佐粧 孝久

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.

OBJECTIVE: To assess articular cartilage degeneration in anterior cruciate ligament (ACL) reconstructed knees as detected by MR T1rho and T2 mapping relative to controls and longitudinally at 3 months and 1 year after ACL reconstruction (ACLR). DESIGN: Twenty-five patients with acute ACL injury were enrolled (13 women and 12 men; mean age 30.8), and 14 healthy controls were selected by sex and age matching. The affected knees of the ACLR participants were imaged using a 3.0T magnetic resonance (MR) scanner 3 months and 1 year after ACLR. Cartilage T1rho and T2 values were quantified for subcompartments in the full-thickness, superficial, and deep layers and were compared with the matched subcompartments of control knees. The influence of concomitant meniscal tears identified using proton density-weighted imaging (PDWI) was also investigated. RESULTS: In the posterior lateral tibia, T1rho and T2 values were significantly higher in ACLR participants at 3 months and slightly decreased at 1-year compared to the control group. T1rho values in the medial compartment exhibited a significant increase at 1-year compared with those of control knees, while T2 showed no significance. In cartilage with medial meniscal tears, the T1rho values in multiple medial subcompartments were significantly higher than those in cartilage without medial meniscal tears, and this alteration was relatively detectable by T1rho. CONCLUSIONS: T1rho and T2 mapping is effective in evaluating cartilage degeneration following ACLR. T1rho may exhibit greater sensitivity for assessing the progression of early degeneration in the medial compartment after ACLR.

BACKGROUND: Clamping along the transsyndesmotic (TS) axis decreases the risk of malreduction when reducing syndesmotic diastasis. We aimed to measure the difference between the TS axis and the axis determined by the newly proposed fluoroscopic incisura tangent (IT) method. The measurements were compared to those between the TS axis and those based on the center-center (CC) and talar dome lateral (TL) methods. METHODS: We analyzed computed tomographic images of 43 normal ankles. The IT view was simulated using a digitally reconstructed radiograph, in which the anterior and posterior fibular incisura tubercles overlapped on the internally rotated anteroposterior view. The interaxis angle between the TS and the axes determined by the IT method was measured on the axial computed tomographic image corresponding to the radiographic image. The same procedure was repeated using the CC and TL methods. The measured values were compared between the three methods using a one-factor analysis of variance. Furthermore, the measurements of the anteverted and retroverted incisurae were compared for each fluoroscopic method. RESULTS: The mean interaxis angles between the TS were - 0.5 degrees, 6.3 degrees, and - 1.8 degrees for the IT, CC, and TL methods, respectively, with a significantly larger value for the CC method than for the IT and TL methods (P < .001). No significant difference was found in the interaxis angle in the anteverted (-0.1 degrees) and retroverted (-1.0 degrees) incisurae when using the IT method (P = .15). The angles in the retroverted incisurae were larger than those of the anteverted incisurae for the CC and TL methods. CONCLUSION: The fluoroscopic IT method accurately estimated the TS axis. The interaxis angles were consistent, regardless of the incisura anatomy. The fluoroscopic method can be used to clamp and fix the syndesmosis along the TS axis. LEVEL OF EVIDENCE: Ⅳ.

Introduction Restoring knee joint stability and resuming sports activities are important objectives of anterior cruciate ligament (ACL) reconstruction. The maintenance of anterior knee stability after ACL reconstruction is contingent on graft tension. Various devices and techniques have been used to achieve robust tibial graft tendon fixation, and their advantages and disadvantages are established. However, a gold standard has not been established. Therefore, we aimed to determine whether anterior knee joint stability and clinical outcomes of graft tendon fixation could be improved using a recently modified suture button (MSB) compared with using an adjustable suspensory fixator (ASF) at 1 year after double-bundle ACL reconstruction. Methods This study retrospectively analyzed postoperative data derived from 79 patients at a single center between January 2016 and December 2021. The patients were assigned to groups that underwent double-bundle ACL reconstruction with tibial fixation using an MSB (n = 30) that maintains tension while tying sutures, or an ASF (n = 49). We then compared complications, clinical outcomes and knee joint stability at 1 year postoperatively. Rates of postoperative infection, graft rupture, implant removal and residual anterior knee laxity (AKL) were compared between the groups using chi-square tests. Patient-reported outcome measures (PROM) based on Forgot Joint Score-12, Knee Injury and Osteoarthritis Outcome, and Lysholm Knee scores were compared using Mann-Whitney U tests. Results One patient in the MSB group developed postoperative infection. Rates of graft rupture and implant removal in the MSB and ASF groups were 3.3% and 4.1%, and 3.6% and 10.2%, respectively. None of the PROMs differed between the groups. The proportions of postoperative AKL were 3.6% and 14.9% in the MSB and ASF groups, respectively. A trend towards lower postoperative AKL in the MSB group did not reach statistical significance (p = 0.25). Conclusions The incidence of AKL at a year after ACL reconstruction using the MSB was 3%. Postoperative AKL and clinical outcomes were comparable between the MSB and ASF groups. A low AKL rate and positive postoperative outcomes indicated that MSB could be an option for tibial-side fixation in ACL reconstruction.

BACKGROUND/OBJECTIVE: The purpose of this study was to find factors indicating the occurrence of the Segond fracture, a specific type of anterolateral ligament injury. METHODS: From January 2015 to December 2017, we retrospectively reviewed the medical records of patients diagnosed with acute anterior cruciate ligament (ACL) injury who underwent reconstruction within 90 days of injury. Diagnosis of the Segond fracture was determined either by magnetic resonance imaging or plain radiographs. Factors examined were: age at surgery, sex, body mass index (kg/m2), status of menisci, and activities led to ACL injury. After univariate screening, multivariate logistic regression analyses were performed. Patients were divided into four groups based on the presence of lateral meniscal (LM) and/or medial meniscal (MM) injuries and compared with respect to the occurrence of Segond fractures. RESULTS: A total of 375 patients were included (163 males, 212 females), with mean age 25.8 years old. Among them, 22 of 375 (5.9 %) had a Segond fracture. We identified injured lateral menisci (adjusted odds ratio (aOR), 3.029; 95 % Confidence Interval (CI), 1.206-7.609; P = 0.018), intact medial menisci (aOR, 0.229; 95 % CI, 0.065-0.810; P = 0.022), and higher body mass index (aOR, 1.102; 95 % CI, 1.008-1.205; P = 0.034) as factors indicative of the occurrence of Segond fracture. LM injury without MM injury suggested the existence of a Segond fracture. CONCLUSION: LM injury without a MM injury indicated the occurrence of a Segond fracture. Higher body mass index also increased the risk for Segond fracture occurrence.

BACKGROUND: In quantitative ankle stress sonography, different examiners use different techniques, which may cause measurement variability. This study aimed to clarify whether standardizing stress sonography techniques reduces variability in the quantitative measurement of anterior talofibular ligament length change. METHODS: Fourteen examiners with a mean ultrasound experience of 8.7 years participated in this study. Each examiner performed stress ultrasonography of the ankle using their preferred method on one patient with an intact anterior talofibular ligament (Patient 1) and on two patients with chronic ankle instability (Patient 2 and 3). Changes in the ligament length between the resting and stressed positions were determined. A consensus meeting was then conducted to standardize the sonographic technique, which was used by the examiners during a repeat stress sonography on the same patients. The variance and measured values were compared between the preferred and standardized techniques using F-tests and paired t-tests, respectively. RESULTS: At a consensus meeting, a sonographic technique in which the examiner pushed the lower leg posteriorly against the fixed foot was adopted as the standardized technique. In Patient 1, the change in the anterior talofibular ligament length was 0.4 (range, -2.3-1.3) mm and 0.6 (-0.6-1.7) mm using the preferred and standardized techniques, respectively, with no significant difference in the variance (P = 0.51) or the measured value (P = 0.52). The length changes in Patient 2 were 2.0 (0.3-4.4) mm and 1.7 (-0.9-3.8) mm using the preferred and standardized techniques, respectively. In Patient 3, the length changes were 1.4 (-2.7-7.1) mm and 0.7 (-2.0-2.3) mm. There were no significant differences between the techniques in either patient group. CONCLUSION: Variability in the quantitative measurement of ankle stress sonography was not reduced despite the standardization of the technique among examiners. Hence, comparing the measured values between different examiners should be avoided.

BACKGROUND: Placement of clamp forceps along the transsyndesmotic (TS) axis reduces the risk of iatrogenic syndesmotic malreduction during ankle fracture surgery with tibiofibular diastasis. This study aimed to measure the difference between the TS axis and the axis determined by an intraoperative fluoroscopic technique using the center-center (CC) method. We also compared the values obtained when the CC method was performed at different heights from the tibial plafond. METHODS: We evaluated the computed tomography scans of 150 patients with normal syndesmosis. The CC method was simulated using digitally reconstructed radiographs. The TS and CC axes were projected onto an axial computed tomographic image linked to digitally reconstructed radiography. The angle between the two axes (interaxis angle) and the distance between the intersection of these axes and the medial tibial cortex (interaxis distance) were measured. The procedures were performed 0, 10, and 20 mm proximal to the tibial plafond, and the measurements were compared among the different heights using a 1-way repeated-measures analysis of variance. RESULTS: The TS axis was found to be externally rotated to the CC axis, with an interaxis angle of 8.5 degrees (SD, 6.8 degrees). The interaxis angle increased from 1.9 degrees at a height of 0 mm to a greater angle at higher heights (P < .001). The overall interaxis distance was 7.7 (SD, 6.3) mm, increasing from 2.0 mm at a height of 0 mm to a greater distance at higher heights (P < .001). CONCLUSION: The TS axis was externally rotated relative to the CC axis, and the difference between the 2 axes was greater when the CC method was performed on the higher heights from the tibial plafond. To clamp the syndesmosis along the TS axis, the CC method should be applied close to the ankle joint. LEVEL OF EVIDENCE: Level IV, case series.

BACKGROUND: This study aimed to quantify the readability and quality of online patient resources on knee osteoarthritis and lumbar spinal stenosis in Japan. METHODS: Three search engines (Google, Yahoo, and Bing) were searched for the terms knee osteoarthritis and lumbar spinal stenosis. The first 30 websites of each search were screened. Duplicate websites and those unrelated to the searched diseases were excluded. The remaining 125 websites (62 on knee osteoarthritis, 63 on lumbar spinal stenosis) were analyzed. The text readability was assessed using two web-based programs (Obi-3 and Readability Research Lab) and lexical density. Website quality was evaluated using the DISCERN score, Clear Communication Index, and Journal of American Medical Association benchmark criteria. RESULTS: Readability scores were high, indicating that the texts were difficult to understand. Only 24 (19%) and six (5%) websites were classified as average difficulty readability according to Obi-3 and Readability Research Lab, respectively. The overall quality of information was low, with only four (3%) being rated as having sufficient quality based on the Clear Communication Index and Journal of American Medical Association benchmark criteria. None of the websites satisfied the DISCERN quality criteria. CONCLUSIONS: Patient information on Japanese websites regarding knee osteoarthritis and lumbar spinal stenosis were difficult to understand. Moreover, the quality of the websites was insufficient. Orthopaedic surgeons should contribute to the creation of high-quality easy-to-read websites to facilitate patient-physician communication.

INTRODUCTION: We aimed to evaluate the associations of sports participation with self-rated health and depressive symptoms in a nationally representative sample of Japanese adolescents. METHODS: A questionnaire survey was conducted with 1,658 adolescents aged between 12 and 21 years. Sports participation levels were divided into high-frequency, moderate-frequency, low-frequency, and no-participation groups. Self-rated health was evaluated using a four-grade scale. Depressive symptoms were assessed using the Japanese version of the Patient Health Questionnaire-8. Other lifestyle behaviors were also surveyed. The associations of sports participation with self-rated health and depressive symptoms were examined using multiple logistic regression analysis. RESULTS: The participants in the high- (odds ratio (OR), 0.45) and moderate-frequency (OR, 0.46) groups were less likely to self-report poor health than those in the non-participation group. By contrast, a U-shaped association was found between sports participation and depression, in which the participants in the moderate-frequency group (OR, 0.52) were less likely to have depressive symptoms. The OR for the high- (0.89) and low-frequency (0.91) groups were not significant. Furthermore, eating regular breakfasts, six or more days/week, and having shorter screen times of less than two hours/day were negatively associated with poor self-reported health and depressive symptoms. CONCLUSION: Moderate- to high-frequency sports activities are associated with a reduced risk of poor self-rated health among Japanese adolescents. However, only moderate-frequency activities were associated with a reduced risk of depression. Participation in optimal sports activities may effectively lower the risk of poor health in adolescents.

Background In recent years, advances in the treatment of malignant tumors have improved life expectancy and diversified treatment options. However, maintaining high activities of daily living in patients is essential for appropriately treating the primary disease, and interventions for patients with impaired motor function will lead to improved quality of life. Here, we compared the muscle mass of malignant tumor patients who are visiting bone metastasis outpatient clinics with that of healthy subjects. Methods We compared the muscle mass of 61 malignant tumor patients with an Eastern Cooperative Oncology Group (ECOG) performance status ≤ 2 (mean 66.3 ± 12.0 years; 30 males and 31 females) attending our bone metastasis outpatient clinic since 2018 with that of 315 healthy subjects (mean 65.0 ± 17.7 years; 110 males and 205 females). Body mass index, skeletal muscle mass, and body fat percentage were assessed by bioimpedance analysis, and the skeletal muscle mass index (SMI) was calculated. Results To eliminate age bias in the malignant tumor patients and healthy subjects, 1:1 propensity score matching was performed separately for males and females. There was no significant difference in right upper limb, left upper limb, right lower limb, or left lower limb mass or SMI between the two groups, whereas trunk muscle mass and muscle mass were significantly higher in the healthy females compared with malignant tumor females. Conclusion There was no significant difference in the SMI measured by bioimpedance analysis between the two groups in either males or females, while muscle mass and trunk muscle mass were significantly lower in female malignant tumor patients than in healthy subjects. These results suggest that even malignant tumor patients whose performance status was maintained enough to allow outpatient visits still had impaired motor function.

Mechanical overload and chemical factors are both related to obesity-induced progression of knee osteoarthritis. The circadian rhythm is related to the development of metabolic syndrome and the progression of osteoarthritis, and the core clock genes nuclear receptor subfamily 1 group D member 1 (NR1D1) and brain and muscle arnt-like protein 1 (BMAL1) are dysregulated in cartilage from patients with osteoarthritis. Here, we focused on NR1D1 and investigated osteoarthritis-related changes and gene expression in a mouse model of diet-induced obesity. A high-fat diet was provided to C57BL6/J mice, and changes in body weight, blood lipids, and gene expression were investigated. Destabilization of the medial meniscus or sham surgery was performed on mice fed a high-fat diet or normal diet, and histological osteoarthritis-related changes and NR1D1 expression were investigated. The effects of the NR1D1 agonist SR9009 were also assessed. Mice fed a high-fat diet developed significant obesity and dyslipidemia. Nr1d1 and Bmal1 gene expression levels decreased in the liver and knee joints. Moreover, increased osteoarthritis progression and decreased NR1D1 protein expression were observed in high-fat diet-fed mice after surgical osteoarthritis induction. SR9009 decreased the progression of obesity, dyslipidemia, and osteoarthritis. Overall, obesity and dyslipidemia induced by the high-fat diet led to osteoarthritis progression and decreased NR1D1 expression. Thus, NR1D1 may play an important role in obesity-induced osteoarthritis.

BACKGROUND: Lower limb flexibility (LLF) is an essential motor function. However, assessing LLF during adolescence is difficult because of the influence of marked physical changes. We, therefore, assessed LLF and investigated the relationship between LLF and sex and age in healthy children and adolescents. METHODS: We conducted a five-year cross-sectional study with students aged 8-14 years at a single school in Japan. We evaluated the heel-buttock distance (HBD), straight leg raising angle (SLRA), and dorsiflexion angle of the ankle joint (DFA) at the beginning of each year. We conducted a comparative analysis on the performance of the HBD, SLRA, and DFA techniques, stratified by both sex and age. The statistical significance of observed differences was assessed through the application of Mann-Whitney U and Kruskal-Wallis tests. Furthermore, we analyzed the effects of sex, age, height, and weight on LLF using a multivariable linear regression model. RESULTS: Of the 4221 initial study participants, 3370 were analyzed. Mean HBD, SLRA, and DFA values were 1.6 cm, 77.0°, and 15.7°, respectively. Girls showed significantly higher HBD and lower SLRA and DFA values than boys and 14-year-olds (p < 0.01). Median HBD value for girls was 0 cm, whereas for boys, it exceeded 0 cm after age 13. The median SLRA value for girls was 80-85°, while for boys, it was 70-75°. The median DFA value for girls was 15-19°, and for boys, it was 12-15°. A multivariable linear regression model indicated that boys had significantly greater tightness than girls (p < 0.01). CONCLUSIONS: The reference values of HBD, SLRA, and DFA differed according to age and sex. Furthermore, we showed that sex differences were significantly associated with LLF. Data in this study provide the reference value for assessing LLF in children and adolescents.

We report a 15-year-old female patient who sustained peroneus brevis injury caused by an impingement between the hypertrophied peroneal tubercle and lateral malleolus. The patient had pain for 3 years in the lateral side of her left ankle with unsuccessful conservative treatment. The oblique sagittal images of 3-dimensional magnetic resonance imaging and ultrasonography were useful in depicting the peroneus brevis injury and identifying the location of impingement between the hypertrophied peroneal tubercle and the tip of the lateral malleolus. The flatfoot deformity of the patient further aggravated the impingement. The patient was treated surgically, with excision of the enlarged tubercle and tendon repair. The ankle pain resolved 12 months postoperatively. Although rare, clinicians should recognize this condition as the cause of lateral ankle pain.

BACKGROUND: This study aimed to clarify the variability in the measurements of stress sonography of the ankle and determine the effects of examiner experience on the measurements. METHODS: Twenty examiners (10 experienced and 10 beginners) were included in the study. Each examiner performed stress ultrasonography on a patient with a chronic anterior talofibular ligament injury and a patient with an intact ligament using the reverse anterior drawer method. Changes in ligament length before versus after stress were determined. The same 20 examiners performed ultrasonography on two other patients with an injured or intact ATFL using the anterior drawer method. The length change values and variance were compared between the groups using t-tests and F-tests. RESULTS: Using the reverse anterior drawer method, the change in the anterior talofibular ligament length was 3.3 mm (range, 2.2-4.8 mm) in the experienced group and 2.7 mm (0.0-4.1 mm) in the beginner group for the ligament injured patient. The length changes for the patient with intact anterior talofibular ligament were 0.5 mm (0.1-0.9 mm) and 0.4 mm (-0.1-1.5 mm) in the experienced and beginner groups, respectively. There were no significant intergroup differences in measurement amount (P = 0.37) or variance (P = 0.72). Similarly, using the anterior drawer method, no significant differences between the groups were found in measurement amount or variance. CONCLUSION: The quantitative evaluation of stress sonography of the ankle was variable regardless of examiner experience or stress method, particularly in patients with an anterior talofibular ligament injury. The amount of variability appeared to be unacceptably large for clinical application. Our study results highlight the need for technical standardization.

OBJECTIVES: This study aimed to characterize the content of frequently asked questions about the treatment of rheumatoid arthritis (RA) on the internet in Japan and to evaluate the quality of websites related to the questions. METHODS: We searched terms on the treatment of RA on Google and extracted frequently asked questions generated by the Google "people also ask" function. The website that answered each question was also obtained. We categorized the questions based on the content. The quality of the websites was evaluated using the brief DISCERN, Journal of American Medical Association benchmark criteria, and Clear Communication Index. RESULTS: Our search yielded 83 questions and the corresponding websites. The most frequently asked questions were regarding the timeline of treatment (n = 17, 23%) and those on the timeline of the clinical course (n = 13, 16%). The median score of brief DISCERN was 11 points, with only 7 (8%) websites having sufficient quality. Websites having sufficient quality based on the Journal of American Medical Association benchmark criteria and Clear Communication Index were absent. CONCLUSIONS: The questions were most frequently related to the timeline of treatment and clinical course. Physicians should provide such information to patients with RA in the counseling and education materials.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic has had a profound impact on children's lifestyles. Some studies have reported psychological changes in children after the pandemic, but information on musculoskeletal problems is scarce. This study aimed to investigate the incidence of knee pain and changes in physical activity after the spread of COVID-19 among elementary and junior high school students in Japan. METHODS: Knee pain and amount of physical activity were recorded on a monthly basis between August 2019 and February 2021 in children aged 8-14 years using a self-administered questionnaire. The amount of physical activity was scored using the Hospital for Special Surgery Pediatric Functional Activity Brief Scale (HSS Pedi-FABS). The period until February 2020 was defined as "Before pandemic," and the period from March 2020 was defined as "After pandemic." The incidences of knee pain and HSS Pedi-FABS scores before and after the COVID-19 pandemic were compared. Additionally, we compared the prevalence of knee pain and HSS Pedi-FABS scores according to sex and age. RESULTS: We enrolled 886 and 881 participants before and after the pandemic, respectively. The prevalence of knee pain among the participants before and after the pandemic was 6.7% and 7.9%, respectively (p = 0.032). The mean HSS Pedi-FABS scores before and after the pandemic were 14.8 and 14.5, respectively (p = 0.005). Participants aged 14 years had a significantly lower incidence of knee pain (p = 0.013) and significantly higher HSS Pedi-FABS scores (p < 0.001) after the spread of COVID-19. CONCLUSIONS: In elementary and junior high school students, increase in the incidence of knee pain and decrease in the amount of physical activity after the spread of COVID-19 were observed.

BACKGROUND: The development of computer-assisted technologies to diagnose anterior cruciate ligament (ACL) injury by analyzing knee magnetic resonance images (MRI) would be beneficial, and convolutional neural network (CNN)-based deep learning approaches may offer a solution. This study aimed to evaluate the accuracy of a CNN system in diagnosing ACL ruptures by a single slice from a knee MRI and to compare the results with that of experienced human readers. METHODS: One hundred sagittal MR images from patients with and without ACL injuries, confirmed by arthroscopy, were cropped and used for the CNN training. The final decision by the CNN for intact or torn ACL was based on the probability of ACL tear on a single MRI slice. Twelve board-certified physicians reviewed the same images used by CNN. RESULTS: The sensitivity, specificity, accuracy, positive predictive value and negative predictive value of the CNN classification was 91.0%, 86.0%, 88.5%, 87.0%, and 91.0%, respectively. The overall values of the physicians' readings were similar, but the specificity was lower than the CNN classification for some of the physicians, thus resulting in lower accuracy for the human readers. CONCLUSIONS: The trained CNN automatically detected the ACL tears with acceptable accuracy comparable to that of human readers.

BACKGROUND: Patellar and patellar tendon pain is a common limitation to children's participation in social and physical activities. Some factors have been implicated in the occurrence and protraction of knee pain, but the causal relationship is unknown. The purpose of this study was to investigate whether participants' physical characteristics and activity level are risk factors for the occurrence and protraction of patellar and patellar tendon pain in children and adolescents. METHODS: A three-year prospective cohort study was conducted with healthy students who were aged 8-14 years old, in Japan. Height, weight, heel-buttock distance, straight leg raising angle, and dorsiflexion angle of the ankle joint were collected as individual physical factors at the beginning of each year. The presence of self-reported patellar and patellar tendon pain and the Hospital for Special Surgery Pediatric Functional Activity Brief Scale (HSS Pedi-FABS) was collected every month. Protraction was defined as either (1) pain lasting for more than three continuous months or (2) recurrent pain after more than three months of complete recovery. Participants who did not have any pain at the beginning of the observation period were included in the analysis. We analyzed the odds ratio (OR) of pain occurrence within a year of registration and protraction throughout the study period for all physical factors and HSS Pedi-FABS. RESULTS: We included 1133 participants in the analysis and 252 participants developed knee pain within a year. 34.8% of participants with pain experienced protraction during the follow-up period. A high HSS Pedi-FABS significantly predicted knee pain occurrence (OR 1.03, 95% confidence interval [CI] 1.01-1.05) and protraction (OR 1.03, 95% CI 1.00-1.05). In addition, younger children and girls were at a significantly higher risk of patellar and patellar tendon pain protraction (age, OR 0.81, 95% CI, 0.73-0.90; sex, OR 1.69, 95% CI, 1.09-2.64). Other physical factors did not significantly predict the occurrence or protraction of knee pain. CONCLUSIONS: This study showed that a greater physical activity level was a risk factor for the occurrence and protraction of patellar and patellar tendon pain in childhood. In addition, younger age and female sex predicted higher risk of protraction of pain.

type:text [ABSTRACT]【Objectives】Radial tears of the lateral meniscus are difficult to treat because the circumferential fibers that constitute the meniscal body are torn, and simple sutures intended to maintain both ends of the torn sites can easily slip and cut out. To overcome this, we developed a new suture construct to fix the radial tear in the meniscus. In this study, we examined the biomechanical properties of a new suture construct using a 6-degree-of-freedom (DOF) robotic system and a porcine knee.【Methods】Five intact fresh frozen porcine knees and a 6-DOF robotic system was used in this study. First, we investigated whether a radial tear of the lateral meniscus would reduce the resultant force. Second, we investigated whether meniscal sutures would improve the resultant force. We also investigated the differences in the tibial shift and rotation.【Results】The resultant force with a radial tear was significantly smaller than that with an intact meniscus, and the novel sutures and horizontal sutures improved the resultant force. The tibia shifted medially and posteriorly at 30° of knee flexion and medially at 45° of knee flexion with a radial tear below the 5 Nm valgus torque. Significant improvement was observed with the meniscus suture. Furthermore, the tibia rotated the valgus with a radial tear and improved with a meniscus suture under the 5 Nm valgus torque.【Conclusions】Our new suture method may provide new insights into treatment of radially torn lateral meniscus with a minimum number of sutures.

OBJECTIVE: To elucidate the time course of magnetic resonance imaging (MRI)-based morphological and qualitative outcomes after an atelocollagen-assisted autologous chondrocyte implantation (ACI) and to analyze the correlation between arthroscopic and MRI-based assessment. DESIGN: We included ACI recipients from a multicenter registration study (CaTCh [Cartilage Treatment in Chiba] study). Morphological (3-dimensional magnetic resonance observation of cartilage repair tissue: 3D-MOCART, MOCART2.0) and qualitative assessment (T2- and T1rho-mapping) by MRI were conducted at 6, 12, and 24 months post-implantation. Global T2 and T1rho indices (T2 and T1rho in repair tissue divided by T2 and T1rho in normal cartilage) were calculated. Arthroscopic second-look assessment was performed in 4 and 15 knees at 12 and 24 months post-implantation, respectively. RESULTS: The 3D-MOCART over 12 months witnessed significant patient improvement, but some presented subchondral bone degeneration as early as 6 months. The MOCART2.0 improved from 57.5 to 71.3 between 6 and 24 months (P = 0.02). The global T2 index decreased from 1.7 to 1.2 between 6 and 24 months (P < 0.001). The global T1rho index decreased from 1.5 to 1.3 between 6 and 24 months (P = 0.004). Normal or nearly normal ICRS-CRA (cartilage repair assessment scale developed by the International Cartilage Repair Society) grades were achieved in 86% and 93% of the lesions at 12 and 24 months, respectively. Better ICRS-CRA grade corresponded to better MOCART2.0, with no trend in the T2 and T1rho values. CONCLUSIONS: Atelocollagen-assisted ACI improved the MRI-based morphological and qualitative outcomes until 24 months post-surgery, and normal or nearly normal grades were achieved in most lesions by arthroscopic assessment. MRI assessment may be an alternative to arthroscopic assessment.

<title>Abstract</title><sec> <title>Background</title> The evaluation of postoperative total knee arthroplasty (TKA) alignment mainly relies on measurement data obtained from plain radiographs. The aim of this retrospective observational study was to document the intra- and inter-observer reliability in assessment of TKA component positioning after surgery using a three-dimensional (3D) computed tomography (CT) image matching system. </sec><sec> <title>Methods</title> Fourteen knees from 14 patients who received primary TKA were included, and images were analyzed by blinded readers not associated with the surgeries. The examiner digitized the reference points according to defined landmarks, and the designated size component was superimposed to the 3D reconstructed CT model for measurement. In addition to the evaluation of implant position against the coronal and sagittal lower limb mechanical axes that were defined based on bony landmarks, implant position against axes connecting implant-based reference points that are easier to indicate was evaluated. </sec><sec> <title>Results</title> The overall intra- and inter-observer reliabilities determined by the intraclass correlation coefficients (ICC) of the implant alignment measurement for both femoral and tibial components were good (ICC &gt; 0.60), except in the direction of femoral flexion and extension, for both mechanical and implant-based axes. The difference between implant alignment measurements according to the traditional mechanical axis and the implant-based axis ranged between means of 0.08^o and 1.70^o and were statistically significantly different. </sec><sec> <title>Conclusions</title> The postoperative evaluation of implant position in the coronal and sagittal planes using 3D-CT image matching is reliable and has good reproducibility except for the sagittal alignment assessment of the femoral component. The measured implant position according to the traditional mechanical axis and the implant-based axis were slightly but significantly different. </sec>

Background: Thus far, the clinical results of anterior cruciate ligament (ACL) reconstruction have been observed to be comparable between young and older patients. In contrast, age-related changes in the structural and mechanical properties of tendons used for autografts have been described. However, age-related changes associated with graft maturation remain poorly understood. Hypotheses: The hypotheses of this study were that (1) clinical outcomes after ACL reconstruction would be comparable between younger and relatively older patients and (2) younger patients would show lower signal intensity changes on magnetic resonance imaging scans indicative of graft maturation that would be better than that in relatively older patients. Study Design: Cohort study; Level of evidence, 3. Methods: We retrospectively evaluated 236 patients who underwent double-bundle ACL reconstruction via the outside-in technique using hamstring autograft between January 2012 and December 2015. The patients were categorized by age into 3 groups: &lt;20 years old, 20 to 39 years old, and ≥40 years old. Clinical outcomes were evaluated using the subjective International Knee Documentation Committee (IKDC) score, Tegner activity scale, Lysholm score, and objective assessment of joint laxity 24 months after surgery. In addition, graft maturation was evaluated using magnetic resonance imaging–derived measures of the signal intensity ratio (SIR) at 3, 6, 12, and 24 months postoperatively. Clinical outcomes and graft maturation were compared among the 3 groups. Results: The SIR of both bundles increased from 3 months to 12 months and decreased by 24 months, showing the same tendency in all groups. No significant difference was found in the SIR among the 3 groups at any time point ( P &gt; .05). The IKDC score was significantly lower in the ≥40-year group than in the &lt;20-year group ( P &lt; .01). In contrast, no significant differences were noted in other clinical outcomes. Conclusion: Patients aged ≥40 years exhibited lower IKDC scores compared with younger patients, although the results of graft maturation were comparable.

BACKGROUND: Abnormal foot morphology in children and adolescents is a possible risk factor for lower extremity pain. Foot posture index-6 (FPI-6) is a valid and reliable tool to assess foot morphology. However, the normative data on the age distribution for FPI-6 in Asian children and adolescents are still minimal. Further, the correlation of FPI-6 with lower extremity pain is poorly understood. We aimed to investigate the normative distribution for FPI-6 and the relationship between FPI-6 scores and knee and heel pain in Japanese children. METHODS: We included 2569 Japanese children, aged 9-15 years, at a single school from 2016 to 2018. We summarized the age distribution of children and their mean bilateral FPI-6 scores. Additionally, we assessed the tenderness at the apophysis or tendon insertions at the knee and heel. We performed a cross-sectional analysis to investigate the correlations between FPI-6 scores and sex, age, and knee and heel pain for the data obtained each year. RESULTS: The mean FPI-6 score was 3.1 ± 2.4, 3.4 ± 2.0, and 3.2 ± 1.9 for the left foot and 3.0 ± 2.4, 3.2 ± 1.9, and 3.1 ± 1.9 for the right foot in 2016, 2017, and 2018, respectively. Boys tended to have higher scores than girls, and the FPI-6 score of the left foot was significantly higher than that of the right foot (p < 0.05). There was no correlation between FPI-6 scores and knee and heel pain. CONCLUSION: Children and adolescents between 9 and 15 years of age have neutral to slightly pronated foot morphology and an average FPI-6 score of 3.0-3.4. In addition, there was no relationship between foot morphology and knee and heel pain. This normative distribution for FPI-6 in Japanese children could serve as a reference value for future research and clinical evaluation.