-up (p < 0.01), and the mean KSFS improved from 41.1 to 80.9 (p < 0.01). The mean maximum flexion angle changed from 109.1° to 117.3° (no statistical significance) and the maximum extension angle improved from -9.7° to -3.6° (p < 0.05) postoperatively. The postoperative radiological FTA was 172.4°, which was closer to a neutral angle (174°) than the preoperative FTA (166.4°) (p < 0.01). None of the patients had undergone revision surgery by the final follow-up. As a conclusion, TKA with the NexGen LPS-Flex implant for osteoarthritis in the valgus knee resulted in satisfactory improvement regarding objective outcomes, although a longer term follow-up with a greater number of cases is necessary to verify these results.2015年02月, European journal of orthopaedic surgery & traumatology : orthopedie traumatologie, 25(2) (2), 375 - 80, 英語, 国際誌研究論文（学術雑誌）
- BACKGROUND: The success of unicompartmental knee arthroplasty relies on a lot of factors such as correct osteotomy and proper soft-tissue tensioning. A selection of insert thickness depends solely on the surgeon's subjective feeling. Recently, a tensor that is designed to assess soft tissue balance during unicompartmental knee arthroplasty has been developed. The purpose of this study was to compare the component gap throughout the range of motion among different distraction forces and examine the correlation between the component gap and the insert thickness. METHODS: 30 cases of 29 patients were included. All the patients received a conventional medial Zimmer Unicompartmental High Flex Knee System. Using a tensor under 10, 20, 30, and 40 lb distraction forces, after femoral component placement, the component gaps were assessed throughout the range of motion. The correlations between the component gap and the insert thickness selected were examined. FINDINGS: The component gap showed the same kinematic pattern among the different distraction forces and the value increased in proportion to the increase of the distraction force in unicompartmental knee arthroplasty. The insert thickness in unicompartmental knee arthroplasty was found to have a strong positive correlation with the component gap from 10 to 45° of knee flexion with a distraction force of more than 20 lb INTERPRETATION: With the use of the tensor, surgeons can quantify the component gap and objectify their insert thickness decision compared with the use of tension gauge.2015年01月, Clinical biomechanics (Bristol, Avon), 30(1) (1), 95 - 9, 英語, 国際誌研究論文（学術雑誌）