木村 青児

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.

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: 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.

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.

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.

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 Hospital for Special Surgery Pediatric Functional Activity Brief Scale (HSS Pedi-FABS) is a specifically designed scoring system for children and has been translated into several languages. However, to date, no validated Japanese version of this scoring system is available. PURPOSE: To translate the HSS Pedi-FABS into Japanese and assess its reliability and validity. STUDY DESIGN: Cohort study (diagnosis); Level of evidence, 2. METHODS: The HSS Pedi-FABS was translated into Japanese and back-translated into English to confirm the appropriateness of the translation. A total of 764 children aged 9 to 15 years participated in the validation study. The participants answered the Japanese version of the HSS Pedi-FABS along with 2 other questionnaires in Japanese (the Physical Activity Questionnaire for Older Children [PAQ-C] and the physical activity questionnaire of the World Health Organization's Health Behavior in School-aged Children [HBSC PAQ]). At 1 month after the first assessment, the children answered the Japanese version of the HSS Pedi-FABS again. We evaluated reliability using the Cronbach alpha and the intraclass correlation coefficient. Validity was evaluated by quantifying floor and ceiling effects, correlations between the HSS Pedi-FABS and the PAQ-C, the HSS Pedi-FABS discrepancy between active and inactive groups divided by the HBSC PAQ, and correlation between the HSS Pedi-FABS and body mass index. RESULTS: HSS Pedi-FABS scores were slightly but significantly higher in male participants (mean = 16.7) than in female participants (mean = 13.2). The Cronbach alpha coefficient was .90, and the intraclass correlation coefficient value was 0.90, indicating excellent internal consistency and test-retest reliability, respectively. No floor (2.6%) or ceiling effect (1.0%) was observed. The HSS Pedi-FABS was significantly correlated with the PAQ-C (r = 0.70). The active group demonstrated a significantly higher score on the HSS Pedi-FABS (mean = 18.9) than did the inactive group (mean = 11.2). In terms of discriminative validity, the HSS Pedi-FABS was not correlated with body mass index (r = -0.15). CONCLUSION: The Japanese version of the HSS Pedi-FABS demonstrated appropriate reliability and validity, indicating that it is a useful tool to assess physical activity levels in Japanese children.

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.

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.

<sec><title>Background:</title> Nationwide epidemiologic studies in Scandinavian countries have shown that the incidence of Achilles tendon ruptures (ATRs) has increased, and the rate of surgical treatment has declined markedly in the past decade. However, there is a lack of national-level data on the trend of ATRs and surgical procedures in other regions. </sec><sec><title>Purpose:</title> To clarify the trend in the incidence of ATRs and the proportion of surgery using the nationwide health care database in Japan. </sec><sec><title>Study Design:</title> Descriptive epidemiology study. </sec><sec><title>Methods:</title> Age- and sex-stratified data on the annual number of ATRs and surgical procedures between 2010 and 2017 were obtained from the Japanese national health care database, which includes almost all inpatient and outpatient medical claims nationwide. The Japanese population data were also obtained from the population census. The change in the annual incidence of ATRs per 100,000 people was assessed using a Poisson regression analysis. The trend in the annual proportion of surgeries relative to the occurrence of tendon ruptures was determined using a linear regression analysis. </sec><sec><title>Results:</title> A total of 112,601 ATRs, with men accounting for 67%, were identified over 8 years. Patients aged ≥60 years accounted for 27,106 (24%), while those aged 20 to 39 years and 40 to 59 years accounted for 36,164 (32%) and 49,331 (44%), respectively. The annual incidence of ATR ranged from 12.8/100,000 to 13.9/100,000 (women, 8.2-8.9/100,000; men, 17.2-19.5/100,000), which did not change over the study period ( P = .82). Moreover, the annual incidences did not change across sexes and age categories. The annual proportion of surgery increased significantly, from 67% in 2010 to 72% in 2017 ( P = .003). The annual proportions increased across sexes and age categories except for women aged 40 to 59 years. </sec><sec><title>Conclusion:</title> The incidence of ATR did not change between 2010 and 2017, according to the Japanese nationwide health care database. Furthermore, the proportion of surgical treatment increased during the study period. Overall, 70% of patients underwent surgical treatment. This study suggested that the trend in ATR and surgery differed across regions. </sec>

INTRODUCTION: Unicompartmental knee arthroplasty (UKA) and high tibial osteotomy (HTO) are established treatments for medial compartment osteoarthritis (OA) or osteonecrosis (ON) of the knee joint, and the predominance of either procedure is inconclusive. We compared the awareness of the knee after UKA and HTO using the Forgotten joint score-12 (FJS). MATERIALS AND METHODS: This was a retrospective, multicenter study. Ninety-six knees of 90 patients who received UKA or HTO and were followed-up for at least 1 year were analyzed. Postoperative FJS was compared between the two groups and evaluated for the effect of patient-related factors and clinical outcomes. Multiple linear regression analysis was performed to predict FJS. RESULTS: There was no significant difference in the FJS between the UKA and HTO groups (p = 0.24). FJS did not correlate with any of the patient-related factors. There was a correlation between the FJS and each item of the Knee Injury and Osteoarthritis Outcome Scores (KOOS) and Lysholm Knee Scoring Scale (LKS). In multiple linear regression analysis, lower BMI, the diagnosis of OA Kellgren-Lawrence (KL) grade ≥ 3, and ON were significant predictors of better FJS. In both groups, FJS was correlated with each item of the KOOS and LKS. Internal consistency in terms of Cronbach's alpha was excellent. CONCLUSIONS: There was no significant difference in FJS between patients who underwent UKA and HTO. Lower BMI, the diagnosis of OA KL grade ≥ 3, and ON were significant predictors of better FJS.

OBJECTIVE: Cartilage lesions in the knee joint can lead to joint mechanics changes and cause knee pain. Bone marrow stimulation (BMS) promotes cartilage regeneration by perforating the subchondral bone just below the injury and inducing bone marrow cells. This study aimed to investigate whether systemic administration of granulocyte colony-stimulating factor (G-CSF) with BMS improves repair of chronic partial-thickness cartilage defects (PTCDs). DESIGN: Eighteen 6-month-old New Zealand white rabbits were divided into 3 groups: control (C, n = 6), BMS alone (n = 6), and BMS + G-CSF (n = 6). Partial cartilage defects with 5 mm diameter were created in the trochlear region of both knees; after 4 weeks, the BMS alone and BMS + G-CSF groups underwent BMS; G-CSF (50 µg/kg) or saline was administered subcutaneously for 5 days starting from 3 days before BMS. At 8 and 16 weeks after cartilage defect creation, the area of cartilage defects was macroscopically and histologically evaluated. RESULTS: International Cartilage Repair Society (ICRS) grades for macroscopic assessment were 0, 0.7, and 0.7 at 8 weeks and 0, 1.2, and 1.3 at 16 weeks in the C, BMS, and BMS + G-CSF groups, respectively. Wakitani scores for histological assessment were 9.8, 8.7, and 8.2 at 8 weeks and 9.5, 9, and 8.2 at 16 weeks in the C, BMS, and BMS + G-CSF groups, respectively. The BMS + G-CSF group showed significantly more repair than the C group, but there was no difference from the BMS group. CONCLUSIONS: The effect of BMS and G-CSF on chronic PTCDs in mature rabbit knees was limited.

BACKGROUND: Evaluation over time is important in assessing the reduction of the syndesmosis after suture-button fixation for ankle malleolar fractures. The purposes of this study were to evaluate time-dependent change in the syndesmotic reduction immediately after suture-button fixation for ankle malleolus fractures and 1 year after surgery using computed tomography, and to investigate the reliability of the measurement values to evaluate the reduction of syndesmosis. METHODS: We assessed 28 patients who underwent suture-button fixation for ankle fractures. Syndesmotic reduction was assessed within 2 weeks of the fracture surgery and 1 year after surgery using axial computer tomographic images. Side-to-side differences in the anterior, central, and posterior tibiofibular distances, anteroposterior fibular translation, fibular rotation, and syndesmosis area were measured. RESULTS: The mean anterior tibiofibular distance and anteroposterior fibular translation were 1.8 mm and 1.5 mm, respectively, after syndesmotic fixation. They decreased to 1.2 mm and 0.6 mm, respectively, at 1 year after surgery (P = .03 and P = .01, respectively). The other measurement values did not change over time. The minimum detectable change in the distance of measurements was 1 mm or less. CONCLUSION: The anterior tibiofibular distance and anteroposterior fibular translation had decreased 1 year after fixation in ankle malleolar fractures with syndesmotic suture button. Even if the fibula is posteriorly malreduced by the time computed tomography is performed immediately after surgery, the fibula may return to a good position 1 year after surgery. LEVEL OF EVIDENCE: Level IV, case series.

Background: To investigate in vivo kinematics of total knee arthroplasty (TKA) with the introduction of a mildly constrained (MC) type of polyethylene (PE). We compared the knee kinematics with a reported pattern after surgery using the same component with a conventionally constrained (CC) type of PE. Methods: Finite element analysis (FEA) was performed to examine different peak stress distribution of both types of PE. For in vivo study, patients who underwent cruciate-retaining TKA using a total knee system with MC-PE were included. Fluoroscopic surveillance was used to measure the weight-bearing deep knee bend (squatting) using a two-dimensional/three-dimensional (2-D/3-D) registration technique. Results: FEA analysis revealed the edge loading of the femoral component on PE in CC but not in MC. During the study period, 42 patients underwent TKA with MC-PE. Among them, 13 agreed to participate in the present study. In vivo kinematics analysis found that starting from an average external rotation of femur being 7.1° at 0° of flexion, the rotation slightly decreased to 6.8° at 10° of flexion, then increased with increasing knee flexion until it reached 10.8° at 80° of flexion, and finally decreased to 9.8° at 100° of knee flexion. The results indicate a modest medial pivot pattern. Although the overall pattern was similar for both MC-PE and CC-PE, a slight difference was observed. MC-PE showed a slight internal rotation of 0.3° from 0 to 10° of knee flexion, whereas CC-PE showed a gradual increase of external rotation in this range. Conclusions: Change of configuration from CC to MC did not substantially affect in vivo kinematics of knees after TKA. Considering the theoretical wider range of allowance of rotation, MC-PE is easier for knee surgeons to use.

BACKGROUND: The purpose of this study was to clarify the incidence rate and the risk factors for the progression of the hallux valgus deformity. METHODS: Patients who had weight-bearing radiographs of the foot taken twice or more, with a ≥2-year interval, were retrospectively analyzed. Progression of the deformity was defined as an increase in the hallux valgus angle of ≥5° during the follow-up. The association of hallux valgus progression with patient characteristics and radiographic measurements at baseline was determined using univariate and multivariate analyses. RESULTS: Totally, 268 patients (217 women and 51 men; median age, 64 years) were analyzed. An increase in the hallux valgus angle of ≥5° occurred in 44 (17%) patients in a median follow-up of 49 months. Large hallux valgus angle (odds ratio, 1.07) on the dorsoplantar radiograph at baseline were independent risk factors for the progression of the deformity. CONCLUSION: Progression of the hallux valgus deformity occurred in one of six patients. Furthermore, large hallux valgus angle was the risk factor for subsequent deformity progression. Patients with large hallux valgus angle should be informed about the possible progression of the deformity.

BACKGROUND: The purpose of this study was to compare physical activity levels and the proportion of patients who met physical activity recommendations in patients with ankle osteoarthritis and controls. METHODS: Ankle osteoarthritis patients (n = 50) and controls (n = 50) were recruited. physical activity was measured using an accelerometer-based monitor. Physical activity parameters, including the step count/day, the proportion of patients who met physical activity recommendations of ≥7000 steps/day, and moderate to vigorous physical activity minutes/day, were compared between the patient groups. RESULTS: The patients with ankle osteoarthritis walked 3998 steps/day, while the controls walked 6531 steps/day (P < .001). Only 7 (14%) ankle osteoarthritis patients and 17 (34%) controls met the physical activity recommendations of ≥7000 steps/day (P =  .01). Time spent performing moderate to vigorous physical activity was 58 and 78 min/day in the ankle osteoarthritis and controls, respectively. CONCLUSIONS: The physical activity level of ankle osteoarthritis patients was lower than that of controls. Only a limited proportion of ankle osteoarthritis patients met the physical activity recommendation.

Background: Osteochondritis dissecans (OCD) rarely occurs in multiple joints. Furthermore, the existence of left-right asymmetric OCDs in different joints of the contralateral side of the body and lesions occurring with a temporal difference is rare. Here, we report a rare case with multiple OCDs sequentially detected in various joints. Case Presentation. The 15-year-old male patient was referred to our hospital for an OCD in the medial femoral condyle of the left knee. He had a history of an OCD in his right elbow, and his father had a history of surgically treated OCDs in both knees. One year and five months after, surgery was performed to the lesion in his left medial femoral condyle, a new OCD lesion occurred in the femoral trochlea of the same knee, which was again treated surgically. Five months after the second surgery, the patient returned with pain in the right knee, and an OCD on the right femoral trochlea was detected by an MRI scan. This lesion remained stable without any further restriction in physical activities for 17 months until detachment occurred and was again treated surgically. Conclusion: In cases with history and a family history of multiple OCDs, in particular, with a short stature, an MRI scan should be performed for the symptomatic joint to detect and treat the lesion before progression.

BACKGROUND: The purpose of this study was to evaluate the associations of the shape of the first metatarsal head with (1) the presence of osteoarthritis in the sesamoid-metatarsal joint and (2) the pronation angle of the first metatarsal head on foot radiographs. METHODS: A total of 121 patients, with the mean age of 61 years, underwent weight-bearing dorsoplantar, lateral, and first metatarsal axial radiographs. The shape of the first metatarsal head's lateral edge was classified as either rounded, intermediate, or angular in shape in the dorsoplantar view. The presence of osteoarthritis in the sesamoid-metatarsal joint and the pronation angle of the first metatarsal head were assessed in the first metatarsal axial view. Other variables that could affect the first metatarsal shape, including the lateral first metatarsal inclination angle, were also assessed. Univariate and multivariate analyses were performed to determine the associations. RESULTS: The prevalence of sesamoid-metatarsal osteoarthritis was significantly higher (77%, 27%, and 29% for rounded, intermediate, and angular, respectively, P < .001), and the metatarsal pronation angle was significantly larger (14°, 8°, and 4° for rounded, intermediate, and angular, respectively, P < .001) in feet with a rounded metatarsal head. These associations were also significant in the multiple regression analysis. CONCLUSION: A rounded metatarsal head was associated with a higher prevalence of osteoarthritis within the sesamoid-metatarsal joint, as well as a larger first metatarsal head pronation angle. A negative round sign can be used as a simple indicator of an effective correction to the first metatarsal pronation angle during hallux valgus surgery. However, in feet with sesamoid-metatarsal osteoarthritis, surgeons will need to be cautious as overcorrection may occur.

BACKGROUND: The purpose of this study was to clarify 1) the measurement error of the pronation angle using the first metatarsal axial radiograph with the pronation angle along the longitudinal axis of the first metatarsal as the reference standard, 2) the influence of variability in the foot position on the measurement error, and 3) the intra- and interrater reliability of pronation angle measurement using digitally reconstructed radiographs. METHODS: Digitally reconstructed radiographs of the first metatarsal were generated from the computed tomography images of 10 feet without hallux valgus (non-HV group) and 10 feet with hallux valgus (HV group). In total, 135 images were created at different degrees of supination, plantarflexion, and adduction from each foot to simulate the first metatarsal axial view. Then, the pronation angle of the first metatarsal was measured. The measurement error was determined using the mean error and 95% limits of agreement. Simple linear regression analysis was used to test the correlations of the measurement error with pronation, plantarflexion and adduction angles. The intra- and interrater reliability of measurement was assessed using the intraclass correlation coefficient and minimum detectable change values. RESULTS: The mean measurement errors were 0.1° for both the non-HV and HV groups. There was no significant correlation of the measurement error with pronation, plantarflexion or adduction angles for both groups. Additionally, the intraclass correlation coefficients for the intra- and interrater reliability were more than 0.9 in both the non-HV and HV groups with the minimum detectable change values ranging from 0.7° to 1.4°. CONCLUSION: The measurement error of first metatarsal pronation using the axial view was clinically acceptable. The measurements were not influenced by the variability in foot position while obtaining the radiograph. The first metatarsal axial view could be used to quantify the first metatarsal coronal rotation.