Clinical characteristics and prognosis of patients with incidentally discovered chest wall sarcoma compared with those of symptomatic patients.

OBJECTIVE: Sarcomas of the bone and soft tissues are detected after the onset of pain, detectable mass and related symptoms in the absence of a standardized screening examination. However, primary chest wall sarcomas can be incidentally detected upon chest X-ray or computed tomography. Previous studies of incidental primary chest wall sarcomas lack prognosis and disease-specific clinical data. This study aimed to investigate the prognoses of patients with incidental chest wall sarcomas and compare them with those of symptomatic patients. METHODS: This study included 18 patients diagnosed with primary chest wall sarcoma between 2010 and 2023. Patient information such as age, sex, tumour diameter, tumour location, symptoms, treatment, time to treatment initiation, pathological diagnosis and outcome were retrospectively analysed. RESULTS: Among the 18 patients, the sarcomas were incidentally detected in five by chest X-ray and computed tomography in three and two patients, respectively. The pathological diagnoses of the patients were Ewing sarcoma, Chondrosarcoma grade 1, grade 2, periosteal osteosarcoma and malignant peripheral nerve sheath tumour. The patients had no symptoms at the first visit to our hospital, and no lesions in other organs were detected at the time of the initial examination. At the final follow-up, the patients remained disease-free after radical treatment. The tumour sizes of the five patients were significantly smaller than those of patients with symptoms (P = 0.003). CONCLUSIONS: The incidental detection of chest wall sarcomas and consequent early detection and treatment of tumours improves patient prognosis relative to that of symptomatically diagnosed patients.

Knee pain in young sports players aged 6-15 years: a cross-sectional study in Japan.

BACKGROUND: Knee is the most commonly injured part of the body in young athletes. Knee pain in several studies have been seen to be more prevalent in active adolescents compared to inactive, although common in both groups. Nevertheless, few studies with large sample size have been published reporting the difference of the prevalence of knee pain for each sport among young sports players. This study investigated the point prevalence of knee pain among young sports players aged 6-15 years old according to age, sex, and sports discipline. Furthermore, this study investigated the association between knee pain and sports discipline among young sports players. METHODS: A cross-sectional study was conducted using a self-reported questionnaire on young sports players aged 6-15 years from the Miyagi Amateur Sports Association. Multivariable logistic regression models were used to examine the association between knee pain and sports discipline and were adjusted for age, sex, body mass index (BMI), training days per week, and training hours per weekday and weekend. RESULTS: A total of 7234 young sports players were included. The point prevalence of knee pain was 10.9%. Females (13.3%) had more knee pain than males (9.8%). Young, 13-year-old sports players had the highest prevalence of knee pain (19.1%). The multivariable analysis showed that the highest odds ratio [95% confidence interval] was observed for handball players (2.42 [1.01-5.81]). In addition, hand ball, mini-basketball (odds ratio 1.85; 95% CI 1.38-2.47), and basketball (odds ratio 1.66; 95% CI 1.23-2.26) were significantly associated with knee pain, compared with football. The lowest odds ratio was observed for swimming (0.34 [0.05-2.54]), followed by karate (odds ratio 0.38; 95% CI 0.16-0.89) and baseball (odds ratio 0.47; 95% CI 0.35-0.64). CONCLUSION: The prevalence of knee pain among young athletes differed according to age, sex, and sports discipline. Their parents and clinicians should recognize this information to manage knee pain among young sports players.

Sleep disturbance is associated with neck pain: a 3-year longitudinal study after the Great East Japan Earthquake.

BACKGROUND: Neck pain is a common health problem in the general population as well as in people after natural disasters. Sleep disturbances are gaining attention as risk factors for musculoskeletal pain; however, the association between sleep disturbance and neck pain has not been clarified. The present study aimed to clarify the association between sleep disturbance and neck pain, especially focusing on the effect of the duration of sleep disturbance, after the Great East Japan Earthquake. METHODS: This study used 3-year longitudinal data obtained from individuals (n = 2,059) living in disaster-affected areas after the Great East Japan Earthquake. Sleep disturbance and neck pain were investigated at 4, 5, 6, and 7 years after the disaster. Multivariate logistic regression analyses were used for the assessment. RESULTS: Sleep disturbance was significantly associated with neck pain, and the association was stronger as the duration of sleep disturbance increased (adjusted odds ratios [95% confidence intervals]: 1.84 [1.23-2.75] for " < 1 year"; 2.41 [1.53-3.81] for " ≥ 1 year and < 2 years"; 2.80 [2.09-3.76] for " ≥ 2 years"). Furthermore, preceding sleep disturbance was significantly associated with the onset of neck pain, and the association was stronger as the duration of sleep disturbance increased (adjusted odds ratios [95% confidence intervals]: 1.86 [1.08-3.20] for " < 1 year"; 2.39 [1.22-4.70] for " ≥ 1 year and < 2 years"; 3.00 [1.94-4.65] for " ≥ 2 years"). CONCLUSIONS: Sleep disturbance is associated with neck pain, and long-lasting sleep disturbance strengthens the association. Clinicians should consider this association to effectively treat patients with neck pain, especially those affected by natural disasters.

Limb salvage surgery has a higher complication rate than amputation but is still beneficial for patients younger than 10 years old with osteosarcoma of an extremity.

BACKGROUND/PURPOSE: Limb preserving surgery for the treatment of patients with osteosarcoma younger than 10 years old is challenging and some authors have advocated amputation to reduce the risk of complications. The aim of this study was to compare the clinical outcomes and surgical complications of patients with osteosarcoma of the extremity aged <10 years old who were treated with limb salvage and amputation. PATIENTS AND METHODS: Retrospective review of patients aged <10 years old who were treated for primary osteosarcoma of bone between 2000 and 2018. RESULTS: We analyzed 82 consecutive patients (32 males, 50 females; median age 8, range 3-9 yrs). Limb-salvage surgery (LSS; n = 65, 79%) and amputation (n = 17, 21%) were performed. Fourteen patients had metastasis at surgery. In patients without metastasis at surgery, the metastasis-free and overall survival rates at 5 years following LSS vs. amputation were 75% vs. 58% (p = 0.162) and 71% vs. 55% (p = 0.516), respectively. The 2-year and 5-year OS rates of the LSS and amputation groups of patients with metastasis at surgery were 88% versus 83% and 50% versus 0%, respectively (p = 0.180). The overall complication rates were 46% post-LSS with 31% requiring re-operation versus 12% post-amputation, with 6% requiring re-operation (p = 0.010). CONCLUSION: The prognosis of patients with localized osteosarcoma aged <10 years undergoing LSS is similar to those treated with amputation, but LSS is associated with a higher risk of complications and subsequent re-operation. LEVEL OF EVIDENCE: Level III.

Clinical outcome of porous hydroxyapatite/collagen graft on bone defects following curettage of bone tumors.

Hydroxyapatite/collagen (HAp/col) has been reported to be a highly useful bone-like nanocomposite. This study included 33 human patients to investigate the details of the clinical outcomes, which are (1) onset of timing of bone regeneration, (2) replacement by regenerated bone of HAp/col and (3) complications, in human cases grafting HAp/col in large bone defects, following curettage of bone tumors. Porous HAp/col initiated bone regeneration approximately 59 days following the surgery. In 15 cases (45%), complete replacement by newly formed bone was observed 12 months after surgery. On the other hand, incomplete replacement of HAp/col at the final follow-up was observed in 13 cases (39%). In these cases, HAp/col could not be detected in the transparent area of postoperative plain radiographs owing to quick absorption; moreover, it was difficult to distinguish whether the transparent area in plain radiographs was remaining HAp/col, recurrence, or remaining tumor. In addition, larger HAp/col implantation volume (≧15 cm3 ) was associated with poorer result of complete replacement (log-rank, p = .005). Further studies are warranted for the construction of a new artificial bone graft substitute that is more quickly and surely regenerated by newly formed bone in large bone defects.

Tissue accumulation of neutrophil extracellular traps mediates muscle hyperalgesia in a mouse model.

Accumulation of uric acid (UA) during muscular trauma is a factor involved in the development of muscle hyperalgesia. Neutrophil extracellular traps (NETs), DNA-based reticular structures to capture UA, play a central role in the pain onset of gout attacks; however, the involvement of NETs via the elevation of local UA level in muscle hyperalgesia due to injuries from muscle overuse remains unknown. The triceps surae muscles (TSMs) in the unilateral hindlimb of mice were electrically stimulated to induce excessive muscle contraction. Mechanical withdrawal thresholds, tissue UA levels, neutrophil recruitment, and protein amount of citrullinated histone 3 (citH3), a major marker of NETs, were investigated. Furthermore, whether neutrophil depletion, extracellular DNA cleavage, and administration of the urate-lowering agent febuxostat improved muscle hyperalgesia caused by NET formation was examined. CitH3 expression upon neutrophil recruitment was significantly increased in the stimulated TSMs with increased tissue UA levels, whereas febuxostat administration improved muscle hyperalgesia with decreased citH3 and tissue UA levels, as observed in neutrophil depletion and extracellular DNA digestion. The underlying mechanism of muscle hyperalgesia associated with locally recruited neutrophils forming NETs due to increased tissue UA levels potentially plays a significant role in creating a vicious circle of muscle pain.

Factors Associated with Thickening of the Ligamentum Flavum on Magnetic Resonance Imaging in Patients with Lumbar Spinal Canal Stenosis.

STUDY DESIGN: Experimental study of the ligamentum flavum (LF) thickness among patients with lumbar spinal canal stenosis (LSCS). OBJECTIVES: To elucidate the factors associated with thickening of the LF on magnetic resonance imaging (MRI). SUMMARY OF BACKGROUND DATA: Thickening of the LF is a major contributor to LSCS. This thickening is attributed to tissue hypertrophy or buckling of the ligament, and there may be several associated factors on MRI; however, these factors remain unclear. METHODS: We studied the LF in 56 patients (a total of 106 ligaments) with LSCS, who underwent decompressive surgery; among them, 23 were receiving haemodialysis. The Pearson correlation coefficient was used to assess relationships between the thickness of the LF on MRI and the thickness of the LF tissue, age, disc height, disc degeneration, and disc level. Patients were also categorised into 2 groups based on whether they were undergoing haemodialysis, and the relationships were assessed similarly. RESULTS: Among patients with LSCS, the thickness of the LF on MRI showed a significant positive linear relationship with the thickness of the LF tissue, and no association with disc height. Except for in those receiving haemodialysis, the thickness of the LF on MRI showed a significant positive relationship with age, disc degeneration, and disc level among patients with LSCS. CONCLUSION: In patients with LSCS, thickening of the LF on MRI appears to represent tissue hypertrophy. The association between the thickness of the LF on MRI and age, disc degeneration, and disc level may indicate simultaneous alterations of spine components along with aging that was cancelled by the effects of haemodialysis.

Association Between Sleep Disturbance and Low Back Pain: A 3-Year Longitudinal Study After the Great East Japan Earthquake.

STUDY DESIGN: A longitudinal study. OBJECTIVE: The aim of this study was to clarify the association between sleep disturbance and low back pain (LBP) using 3-year longitudinal data after the Great East Japan Earthquake, with a focus on the duration or frequency of sleep disturbance and the effect of sleep disturbance on LBP. SUMMARY OF BACKGROUND DATA: Sleep disturbance and LBP are common health problems in the general population and natural disaster survivors. However, a longitudinal study in this field is rare, and the association between sleep disturbance and LBP has not been clarified. METHODS: A 3-year longitudinal study was conducted among people living in disaster-stricken areas after the Great East Japan Earthquake (n = 2059). Sleep disturbance and LBP were assessed at 4, 5, 6, and 7 years after the disaster. Multiple logistic regression analysis was performed to assess the association between the duration or frequency of sleep disturbance and LBP, and the effect of preceding sleep disturbance on the onset of LBP. The χ2 test and crude and multiple logistic regression models were used in data analysis. RESULTS: The duration and frequency of sleep disturbance were significantly associated with LBP, and the effect was stronger with longer duration and increased frequency of sleep disturbance. Furthermore, the duration and frequency of preceding sleep disturbance were significantly associated with the onset of LBP, and the effect was stronger with an increase in the duration and frequency of sleep disturbance. CONCLUSION: Sleep disturbance is associated with LBP in a dose-dependent manner. Attention should be paid to sleep disturbance for the treatment and prevention of LBP, especially with regard to the duration and frequency of sleep disturbance.Level of Evidence: 3.

The 5-Year Course of Neck Pain Among Natural Disaster Survivors: The Association of Prior Neck Pain with New Episodes of Neck Pain.

OBJECTIVE: Neck pain is a common health problem among both the general population and natural disaster survivors. However, the long-term course of neck pain has rarely been reported. The aim of this study was to elucidate the 5-year course of neck pain among survivors of the Great East Japan Earthquake (GEJE) by assessing the association of neck pain 2 and 4 years after the disaster with that at 7 years. STUDY DESIGN: Longitudinal study. METHODS: A panel study was conducted on GEJE survivors (n = 1,821) through the administration of a self-reported questionnaire at 2 (first time point), 4 (second time point), and 7 years (third time point) after the disaster. Multivariate logistic regression analyses were performed to assess the association between prior neck pain and subsequent neck pain. RESULTS: The rates of neck pain at the first, second, and third time points were 20.7%, 21.1%, and 20.1%, respectively. Neck pain at the first time point was significantly associated with neck pain at the third time point (adjusted odds ratio [95% confidence interval]: 5.96 [4.53-7.83]). Furthermore, neck pain at the first and second time points was significantly associated with neck pain at the third time point (adjusted odds ratio [95% confidence interval]: 5.71 [4.19-7.78] for neck pain at either time point; 15.94 [10.99-23.12] for neck pain at both time points; P for trend <0.001). CONCLUSIONS: Prior neck pain was significantly associated with neck pain 5 years later, and the effect was stronger with an increase of prior neck pain episodes. Clinicians should base their selection of treatment method on an individual's history of neck pain.

Comparative proteome analysis of the ligamentum flavum of patients with lumbar spinal canal stenosis.

Background: Thickening of the ligamentum flavum is considered to be the main factor for lumbar spinal canal stenosis (LSCS). Although some mechanisms have been speculated in the thickening of the ligamentum flavum, there are only a few comprehensive approaches to investigate its pathology. The objective of this study was to investigate the pathology of thickened ligamentum flavum in patients with LSCS based on protein expression levels using shotgun proteome analysis. Methods: Ligamentum flavum samples were collected from four patients with LSCS (LSCS group) and four patients with lumbar disc herniation (LDH) as controls (LDH group). Protein mixtures were digested and analyzed by liquid chromatography/mass spectrometry analysis. To compare protein expression levels between the LSCS and LDH groups, the mean Mascot score was compared. Biological processes were assessed using Gene Ontology analysis. Results: A total of 1151 proteins were identified in some samples of ligamentum flavum. Among these, 145 proteins were detected only in the LSCS group, 315 in the LDH group, and 691 in both groups. The demonstrated biological processes occurring in the LSCS group included: extracellular matrix organization, regulation of peptidase activity, extracellular matrix disassembly, and negative regulation of cell growth. Proteins related to fibrosis, chondrometaplasia, and amyloid deposition were found highly expressed in the LSCS group compared with those in the LDH group. Conclusions: Tissue repair via fibrosis, chondrometaplasia, and amyloid deposits may be important pathologies that occur in the thickened ligamentum flavum of patients with LSCS.

Low Back Pain in Young Sports Players: A Cross-sectional Study in Japan.

STUDY DESIGN: A cross-sectional study. OBJECTIVE: The purpose of this large cohort study was to assess the prevalence of low back pain (LBP) among young players participating in several types of sports. SUMMARY OF BACKGROUND DATA: LBP is a significant problem among young sports players. Sport discipline among young players is thought to be associated with LBP. However, similar previous studies did not specifically analyze LBP by age and sex. METHODS: A cross-sectional study was conducted with young sports players (ages 6-15 years, n = 7277) using a self-reported questionnaire. The prevalence of LBP was assessed using the variables of age, sex, and sport discipline. RESULTS: The point prevalence of LBP among young sports players was 5.0%. The participants between 6 and 8 years' old had the lowest prevalence of LBP (0.4%-1.3%), which increased with aging and reached the highest proportion of 13.5% to 14.8% at 13 to 14 years. Furthermore, female players had significantly higher proportions of LBP than male players (8.1% vs. 3.7%). Regarding sport discipline, the prevalence of LBP was higher in basketball, handball, and volleyball. CONCLUSION: The prevalence of LBP among young sports players was different for age, sex, and sport discipline. Further studies are needed to clarify the association of sport-specific movements to LBP in each sport discipline. This may assist in developing programs or strategies for preventing LBP among young sports players.Level of Evidence: 3.

Contracted joint capsule affects labral and chondral lesions in patients with frozen shoulder.

PURPOSE: Intra-articular pathologies, such as labral and chondral lesions, are common in patients with frozen shoulder. This study evaluated the correlations between the range of motion and labral and chondral lesions in patients with frozen shoulder and investigated their pathophysiologies. METHODS: In total, 125 individuals (53 men and 72 women) who underwent arthroscopic pan-capsular release between 2014 and 2020 were included in the study. The range of motion was measured using scapular fixation and true glenohumeral motion under general anaesthesia. The American Shoulder and Elbow Surgeons Shoulder score and the Shoulder Rating Scale score of the University of California, Los Angeles were used to compare intra-articular pathologies. RESULTS: More than 80% of patients with frozen shoulder had labral pathologies, and nearly half of them had chondral pathologies. Labral lesions extending to the anterior rim of the glenoid had a greater range of motion and the greatest total American Shoulder and Elbow Surgeons Shoulder score. More severe chondral lesions had a lesser range of motion, but presented the greatest function scores and the lowest strength scores according to the Shoulder Rating Scale of the University of California, Los Angeles. The pain scores of the American Shoulder and Elbow Surgeons Shoulder score and the Shoulder Rating Scale of the University of California, Los Angeles were not correlated with the degree of these pathologies. The traction force affected the labrum during true range of motion, and the compression force occurred on the articular cartilage during internal rotation at 90° of forward flexion during diagnostic arthroscopy. CONCLUSION: Labral and chondral lesions are common in patients with frozen shoulder. Adherence to the capsulolabral complex induced a limited range of motion and labral and chondral pathologies. Diagnostic arthroscopy with motion is an important method of reproducing the pathogenesis of intra-articular structures for patients with frozen shoulder. LEVEL OF EVIDENCE: Level III.

Delay in diagnosis of primary osteosarcoma of bone in children: Have we improved in the last 15 years and what is the impact of delay on diagnosis?

AIMS: Examine: (1) If length of symptoms (LS) of children with osteosarcoma has improved in the last 15 years (2) Is delay in diagnosis related to the presence of metastases at presentation? (3) The impact of delay in diagnosis on prognosis. METHODS: 250 consecutive patients with a diagnosis of osteosarcoma of bone treated at a national bone tumor treatment center between 2004 and 2018 were studied retrospectively. Three groups comprising those diagnosed over a five-year period (Group 1: 2004-2008, Group 2: 2009-2013; Group 3: 2014-2018) were studied. RESULTS: There were 126 males and 124 females with a mean age 12.2 years. The median LS for all patients was eight weeks. The median LS for Group 3 was significantly shorter than that for other groups. Development of metastasis during follow-up period was significantly less in Group 3 compared to the other groups. Overall survival gradually improved over the whole study period. There was no difference in the proportion presenting with metastases at diagnosis between the three groups. The survival rates in patients with LS shorter than 4 weeks was better than those with LS longer than 4 weeks, irrespective of the study time period. CONCLUSIONS: There has been an improvement in the LS in patients diagnosed with osteosarcoma over the last 15 years. The development of metastasis during follow-up has reduced and the overall survival in the last 15 years has improved. LS longer than 4 weeks is associated with a poorer prognosis.

Characteristics of Parents Who Feel a Lack of Communication with Coaches of Youth Sports.

Communication between parents and their children's coaches is important for children's sports activities, but the relationship between parents and coaches is not well understood. It is possible that parents feel a lack of communication with coaches, which could be due to parents' experience with sports activities or the social environment of the team. This study aimed to elucidate the characteristics of parents who feel a lack of communication with their children's coaches of youth sports. A cross-sectional study was conducted on parents of young athletes (n = 6,641) and multivariate logistic regression analyses were performed to assess factors related to parents' feeling of a lack of communication with their children's coaches. Among the respondents, 29.4% of parents felt a lack of communication with their children's coaches. The factors related to the parents' feeling were a shorter duration of their children playing the present sport, an absence of experience playing the same sport as their children or playing in a team with high competition level, dissatisfaction with their children's attitude towards sports activities, and an awareness of verbal and/or physical abuse by the coaches and bullying by the teammates in their children's team. Parents' previous sports experience and awareness of interpersonal violence in their children's team were associated with their feeling of a lack of communication with coaches. Educating parents on the sport and their roles in youth sport is necessary to make appropriate mutual communication between parents and coaches, which could lead to better circumstances for young athletes.

Association of musculoskeletal pain in other body parts with new-onset shoulder pain: a longitudinal study among survivors of the Great East Japan Earthquake.

OBJECTIVE: Shoulder pain is a common health problem coexisting with other musculoskeletal pain. However, the effects of pre-existing musculoskeletal pain on the development of shoulder pain are not clear. The present study aimed to elucidate the association between coexisting musculoskeletal pain at other body sites and new-onset shoulder pain among survivors of the Great East Japan Earthquake (GEJE). DESIGN: This is a longitudinal study. SETTING: The study was conducted at the severely damaged coastal areas in Ishinomaki and Sendai cities. PARTICIPANTS: The survivors who did not have shoulder pain at 3 years after the GEJE were followed up 1 year later (n=2131). INTERVENTIONS: Musculoskeletal pain (low back, hand and/or foot, knee, shoulder and neck pain) was assessed using self-reported questionnaires. MAIN OUTCOME MEASURES: The outcome of interest was new-onset shoulder pain, which was defined as shoulder pain absent at 3 years but present at 4 years after the disaster. The main predictive factor for new-onset shoulder pain was musculoskeletal pain in other body parts at 3 years after the GEJE; this was categorised according to the number of pain sites (0, 1, ≥2). Multiple regression analyses were conducted to calculate the odds ratio (OR) and 95% confidence interval (CI) for new-onset shoulder pain due to musculoskeletal pain in other body parts. RESULTS: The incidence of new-onset shoulder pain was 6.7% (143/2131). Musculoskeletal pain in other body parts was significantly associated with new-onset shoulder pain. Using the survivors without other musculoskeletal pain as reference, the adjusted OR and 95% CI for new-onset shoulder pain were 1.86 (1.18 to 2.94) for those with one body part and 3.22 (2.08 to 4.98) for those with ≥2 body parts presenting with musculoskeletal pain (p<0.001). CONCLUSIONS: Pre-existing musculoskeletal pain in other body parts was significantly associated with new-onset shoulder pain among survivors; this provides useful information for clinical and public health policies.

A 5-year Longitudinal Study of Low Back Pain in Survivors of the Great East Japan Earthquake.

STUDY DESIGN: A longitudinal panel study. OBJECTIVE: The aim of this study was to examine the occurrence of low back pain (LBP), especially the association of previous LBP with further episodes of LBP, in survivors of the Great East Japan Earthquake (GEJE) during the course of 5 years. SUMMARY OF BACKGROUND DATA: LBP is common among survivors of natural disasters, but its long-term course is not clear. METHODS: A 5-year longitudinal study was conducted among survivors of the GEJE (n = 1821). The presence of LBP was assessed using a self-reported questionnaire at 2, 4, and 7 years after the disaster (termed the first, second, and third time points, respectively). Multiple logistic regression analysis was performed to assess a potential association between LBP at the first and second time points with LBP at the third time point, and the odds ratios (ORs) and 95% confidence intervals (CI) were calculated. RESULTS: The prevalence of LBP was 25.3%, 27.3%, and 27.2% at the first, second, and third time points, respectively. The occurrence of LBP at the first time point was significantly associated with LBP at the third time point, and the adjusted odds ratio (OR) (95% confidence interval [CI]) was 5.47 (4.28-6.98). Furthermore, LBP at the first and second time points was significantly associated with LBP at the third time point. Compared to no LBP at the first and second time points, the adjusted OR (95% CIs) for LBP at the third time point was 4.12 (3.14-5.41) in the case of LBP at either of the first or second time points and 10.73 (7.80-14.76) for LBP at both time points (P for trend < 0.001). CONCLUSION: Previous LBP was associated with LBP 5 years later among survivors of the GEJE. Furthermore, the effect on subsequent LBP was stronger with a higher frequency of previous LBP episodes.Level of Evidence: 3.

Bladder perforation by orthopedic implants 26 years after limb-sparing surgery for left proximal femoral chondrosarcoma: A case report.

INTRODUCTION: The need for implant use during orthopedic surgeries has been increasing. Accordingly, increased implant failures have been reported. However, bladder perforation remains a rare complication after orthopedic surgery. Although a few reports have described bladder perforation after total hip arthroplasty, no previous studies have reported the migration of staples into the bladder after limb-sparing surgery. PRESENTATION OF CASE: A 65-year-old patient underwent limb-sparing surgery to remove a chondrosarcoma in the left proximal thigh. Twenty-six years after surgery, a staple that had been used to fix artificial ligaments to the pubis migrated to perforate the bladder, resulting in painful urination. The staple was removed, and her symptoms improved. DISCUSSION: In this case, bladder perforation by the staple resulted in painful urination. The bladder perforation was not detected until 26 years after the initial surgery. CONCLUSION: Our observations emphasize that implant complications may occur even after a long postoperative period, and the possibility of delayed bladder perforation from previous pelvic surgeries should be considered in patients presenting with urinary tract symptoms.

Chondrosarcoma of bone in children and adolescents.

PURPOSE: Chondrosarcomas typically present in adults during the fifth to seventh decades and are rare in young patients. The biological behaviour and oncological outcomes may be different in children and adolescents. METHODS: We retrospectively evaluated the outcomes of all patients with chondrosarcoma of bone who were younger than 18 years of age at the time of diagnosis and were treated at our centre between 1995 and 2018. RESULTS: The 15 consecutive patients studied included nine male and six female cases, with a mean age at diagnosis of 13 years (7 to 17). The median follow-up was 117 months (30 to 277). The tumours were primary and secondary in ten and five patients, respectively. The tumours were central in 13 and surface in two patients. The tumour locations were the humerus in five, digits in five, femur in three, radius in one and pelvis in one patient. The histological grades were grade I in seven, grade II in seven and grade III in one patient. The surgical treatments were limb salvage in ten patients and ray amputation in five patients. The surgical margins were wide in eight, marginal in two and intralesional in five patients. All the patients were alive and continuously free of disease at the time of the last follow-up. No patient developed metastases or local recurrence. CONCLUSION: Chondrosarcoma of bone in children and adolescent patients has a very good prognosis and is less aggressive compared with published outcomes in older patients. LEVEL OF EVIDENCE: IV.

Low Back Pain in School-Aged Martial Arts Athletes in Japan: A Comparison among Judo, Kendo, and Karate.

Martial arts, such as judo, kendo, and karate, are popular worldwide, not only among adults but also among children and adolescents. Although low back pain (LBP) is considered to be a common problem in these sports, it has been scarcely studied, especially in young athletes. The purpose of this study was to elucidate the point prevalence of and factors related to LBP among school-aged athletes in judo, kendo, and karate. A cross-sectional study was conducted in school-aged athletes (age, 6-15 years; n = 896) using a self-reported questionnaire. Multiple logistic regression models were used to assess the factors related to LBP along with the odds ratio (OR) and 95% confidence interval (95% CI). Variables included in the analysis were sex, age, body mass index, team level, number of days and hours of training, frequency of participation in games, practice intensity, and lower extremity pain. The prevalence of LBP was 6.9% in judo, 4.7% in kendo, and 2.9% in karate. Older age was significantly associated with LBP in judo (adjusted OR, 2.12 [95% CI, 1.24-3.61]), kendo (1.77 [1.27-2.47]), and karate (2.22 [1.14-4.33]). Lower extremity pain was significantly associated with LBP in judo (6.56 [1.57-27.34]) and kendo (21.66 [6.96-67.41]). Coaches should understand the characteristics of LBP in each martial art to develop strategies to prevent LBP among school-aged martial arts athletes.

High prevalence of low back pain among young basketball players with lower extremity pain: a cross-sectional study.

BACKGROUND: Low back pain (LBP) is a common problem among young basketball players in addition to lower extremity injuries. However, studies that focus on LBP with lower extremity pain are limited. From the perspective of the kinematic chain, disrupted lower extremity function can lead to LBP. The association between these two symptoms in basketball players, however, has not been reported. Therefore, this study aimed to clarify the association between lower extremity pain and LBP among young basketball players. METHODS: This cross-sectional study was conducted on school-aged basketball players (n = 592). Information regarding their sporting activities was collected using a self-reported questionnaire. Musculoskeletal pain such as low back, knee, and ankle pain was assessed. The sports players with knee and/or ankle pain were defined as having lower extremity pain. Multivariate logistic regression analysis was used to assess the association between lower extremity pain and LBP. Odds ratios (OR) and 95% confidence intervals (95% CI) were calculated. The associations of knee or ankle pain with LBP were similarly assessed. RESULTS: School-aged basketball players had a point prevalence of 12.8% for LBP. Compared with the players without lower extremity pain, the players with lower extremity pain had higher rates of LBP, with an adjusted OR (95% CI) of 6.21 (3.57-10.80). There was also a significant association of knee and ankle pain with LBP. Compared with the players without knee or ankle pain, the adjusted ORs (95% CI) for LBP were 4.25 (2.55-7.07) in the players with knee pain and 3.79 (2.26-6.36) in the players with ankle pain. CONCLUSIONS: Lower extremity pain was associated with LBP among school-aged basketball players. Further research is needed to clarify the mechanism of this association, which will provide useful information for prevention and treatment of LBP among young basketball players.