Investigating the Potential of Multilineage Differentiating Stress-Enduring Cells for Osteochondral Healing.

OBJECTIVE: Multilineage differentiating stress-enduring (Muse) cells, a pluripotent stem cell subset of mesenchymal stem cells (MSCs), have shown promise for various tissue repairs due to their stress tolerance and multipotent capabilities. We aimed to investigate the differentiation potential in vitro, the dynamics in vivo, and the reparative contribution of Muse cells to osteochondral lesions. DESIGN: Labeled MSCs were cultured and sorted into Muse and non-Muse (MSCs without Muse cells) groups. These cells were then formed into spheroids, and chondrogenic differentiation was assessed in vitro. Twenty-one immunocompromised mice were used as the in vivo models of osteochondral lesions. Live imaging, macroscopic evaluation, and histological and immunohistochemical analyses were conducted at the 4- and 8-week time points. RESULTS: Muse cell spheroids were formed, which were larger and stained more intensely with toluidine blue than non-Muse spheroids, indicating better chondrogenic differentiation. Live imaging confirmed luminescence in all 4-week model knees, but only in a few knees at 8 weeks, suggesting cell persistence. Macroscopically and histologically, no significant differences were observed between the Muse and non-Muse groups at 4 and 8 weeks; however, both groups showed better cartilage repair than that of the vehicle group at 8 weeks. No collagen type II generation was observed in the repaired tissues. CONCLUSION: The implantation of the spheroids of Muse and non-Muse cells resulted in better healing of osteochondral lesions than that of the controls, and Muse cells had a higher chondrogenic differentiation potential in vitro than non-Muse cells.

Variability in sonographic anterior drawer test measurements of the ankle: Experienced versus beginner examiners.

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.

Do standardization of the procedure reduce measurement variability of the sonographic anterior drawer test of the ankle?

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.

Internet search analysis on the treatment of rheumatoid arthritis: What do people ask and read online?

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.

Differential Associations of Sports Participation With Self-Rated Health and Depressive Symptoms Among Japanese Adolescents.

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.

Validity of the Center-Center Method for the Syndesmotic Fixation Axis Compared to the Transsyndesmotic Axis.

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.

Referential values for lower limb flexibility in healthy children and adolescents in Japan: A five-year cross-sectional study.

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.

Foot morphology and correlation with lower extremity pain in Japanese children: A cross-sectional study of the foot posture Index-6.

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.

Impact of pain in other body regions on the foot-specific quality of life in patients with hallux valgus.

OBJECTIVES: The purpose of this study was to clarify the prevalence of pain outside the foot, and to determine the associations of pain outside the foot with foot-specific quality of life (QOL) in patients with hallux valgus. METHODS: Patients scheduled to undergo hallux valgus surgery were recruited. Patients answered whether they experienced disabling pain in 13 body regions other than the foot. Foot-specific QOLwas assessed using the Self-Administered Foot Evaluation questionnaire (SAFE-Q). Foot pain was quantified using the visual analogue scale (VAS). Patient characteristics, including age, sex, comorbidity, anxiety, and depression, were also surveyed. The association between pain elsewhere and the SAFE-Q and pain VAS scores were assessed using univariate and multivariate analyses. RESULTS: Of 102 patients, 55 (54%) experienced pain other than the foot. All SAFE-Q subscale scores were lower, and pain VAS was higher in patients with pain elsewhere than in patients without. In the multivariate analysis, an increase in the number of pain regions was independently associated with a decrease in SAFE-Q scores and an increase in pain VAS. CONCLUSION: More than half of the patients with hallux valgus experienced pain elsewhere. The presence of pain elsewhere was associated with poorer foot-specific QOL and severer foot pain.

The influence of COVID-19 pandemic on the incidence of knee pain and physical activity level in children and adolescents in Japan: A prospective observation study.

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.

Nuclear receptor subfamily 1 group D member 1 in the pathology of obesity-induced osteoarthritis progression.

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.

Cross-cultural Adaptation and Validation of the Japanese Version of the Hospital for Special Surgery Pediatric Functional Activity Brief Scale (HSS Pedi-FABS).

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.

Automated detection of anterior cruciate ligament tears using a deep convolutional neural network.

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.

Risk factors for the occurrence and protraction of patellar and patellar tendon pain in children and adolescents: a prospective cohort study of 3 years.

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.

Decreased physical activity in patients with ankle osteoarthritis. A case-control study comparing daily step counts.

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.

Anatomical factors associated with progression of hallux valgus.

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.

Comparison of joint awareness after medial unicompartmental knee arthroplasty and high tibial osteotomy: a retrospective multicenter study.

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.

Increase in Achilles Tendon Rupture Surgery in Japan: Results From a Nationwide Health Care Database.

BACKGROUND: 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. PURPOSE: To clarify the trend in the incidence of ATRs and the proportion of surgery using the nationwide health care database in Japan. STUDY DESIGN: Descriptive epidemiology study. METHODS: 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. RESULTS: 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. CONCLUSION: 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.