Objective: This study clarified the relationship between ultrasonography results for infraspinatus muscle atrophy and shoulder joint function in high school volleyball players.
Methods: Subjects included male volleyball players from eight high schools. Muscle atrophy was assessed using ultrasonography and infraspinatus muscle atrophy was determined using criteria from previous studies. Statistical analyses were performed on basic information and physical function between atrophic and normal groups. A stepwise method was used for binary logistic regression analysis. The significance level was set at 5%.
Results: A total of 68 subjects were analyzed, with 19 (27.5%) showing infraspinatus muscle atrophy. Between-group comparisons found more individuals with shoulder pain history and positive dominant-hand HFT (Horizontal Flexion Test) results in the atrophy group. Binary logistic regression analysis identified dominant-hand HFT as a significant factor (odds ratio: 4.19).
Conclusion: Positive dominant-hand HFTs are associated with infraspinatus muscle atrophy.

Objective: This study aimed to compare any differences in pain intensity, pain catastrophizing, and central sensitivity syndrome in osteoporotic vertebral fractures based on different timings of getting out of bed.
Method: Patients who were hospitalized for osteoporotic vertebral fractures (71 patients) were classified into two groups: those who mobilized within 14 days of admission (the early mobilization group: 55 patients) and those who mobilized after 14 days of admission (the delayed mobilization group: 16 patients). Pain intensity, short form of pain catastrophizing scale (PCS-6), and short form of central sensitization inventory (CSI-9) scores were compared between the two groups (early and delayed mobilization) and duration (at admission and discharge).
Result: The pain intensity and PCS-6 scores were significantly worse at admission when compared with those at discharge in both groups. PCS-6 and CSI-9 scores at admission were significantly worse in the delayed mobilization group when compared with that of the early mobilization group.
Conclusion: This study suggested that delayed mobilization in patients may be associated with worsening of PCS-6 and CSI-9 scores.

Objective: Exploratory factor analysis and hypothesis testing, following the COSMIN methodology, were conducted to assess the utility of different components of observational gait assessment in identifying gait abnormalities in female patients after hip osteoarthritis surgery.
Methods: Walking videos of 21 postoperative female patients were evaluated by three independent observers. Representative scores from each observer were used for exploratory factor analysis. Hypothesis testing was conducted by examining the correlations between the total observational gait assessment scores and individual scores on the 10-meter walk test (10MWT), timed up and go (TUG) test, and 6-minute walk test (6MWT).
Results: Factor analysis identified two primary factors. The first factor included the trunk tilt angle at mid-stance, pelvic tilt and hip adduction angles, and the stance time difference between the left and right leg. The second factor comprised the ankle joint angle at heel contact and the hip extension angle at heel-off. Higher total gait assessment scores were associated with slower performance on the 10MWT and TUG.
Conclusion: The identified components of the observational gait assessment met the criteria for structural validity and hypothesis testing. These findings suggest that deviations from normal gait following hip osteoarthritis surgery can be effectively quantified based on the presence and severity of postural abnormalities through observational gait assessment.

Objective: To investigate the association between pre-operative central sensitization (CS) assessed using the Japanese version of the Central Aspects of Pain in the Knee (CAP-Knee J) score and the presence or absence of chronic pain following knee joint replacement (KJR).
Methods: The study included 731 patients who had a KJR (542 females, mean age: 74.6 ± 7.9 years), and the CAP-Knee J was used for assessment of CS. Multiple logistic regression analysis was performed with the presence or absence of post-operative chronic pain as the dependent variable, the pre-operative CAP-Knee J score as the independent variable, and age, sex, body mass index, pre-operative knee extensor muscle strength, and pre-operative knee pain intensity as covariates.
Results: The presence of chronic pain after KJR was significantly influenced by the pre-operative CAP-Knee J score (odds ratio, 1.20; 95% confidence interval, 1.07–1.34; p = 0.002).
Conclusion: The CAP-Knee J score is a useful tool for predicting chronic pain after KJR.

Objective: This study aimed to investigate the preoperative factors affecting the achievement of a patient acceptable symptom state (PASS) for all four Knee Injury and Osteoarthritis Outcome Score (KOOS) subscales one year after total knee arthroplasty (TKA).
Methods: 95 patients who underwent posterior stabilized TKA between October 2020 and February 2023. Patients were divided into two groups based on whether they achieved PASS for all four KOOS subscales (symptom, pain, activities of daily living and quality of life) one year postoperatively. Logistic regression analysis was conducted with significant variables between both groups as independent factors to identify preoperative factors influencing the achievement of PASS one year postoperatively.
Results: The proportion of patients who achieved PASS for all four subscales was 54%. Regression analysis identified preoperative knee flexion pain (p = 0.033) and the Pain Catastrophizing Scale (PCS) (p = 0.023) as factors influencing PASS achievement.
Conclusion: Improvements in preoperative knee flexion pain and PCS may enhance patient satisfaction, as measured using the KOOS.

Objective: To investigate changes in living space after surgery for spinal degenerative disease and preoperative factors that influence postoperative living spaces among older individuals.
Methods: Fifty patients (mean age 76.8 years) who underwent surgery for spinal degenerative disease were included. Life Space Assessment (LSA), a measure of living space, was performed preoperatively and 3 and 6 months postoperatively. Statistical analysis was conducted using a mixed-effects model to analyze the changes in LSA over time. Single and multiple regression analyses were performed to examine the preoperative factors affecting postoperative LSA. The dependent variable was LSA at 6 months postoperatively, and the independent variables were preoperative factors.
Results: The mixed-effects model showed that LSA improved significantly at 3 and 6 months postoperatively compared with preoperatively. Single and multiple regression analyses showed that body mass index (BMI) and the Modified Gait Efficacy Scale (mGES) met significance levels.
Conclusion: The living spaces of older patients with degenerative spinal disease improved postoperatively. Preoperative BMI and mGES were found to influence postoperative living spaces.

Objectives: This study aimed to investigate the reliability of measurement positioning and change in Kager’s fat pad (KFP) thickness during contraction of the flexor hallucis longus (FHL) in the dynamic evaluation of the proximal part of the KFP using an ultrasound device.
Methods: Twelve healthy adults participated in the study. In the KFP long axis image, the distance between the deepest part of the tendon located directly above the posterior malleolus of the tibia and the deepest part of the KFP was defined as the “KFP thickness,” and the distance between the maximum bulge of the posterior malleolus and the most superficial part of the epidermis located directly above it was defined as the “distance from the epidermis to the posterior malleolus of the tibia.” Measurements were taken at rest and during FHL contraction. Two examiners performed the measurements and one examiner remeasured several days later. We investigated intra- and inter-examiner reliability and the amount of change in KFP thickness.
Results: Regarding the reliability of KFP thickness and “distance from the epidermis to the posterior malleolus of the tibial bone,” the intraclass correlation coefficient was classified as “fair-great (0.88-0.96),” and no systematic error was observed. KFP thickness increased significantly during contraction.
Conclusion: Ultrasound evaluation of proximal KFP dynamics during FHL contraction demonstrated good reliability and showed increased KFP thickness with contraction.