Aging effects on osteoclast progenitor dynamics affect variability in bone turnover via feedback regulation.

Bone turnover markers (BTMs) are commonly used in osteoporosis treatment as indicators of cell activities of bone-resorbing osteoclasts and bone-forming osteoblasts. The wide variability in their values due to multiple factors, such as aging and diseases, makes it difficult for physicians to utilize them for clinical decision-making. The progenitors of osteoclasts and osteoblasts are indispensable for a comprehensive interpretation of the variability in BTM values because these upstream progenitors strongly regulate the downstream cell activities of bone turnover. However, understanding the complex interactions among the multiple populations of bone cells is challenging. In this study, we aimed to gain a fundamental understanding of the mechanism by which the progenitor dynamics affect the variability in bone turnover through in silico experiments by exploring the cell dynamics with aging effects on osteoporosis. Negative feedback control driven by the consumptive loss of progenitors prevents rapid bone loss due to excessive bone turnover, and through feedback regulation, aging effects on osteoclast differentiation and osteoclast progenitor proliferation cause variability in the osteoclast and osteoblast activity balance and its temporal transition. By expressing the variability in the bone turnover status, our model describes the individualities of patients based on their clinical backgrounds. Therefore, our model could play a powerful role in assisting tailored treatment and has the potential to resolve the various health problems associated with osteoporosis worldwide.

Embryonal and alveolar rhabdomyosarcoma in adolescents/young adults, adults and older adults: a population-based cohort study.

BACKGROUND: The clinical characteristics, outcomes, and prognostic factors of adult embryonal rhabdomyosarcomas (ERMS) and alveolar rhabdomyosarcomas (ARMS), particularly the differences among adolescents/young adults (AYA), adults, and older adults, remain unclear. We assessed the clinicopathological features and survival outcomes of adult patients with ERMS and ARMS in Japan and to compare these features among AYA, adult, and older adult patients. METHODS: We retrospectively analyzed data from the Bone and Soft Tissue Tumor Registry of Japan and enrolled patients aged ≥15 years with ERMS and ARMS. Disease-specific overall survival (DOS) was estimated using the Kaplan-Meier method, and a Cox regression model was used to identify prognostic factors. RESULTS: Among 184 patients with ERMS and ARMS (median age, 27 years; interquartile range, 18-49 years), a high rate of distant and regional nodal metastases was initially observed in 65 (35%) and 66 (36%) cases, respectively. Older age and distant metastasis at first presentation were statistically poor prognostic factors, and histological subtype and site of tumor origin were not associated with DOS. In patients with localized ERMS and ARMS, older age and nodal metastasis were poor prognostic factors; the 5-year DOS rates of patients with and without nodal metastasis were 23% and 72%, respectively. CONCLUSIONS: Older patients with rhabdomyosarcoma had a dismal prognosis, and distant metastasis was a poor prognostic factor. The prognostic factors differed between adult and pediatric patients with rhabdomyosarcoma; biological analyses, such as genome analysis of adult rhabdomyosarcoma and clinical trials with pediatric oncologists, are needed to improve the prognosis of adult rhabdomyosarcoma.

Effect of single-radius design on in vivo kinematics during stair activities after total knee arthroplasty.

BACKGROUND: The single-radius design is one of the major total knee arthroplasty (TKA) designs and widely used all over the world. The objective of this study was to compare in vivo kinematics between the anteroposterior (AP) single-radius design with mediolateral (ML) single-radius (Non Restricted Geometry; NRG) and ML dual-radius (Triathlon) during stair activities. METHODS: A total of 21 knees in 18 patients (NRG group: 10 knees in 7 patients, Triathlon group: 11 knees in 11 patients) with a clinically successful posterior stabilized TKA were examined. Under fluoroscopic surveillance, each patient performed stair ascending and descending motions. In vivo kinematics were analyzed using 2D/3D registration technique. The knee flexion angle, rotation angle, varus-valgus angle, AP translation of the femorotibial contact point for both the medial and lateral sides of the knee, and post-cam engagement were evaluated. RESULTS: There were no significant differences between the two groups in rotation angle and AP translation at each flexion angle. Examining the varus-valgus angle, the NRG group showed varus position at an early flexion angle during both stair activities.Post-cam engagement was observed in both groups during both stair activities. The mean flexion angle of engagement in the NRG group, the post of which was located anterior to the Triathlon, was larger than that in the Triathlon group during both stair activities. CONCLUSION: Despite the same AP single-radius TKA, ML single-radius might affect varus motion at an early flexion angle.

Intraoperative reliability of the tibial anteroposterior axis "Akagi's Line" in total knee arthroplasty.

Purpose: The tibial anatomical anteroposterior (AP) axis "Akagi's line" was originally defined on computed tomography (CT) in total knee arthroplasty (TKA); however, its intraoperative reproducibility remains unknown. This study aimed to evaluate the intraoperative reproducibility of the Akagi's line and its effect on postoperative clinical outcomes. Methods: This prospective study included 171 TKAs. The rotational angle of the intraoperative Akagi's line relative to the original Akagi's line (RAA) defined on CT was measured. The RAA was calculated based on the tibial component rotational angles relative to the intraoperative Akagi's line measured using the navigation system and CT. The effects of RAA on postoperative clinical outcomes and rotational alignments of components were also evaluated. Results: The mean absolute RAA (standard deviation) value was 5.5° (3.9°). The range of RAA was 22° internal rotation to 16° external rotation. Intraoperative Akagi's line outliers (RAA > 10°) were observed in 14% of the knees (24 knees). In outlier analysis, the tibial component rotation angle was externally rotated 6.5° (5.6°) in the outlier group and externally rotated 3.7° (4.2°) in the nonoutlier group (≤10°), with a significant difference between the two groups. Additionally, the outlier group (RAA > 10°) showed lower postoperative clinical outcomes. Conclusion: The original Akagi's line defined on CT showed insufficient reproducibility intraoperatively. The poor intraoperative detection of Akagi's line could be the reason for the tibial component rotational error and worse postoperative clinical outcomes. Level of Evidence: Level IV, case series.

Postoperative Complications of Surgery for Cervical Spondylotic Myelopathy with and Without Athetoid Cerebral Palsy.

STUDY DESIGN: Retrospective cohort study. OBJECTIVES: With the aging of the Japanese population, patients with athetoid cerebral palsy (ACP) are getting older, and the rate of surgery for CSM is increasing in ACP patients. However, postoperative complications of such surgery among adult patients with ACP have not been reported yet. We investigated postoperative complications of surgery for CSM with ACP and compared them with those of surgery for CSM without ACP using a national inpatient database of Japan. METHODS: Using the Diagnosis Procedure Combination database, we identified 61382 patients who underwent surgery for CSM from July 2010 to March 2018. We examined patient backgrounds, surgical procedures, and type of hospital, and a 4:1 propensity score matching was performed to compare the outcomes between the non-ACP and ACP groups. RESULTS: There were 60 847 patients without ACP and 535 patients with ACP. The mean age was 68.5 years in the non-ACP group and 55 years in the ACP group. The percentages of patients who underwent fusion surgery were 21.6% and 68.8% in the non-ACP and ACP groups, respectively. The 4:1 propensity score matching selected 1858 in the non-ACP group and 465 in the ACP group. The ACP group was more likely to have postoperative urinary tract infection (.4% vs 2.8%, P < .001), postoperative pneumonia (.4% vs 2.4%, P < .001), and 90-day readmission for reoperation (1.9% vs 4.3%, P = .003). CONCLUSIONS: We found that ACP patients were more vulnerable to postoperative complications and reoperation after CSM than non-ACP patients.

Ten-year trends in values of joint space width and osteophyte area of knee joints: Comparison of the baseline and fourth ROAD study surveys.

Objective: Considering the joint space width and osteophyte area (OPA) of the knee joints of Japanese adults, this study elucidated the ten-year trends in medial minimum joint space width (mJSW) and OPA using data of two independent cohorts from a population-based cohort study. Methods: The baseline survey of the Research on Osteoarthritis/Osteoporosis Against Disability study was conducted from 2005 to 2007; 2975 participants (1041 men, 1934 women) completed all knee osteoarthritis (OA) examinations. The fourth survey was performed from 2015 to 2016; distinct 2445 participants (764 men, 1681 women) completed identical examinations. The medial mJSW and medial tibial OPA were measured bilaterally using an automated system. Results: The mean medial mJSW (standard deviation) was 3.22 (0.96) mm and 2.65 (0.95) mm at baseline and 3.81 (1.20) mm and 3.13 (1.15) mm in the fourth survey for men and women, respectively. The mean medial mJSW in the fourth survey was significantly greater in both men and women in all age groups than at baseline (p â€‹< â€‹0.01). The mean OPAs in men aged 40-49 and 60-69 years and women aged 40-49, 50-59, 60-69, and 70-79 years were significantly smaller in the fourth survey (p â€‹< â€‹0.05). The trend in mJSW remained the same even after adjusting for confounding factors in the multivariate analysis, but the trend in OPA was weakened. Conclusions: A significant improvement in the medial mJSW within 10 years could decrease the incidence and progression of knee OA and prevent the risk of walking disability.

Clinical genomic profiling of malignant giant cell tumor of bone: A retrospective analysis using a real­world database.

Malignant giant cell tumor of bone (GCTB) is identified by the presence of multinucleated giant cells, with an aggressive behavior and a high risk of metastasis, which has not been genetically characterized in detail. H3 histone family member 3A (H3F3A) gene mutations are highly recurrent and specific in GCTB. The present study analyzed the clinical information and genomic sequencing data of eight cases of malignant GCTB (out of 384 bone sarcoma samples) using an anonymized genomic database. There were 5 males and 3 females among the cases, with a median age of 33 years at the time of the initial diagnosis. H3F3A G34W and G34L mutations were detected in 3 patients and 1 patient, respectively. In 75% of cases without H3F3A mutation, mitogen-activated protein kinase (MAPK) signaling pathway gene alterations were found (KRAS single nucleotide variant, KRAS amplification, nuclear respiratory factor 1-BRAF fusion). Moreover, the collagen type I alpha 2 chain-ALK fusion was detected in remaining one case. The most frequent gene alterations were related to cell cycle regulators, including TP53, RB1, cyclin-dependent kinase inhibitor 2A/B and cyclin E1 (75%, 6 of 8 cases). On the whole, the present study discovered recurrent MAPK signaling gene alterations or other gene alterations in cases of malignant GCTB. Of note, two fusion genes should be carefully validated following the pathology re-review by sarcoma pathologists. These two fusion genes may be detected in resembling tumors, which contain giant cells, apart from malignant GCTB. The real-world data used herein provide a unique perspective on genomic alterations in clinicopathologically diagnosed malignant GCTB.

Automatic estimation of hallux valgus angle using deep neural network with axis-based annotation.

OBJECTIVES: We developed the deep neural network (DNN) model to automatically measure hallux valgus angle (HVA) and intermetatarsal angle (IMA) on foot radiographs. The objective is to assess the accuracy of the model by comparing to the manual measurement of foot and ankle surgeons. MATERIALS AND METHODS: A DNN was developed to predict the bone axes of the first proximal phalanx and all metatarsals from the first to the fifth in foot radiographs. The dataset used for model development consisted of 1798 radiographs collected from a population-based cohort and patients at our foot and ankle clinic. The retrospective validation cohort comprised of 92 radiographs obtained from 92 consecutive patients visiting our foot and ankle clinic. The mean absolute error (MAE) between automatic measurements by the model and the median of manual measurements by three foot and ankle surgeons was compared to 3° using one-tailed t-test and was also compared to the inter-rater difference in manual measurements among the three surgeons using two-tailed paired t-test. RESULTS: The MAE for HVA was 1.3° (upper limit of 95% CI 1.6°), and this was significantly smaller than the inter-rater difference of 2.0 ± 0.2° among the surgeons, demonstrating the superior accuracy of the model. In contrast, the MAE for IMA was 0.8° (upper limit of 95% CI 1.0°) that showed no significant difference from the inter-rater difference of 1.0 ± 0.1° among the surgeons. CONCLUSION: Our model demonstrated the ability to measure the HVA and IMA with an accuracy comparable to that of specialists.

The 2023 Guidelines for the management and treatment of glucocorticoid-induced osteoporosis.

INTRODUCTION: Although synthetic glucocorticoids (GCs) are commonly used to treat autoimmune and other diseases, GC induced osteoporosis (GIOP) which accounts for 25% of the adverse reactions, causes fractures in 30-50% of patients, and markedly decreases their quality of life. In 2014, the Japanese Society for Bone and Mineral Research (JSBMR) published the revised guidelines for the management and treatment of steroid-induced osteoporosis, providing the treatment criteria based on scores of risk factors, including previous fractures, age, GC doses, and bone mineral density, for patients aged ≥18 years who are receiving GC therapy or scheduled to receive GC therapy for ≥3 months. MATERIALS AND METHODS: The Committee on the revision of the guidelines for the management and treatment of GIOP of the JSBMR prepared 17 clinical questions (CQs) according to the GRADE approach and revised the guidelines for the management and treatment of GIOP through systematic reviews and consensus conferences using the Delphi method. RESULTS: Bisphosphonates (oral and injectable formulations), anti-RANKL antibody teriparatide, eldecalcitol, or selective estrogen receptor modulators are recommended for patients who has received or scheduled for GC therapy with risk factor scores of ≥3. It is recommended that osteoporosis medication is started concomitantly with the GC therapy for the prevention of fragility fractures in elderly patients. CONCLUSION: The 2023 guidelines for the management and treatment of GIOP was developed through systematic reviews and consensus conferences using the Delphi method.

In Vivo Kinematics and Cruciate Ligament Tension Are Not Restored to Normal After Bicruciate-Preserving Arthroplasty.

BACKGROUND: Whether cruciate ligament forces in cruciate-preserving designs, such as unicompartmental knee arthroplasty (UKA) or bi-cruciate-retaining total knee arthroplasty (BCR-TKA), differ from those in normal knees remains unknown. The purpose of this study was to compare the in vivo kinematics and cruciate ligament force in knees before and after UKA or BCR-TKA to those in normal knees during high-flexion activity. METHODS: Overall, twenty normal knees, 17 knees with medial UKA, and 15 knees with BCR-TKA were fluoroscopically examined while performing a squatting activity. A 2-dimensional or 3-dimensional registration technique was employed to measure tibio-femoral kinematics. Ligament strains and tensions in the anteromedial bundle of the anterior cruciate ligament and posterolateral bundle of the anterior cruciate ligament and the anterolateral bundle of the posterior cruciate ligament (aPCL) and posteromedial bundle of the posterior cruciate ligament (pPCL) during knee flexion were analyzed. RESULTS: Tension in both bundles of the anterior cruciate ligament decreased with flexion. At 60° of flexion, anteromedial bundle of the anterior cruciate ligament tension in postoperative UKA knees was greater than that in normal knees. At 30° of flexion, posterolateral bundle of the anterior cruciate ligament tension in postoperative UKA knees was greater than that in normal knees. On the other hand, aPCL and pPCL tensions increased with flexion. From 40 to 110° of flexion, the postoperative aPCL tension in UKA knees was greater than that in normal knees. At 110° of flexion, the preoperative pPCL tension in UKA knees was greater than that in normal knees. In addition, the postoperative pPCL tension in UKA knees was larger than that in normal knees beyond 20° of flexion. Furthermore, the pPCL tension of postoperative BCR-TKA knees was larger than that in normal knees from 20 to 50° and beyond 90° of flexion. CONCLUSIONS: The cruciate ligament tensions, especially posterior cruciate ligament tension in knees after UKA, were greater than those in the normal knees. Surgeons performing bi-cruciat-preserving knee arthroplasties should therefore balance cruciate ligament tension more carefully in flexion and extension.

Treatment for complete extensor tendon rupture: A case report on extensor pollicis longus tendon transfer and tenodesis procedure to radius for a patient with rheumatoid arthritis.

The complete loss of finger extension leads to significant inconvenience in daily life and often requires surgical treatment. Despite some disadvantages, the Boyes method, which uses the flexor digitorum superficialis tendon, is commonly performed for complete extensor rupture. We report the case of a 73-year-old woman living alone diagnosed with a subcutaneous rupture of all extensor tendons from the index to the little finger. The favourable range of motion of her wrist allowed us to perform extensor tenodesis. Additionally, the patient had a dislocated thumb interphalangeal (IP) joint, enabling us to use the extensor pollicis longus (EPL) tendon for tendon transfer in combination with thumb IP joint fusion. The patient demonstrated favourable finger range-of-motion outcomes at the 6-month postoperative assessment. The case shows that EPL tendon transfer and tenodesis may be a viable treatment option for patients with complete extensor rupture accompanied by thumb IP joint deformity and normal wrist range of motion.

Anti-osteoporotic drug efficacy for periprosthetic bone loss after total hip arthroplasty: A systematic review and network meta-analysis.

BACKGROUND: Periprosthetic bone loss following total hip arthroplasty (THA) threatens prosthesis stability. This systematic review and network meta-analysis aimed to compare the efficacy of anti-osteoporotic drugs for measures of hip function according to functional outcomes, periprosthetic femoral bone mineral density loss in each Gruen zone, and revision surgery after THA. METHODS: The systematic search of six literature databases was conducted in December 2021 in accordance with PRISMA guidelines. Adult participants who underwent primary THA were included. A random-effects network meta-analysis was performed within a frequentist framework, and the confidence in the evidence for each outcome was evaluated using the CINeMA tool, which assessed the credibility of results from the network meta-analysis. We included 22 randomized controlled trials (1243 participants) comparing the efficacy and safety of bisphosphonates (including etidronate, clodronate, alendronate, risedronate, pamidronate, and zoledronate), denosumab, selective estrogen receptor modulator, teriparatide, calcium + vitamin D, calcium, and vitamin D. We defined the period for revision surgery as the final follow-up period. RESULTS: Raloxifene, bisphosphonate, calcium + vitamin D, and denosumab for prosthetic hip function might have minimal differences when compared with placebos. The magnitude of the anti-osteoporotic drug effect on periprosthetic femoral bone loss varied across different Gruen zones. Bisphosphonate, denosumab, teriparatide might be more effective than placebo in Gruen zone 1 at 12 months after THA. Additionally, bisphosphonate might be more effective than placebo in Gruen zones 2, 5, 6, and 7 at 12 months after THA. Denosumab was efficacious in preventing bone loss in Gruen zones 6 and 7 at 12 months after THA. Teriparatide was likely to be efficacious in preventing bone loss in Gruen zone 7 at 12 months after THA. Raloxifene was slightly efficacious in preventing bone loss in Gruen zones 2 and 3 at 12 months after THA. Calcium was slightly efficacious in preventing bone loss in Gruen zone 5 at 12 months after THA. None of the studies reported revision surgery. CONCLUSIONS: Bisphosphonate and denosumab may be effective anti-osteoporotic drugs for preventing periprosthetic proximal femoral bone loss due to stress shielding after THA, particularly in cementless proximal fixation stems, which are the most commonly used prostheses worldwide.

In vivo three-dimensional kinematic comparison of normal knees between flexion and extension activities.

Background/Objective: Normal knee kinematics during flexion and extension activities over the whole range of motion remains unknown. This study aimed to clarify in vivo kinematics during knee flexion and extension activities of normal knees by comparing continuous flexion and extension activities up to a high flexion angle. Methods: Twenty knees of 10 Japanese volunteers were enrolled in this study. Each volunteer performed a continuous squatting motion under fluoroscopy, and a two- or three-dimensional registration technique was used. Rotation and anteroposterior translation of the medial and lateral sides of the femur relative to the tibia at each flexion angle were evaluated. Results: Femoral external rotation was significantly smaller from 10° to 40° flexion during extension activities than during flexion activities. However, the femoral external rotation was larger from 120° to 130° flexion during extension activities than during flexion activities. From 10° to 60° of flexion, the medial side was significantly more posteriorly located during extension activities than during flexion activities. Furthermore, the lateral side was significantly more posteriorly located at 130° of flexion during extension activities than during flexion activities. Conclusion: In vivo kinematics of normal knees during extension activities differ from those during flexion activities in early and high flexion.

Factors Associated With a Lateral Ankle Sprain in Young Female Soccer Players: A Prospective Cohort Study.

Background: Previous studies have attempted to determine if certain risk factors can predict the occurrence of a lateral ankle sprain (LAS) in female soccer players. Unfortunately, there is limited evidence with regard to risk factors associated with an LAS in female soccer players. Purpose: To identify intrinsic risk factors for an LAS among young female soccer players. Study Design: Cohort study; Level of evidence, 2. Methods: Participants were 161 young female soccer players in Japan who were evaluated for LAS risk factors during a preseason medical assessment. The assessment included anthropometric, joint laxity, joint range of motion, muscle flexibility, muscle strength, and balance measurements. Each athlete's history of LASs was also collected. The participants were monitored during a single-yearseason for LASs, as diagnosed by physicians. Results: There were 26 instances of an LAS in 25 players (15.5%) during the season. Injured players were significantly more likely to have sustained a previous ankle sprain (P = .045) and demonstrated significantly worse balance than their peers without an LAS during the double- and single-leg balance tests (P = .008 for both). Athletes with lower hamstring-to-quadriceps muscle strength ratios were also significantly more likely to sustain an LAS (P = .02). Conclusion: Poor balance, a low hamstring-to-quadriceps ratio, and a history of ankle sprains were associated with an increased risk of LASs in young female soccer players in the current study. These findings may be useful for developing a program to prevent LASs in this population.

In Vivo Kinematic Analysis of Mobile-Bearing Unicompartmental Knee Arthroplasty during High Flexion Activities.

Mobile-bearing (MB) unicompartmental knee arthroplasty (UKA) has high conformity between the femoral articular surface and the meniscal bearing; therefore, the surface and subsurface contact stress is reduced. Additionally, the survival rate is high. However, the in vivo kinematics of MB UKA knees during high-flexion activities of daily living remain unknown. The aim of this study was to investigate in vivo the three-dimensional kinematics of MB UKA knees during high-flexion activities of daily living. A total of 17 knees of 17 patients who could achieve kneeling after MB UKA were examined. Under fluoroscopy, each patient performed squatting and kneeling motions. To estimate the spatial position and orientation of the knee, a two-dimensional/three-dimensional registration technique was used. We evaluated the femoral rotation and varus-valgus angle relative to the tibia and the anteroposterior translation of the medial sulcus (medial side) and lateral epicondyle (lateral side) of the femur on the plane perpendicular to the tibial mechanical axis in each flexion angle. From 130° to 140° of flexion, the femoral external rotation during squatting was significantly smaller than that during kneeling. Additionally, the medial side of the femur during squatting was significantly more posteriorly located compared with that during kneeling. There was no significant difference between squatting and kneeling in terms of the lateral side of the femur and the varus-valgus position in each flexion angle. At high flexion angle, the kinematics of MB UKA knees may differ depending on the performance.

Coexisting Lower Back Pain in Patients With Cervical Myelopathy.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: The aim of the present study is to investigate the coexisting lower back pain (LBP) in patients with cervical myelopathy and to evaluate changes in LBP after cervical spine surgery. SUMMARY OF BACKGROUND DATA: Only a few studies with a small number of participants have evaluated the association between cervical myelopathy surgery and postoperative improvement in LBP. METHODS: Patients who underwent primary cervical decompression surgery with or without fusion for myelopathy and completed preoperative and 1-year postoperative questionnaires were reviewed using a prospectively collected database involving 9 tertiary referral hospitals. The questionnaires included the patient-reported Japanese Orthopaedic Association (PRO-JOA) score and Numerical Rating Scales (NRS). The minimum clinically important difference (MCID) for NRS-LBP was defined as >30% improvement from baseline. Patient demographics, characteristics, and PRO-JOA score were compared between patients with and without concurrent LBP, and the contributor to achieving the MCID for LBP was analyzed using logistic regression analysis. RESULTS: A total of 786 consecutive patients with cervical myelopathy were included, of which 525 (67%) presented with concurrent LBP. LBP was associated with a higher body mass index (P<0.001) and worse preoperative PRO-JOA score (P<0.001). Among the 525 patients with concurrent LBP, the mean postoperative NRS-LBP significantly improved from 4.5±2.4 to 3.4±2.7 (P<0.01) postoperatively, with 248 (47%) patients reaching the MCID cutoff. Patients with a PRO-JOA recovery rate >50% were more likely to achieve MCID compared with those with a recovery rate <0% (adjusted odd ratio 4.02, P<0.001). CONCLUSIONS: More than 50% of patients with myelopathy reported improvement in LBP after cervical spine surgery, and 47% achieved the MCID for LBP, which was positively correlated with a better PRO-JOA recovery rate. Treating cervical myelopathy in patients with concomitant LBP may be sufficient to mitigate concomitant LBP. LEVEL OF EVIDENCE: Level Ⅲ.

Factors associated with cam deformity in Japanese local residents.

Femoroacetabular impingement has increasingly been recognized as a cause of primary hip osteoarthritis; however, its epidemiological indications remain unclear. We aimed to clarify the epidemiological indications and factors associated with cam deformity in a large-scale population-based cohort in Japan. Overall, 1480 participants (2960 hips) (491 men, 989 women; mean age, 65.3 years) analyzed in the third survey of the Research on Osteoarthritis/Osteoporosis Against Disability study were included. The α angle and spinopelvic parameters (lumbar lordosis, sacral slope, pelvic tilt, and pelvic incidence) were radiographically measured. Cam deformity was defined as α angle ≥ 60°. Overall, the cam deformity prevalence was 147/2960 (5.0%). Cam deformity prevalence tended to increase with age; in the univariate analysis, a higher percentage of men was observed in the group with cam deformity than in the group without it. No relationship was observed between cam deformity and hip pain. Factors associated with α angle were examined via multiple regression analysis for each gender; α angle was significantly associated with age and BMI in each gender. The α angle and PT were correlated in women. Thus, α angle and cam deformity prevalence increase with age in Japanese individuals. Accordingly, cam deformity can be considered a developmental disease.

Lower hamstring to quadriceps muscle strength ratio and lower body weight as factors associated with noncontact anterior cruciate ligament injury in male American football players: A prospective cohort study.

Background: Previous studies have aimed to determine the use of certain risk factors in predicting the occurrence of noncontact anterior cruciate ligament (ACL) injuries. Unfortunately, evidence regarding noncontact ACL injuries in male American football players is limited. This prospective cohort study aimed to identify intrinsic risk factors for noncontact ACL injury among male American football players. Methods: This study evaluated 152 male American football players in Japan for potential noncontact ACL injury risk factors during a preseason medical assessment, including anthropometric, joint laxity, and flexibility, muscle flexibility, muscle strength, and balance measurements. A total of 25 variables were examined. Participants were monitored during each season for noncontact ACL injury, as diagnosed by physicians. Results: Noncontact ACL injuries occurred in 11 knees of 11 players (prevalence; 7.1 %). Injured players were significantly more likely to have lightweight (P = 0.049). No statistically significant between-group differences were found for any other variables. Participants with a lower hamstring to quadriceps (H/Q) ratio (P = 0.04) were more likely to sustain noncontact ACL injuries. Conclusion: Lower H/Q ratio and lower body weight were significantly associated with new-onset noncontact ACL injury in male American football players. These findings will help develop strategies to prevent noncontact ACL injuries in male American football players.

Prognostic factors and treatment outcomes in patients with pleomorphic rhabdomyosarcoma: a population-based cohort study.

BACKGROUND: Pleomorphic rhabdomyosarcoma is a rare sarcoma in adults. The clinical characteristics, outcomes and prognostic factors associated with pleomorphic rhabdomyosarcoma remain unclear. METHODS: We retrospectively analyzed data from the Bone and Soft Tissue Tumor Registry of Japan, and enrolled patients with pleomorphic rhabdomyosarcoma. Disease-specific overall survival, local recurrence-free survival and distant metastasis-free survival were estimated using the Kaplan-Meier method; Cox regression model was used to identify prognostic factors. RESULTS: In total, 182 patients with pleomorphic rhabdomyosarcoma were included. Median age was 63 (range 20-95) years. The lower extremity (48%) was the most frequent tumor origin site, while head and neck were rare (4%). A total of 43 patients (24%) had distant or regional nodal metastases at first presentation. In all cases, the 2-year and 5-year survival rates were 66.3% and 54.1%, respectively. Distant metastasis was a significant poor prognostic factor (Hazard ratio 6.65; 95% confidence intervals, 3.00-14.75, P < 0.0001), with median survival of such patients being 9.4 (95% confidence intervals: 5.3-12.2) months. In 134 localized cases, the 2-year and 5-year survival rates were 91.5% and 68.3%, respectively. Large tumor size and older age were associated with poorer prognosis. Through data from localized and locally curative cases extracted and adjusted by propensity score matching, we found that perioperative chemotherapy did not improve disease-specific overall survival, distant metastasis-free survival or local recurrence-free survival. CONCLUSIONS: Clinical characteristics and outcomes of pleomorphic rhabdomyosarcoma are similar to those of other high-grade soft tissue sarcomas. Pleomorphic rhabdomyosarcoma may be less chemosensitive, and a strategy other than the standard cytotoxic chemotherapy is required to improve its prognosis.

Extended curettage for tumour-induced osteomalacia in the bone.

BACKGROUND: extended curettage is generally used to treat infiltrative bone tumours. However, the extent of the curettage performed in previous studies remains unclear. This study aimed to investigate the efficacy of extended curettage for bone tumour-induced osteomalacia. METHODS: we included 12 patients with tumour-induced osteomalacia who underwent extended curettage at our hospital between 2000 and 2022. Extended curettage was applied in cases where tumour resection could cause functional impairment or necessitate complex reconstruction. We investigated patients' clinical and oncological outcomes. RESULTS: patients had a mean age of 55 (24-81) years, and the median follow-up duration after surgery was 3.9 (1.0-14.0) years. The causative tumours were located in the pelvis and lumbar spine. Imaging revealed the tumours to be of the sclerotic, intertrabecular, lytic and mixed types. Intraoperative 3D fluoroscopy was used in 10 patients. Extended curettage with high-speed burring and adjuvant therapy with cauterization using an electric scalpel and ethanol resulted in a remission rate of 83%; no recurrence or metastasis was observed in cases of early postoperative biochemical remission. In cases where the causative tumour was at the lumbar spine and ischium close to the acetabulum, no postoperative biochemical remission was observed, and conservative treatment was continued. Except for one patient with a tumour in the lumbar spine, all patients could walk without a cane. CONCLUSIONS: extended curettage for bone tumour-induced osteomalacia is oncologically and functionally favourable, especially in cases where resection of the causative tumour could cause functional impairment or necessitate complex reconstruction.