山口 智志

BACKGROUND: The ability to perform deep squats in children and adolescents is an essential component of lower extremity function. Especially for school-aged children and adolescents, the ability to perform deep squats is related to their daily life and school activities. Few reports have investigated the factors associated with deep squats ability in this population. This study aimed to identify the factors associated with deep squat ability in healthy Japanese children and adolescents. METHODS: A retrospective cohort study was conducted with children and adolescents aged 8-14 years in Japan from 2017 to 2019. Data on height, weight, ability to perform deep squats, general joint laxity, lower limb tightness, and the Hospital for Special Surgery Pediatric Functional Activity Brief Scale score were collected at the beginning of each year. Participants who were able to squat during their musculoskeletal screening were divided into two groups: those who could deep squat the following year and those who could not. Logistic regression analysis with variable selection was performed to calculate the odds ratio for each predicted risk factor associated with the inability to perform a deep squat. RESULTS: A total of 636 children and adolescents were included in the analysis, with 7.5 % of them being unable to perform deep squats the following year. The risk of being unable to deep squats significantly decreased with increasing age (odds ratio 0.66, 95 % confidence interval 0.50-0.87). In addition, higher weight (odds ratio 1.12, 95 % confidence interval 1.07-1.17) and higher Hospital for Special Surgery Pediatric Functional Activity Brief Scale score (odds ratio 1.05, 95 % confidence interval 1.01-1.10) were identified as risk factors associated with the inability to perform a deep squat. Other physical factors did not significantly contribute to the occurrence of deep squat abnormalities. CONCLUSIONS: Age, body weight, and physical activity levels were found to be associated with the ability to perform deep squats in healthy Japanese children and adolescents.

BACKGROUND: The factors contributing to osteoarthritis progression after anterior cruciate ligament (ACL) injury and reconstruction (ACLR) are not fully understood. Quantitative magnetic resonance imaging (MRI) offers a noninvasive way to evaluate cartilage biochemical composition using T1ρ mapping, thereby detecting early cartilage degeneration. The specific impact of preoperative quantitative MRI on long-term outcomes after ACLR remains underreported. PURPOSE/HYPOTHESIS: The purpose of this study was to investigate the effects of various factors, including preoperative cartilage T1ρ values, on the 10-year outcomes after ACLR. It was hypothesized that individual differences in baseline cartilage degeneration would influence osteoarthritis progression at 10 years postoperatively. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: This case series involved 13 patients with primary ACL injury who underwent anatomical double-bundle ACLR using hamstring tendon autograft between April 2012 and August 2013. All patients underwent preoperative quantitative MRI using a 3.0-T scanner with an 8-channel knee coil. Cartilage was divided into 18 compartments for compositional analysis, and average T1ρ values were calculated for each compartment. At the 10-year follow-up, 9 of the patients were available for patient-reported outcome (PRO) measures and radiographs. RESULTS: The 9 patients (6 female, 3 male) had a mean age of 26.4 years and a mean body mass index of 23.3 at surgery. All patients exhibited favorable PRO scores at the 10-year follow-up, but 5 patients showed osteoarthritis progression according to Kellgren-Lawrence (KL) grade. Although preoperative T1ρ values did not significantly correlate with PRO scores, patients with KL grade progression had significantly higher preoperative T1ρ values in the posterolateral tibial cartilage than those without progression (P = .04). CONCLUSION: Ten years after anatomical double-bundle ACLR, most patients reported favorable outcomes. Preoperative T1ρ values were not directly correlated with PROs, although the presence of a patient subset with progressive KL grades suggests that preoperative posterolateral tibial cartilage condition may influence long-term osteoarthritis progression.

BACKGROUND: We aimed to evaluate the intra- and interrater measurement reliability of the lateral ankle ligament attachment locations using three-dimensional magnetic resonance imaging. METHODS: We analysed 54 participants with a mean age of 43 years who underwent three-dimensional ankle magnetic resonance imaging and had normal lateral ligaments. Bony landmarks of the distal fibula, talus, and calcaneus were identified in the reconstructed images. The centers of the anterior talofibular ligament and calcaneofibular ligament attachments were also identified. The distances between the landmarks and attachments were measured. Two raters performed the measurements twice, and intra- and interrater intraclass correlation coefficients were calculated. RESULTS: The intrarater intraclass correlation coefficient values were between 0.71 and 0.96 for the anterior talofibular ligament attachment measurements and between 0.77 and 0.95 for the calcaneofibular ligament attachments. The interrater intraclass correlation coefficient was higher than 0.7, except for the distance between the anterior talofibular ligament superior bundle and fibular obscure tubercle. The fibular attachment of a single-bundle anterior talofibular ligament was located 13.3 mm from the inferior tip and 43% along the anterior edge of the distal fibula. The superior and inferior bundles of the double-bundle ligament were located at 43% and 23%, respectively. The calcaneofibular ligament fibular attachment was 5.5 mm from the inferior tip, at 16% along the anterior edge of the distal fibula. CONCLUSION: The measurements of anterior talofibular ligament and calcaneofibular ligament attachment locations identified on three-dimensional magnetic resonance imaging were sufficiently reliable. This measurement method provides in vivo anatomical data on the lateral ankle ligament anatomy.