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This study aimed to evaluate the relationship between generalized joint laxity (GJL) and stress ultrasonographic (US) findings of the anterior talofibular ligament (ATFL) of healthy young men.The ATFL lengths of healthy young men were consecutively measured in the stress and nonstress positions. The ATFL ratio was calculated as an indicator of lateral ankle laxity. GJL was evaluated using the Beighton score (BS), and a BS of ≥ 5 was considered GJL. The manual anterior drawer test (ADT) was also performed. The results of stress US and ADT were compared between subjects with and without GJL, and the correlation between GJL and US findings was examined.A total of 13 subjects with GJL and 95 without GJL were included in the study. The mean BSs in the GJL and no-GJL groups were 5.9 ± 0.9 and 1.1 ± 1.3, respectively (p 0.0001). The GJL group showed a higher grade of ADT than the no-GJL group (p 0.0001). Significant differences were found in the stress ATFL length (23.6 ± 1.8 mm vs. 21.7 ± 1.8 mm, p = 0.002) and ATFL ratio (1.15 ± 0.06 vs. 1.07 ± 0.03, p 0.0001) between the GJL and no-GJL groups. Spearman's correlation coefficients showed a moderate correlation between the BS and ATFL ratio (r = 0.45, p 0.0001).The present study showed significant differences in the ATFL ratio and stress ATFL length between young men with and without GJL. The BS was moderately correlated with the lateral ankle laxity in this population.Level IV.

Epithelial protein lost in neoplasm (EPLIN) is an actin-associated cytoskeletal protein that plays an important role in epithelial cell adhesion. EPLIN has two isoforms: EPLINα and EPLINβ. In this study, we investigated the role of EPLINβ in osteoblasts using EPLINβ-deficient (

Background In 2020, the Japanese Orthopaedic Association established a new stage 3 in clinical decision limits (CDL) to evaluate the stage of locomotive syndrome (LS). This study focused on total CDL stage 3 with the aim of investigating indicators related to improvements in total CDL by evaluating the improvement of LS in patients who underwent total hip arthroplasty (THA). Methods Of the 125 patients who underwent THA at our hospital, the subjects of the analysis were 105 patients determined to be total CDL stage 3 in an evaluation performed before THA. LS was evaluated using the stand-up test, two-step test, and 25-Question Geriatric Locomotive Function Scale (GLFS-25). Indicators related to improvements in total CDL were also investigated. All evaluation items were measured before THA and three months after THA. Results Before THA, all subjects (n = 105) were classified as total CDL stage 3. Three months after THA, improvements in total CDL were seen in 49 subjects (46.7%). The results of stepwise multiple logistic regression analysis showed that the before THA stand-up test and GLFS-25 were significantly related to improvements in total CDL. Conclusions Three months after THA, improvements in LS were seen in approximately half of the subjects. The stand-up test and GLFS-25 can be used as indicators of improvement in total CDL. Design Prospective cohort study design.

Background Clavicle fractures are common injuries, especially in young, active individuals. Operative treatment is recommended for completely displaced clavicle shaft fractures, and plate fixation is stronger than the use of intramedullary nails. Few studies have reported on iatrogenic injuries to the muscle attached to the clavicle during fracture surgery. The aim of this study was to clarify the area of the insertion sites of muscles attached to the clavicle in Japanese cadavers using gross anatomy and three-dimensional (3D) analysis. We also aimed to compare the effects of anterior plate templating and superior plate templating on clavicle shaft fractures using 3D images. Methods Thirty-eight clavicles from Japanese cadavers were analyzed. We removed all clavicles to identify the insertion sites and measured the size of the insertion area of each muscle. Three-dimensional templating was performed on both the superior and anterior plates of the clavicle using data obtained from computed tomography. The areas covered by these plates on the muscles attached to the clavicle were compared. Histological examination was performed on four randomly selected specimens. Results The sternocleidomastoid muscle was attached proximally and superiorly; the trapezius muscle was attached posteriorly and partly superiorly; and the pectoralis major muscle and deltoid muscles were attached anteriorly and partially superiorly. The non-attachment area was located mainly in the posterosuperior part of the clavicle. It was difficult to distinguish the borders of the periosteum and pectoralis major muscles. The anterior plate covered a significantly broader area (mean 6.94 ± 1.36 cm2) of the muscles attached to the clavicle than did the superior plate (mean 4.11 ± 1.52 cm2) (p Conclusion Most of the pectoralis major and deltoid muscles were attached anteriorly. The non-attachment area was located mainly from the superior to posterior part of the clavicle midshaft. Both macroscopically and microscopically, the boundaries between the periosteum and these muscles were difficult to demarcate. The anterior plate covered a significantly broader area of the muscles attached to the clavicle than that by the superior plate.

Introduction: Before corrective surgery for idiopathic scoliosis, the stress x-rays are indispensable to collect information regarding the reducibility of deformity, deciding fusion levels, and categorizing curve types and so on. The hanging radiograph has not been conducted preoperatively so far as known. The objective of this study was to investigate retrospectively the significance of the hanging radiograph for prediction of the curve correction with surgical procedure by comparing with the side-bending and the traction radiographs. Methods: The subjects enrolled in current study were 22 cases of idiopathic scoliosis who performed posterior instrumentation and fusion by ISOLA method between 2008 and 2014. They included 2 males and 20 females, with a mean age of 16 years and 8 months. The type of curves by Lenke classification were type 1 in 20 cases, type 2 in 1 case, and type 3 in 1 case. We investigated the correction rates of main thoracic curves in side-bending, traction, and hanging positions and compared them with that after surgery. In addition, correction indices were also calculated and compared among these stress x-rays. Results: The correction rate after surgery was 65.9% that was statistically higher than those in side-bending (44.2%), traction (46.6%), and hanging (22.1%) positions. There were statistical correlations between the correction rates after surgery and in side-bending position (R=0.73) and those after surgery and in traction position (R=0.57). However, there was no statistical correlation between the correction rates after surgery and in hanging position (R=-0.01). With regard to the correction indices, that in hanging position (3.67) was statistically higher than those in side-bending (1.51) and traction (1.45) positions. Conclusion: The correction rates in side-bending and traction positions seem to be useful to estimate the amount of curve correction before surgery whereas, that in hanging position did not have any significance as preoperative evaluation.

An amendment to this paper has been published and can be accessed via the original article.

High-mobility group box 2, a chromatin-associated protein that interacts with deoxyribonucleic acid, is implicated in multiple biological processes, including gene transcription, replication, and repair. High-mobility group box 2 is expressed in several tissues, including the testis; however, its functional role is largely unknown. Here, we elucidated the role of high-mobility group box 2 in spermatogenesis. Paraffin-embedded testicular tissues were obtained from 8-week-old and 1-year-old wild-type and knock-out mice. Testis weight and number of seminiferous tubules were decreased, whereas atrophic tubules were increased in high-mobility group box 2-depleted mice. Immunohistochemistry revealed that atrophic tubules contained Sertoli cells, but not germ cells. Moreover, decreased cell proliferation and increased apoptosis were demonstrated in high-mobility group box 2-depleted mouse testis. To elucidate the cause of tubule atrophy, we examined the expression of androgen and estrogen receptors, and the results indicated aberrant expression of androgen receptor and estrogen receptor alpha in Sertoli and Leydig cells. Southwestern histochemistry detected decreased estrogen response element–binding sites in high-mobility group box 2-depleted mouse testis. High-mobility group box 1, which has highly similar structure and function as high-mobility group box 2, was examined by immunohistochemistry and western blotting, which indicated increased expression in testis. These findings indicate a compensatory increase in high-mobility group box 1 expression in high-mobility group box 2 knock-out mouse testis. In summary, depletion of high-mobility group box 2 induced aberrant expression of androgen receptor and estrogen receptor alpha, leading to decreased germ cell proliferation and increased apoptosis which resulted in focal seminiferous tubule atrophy.

Osteotomy of the distal fibula or anterolateral corner of the tibia is usually required to fix a displaced osteochondral fracture of the talus that is located central to posterior area of the lateral talar dome. However, osteotomy is an invasive procedure and is associated with complications, including nonunion, persistent pain, and hardware-related problems. Lateral inverted osteochondral fracture of the talus (LIFT) lesion is an extremely rare type of displaced osteochondral lesion of the talus. We describe a case in which a LIFT lesion was fixed using an innovative surgical approach, inverting capsulo-lateral fibulotalocalcaneal ligament (LFTCL)-fibular periosteum complex, with a favorable short-term clinical outcome.

Background High-Mobility Group Box 1 (HMGB1) and HMGB2 are chromatin-associated proteins that belong to the HMG protein family, and are involved in the regulation of DNA transcription during cell differentiation, proliferation and regeneration in various tissues. However, the role of HMGB2 in ovarian folliculogenesis is largely unknown. Methods We investigated the functional role of HMGB1 and HMGB2 in ovarian folliculogenesis and fertilization using C57BL/6 wild type (WT) and HMGB2-knockout (KO) mice. Ovarian tissues were obtained from WT and HMGB2-KO mice at postnatal days 0, 3, 7, and 2, 6 months of age, then performed immunohistochemistry, qPCR and Western blotting analyses. Oocyte fertilization capability was examined by natural breeding and in vitro fertilization experiments. Results In HMGB2-KO mice, ovary weight was decreased due to reduced numbers of oocytes and follicles. Natural breeding and in vitro fertilization results indicated that HMGB2-KO mice are subfertile, but not sterile. Immunohistochemistry showed that oocytes expressed HMGB2, but not HMGB1, in neonatal and adult WT ovaries. Interestingly, in HMGB2-KO ovaries, a compensatory increase in HMGB1 was found in oocyte nuclei of neonatal and 2-month-old mice; however, this was lost at 6 months of age. Conclusions The depletion of HMGB2 led to alterations in ovarian morphology and function, suggesting that HMGB2 plays an essential role in ovarian development, folliculogenesis and fertilization.

Backgroud: To evaluate the influence of intra-articular hemarthrosis on activities of a disintegrin and metalloprotease with thrombospondin motifs (ADAMTS) family and matrix metalloproteases (MMPs) in the acute phase after anterior cruciate ligament reconstruction (ACLR). Methods: Intra-articular hemarthrosis was collected from 17 patients who underwent primary ACLR on postoperative day POD1, POD4 and POD7. As control samples, synovial fluid without intra-articular hemarthrosis was obtained from ipsilateral knees prior to ACLR. ADAMTS-4, -5, and -9 and MMP-2 and -9 were measured by enzyme-linked immunosorbent assay (ELISA). Results: Expression levels of ADAMTS-4 were significantly higher in POD4 and POD7 samples than in control (Pc-4c-7c-1=0.0007). MMP-2 expression levels in POD4 and POD7 samples were significantly increased compared to control samples (Pc-4=0.0017, Pc-7=0.0013). Expression levels of MMP-9 were increased in POD1, POD4 and POD7 samples, significantly higher than in control (Pc-1c-4c-7=0.0004). Conclusion: These findings indicate that intra-articular hemarthrosis induces expression of ADAMTS-4, -5, MMP-2 and -9 in the acute phase, and especially increasing ADAMTS-4, -5 after ACLR may lead to cartilage degeneration. So intra-articular hemarthrosis may be suggested to remove as soon as possible after knee injury or surgery.

Background Recently, cryotherapy has become a common practice for postoperative pain management. The current accepted practice in Japan is the use of cryotherapy at 5 °C after arthroscopic shoulder surgery. However, this therapy has been reported to be highly intense because the sustained low temperature causes discomfort for patients. The optimum temperature and duration of cooling required for comfortable and effective cryotherapy after arthroscopic shoulder surgery were investigated. Methods Because pain levels might differ depending on the condition, we selected 52 patients with rotator cuff injuries, which were the most common disorders indicated for arthroscopic shoulder surgery. Patients were treated with cryotherapy at 5 °C or 10 °C for 16 h or 24 h. The pain level was determined using the visual analogue scale, and deep shoulder joint temperatures were recorded at different time points for analysis. Results Pain after arthroscopic shoulder surgery was found to be related to the presence of a brachial plexus block using the interscalene approach during surgical anesthesia. To obtain effective analgesia with cryotherapy, the cooling temperature and duration of cryotherapy had to be changed based on the presence or absence of the brachial plexus block. Patients who received brachial plexus blocks had the lowest recorded pain scores after receiving cryotherapy at 5 °C for 24 h after surgery. Patients who did not receive the block had the lowest recorded pain scores when receiving cryotherapy at either 5 °C for 16 h or 10 °C for 24 h. Conclusions Using universal cryotherapy intensity and duration settings regardless of the use of other interventions is likely to unintentionally increase postoperative pain levels. This study revealed that cryotherapy at 5 °C for 24 h was optimal for patients who received an anesthesia block and at 5 °C for 16 h or at 10 °C for 24 h for those who did not receive the anesthesia block. These results can be used as a reference for setting the temperature and duration of cryotherapy after arthroscopic shoulder surgery.

The loss of knee range of motion (ROM) is not an uncommon complication after anterior cruciate ligament reconstruction (ACLR). However, the risk factors of loss of knee ROM remain debatable. The purpose of this study was to evaluate the incidence and risk factors of loss of knee ROM at 12 months after primary ACLR performed after regaining full knee ROM preoperatively. Consecutive patients who underwent primary ACLR after regaining full ROM between January 2014 and January 2020 were retrospectively reviewed. Patients who received a surgical arthrolysis within 12 months after ACLR or those who had a loss of knee ROM at 12 months postoperatively were defined as the loss of ROM group. Possible risk factors of loss of knee ROM, including patient demographic, preoperative, surgical, and postoperative factors, were assessed. The notch wide index and radiographic parameters of the tibial spines; medial tibial spine height/tibial length (TL), lateral tibial spine height (LTSH)/TL, and tibial spine width (TSW)/TL, were also assessed. A total of 141 patients (141 knees) were included (mean age, 25.8 ± 11.4 years; male/female, 56/85). Of the 141 patients, three received surgical arthrolysis within 12 months, and 23 had a loss of knee ROM at 12 months after ACLR. On comparing patients with and without loss of knee ROM, significant differences were found in the age (p = 0.04), LTSH/TL (p = 0.02), and TSW/TL (p = 0.02). A multivariate regression analysis showed that the age (odds ratio [OR]; 1.05, 95% confidence interval [CI]: 1.01–1.09, p = 0.02), LTSH/TL (OR: 1.44, 95% CI: 1.01–2.1, p = 0.04), and TSW/TL (OR: 0.79, 95% CI: 0.65–0.97, p = 0.02) were identified as significant independent risk predictors of loss of knee ROM. This study showed that the incidence of loss of knee ROM at 12 months after primary ACLR was 18.4% (26/141). An older age, a higher LTSH/TL, and a smaller TSW/TL may be associated with loss of knee ROM at 12 months after ACLR.

The volume loss of skeletal muscle, including lumbar paravertebral muscles, is negatively correlated with the rate of lumbo-pelvic deformity. Moreover, ectopic fat infiltration with highly expressed adipogenesis promoting genes in the paravertebral muscles may reflect pathology of sarcopenia and may cause age-related lumbo-pelvic deformity., Study Design. A retrospective analysis of a prospective, non-randomized cohort dataset. Objective. To cross-sectionally examine the prevalence of sarcopenia and the association between spine-pelvic deformity and skeletal muscle volume loss and ectopic fat infiltration into lumbar paravertebral muscles (PVMs) in patients who underwent lumbar surgery. Summary of Background Data. Muscle quality deterioration has been considered the main pathology of sarcopenia, reducing muscle strength directly. The qualitative deterioration as well as volume loss in PVM, which contributes significantly to core body extension, might cause aging-related spine deformity. Methods. In total, 184 patients were included. Sarcopenia was diagnosed at baseline, and all patients underwent whole-body X-ray. The amount of fat in lumbar PVM was evaluated with the Goutallier classification in magnetic resonance imaging findings. The expression of adipogenesis- and atrophy-promoting factors in PVM was evaluated with quantitative polymerase chain reaction. Results. In total, 36.1% of adults aged ≥60 years were diagnosed with sarcopenia. The values of skeletal muscle indexes of the limb and trunk were inversely correlated with the sagittal vertical axis, pelvic tilt (PT), and pelvic incidence minus lumbar lordosis (PI-LL) values. The PT and PI-LL were greater, PVM area was smaller, and Goutallier grade was greater in sarcopenic adults than in non-sarcopenic older adults. Additionally, the PVM area correlated with the LL value, and Goutallier's grade correlated with the PT and PI-LL values. Moreover, the amount of ectopic fat in PVMs inversely correlated with skeletal muscle indexes. The expression levels of atrophy gene-1 and muscle ring-finger protein-1 did not differ between the groups and did not correlate with the PVM area. In contrast, the expression of Pparg and Cebpa was upregulated in sarcopenic older adults, where it correlated with Goutallier's grade. Conclusion. The volume loss of skeletal muscle, including lumbar PVM, and ectopic fat infiltration into the PVM, may cause the lumbo-pelvic deformity. Level of Evidence: 3

Background The purpose of the present study was to evaluate the usefulness of the median nerve stenosis rate (MNSR) measured on sagittal sonographic images of the median nerve in the diagnosis of carpal tunnel syndrome (CTS). Methods The study population consisted of 45 hands from 37 patients with idiopathic CTS (CTS group), and 60 hands from 35 asymptomatic healthy subjects (control group). Carpal tunnel syndrome was diagnosed by clinical findings and positive electrophysiological study results. All patients and control subjects underwent ultrasonographic examination. At the carpal tunnel level, the transducer was placed longitudinally to the median nerve, and an image of the longitudinal median nerve was obtained. The minimum median nerve diameter (MND) was measured at the middle part of the capitate level, while the maximum MND was measured at the distal radioulnar joint level. The MNSR was calculated as (1 – minimum MND/maximum MND) × 100 (%). The cross-sectional area of the median nerve was also measured at the level of the pisiform. Results On longitudinal sonographic images, the MNSR was significantly larger in the CTS group than the control group. When the cut-off value of the MNSR was 26.73%, the sensitivity and specificity were 91.1% and 80%, respectively. The area under the receiver operating characteristic curve was larger for the MNSR than for the cross-sectional area. Conclusion The results suggest that the MNSR proposed in the present study may be useful as an auxiliary method for CTS diagnosis on ultrasonographic examination.

Non-anatomical placement may occur during the surgical implantation of the meniscal implant, and its influence on the resulting biomechanics of the knee joint has not been systematically studied. The purpose of this study was to evaluate the biomechanical effects of non-anatomical placement of the meniscal implant on the knee joint during a complete walking cycle. Three-dimensional finite element (FE) analyses of the knee joint were performed, based on the model developed from magnetic resonance images and the loading conditions derived from the gait pattern of a healthy male subject, for the following physiological conditions: (i) knee joint with intact native meniscus, (ii) medial meniscectomized knee joint, (iii) knee joint with anatomically placed meniscal implant, and (iv) knee joint with the meniscal implant placed in four different in vitro determined non-anatomical locations. While the native menisci were modeled using the nonlinear hyperelastic Holzapfel-Gasser-Ogden (HGO) constitutive model, the meniscal implant was modeled using the isotropic hyperelastic neo-Hookean model. Placement of the meniscal implant in the non-anatomical lateral-posterior and lateral-anterior locations significantly increased the peak contact pressure in the medial compartment. Placement of the meniscal implant in non-anatomical locations significantly altered the tibial rotational kinematics and increased the total force acting at the meniscal horns. Results suggest that placement of the meniscal implant in non-anatomical locations may restrain its ability to be chondroprotective and may initiate or accelerate cartilage degeneration. In conclusion, clinicians should endeavor to place the implant as closest as possible to the anatomical location to restore the normal knee biomechanics.

Addressing the problems facing the elderly, whether living independently or in managed care facilities, is considered one of the most important applications for action recognition research. However, existing systems are not ready for automation, or for effective use in continuous operation. Therefore, we have developed theoretical and practical foundations for a new real-time action recognition system. This system is based on Hidden Markov Model (HMM) along with colorizing depth maps. The use of depth cameras provides privacy protection. Colorizing depth images in the hue color space enables compressing and visualizing depth data, and detecting persons. The specific detector used for person detection is You Look Only Once (YOLOv5). Appearance and motion features are extracted from depth map sequences and are represented with a Histogram of Oriented Gradients (HOG). These HOG feature vectors are transformed as the observation sequences and then fed into the HMM. Finally, the Viterbi Algorithm is applied to recognize the sequential actions. This system has been tested on real-world data featuring three participants in a care center. We tried out three combinations of HMM with classification algorithms and found that a fusion with Support Vector Machine (SVM) had the best average results, achieving an accuracy rate (84.04%).

Background A number of studies have evaluated risk factors for lateral ankle sprain (LAS) or chronic lateral ankle instability (CLAI). However, the definitive risk factors for LAS or CLAI remain controversial. The purpose of this study was to evaluate whether the contralateral healthy ankles of subjects with ipsilateral mechanical lateral ankle laxity (group I) show greater lateral ankle laxity in comparison to the healthy ankles of bilateral healthy controls (group B). Methods From March 2020, anterior talofibular ligament (ATFL) lengths of young adult volunteers were cross-sectionally measured in non-stress and stress positions using a previously reported stress ultrasonography (US) procedure. The ATFL ratio (the ratio of stress ATFL/non-stress ATFL length) was calculated as an indicator of lateral ankle laxity. The manual anterior drawer test (ADT) was also performed. The US findings of healthy ankles from groups I and B were compared. Results A total of 154 subjects in group B (mean age, 24.5 ± 2.8 years; male/female, 84/70) and 40 subjects in group I (mean age, 24.4 ± 2.3 years; male/female, 26/14) were included in the study. There was no significant difference in the ADT between the groups. There were no significant differences in the non-stress ATFL length (19.4 ± 1.8 vs. 19.3 ± 1.9, p = 0.84), stress ATFL length (20.8 ± 1.8 vs. 20.9 ± 1.9, p = 0.66), length change (1.5 ± 0.6 vs. 1.6 ± 0.6, p = 0.12) and ATFL ratio (1.08 ± 0.03 vs. 1.08 ± 0.03, p = 0.13) between the groups. Conclusion No significant difference was detected between the contralateral healthy ankles of subjects with ipsilateral mechanical lateral ankle laxity and those of bilateral healthy controls.

This study was conducted to present remnant-preserving anterior cruciate ligament (ACL) augmentation as a useful option for partial ACL injury in multiligament knee injury (MLKI) cases, which may also contribute to conserving graft resources. The present study involved patients diagnosed with MLKI at our institute from Spring 2006 to February 2021. A total of 71 MLKI cases were provided surgery due to knee instability and disability. For every patient, an arthroscopic diagnostic was performed to ensure that ACL tear and a remnant were present. When the ACL remnant was classified into group 2, 3, or 4 of Nakamae's classification, remnant-preserved single bundle ACL augmentation was performed. Graft selection and the combination of injured ligaments were evaluated. The side-to-side difference under an anterior tibial load of 134 N with an arthrometer and the leg symmetry index at 60 degrees/s were measured. The present procedure was performed for five cases (male/female: 4/1, mean age: 33.6 years). The mean follow-up period was 26.4 months. The combination of torn ligaments was as follows: 3 cases of ACL + medial collateral ligament, one case of ACL + posterior cruciate ligament, and one case of ACL + posterolateral corner. An ACL augmentation graft was performed using an ipsilateral gracilis tendon in 2 cases, a contralateral full semitendinosus tendon in 2 cases, and the ipsilateral distal 1/2 of the semitendinosus tendon in 1 case. The mean side-to-side difference was 1.07 ± 0.4 mm. The mean leg symmetry index was 82.6 ± 12.2% in knee extension and 96.3 ± 9.9% in knee flexion. Although the present study was a small case series, the remnant-preserved single-bundle ACL augmentation for MLKI surgery provided good clinical outcome and conserved the graft resource. Even in the MLKI case, this technique is one of the useful surgical options. The level of evidence of this study is level IV (case series).

Head Injury Assessment (HIA) is the screening tool for head injury during a rugby game. The purpose of this study was to investigate the epidemiology of HIA in the Japan Rugby Top League (JRTL). The incidences of HIA, defined concussion (per 1,000 player-hours) and repeated concussions were evaluated in three seasons (2016-17, 2017–18, 2018–19; total 360 games). The HIA incidence rates were 12.7 (95% confidence interval 9.5–15.9), 20.8 (16.8–24.9), and 25.0 (20.5–29.5) in each season. HIA-1 criteria 2, which is applied for suspected concussion cases, was performed for 46 cases in the 2016–17 season, 81 cases in the 2017–18 season, and 88 cases in the 2018–19 season. The concussion incidence rates were significantly greater in the 2017–18 season (9.6/1000 player-hours, 95% confidence interval 6.8–12.4) and the 2018–19 season (14.4, 11–17.8) compared to the 2016–17 season (4.8, 2.8–6.8). The number of repeated concussion cases in the same season was 1 in the 2016–17 season and 4 in both the 2017–18 and 2018–19 seasons. This study confirmed significantly higher HIA and concussion incidence rates over time. Although the HIA system might have been established in the three seasons in JRTL, comprehensive management needs to be improved to prevent repeated concussions.

Background: A vertebral fracture in a patient with diffuse idiopathic skeletal hyperostosis (DISH) is unstable due to larger moment via the long lever arm of an ankylosed spine. Therefore, surgical treatment is commonly recommended to avoid complications of nonunion and paralysis. In this report, we present 3 cases of vertebral fractures related to DISH which were primarily forced to undertake conservative treatment because of medical comorbidities and advanced age. Case 1: A 93-year-old woman suffered from T10 vertebral fracture by a ground-level fall on her back. A trunk cast for 6 weeks was followed by brace wear for 3 months with administration of daily teriparatide. Then complete bone union was confirmed at 2 years after injury without back pain. Case 2: An 84-year-old man suffered from T12 vertebral fracture by a fall on his back from a chair. A trunk cast for 12 weeks was followed by brace wear for 6 months with administration of daily teriparatide. Then acceptable bone union was confirmed at 1 year after the injury, and activities of daily living became independent. Case 3: An 87-year-old woman suffered from T10 vertebral fracture due to a ground-level fall on her back when doing pruning work. Conservative treatment by trunk cast was first initiated with administration of daily teriparatide. However, delayed paralysis developed at 2 weeks after casting, so minimally invasive spinal stabilization (MISt) was performed. Bone union was obtained at 1 year after the injury without any neurological impairment. Conclusions: Favorable clinical courses have been obtained in 2 cases, whereas MISt was required for delayed paralysis in 1 case. Although surgical stabilization is the first-line treatment for vertebral fracture with DISH, conservative treatment can also be one of the options in cases with high operative risk due to serious medical comorbidities. However, during conservative treatment, cautious observation is necessary not to overlook the occurrence of paralysis. Level of Evidence: 4. Clinical Relevance: Conservative treatment for vertebral fracture with DISH can be one of the options in cases with high operative risk due to serious medical comorbidities.

We aimed to evaluate the feasibility of 3D broadband inversion-recovery-prepared ultrashort echo-time (3D IRP UTE) imaging for assessing ossification of the posterior longitudinal ligament (OPLL). The study consisted of 25 consecutive patients with cervical OPLL [13 women, 12 men; mean age 66.3 (47–84) years] who underwent CT, 3T conventional MR, and 3D IRP UTE imaging studies. Two readers independently assessed the 3D IRP UTE images for the type (mixed, continuous, circumscribed, segmental) and distribution of OPLL. All readers consensually assessed the diagnostic certainty of OPLL on conventional MR and 3D IRP UTE images by using a 3-point scale system. Interobserver and intermodality agreement was assessed by κ statistics. A Wilcoxon signed-rank test was used to evaluate the difference of diagnostic certainty between conventional MR and 3D IRP UTE imaging. Interobserver and intermodality agreements were good (κ = 0.73) and excellent (κ = 0.81) for the OPLL type, and excellent (κ = 0.85) and good (κ = 0.76) for the assessment of the distribution of OPLL, respectively. The mean level of the diagnostic certainty of OPLL was significantly higher for 3D IRP UTE than conventional MR imaging (p = 0.002). 3D IRP UTE imaging may be useful for assessing OPLL.

For anterior cruciate ligament (ACL)-deficient patients, using a single bone-patellar tendon-bone (BPTB) graft for the double-bundle concept is one of the suitable approaches for acquiring better stability and reducing bone tunnel enlargement compared with the use of hamstring grafts. At least 10-mm width of BPTB autograft is needed to achieve this concept; however, it is larger than one-third of the patellar tendon width for small or middle physique patients. This study aimed to assess the clinical and radiographic outcomes of BPTB and gracilis (G) composite autografts for primary double-bundle ACL reconstruction in Asian athletes. Thirty-two Asian patients undergoing double-bundle ACL reconstruction with 7.0 to 7.5 mm of BPTB and 5.0 to 5.5 mm of G composite grafts were compared with 43 double-bundle ACL reconstruction with hamstring graft cases. The BPTB graft was used for the anteromedial bundle (AMB), with the G graft for the posterolateral bundle (PLB). Percentage of femoral bone tunnel enlargement compared with the original size was determined by computed digital radiographs on the first postoperative day and at 12 months in the anteroposterior (AP) and lateral views. Standard clinical evaluations, including the limb symmetry index (LSI), were also performed. Less PLB tunnel enlargement was found in the BPTB + G group than in the hamstring group in the AP (101.9 ± 22.9 vs.113.7 ± 20.6%, p = 0.031) and lateral views (104.4 ± 18.1 vs. 120.6 ± 23.4%, p

Background The biological mechanism of action for osteoprotegerin, a soluble decoy receptor for the receptor activator of nuclear factor‐kappa B ligand in the vascular structure, has not been elucidated. The study aim was to determine if osteoprotegerin affects aortic structural integrity in angiotensin II (Ang II)‐induced hypertension. Methods and Results Mortality was higher ( P P P =0.08), and aortic dissection ( P Conclusions These data suggest that osteoprotegerin protects against aortic rupture and dissection in Ang II‐induced hypertension by inhibiting receptor activator of nuclear factor‐kappa B ligand activity and periostin expression.

Liver regeneration is an extraordinarily complex process involving a variety of factors; however, the role of chromatin protein in hepatocyte proliferation is largely unknown. In this study, we investigated the functional role of high-mobility group box 2 (HMGB2), a chromatin protein in liver regeneration using wild-type and HMGB2-knockout (KO) mice. Liver tissues were sampled after 70% partial hepatectomy (PHx), and analyzed by immunohistochemistry, western blotting and flow cytometry using various markers of cell proliferation. In WT mice, hepatocyte proliferation was strongly correlated with the spatiotemporal expression of HMGB2; however, cell proliferation was significantly delayed in hepatocytes of HMGB2-KO mice. Quantitative PCR demonstrated that cyclin D1 and cyclin B1 mRNAs were significantly decreased in HMGB2-KO mice livers. Interestingly, hepatocyte size was significantly larger in HMGB2-KO mice at 36–72 h after PHx, and these results suggest that hepatocyte hypertrophy appeared in parallel with delayed cell proliferation. In vitro experiments demonstrated that cell proliferation was significantly decreased in HMGB2-KO cells. A significant delay in cell proliferation was also found in HMGB2-siRNA transfected cells. In summary, spatiotemporal expression of HMGB2 is important for regulation of hepatocyte proliferation and cell size during liver regeneration.

Background Different methods of acetabular reconstruction with total hip arthroplasty (THA) for Crowe II and III of adult developmental dysplasia of the hip (DDH) acetabular bone defect have been implemented clinically. However, the biomechanical effect of different augmented materials for acetabular reconstruction in THA on shell stability has never been discussed. Methods In the present study, autologous bone graft (BG)and metal (Ti6Al4V) augment (MA) were simulated with several acetabular bone defect models of DDH in THA. The contact pressure and micromotion between the shell and host bone were measured for evaluating the shell stability using a finite element method. Results The peak contact stress between shell and host bone was higher in the MA situation (12.45 vs 8.71 MPa). And the load transfer path was different, for BG models, the high local contact stresses were found at the junction of bone graft and host bone while for MA models the concentrated contact stresses were at the surface of MA. The peak relative micromotion between shell and host bone was higher in the MA situation (12.61 vs 11.13 µm). However, the peak micromotion decreased in the contact interface of MA and cup compared to the BG models. Conclusions The higher micromotion was found in MA models, however, enough for bone ingrowth, and direct stronger fixation was achieved in the MA-cup interface. Thus, we recommended the MA can be used as an option, even for Crowe III, however, the decision should be made from clinical follow-up results.

The effect of dried and UV-C-irradiated mushroom powder on lipid oxidation and vitamin D content in fish meat was investigated. To this end, Flammulina velutipes, Grifola frondosa, Hypsizygus marmoreus, Lentinula edodes, Pleurotus eryngii, Pleurotus ostreatus were dried by hot air and irradiated by UV-C and evaluated the effect of these treatments on the components. In general, the ergothioneine content did not change substantially, the total phenolic compound content decreased by hot-air drying, and the ergocalciferol content increased by UV-C irradiation. To the evaluate effect of mushroom powder on lipid oxidation and vitamin D content in fish meat, 5% of the hot air dried and UV-C-irradiated mushroom powder was added to fish meat and oxidized. Consequently, all six mushrooms prevented lipid oxidation, and ergocalciferol content in each mushroom powder remained between 58.2% and 69.7%. Overall, P. eryngii, L. edodes, and P. ostreatus strongly prevented the generation of lipid peroxide and aldehyde.

Background After a total hip arthroplasty (THA), standing and walking balance are greatly affected in the early stages of recovery, so it is important to increase the weight-bearing amount (WBA) on the operated side. Sometimes, traditional treatments may not be enough to improve WBA and weight-bearing ratio (WBR) on the operated side in a satisfactory way. To solve this problem, we came up with a new weight-shifting-based robot control system called LOCOBOT. This system can control a spherical robot on a floor by changing the center of pressure (COP) on a force-sensing board in rehabilitation after THA. The goal of this study was to find out how rehabilitation with the LOCOBOT affects the WBR and balance in a static standing position in patients with unilateral hip osteoarthritis (OA) who had a primary uncemented THA. Methods This randomized controlled trial included 20 patients diagnosed with Kellgren–Lawrence (K–L) grade 3 or 4 hip OA on the operative side and K–L grade 0 normal hip on the nonoperative side. We used the minimization method for allocation and randomly assigned patients to either the LOCOBOT group or the control group. As a result, 10 patient seach were randomly assigned to the LOCOBOT and control groups. Both groups received 40 min of rehabilitation treatment. Out of the 40 min, the LOCOBOT group underwent treatment for 10 min with LOCOBOT. The control group performed COP-controlled exercises on a flat floor instead of using LOCOBOT for 10 of the 40 min. All theoutcome measures were performed pre-THA and 11.9 ± 1.6 days after THA (12 days after THA). The primary outcome measure included WBR in the static standing position. Results After12 days of THA, the LOCOBOT group exhibited significantly higher mean WBR and WBA (operated side) values than the control group. Furthermore, the LOCOBOT group exhibited significantly lower mean WBA (non-operated side) and outer diameter area (ODA) values than the control group. From pre-THA to 12 days after THA, the LOCOBOT group exhibited a significant improvement in mean WBR and WBA (operated side). Moreover, the mean WBA (non-operated side) and ODA significantly decreased. From pre-THA to 12 days after THA, the control group showed a significant increase in total trajectory length and ODA. Conclusions The most important finding of this study was that patients were able to perform the LOCOBOT exercise as early as the second day after THA, and that WBR and ODA significantly improved by the 12th day after THA. This result demonstrated that the LOCOBOT effectively improves WBR in a short period of time after THA and is a valuable system for enhancing balance ability. This expedites the acquisition of independence in activities of daily living after THA and may contribute to optimizing the effectiveness of medical care.

Osteochondral lesions of the talus (OLT) are common injuries in young athletes. Various kinds of surgical procedures are available for orthopaedic surgeons, but which surgical technique is the best remains controversial. Many surgical procedures require malleolar osteotomy to obtain appropriate surgical exposure to the OLT because of the anatomic characteristics of the ankle joint. However, malleolar osteotomy is invasive and has a potential risk of complications, such as tibial chondral damage and pseudoarthrosis. This article aims to introduce a novel surgical procedure for the treatment of OLTs: retrograde autologous talar osteocancellous bone grafting without the need for osteotomy and harvesting a graft from anywhere other than the talus. First, an arthroscopic evaluation is performed to verify the location, size, and cartilage quality of the OLT as well as concomitant lesions. After confirming the position of the guide pin using a guide device arthroscopically, a talar osteocancellous bone plug is harvested using a coring reamer. The OLT of the harvested talar bone plug is removed, and under arthroscopy, the talar osteocancellous bone plug is retrogradely inserted into the talar bone tunnel. To stabilize the implanted bone plug, one or two bioabsorbable pins are inserted from the lateral wall of the talus while applying counterforce to the articular surface of the bone plug. The present surgical technique can minimally invasively address the OLT without the need for malleolar osteotomy and harvesting a graft from the knee joint or iliac bone.

The Beighton score (BS) is widely used to evaluate generalized joint laxity. However, the association between the BS and lateral ankle laxity is unclear. This study compared the ultrasonographic (US) findings of the anterior talofibular ligament (ATFL) between high- (≥6) and low- (≤3) BS groups of healthy young women. The ATFL lengths of healthy young women were measured in the stress and nonstress positions using the previously reported technique from March 2021 to January 2022. The ATFL ratio (ratio of stress to nonstress ATFL length) was used as an indicator of lateral ankle laxity. The anterior drawer test (ADT) was performed. The correlation between the BS and US findings was also examined. A total of 20 (high-BS group) and 61 (low-BS group) subjects with a mean age of 23.8 ± 1.0 years were included. The high-BS group showed a higher grade of ADT than the low-BS group. No significant differences were found in the nonstress and stress ATFL lengths and ATFL ratio (1.10 ± 0.05 vs. 1.09 ± 0.05, p = 0.19) between the groups. No correlation was found between the BS and US findings. In conclusion, this study did not detect significant differences in the US findings of the ATFL between the high- and low-BS groups.

BackgroundKnee extensor structure disruption is sometimes combined with multi-ligament knee injury (MLKI). These cases could not be classified into the previous classification for knee dislocation or MLKI. To propose a new classification of MLKI that addresses both femorotibial and patellofemoral (PF) factors.MethodsThe present study involved patients diagnosed with MLKI at our institute. Cases with two or more injured structures diagnosed clinically and by MRI and X-ray examinations were included. Details of injured structures were defined as follows: ‘cruciate ligaments’, including the ACL and PCL; ‘collateral ligaments’, including the MCL and the posterolateral corner (PLC); and the ‘PF joint factor’, including the medial patellofemoral ligament (MPFL), quadriceps tendon, and patellar tendon. A total of 65 cases met the inclusion criteria from 2007 to August 2020 and were enrolled in this study.Based on the number of injured structures, cases were categorized as: Type A, two structures injured; Type B, three structures injured; Type C, four structures injured; and Type D, five structures injured. Depending on the combination of injured structures, they were subdivided into 1 to 5 in Types A and B and into 1 to 3 in Type C. Additional injuries were subdivided as follows: MLKI with fracture was defined as X, with neurovascular injury as Y, and both fracture and neurovascular injury as Z. MLKI cases were divided into both Schenck’s KD classification and the present classification.ResultsFourteen of 65 cases (21.5%) could not be categorized using Schenck’s KD classification; two cases of PLC+MPFL (Type-A5 in new classification), ACL+PLC with periarticular fracture (Type-A1-X), and single cases of ACL+MCL+PLC (Type-B2), ACL+PCL+MCL+PLC+MPFL (Type-D), ACL+MPFL (Type-A4), ACL+MCL+MPFL (Type-B3), PCL+PLC+ patellar tendon with periarticular fracture (Type-B3-X), and PCL+ patellar tendon (Type-A4), ACL+PLC with neurovascular injury (Type-A1-Y), and three cases of PCL+PLC with complications (Type-A1-X, -Y, -Z). With the new classification for MLKI and complications, all cases were successfully assigned to each category.ConclusionIn the present classification, every combination of MLKI cases containing both tibiofemoral and patellofemoral factors, with or without complications, was successfully classified into a suitable category.

High-mobility group box 2 (HMGB2) is a chromatin-associated protein that is an important regulator of gene transcription, recombination, and repair processes. The functional importance of HMGB2 has been reported in various organs, including the testis, heart, and cartilage. However, its role in the ovary is largely unknown. In this study, ovary tissues from wild-type (WT) and HMGB2-knock-out (KO) mice were examined by histopathological staining and immunohistochemistry. The ovary size and weight were significantly lower in HMGB2-KO mice than in age-matched WT littermates. Histopathological analysis revealed ovarian atrophy and progressive fibrosis in 10-month-old HMGB2-KO mouse ovaries. Compared to age-matched WT mice, the numbers of oocytes and developing follicles were significantly decreased at 2 months of age and were completely depleted at 10 months of age in HMGB2-KO mice. Immunohistochemistry revealed the expression of HMGB2 in the granulosa cells of developing follicles, oocytes, some corpora lutea, and stromal cells. Importantly, HMGB2-positive cells were co-localized with estrogen receptor beta (ERβ), but not ERα. Estrogen response element-binding activity was demonstrated by southwestern histochemistry, and it was decreased in HMGB2-KO mouse ovaries. Cell proliferation activity was also decreased in HMGB2-KO mouse ovaries in parallel with the decreased folliculogenesis. These results indicated that the depletion of HMGB2 induced ovarian atrophy that was characterized by a decreased ovarian size and weight, progressive fibrosis, as well as decreased oocytes and folliculogenesis. In conclusion, we demonstrated the crucial role of HMGB2 in mouse ovarian folliculogenesis through ERβ expression.

[Purpose] Exercise guidance is an effective measure against locomotive syndrome. Appropriate nutritional management is also considered necessary in order to maintain the motor function. This study is the first exploratory and prospective research on the effects of exercise guidance and feeding high-protein foods in order to improve locomotive syndrome, in elderly people. [Method] We conducted a survey regarding five items related to locomotorium on the basic checklist prepared by the Japanese Ministry of Health, among men and women in their 60s and over living in Miyazaki Prefecture. Participation was solicited from those who responded “applicable” to three or more items, with those who gave their consent assigned to a food + exercise intervention group (EF group), an exercise intervention group (EX group), and a control group (C group) for research. Motor function surveys such as interviews, questionnaire, and locomotive syndrome risk test were conducted at the start of the study and three months later. The EX and EF groups were instructed to carry out locomotion training, while the EF group was asked to ingest one bag of high-protein test food daily immediately following exercise. The participants carried an activity meter and kept a record of their life in a diary during the study period. The EX and EF groups were encouraged to make recordings in a diary and carry an activity meter, while also getting a regular telephone contact once a week. [Results] An improvement in the motor function was observed in the EX and EF group compared to the C group via Locomotive syndrome risk testing. While the muscle mass decreased significantly during the study period in the C and EX group, no significant change was observed in limbs/trunk muscle mass in the EF group. [Conclusion] The locomotion training improved the results of the Locomotive syndrome risk testing. Although muscle mass decreased with exercise guidance alone, muscle mass loss was suppressed by feeding high-protein foods in addition to exercise. We conclude that feeding high-protein foods is useful for improving motor function and maintaining muscle mass, in addition to exercise guidance, as a measure against locomotive syndrome in elderly.

Muscle herniation of the lower extremity, such as tibialis anterior muscle herniation (TAMH), is not a rare cause of leg pain in athletes. However, a few studies have reported surgical treatment for TAMH, and the optimal surgical procedure remains controversial. Fasciotomy was reported to be effective for patients with TAMH. However, this procedure would be associated with a risk of intraoperative injury to the superficial peroneal nerve (SPN), although no previous literature has reported this complication. This case report aimed to report a case of bilateral TAMHs in which a traumatic neuroma of the SPN developed after fasciotomy. A 16-year-old baseball player presented with painful swelling lesions of the bilateral lower extremities (1 lesion on the right, 3 lesions on the left) after sports activities. An ultrasonographic evaluation showed swelling lesions of the anterolateral parts of the bilateral lower extremities in the standing position after dashing, while these lesions were not detected in the supine position. A fasciotomy of the crural fascia was performed after conservative treatment failed. Several days after surgery, the patient presented with weakened touch sensation over the dorsal area of the left foot. At the three-month follow-up examination, a swelling lesion with hard elasticity was identified. The palpation of this lesion caused a radiating sensation in the area supplied by the SPN. He was able to return to playing baseball six months after surgery. The patient was asymptomatic without palpation of the traumatic neuroma of the SPN at the latest follow-up examination. In conclusion, the present case report suggests that orthopedic surgeons need to consider the risk of iatrogenic injury to the SPN during fasciotomy for the treatment of TAMHs. However, there may be a risk of injuring the SPN because of the many variants of the course of the SPN within the compartment of the lower extremities.

This study aimed to evaluate the influence of various posterior tibial slopes (PTSs) and tibial tunnel angles (TTAs) on “killer turn” in posterior cruciate ligament (PCL) reconstruction by using three-dimensional finite element analysis (FEA). The study models were created using computed tomography images of a healthy young Asian male. Using SolidWorks, PCL grafts and tibial bone tunnels at different tibial drilling angles (30°, 45°, 60°) were developed. Anterior opening wedge high tibial osteotomy (aOW-HTO) was performed to evaluate the influence of the PTS (+8°, +4°, native, −4°, −8°). An FEA was performed utilizing the ANSYS software program. In the same PTS model, the peak of the equivalent Von Mises stress in PCL grafts decreased as the angle of the TTA increased. In the same TTA model, the peak of the Von Mises in PCL grafts decreased as the PTS angle increased. The “high-contact stress area” (contact stress greater than 10 MPa) was diminished when the TTA and PTS were increased. aOW-HTO was used to steepen the PTS, and a larger TTA may reduce the stress at the “killer turn” during PCL reconstruction. In conclusion, the study findings suggest that using aOW-HTO to steepen the PTS and a larger TTA may reduce the stress at the “killer turn” during PCL reconstruction. The usefulness and safety of this surgical procedure need to be evaluated in future clinical studies.

A novel and fun exercise robot (LOCOBOT) was developed to improve balance ability. This system can control a spherical robot on a floor by changing the center of pressure (COP) based on weight-shifting on a board. The present study evaluated leg muscle activity and joint motion during LOCOBOT exercise and compared the muscle activity with walking and sit-to-stand movement. This study included 10 healthy male adults (age: 23.0 ± 0.9 years) and examined basic LOCOBOT exercises (front–back, left–right, 8-turn, and bowling). Electromyography during each exercise recorded 13 right leg muscle activities. Muscle activity was represented as the percentage maximal voluntary isometric contraction (%MVIC). Additionally, the joint motion was simultaneously measured using an optical motion capture system. The mean %MVIC differed among LOCOBOT exercises, especially in ankle joint muscles. The ankle joint was primarily used for robot control. The mean %MVIC of the 8-turn exercise was equivalent to that of walking in the tibialis anterior, and the ankle plantar flexors were significantly higher than those in the sit-to-stand motion. Participants control the robot by ankle strategy. This robot exercise can efficiently train the ankle joint muscles, which would improve ankle joint stability.

Background: It remains unclear what percentage of isolated meniscal tears deteriorates before surgery, especially in older patients. We aimed to evaluate the preoperative deterioration of an isolated meniscal tear in patients aged 40 years or older, and whether time from injury to surgery is associated with worsening of a meniscal tear.Methods: Patients aged 40 years or older who underwent arthroscopic surgery for isolated meniscal tear between 2014 and 2019 were retrospectively reviewed. The diagnostic magnetic resonance imaging (MRI) findings and arthroscopic findings were compared to evaluate the deterioration of meniscal tears. Predictors of the development of meniscal tears; patient demographic factors, duration from injury to surgery (injury to MRI and MRI to surgery), and image findings were assessed. Results: A total of 58 patients (58 knees) were included (mean age, 55.9 ± 8.5 years; male/female, 31/27). An isolated meniscal tear deteriorated in 28 (48.3%). In comparison of patients with and without deteriorated meniscal tear, significant differences were found in the MRI grade of meniscal tear (p = 0.03), duration from injury to MRI (164.2 ± 167.9 vs. 45.2 ± 48.7 days, p < 0.001), and from MRI to surgery (148.8 ± 91.1 vs. 67.6 ± 56.7 days, p < 0.001). A multivariate regression analysis showed that the duration from injury to MRI (odds ratio [OR], 1.03; p < 0.001) and from MRI to surgery (OR, 1.02; p < 0.001) were independent predictors of worsening of a meniscal tear. Conclusions: Approximately 50% of isolated meniscal tears deteriorated preoperatively in patients aged 40 years or older. The duration from injury to MRI and from MRI to surgery were independent predictors of the preoperative worsening of an isolated meniscal tear in this cohort.

Background Elbow injuries are common in young baseball players and evaluating the characteristics of young baseball players in a large-scale population is necessary. However, few studies have compared playing position, length of baseball experience, physical findings, and elbow pain in young baseball players. This retrospective multi-regional cohort study sought to document the physical findings at the elbow in Japanese elementary school baseball players and to examine the relationship between playing position, length of baseball experience, physical findings at the elbow, and elbow pain. Methods In 2014, 720 fifth-grade baseball players from four regions in Japan were invited to participate in a questionnaire survey and undergo physical examination to obtain data on position played, length of baseball experience, presence of elbow pain, and physical findings at the elbow, including range of motion, tenderness, and valgus stress test results. Potential risk factors associated with elbow pain and correlations between physical findings and playing position, length of baseball experience, and elbow pain were investigated. Results The 720 subjects had a mean age of 10.4 years and 29.4% reported having experienced elbow pain for ≥1 week. Risk factors for elbow pain included playing pitcher and catcher, playing pitcher and fielder, and length of baseball experience. The most frequent finding was limitation of flexion (21.1%) followed by tenderness of the medial epicondyle (18.3%) and a positive valgus stress test (14.3%). These three findings were also significantly associated with elbow pain. Elbow extension was limited in 14.9% of subjects but there was no correlation with length of baseball experience or elbow pain. Conclusions Our data show that elementary school baseball players who experienced elbow pain are likely to have valgus stress overload. Elbow pain might be prevented by not playing pitcher and catcher.

This study aimed to estimate the prevalence of locomotive syndrome (LS) risk in age groups using the LS risk test proposed by the Japanese Orthopaedic Association. Based on this, this study identified the lifestyle-related signs that lead to LS, by clarifying the association between LS risk and lifestyle factors.A total of 728 individuals aged 20-91 years who were without specific mobility disorders were evaluated. Participants were asked to perform the LS risk test and complete a self-administered original questionnaire survey for this study. The Mann-Whitney U test was used to examine the relationships of sex and age with LS. The prevalence of LS by sex and age was compared using the Chi-squared test or Student's t-test, as appropriate. The Mantel-Haenszel test was used to examine the relationship of each component of the lifestyle factors.Overall, 36.4% of males and 49.1% of females were classified into the LS group; the prevalence of LS was significantly higher in females than males (p .001). The prevalence of LS tended to increase with age in both males and females (p .05). As for health condition, pain in the locomotive organs, knees, back, and hip joints was significantly associated with LS (p .05). Of the lifestyle-related diseases, only hypertension (p .05) was significantly associated with LS, and drug treatment was significantly associated with LS (p .05). As for lifestyle, anxiety about physical fitness, self-assessed poor health, irregular dietary habits, and lack of exercise were also associated with LS (p .05).Interventions to prevent LS are important during its early stages, especially for females, and lifestyle-related signs of LS, such as pain in the locomotive organs, lifestyle-related disease, drug treatment, and a lower subjective evaluation of health must not be overlooked.

Few studies have reported injuries and physical characteristics in adolescent weightlifters. The purpose of this study was to report the results of orthopaedic medical examinations in adolescent amateur weightlifters that were performed cross-sectionally from 2012 to 2019. The orthopaedic medical examination included physical examinations, generalized joint laxity, muscle and joint tightness, static alignment, muscle volume of the lower extremities, and medial longitudinal arch of the foot (the height from the tip of the navicular tubercle to the ground surface). A questionnaire survey regarding pain in the spine and lower extremities was also performed. A total of 99 adolescent weightlifters were included (male/female, 71/28; mean age, 16.2 ± 0.2 years). A total of 9.1% had received orthopaedic treatments, with spine injuries being the most prevalent. Of those who had not received orthopaedic treatments, 31.1% had pain in the spine or lower extremities (for >4 weeks). There were no significant gender differences in the incidence of pain or positive findings of physical examinations. Female weightlifters had a more reduced dorsiflexion of the ankle joint than male weightlifters (p = 0.02). Male weightlifters had a lower flexibility of the quadriceps than female weightlifters. The results of orthopaedic medical examinations in this study may help clinicians and young weightlifters to prevent injuries in competitive weightlifting.

Osteochondral lesion (OCL) of the patellofemoral (PF) joint is not an uncommon cause of knee pain, and surgery is needed when conservative treatment fails. However, there is a lack of evidence regarding the optimal surgical treatment for OCL of the PF joint. Fixation of OCLs using autogenous osteochondral grafts has been reported to be effective for OCL of the knee. However, in this surgical technique, the biomechanical strength of osteochondral grafts may not be sufficient in patients with open physes due to the specific quality of the cartilage and subchondral bone given their age. There is a lack of studies reporting fixation of the OCL located in the PF joint using autogenous osteochondral grafts. We herein report a case of OCL of the femoral intercondylar groove where autogenous osteochondral grafts augmented with bioabsorbable pins were used to fix the lesion in a 14-year-old patient with open physes. Preoperative MRI revealed a completely detached OCL of the intercondylar groove (36 mm × 20 mm). Although a total of four osteochondral grafts were harvested from the non-weightbearing area of the lateral femoral condyle, cartilage detached from one of the grafts. The quality of the osteochondral grafts was considered to be insufficient for stabilization of the OCL; thus, two bioabsorbable pins were additionally inserted following fixation of the lesion using three osteochondral grafts. After two years of follow-up, postoperative functional scores were favorable without knee pain. The present case suggests that fixation of the OCL using autogenous osteochondral grafts may not be appropriate for young patients with open physes.