Estimating the Thumb Rotation Angle by Using a Tablet Device With a Posture Estimation Artificial Intelligence Model.

MediaPipe Hand (MediaPipe) is an artificial intelligence (AI)-based pose estimation library. In this study, MediaPipe was combined with four machine learning (ML) models to estimate the rotation angle of the thumb. Videos of the right hands of 15 healthy volunteers were recorded and processed into 9000 images. The rotation angle of the thumb (defined as angle θ from the palmar plane, which is defined as 0°) was measured using an angle measuring device, expressed in a radian system. Angle θ was then estimated by the ML model by using parameters calculated from the hand coordinates detected by MediaPipe. The linear regression model showed a root mean square error (RMSE) of 12.23, a mean absolute error (MAE) of 9.9, and a correlation coefficient of 0.91. The ElasticNet model showed an RMSE of 12.23, an MAE of 9.95, and a correlation coefficient of 0.91; the support vector machine (SVM) model showed an RMSE of 4.7, an MAE of 2.5, and a correlation coefficient of 0.99. The LightGBM model achieved high values: an RMSE of 4.58, an MAE of 2.62, and a correlation coefficient of 0.99. Based on these findings, we concluded that the thumb rotation angle can be estimated with high accuracy by combining MediaPipe and ML.

The assessment of canal flare index and proximal femoral bone density can improve stem selection for peri-prosthetic bone maintenance after total hip arthroplasty.

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.

Estimation of Shoulder Joint Rotation Angle Using Tablet Device and Pose Estimation Artificial Intelligence Model.

Traditionally, angle measurements have been performed using a goniometer, but the complex motion of shoulder movement has made these measurements intricate. The angle of rotation of the shoulder is particularly difficult to measure from an upright position because of the complicated base and moving axes. In this study, we attempted to estimate the shoulder joint internal/external rotation angle using the combination of pose estimation artificial intelligence (AI) and a machine learning model. Videos of the right shoulder of 10 healthy volunteers (10 males, mean age 37.7 years, mean height 168.3 cm, mean weight 72.7 kg, mean BMI 25.6) were recorded and processed into 10,608 images. Parameters were created using the coordinates measured from the posture estimation AI, and these were used to train the machine learning model. The measured values from the smartphone's angle device were used as the true values to create a machine learning model. When measuring the parameters at each angle, we compared the performance of the machine learning model using both linear regression and Light GBM. When the pose estimation AI was trained using linear regression, a correlation coefficient of 0.971 was achieved, with a mean absolute error (MAE) of 5.778. When trained with Light GBM, the correlation coefficient was 0.999 and the MAE was 0.945. This method enables the estimation of internal and external rotation angles from a direct-facing position. This approach is considered to be valuable for analyzing motor movements during sports and rehabilitation.

Morphological analysis of the distal femur as a surgical reference in biplane distal femoral osteotomy.

Distal femoral osteotomy (DFO) is performed alone or with high tibial osteotomy (HTO) for patients with osteoarthritis and distal femur deformities. DFO is technically demanding, particularly when creating an anterior flange. Herein, we examined the morphological characteristics of the distal femur based on the cortical shape as a surgical reference for biplanar DFO. Computed tomography images of 50 valgus and 50 varus knees of patients who underwent biplanar DFO or total knee arthroplasty were analyzed. Axial slices at the initial level of the transverse osteotomy in the DFO and slices 10 mm proximal and 10 mm distal to that level were selected. The medial and lateral cortical angles and heights (MCLA, LCLA, MCH, and LCH) were measured on axial slices. Statistical comparisons were performed between the medial and lateral cortices and valgus and varus knees. MCLA and MCH were significantly smaller and lower, respectively, than LCLA and LCH (P < 0.01). The MCLA and MCH of varus knees were significantly smaller and lower, respectively, than those of valgus knees (P < 0.01). Surgeons should carefully observe morphological differences in the distal femur cortex, distinguishing between medial and lateral knees and varus and valgus knees during the creation of the anterior flange in the DFO.

Variations in knee cartilage thickness: Fully automatic three-dimensional analysis of MRIs from five manufacturers.

BACKGROUND: Measurements of knee cartilage thickness derived from MR images are attractive biomarkers for osteoarthritis research. Although some cross-sectional multivendor studies exist, none have employed fully automatic three-dimensional MRI analysis. Our objective was to evaluate the variations in knee cartilage thickness measurements obtained using automated methods and MRI instruments from five different vendors. METHODS: The subjects were 10 healthy volunteers aged 22-60 years. MRI models with 3 Tesla strength from five different companies were used. Cartilage thickness was quantified fully automatically for seven regions. We hypothesized that "the MRI model influences cartilage thickness measurements." Inter-measurement error, defined as the absolute difference between the targeted and median thicknesses determined by the five MRI models, was analyzed using histograms. The factors generating the largest inter-measurement error were also examined. RESULTS: No exceptional trends attributable to a specific instrument model were observed, and the p-value from the Kruskal-Wallis test exceeded 0.05 in all seven regions. Therefore, the study hypothesis was rejected. Of the 350 measurements, the inter-measurement error was ≤0.05 mm in 53 %, ≤0.10 mm in 75 %, and ≤0.20 mm in 95 %. Analysis of the medial tibial cartilage, which had the largest inter-measurement error, revealed mis-extraction of synovial fluid as cartilage. CONCLUSIONS: The choice of MRI model did not influence cartilage thickness measurements. Overall, 95 % of the inter-measurement errors were within 0.20 mm. The greatest error resulted from mis-extracting synovial fluid as cartilage.

Association Between Psychological Readiness to Return to Sports at 3 Months Postoperatively and Risk of Second ACL Injury.

Background: Psychological readiness to return to sports (RTS) has been associated with second anterior cruciate ligament (ACL) injury. However, this relationship is controversial because covariates such as anatomic and knee function characteristics have not been adequately considered. Purpose/Hypothesis: To investigate whether psychological readiness in the early postoperative period can predict the occurrence of a second ACL injury within 24 months after primary ACL reconstruction (ACLR) using propensity score analysis. It was hypothesized that patients with high ACL-RSI after injury (ACL-RSI) scores at 3 months postoperatively would have a second ACL injury within the projected postoperative period. Study Design: Cohort study; Level of evidence, 3. Methods: Included were 169 patients who underwent primary ACLR using hamstring tendon autografts between November 2017 and July 2021 and also underwent knee functional assessments at 3 months postoperatively. The ACL-RSI scale was used to assess psychological readiness for RTS. A second ACL injury was defined if ipsilateral or contralateral ACL injury was confirmed by examination within 24 months postoperatively. Based on a previous study showing that 65 was the highest cutoff value for the ACL-RSI score for RTS, we classified patients into 2 groups: those with high ACL-RSI scores (≥65; group H) and those with low ACL-RSI scores (<65; group L). We generated 1-to-1 matched pairs using propensity score analysis and used log-rank testing to compare the rate of second ACL injury between the 2 groups. Results: More patients returned to any sports activities within 12 months in group H than in group L (90% vs 73%; P = .03). A second ACL injury within 24 months postoperatively was identified in 7% of patients (13/169). The rate of second ACL injury was significantly higher in group H than in group L (17.6% vs 3.4%; P = .001). In 43 matched pairs extracted using propensity scoring, the rate of second ACL injury was also higher in group H than in group L (18.6% vs 4.7%; P = .04). Conclusion: Patients with a higher ACL-RSI score at 3 months exhibited a significantly higher incidence of second ACL injury within 24 months after primary ACLR.

Injuries to both anterolateral ligament and Kaplan fiber of the iliotibial band do not increase preoperative pivot-shift phenomenon in ACL injury.

Background: To assess the incidence of anterolateral ligament (ALL) and Kaplan fiber of the iliotibial band (KF) injuries in patients with acute anterior cruciate ligament (ACL) injury on magnetic resonance imaging (MRI), and to investigate the association between these injuries and the magnitude of preoperative pivot-shift test. Method: One-hundred and five patients with primary ACL injury were retrospectively reviewed. ALL injury and KF injury were assessed by preoperative MRI, and subjects were allocated into four groups: Group A, neither injury; Group B, only ALL injury; Group C, only KF injury; Group D, simultaneous ALL and KF injuries. Before ACL reconstruction, tibial acceleration during the pivot-shift test was measured by an electromagnetic measurement system, and manual grading was recorded according to the International Knee Documentation Committee (IKDC) guideline. Results: In MRI, the ALL was identified in 104 patients (99.1%) and KF in 99 patients (94.3%). ALL and KF injuries were observed in 43 patients (43.9%) and 23 patients (23.5%), respectively. Patient distribution to each group was as follows; Group A: 43 patients (43.9%), Group B: 32 patients (32.7%), Group C: 12 patients (12.2%), Group D: 11 patients (11.2%). No significant differences were observed in tibial acceleration, and manual grading among the four groups. Conclusion: Simultaneous injury to both ALL and KF was uncommon, and preoperative pivot-shift phenomenon did not increase even in those patients. The finding suggests that the role of ALL and KF in controlling anterolateral rotatory knee laxity may be less evident in the clinical setting compared to a biomechanical test setting.

Setting hinge position distal to the proximal margin of the distal lateral femur reduces the maximum principal strains of the hinge area and risk of hinge fractures.

Purpose: The optimal hinge position to prevent hinge fractures in medial closing wedge distal femoral osteotomy (MCWDFO) based on the biomechanical background has not yet been well examined. This study aimed to examine the appropriate hinge position in MCWDFO using finite element (FE) analysis to prevent hinge fractures. Methods: Computer-aided design (CAD) models were created using composite replicate femurs. FE models of the MCWDFO with a 5° wedge were created with three different hinge positions: (A) 5 mm proximal to the proximal margin of the lateral epicondylar region, (B) proximal margin level and (C) 5 mm distal to the proximal margin level. The maximum and minimum principal strains in the cortical bone were calculated for each model. To validate the FE analysis, biomechanical tests were performed using composite replicate femurs with the same hinge position models as those in the FE analysis. Results: In the FE analysis, the maximum principal strains were in the order of Models A > B > C. The highest value of maximum principal strain was observed in the area proximal to the hinge. In the biomechanical test, hinge fractures occurred in the area proximal to the hinge in Models A and B, whereas the gap closed completely without hinge fractures in Model C. Fractures occurred in an area similar to where the highest maximal principal strain was observed in the FE analysis. Conclusion: Distal to the proximal margin of the lateral epicondylar region is an appropriate hinge position in MCWDFO to prevent hinge fractures. Level of Evidence: Level V.

Treatment of Osteoporosis in Men on Androgen Deprivation Therapy in Japan.

Background and Objectives: Androgen deprivation therapy (ADT) for prostate cancer has greatly improved treatment outcomes. As patient survival rates have increased, reports of decreased bone density and increased bone fractures as side effects of ADT have emerged. The prevalence of osteoporosis in Japanese men was 4.6%. The purpose of this study was to evaluate the effect of osteoporosis treatment in prostate cancer patients who underwent ADT in Japan. Materials and Methods: The subjects were 33 male patients who had undergone ADT for prostate cancer, who were noted to have decreased bone density. Mean age was 76.2 ± 7.7 years (64-87). Medications included vitamin D in one case, bisphosphonates (BP) in 27 cases, and denosumab in five cases. The evaluation method examined the rate of change in bone mineral density (BMD) before osteoporosis treatment and 1 year after. For comparison, a group without osteoporosis treatment intervention (n = 33) was selected, and matched for prostate cancer treatment and age. The rate of change in trabecular bone score (TBS) was also calculated. Results: The percentage changes in BMD before and 1 year after treatment were as follows: lumbar spine, 7.1 ± 5.8% in the treatment group versus -3.9 ± 4.1% in the no treatment group; femoral neck, 5.5 ± 6.2% in the treatment group versus -0.9 ± 3.9% in the no treatment group; total femur, 6.6 ± 6.4% in the treatment group versus the no treatment group which was -1.7 ± 3.2%. In all cases, there was a clear significant difference (p < 0.01). The percent change in TBS was further calculated in the same manner. There was no significant difference between the two groups: +1.7 ± 3.8% in the treated group versus +0.3 ± 4.1% in the untreated group. Conclusions: Osteoporosis treatment in Japanese patients with prostate cancer on ADT therapy was found to significantly increase BMD compared to the untreated group. BP and denosumab were found to be very effective in increasing BMD.

What effect does preoperative flexion contracture have on the component angles in unicompartmental knee arthroplasty?

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.

Accuracy of portable navigation during THA in patients with severe developmental dysplasia of hip.

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.

Lateral Collateral Ligament Reconstruction Using the Triceps Brachii Fascia for Posterolateral Rotatory Instability in Cubitus Varus: A Report of Two Cases.

A combination of osteotomy and ligament reconstruction is recommended for posterolateral rotatory instability (PLRI) with large cubitus varus deformities. There is a lack of reports regarding ligament donor selection for ligament reconstruction of PLRI with cubitus varus. Two cases of PLRI with cubitus varus have been described. In case one, a 40-year-old woman presented with left elbow pain. She had a cubitus varus deformity, resulting from a childhood elbow fracture. Radiographs showed an 18-degree cubitus varus deformity. A lateral closing wedge osteotomy and double plate osteosynthesis were performed. The lateral collateral ligament (LCL) was reconstructed with autologous triceps fascia. Postoperative radiographs confirmed correction with 10 degrees of the carrying angle (CA). Bone union at the osteotomy site occurred six months later with excellent results. In case two, a 45-year-old man presented an arm with persistent right elbow instability with cubitus varus deformity. This was due to a childhood supracondylar fracture of the right humerus. Radiographs showed a cubitus varus deformity of 25 degrees on the right. The surgical procedure included a lateral wedge osteotomy, double plate fixation, and LCL reconstruction with autologous triceps fascia. Postoperative radiographs confirmed a corrected CA of 5 degrees. Bone union was achieved at the six-month follow-up with satisfactory results. The use of triceps fascia for LCL reconstruction for PLRI due to cubitus varus would provide a minimally invasive and reasonable treatment option.

Prediction of Postoperative Range of Motion after Mobile-Bearing Medial Unicompartmental Knee Arthroplasty from the Preoperative Range of Motion and Other Preoperative Factors.

Postoperative flexion after unicompartmental knee arthroplasty might be predicted from the preoperative range of motion and other preoperative factors, but this has not been sufficiently investigated. Between 2013 and 2017, 198 patients (198 knees) underwent unilateral knee arthroplasty with medial mobile-bearing unicompartmental knee arthroplasty. Range of motion was measured preoperatively and at the time of final follow-up. To investigate the accuracy of the prediction of preoperative to postoperative gain or loss of the flexion angle, we performed receiver operating characteristic analysis. Logistic regression analysis was used to evaluate other predictive factors. Change in flexion angle was significantly strongly and negatively correlated with the preoperative flexion angle (R = - 0.688; 95% confidence interval: -0.755 to -0.607; p < 0.001). Preoperative flexion angle was suggested to be a significant predictor of gain or loss of the flexion angle with the area under the curve of 0.781; the cutoff value calculated using the Youden index was 140 degrees. Logistic regression analysis showed that in addition to the preoperative flexion angle of the operated side, the postoperative flexion range was significantly affected by the patient's height and by the preoperative flexion angle of the contralateral knee. If the preoperative flexion angle in Oxford mobile-bearing medial unicompartmental knee arthroplasty is <140 degrees, the postoperative flexion angle may be improved; if it exceeds 140 degrees, the postoperative flexion angle may worsen. This predictive ability is further improved by consideration of the patient's height and the range of motion on the contralateral side.

Mid- to Long-Term Results of Total Knee Arthroplasty for Charcot Arthropathy of the Knee.

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.

Effects of high antibiotic concentrations applied to continuous local antibiotic perfusion on human bone tissue-derived cells.

Aims: Continuous local antibiotic perfusion (CLAP) has recently attracted attention as a new drug delivery system for orthopaedic infections. CLAP is a direct continuous infusion of high-concentration gentamicin (1,200 µg/ml) into the bone marrow. As it is a new system, its influence on the bone marrow is unknown. This study aimed to examine the effects of high-concentration antibiotics on human bone tissue-derived cells. Methods: Cells were isolated from the bone tissue grafts collected from six patients using the Reamer-Irrigator-Aspirator system, and exposed to different gentamicin concentrations. Live cells rate, apoptosis rate, alkaline phosphatase (ALP) activity, expression of osteoblast-related genes, mineralization potential, and restoration of cell viability and ALP activity were examined by in vitro studies. Results: The live cells rate (the ratio of total number of cells in the well plate to the absorbance-measured number of live cells) was significantly decreased at ≥ 500 µg/ml of gentamicin on day 14; apoptosis rate was significantly increased at ≥ 750 µg/ml, and ALP activity was significantly decreased at ≥ 750 µg/ml. Real-time reverse transcription-polymerase chain reaction results showed no significant decrease in the ALP and activating transcription factor 4 transcript levels at ≥ 1,000 µg/ml on day 7. Mineralization potential was significantly decreased at all concentrations. Restoration of cell viability was significantly decreased at 750 and 1,000 µg/ml on day 21 and at 500 µg/ml on day 28, and ALP activity was significantly decreased at 500 µg/ml on day 28. Conclusion: Our findings suggest that the exposure concentration and duration of antibiotic administration during CLAP could affect cell functions. However, further in vivo studies are needed to determine the optimal dose in a clinical setting.

Clinical Characteristics, Surgical Outcomes, and Risk Factors for Emergency Surgery in Patients With Spinal Metastases: A Prospective Cohort Study.

OBJECTIVE: To elucidate the patient characteristics and outcomes of emergency surgery for spinal metastases and identify risk factors for emergency surgery. METHODS: We prospectively analyzed 216 patients with spinal metastases who underwent palliative surgery from 2015 to 2020. The Eastern Cooperative Oncology Group performance status, Barthel index, EuroQol-5 dimension (EQ5D), and neurological function were assessed at surgery and at 1, 3, and 6 months postoperatively. Multivariate analysis was performed to identify risk factors for emergency surgery. RESULTS: In total, 146 patients underwent nonemergency surgery and 70 patients underwent emergency surgery within 48 hours of diagnosis of a surgical indication. After propensity score matching, we compared 61 patients each who underwent nonemergency and emergency surgery. Regardless of matching, the median performance status and the mean Barthel index and EQ5D score showed a tendency toward worse outcomes in the emergency than nonemergency group both preoperatively and 1 month postoperatively, although the surgery greatly improved these values in both groups. The median survival time tended to be shorter in the emergency than nonemergency group. The multivariate analysis showed that lesions located at T3-10 (p = 0.002; odds ratio [OR], 2.92; 95% confidence interval [CI], 1.48-5.75) and Frankel grades A-C (p < 0.001; OR, 4.91; 95% CI, 2.45-9.86) were independent risk factors for emergency surgery. CONCLUSION: Among patients with spinal metastases, preoperative and postoperative subjective health values and postoperative survival are poorer in emergency than nonemergency surgery. Close attention to patients with T3-10 metastases is required to avoid poor outcomes after emergency surgery.

LIGHT regulated gene expression in rheumatoid synovial fibroblasts.

BACKGROUND: Synovial hyperplasia caused by rheumatoid arthritis (RA), an autoimmune inflammatory disease, leads to the destruction of the articular cartilage and bone. A member of the tumor necrosis factor superfamily, Lymphotoxin-related inducible ligand that competes for glycoprotein D binding to herpes virus entry mediator on T cells (LIGHT) has been shown to correlate with the pathogenesis of RA. METHODS: We used cDNA microarray analysis to compare the expression of genes in rheumatoid fibroblast-like synoviocytes with and without LIGHT stimulation. RESULTS: Significant changes in gene expression (P-values < 0.05 and fold change ≥ 2.0) were associated mainly with biological function categories of glycoprotein, glycosylation site as N-linked, plasma membrane part, integral to plasma membrane, intrinsic to plasma membrane, signal, plasma membrane, signal peptide, alternative splicing, and topological domain as extracellular. CONCLUSIONS: Our results indicate that LIGHT may regulate the expression in RA-FLS of genes which are important in the differentiation of several cell types and in cellular functions.

Varus placement of the tibial component reduces the potential risk of fracture with adequate bony coverage in the Oxford unicompartmental knee arthroplasty.

A short keel-cortex distance (KCD), especially to the posterior cortex, is a potential risk factor for tibial plateau fracture after Oxford mobile-bearing unicompartmental knee arthroplasty (OUKA). This study aimed to evaluate the effect of tibial component alignment in the coronal plane and tibial proximal morphology on the KCD. Included in this study were 51 patients scheduled for primary Oxford medial unicompartmental knee arthroplasty (UKA). The anterior and posterior KCD were preoperatively assessed using 3D simulation software with the component set perpendicular to the tibial mechanical axis (neutral), 3° valgus, 3° varus, and 6° varus, relative to neutral alignment. We evaluated the existence of overhanging medial tibial condyle where the medial eminence line, the line including the medial tibial eminence parallel to the tibial axis, passes outside of the tibial shaft. In all component alignments, patients with a medial overhanging condyle had significantly shorter posterior KCD than those without. In patients with a medial overhanging condyle, the posterior KCD significantly increased when the tibial component was placed in 3° varus (4.6 ± 1.5 mm, P = 0.003 vs neutral, P < 0.001 vs 3° valgus) and 6° varus (5.0 ± 1.4 mm, P < 0.001 vs neutral, P < 0.001 vs 3° valgus) compared with in neutral (3.5 ± 1.9 mm) or 3° valgus (2.8 ± 1.8 mm). In OUKA, varus implantation increased the KCD. This could potentially decrease the risk of fracture, even in knees with the overhanging medial condyle. Conversely, valgus implantation of the tibial component shortened the KCD, and should therefore be avoided.

Knee Osteotomy Decreases Joint Inflammation Based on Synovial Histology and Synovial Fluid Analysis.

PURPOSE: To examine the biological changes in the joints of patients with knee osteoarthritis (OA) before and after around-knee osteotomy (AKO), focusing on synovial fluid (SF) and synovial pathological changes. METHODS: Patients who underwent AKO for medial compartment knee OA between 2019 and 2021 were examined. SF and synovium were obtained at the time of AKO and plate removal after bone union (mean, 16.8 months [range: 11-38 months] postoperatively). SF volume and interleukin (IL)-6 concentrations in SF were assayed using enzyme-linked immunosorbent assay. Synovitis was assessed histologically using a semiquantitative scoring system. Macrophage infiltration was assessed by immunohistochemistry using a semiquantitative score for F4/80 expression. The M1/M2 ratio was calculated using percentage of cells positive for CD80 and CD163. The expression of proinflammatory cytokines was assessed by the percentage of IL-1ß- and IL-6-positive cells. The number of vascular endothelial growth factor-positive luminal structures was counted to assess angiogenesis. The change in each parameter was compared before and after AKO using the Wilcoxon matched-pairs signed-rank test. RESULTS: Twenty-four knees of 21 patients were included. SF volume and IL-6 concentration significantly decreased postoperatively (12.6 ± 2.1 mL vs 4.2 ± 0.6 mL; P < .0001 and 50.5 ± 8.6 pg/mL vs 20.7 ± 3.8 pg/mL; P = .0001, respectively). A significant reduction in synovitis score (P = .0001), macrophage infiltration (P < .0003), M1/M2 ratio (P < .0007), angiogenesis (P < .0001), and the percentage of IL-1ß- and IL-6-positive cells in the intima (P < .008 and P < .002, respectively) was found after AKO. CONCLUSIONS: SF volume and IL-6 concentrations in the SF decreased and inflammatory synovium pathology improved after AKO. In addition to biomechanical changes, the biological environment of the joint can be improved after AKO. LEVEL OF EVIDENCE: Level IV, retrospective therapeutic case series.

Influence of Distal Reference Point of the Tibial Mechanical Axis on the Ankle and Hindlimb Alignment Change after Total Knee Arthroplasty.

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.