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Background Limited flexibility of the lower extremities, such as hamstring tightness, has long been suggested as a physical risk factor for low back pain among adolescent athletes. However, few prospective cohort studies have examined the direction of causality for this relationship. This prospective cohort study investigated the relationship between limited flexibility of the lower extremities and the occurrence of low back pain among high school baseball players. Methods Participants comprised 335 high school baseball players from 43 high school baseball teams who had undergone baseline medical evaluations (a self-completed questionnaire and physical examination). Occurrence of low back pain during a 1-year follow up, and associations with measurements of flexibility of the lower extremities such as straight-leg-raising angle (hamstring tightness), Thomas test (iliopsoas tightness), heel-buttock-distance (quadriceps tightness), and passive range of motion of the hip were investigated. Results In total, 296 players (88.4%) participated in the 1-year follow-up survey, with 147 of the 296 players (49.7%) reporting the occurrence of low back pain during follow-up. The number of players with low back pain during follow-up peaked in November, then decreased and was lowest in June. After adjusting for factors associated with low back pain using logistic regression modeling, a significant association between hamstring tightness on the non-throwing arm side and low back pain (odds ratio 2.86, 95% confidence interval 1.17–6.94; P = 0.018) was found. Conclusions Hamstring tightness on the non-throwing arm side was identified as a potential risk factor for low back pain in high school baseball players. These results may provide guidance in the development of future prevention programs.

Many adolescent athletes experience low back pain; the most common cause is lumbar spondylolysis. Although early identification of lumbar spondylolysis in adolescent athletes is critical, few studies have focused on identifying the early stages of spondylolysis in baseball players. This study aimed to investigate the clinical characteristics of early-stage spondylolysis in male adolescent baseball players.The participants comprised male junior and high school baseball players. Before magnetic resonance imaging, we recorded their demographic data, low back pain characteristics, and physical findings (lumbar flexion, extension, Kemp's test and the provocative tenderness of a spinous process). After the imaging evaluation, the association among low back pain characteristics, physical findings and the final diagnosis (early-stage spondylolysis or not) were investigated using univariate and multivariable analyses.A total of 171 players were included in this study. Univariate analyses indicated that the characteristics associated with early-stage spondylolysis were longer duration of low back pain (P = 0.0085), low back pain-related interference while running (P = 0.0022), low back pain starting with laterality (P = 0.0001), lumbar extension (P = 0.022), positive Kemp's test (P = 0.020), and the tenderness of a spinous process (P = 0.0003). After adjusting for confounding factors (age and position), we found that early-stage spondylolysis was significantly associated with low back pain duration ≥4 weeks (odds ratio 3.13, 95% confidence interval 1.42-6.92; P = 0.0048), low back pain-related interference while running (odds ratio 2.89, 95% confidence interval 1.30-6.46; P = 0.0094), low back pain starting with laterality (odds ratio 2.78, 95% confidence interval 1.24-6.27; P = 0.0133), and the tenderness of a spinous process (odds ratio 3.00, 95% confidence interval 1.36-6.57; P = 0.0062).Male adolescent baseball players with early-stage spondylolysis might have low back pain duration of more than four weeks, low back pain-related interference while running, and a history of low back pain starting with laterality. The tenderness of a spinous process might be helpful in the diagnosis of early-stage spondylolysis in male adolescent baseball players.

Arthroscopic debridement for elbow osteoarthritis has been widely used as a minimally invasive treatment; however, in some cases, it can be a technically demanding procedure, such as in patients with severe osteoarthritis with large spur formation and severe synovitis. The anterocentral transbrachialis portal is a recently developed portal for elbow arthroscopy, which allows easy and convenient access to the anterior compartment for sufficient debridement. This report describes in detail the anterocentral transbrachialis portal and its usefulness for debridement of the elbow joint in osteoarthritis., Technique Video Video 1 This report describes in detail the establishment of the anterocentral transbrachialis portal and its usefulness. The authors have no financial conflicts of interest to disclose concerning the study. The open anterior transbrachialis approach, described by Itou in 1994, is a safe and easy approach to access the anterior compartment of the elbow joint. The anterocentral transbrachial portal is based on the open anterior transbrachialis approach for elbow arthroscopy. The patient is positioned supine with their arm on an arm table and the upper arm is completely free without any traction device (arm-free supine position). A horizontal skin incision is made just lateral to the biceps tendon. The subcutaneous tissue is carefully dissected and the lateral antebrachial cutaneous nerve is identified. The lateral antebrachial cutaneous nerve is retracted medially and the biceps tendon is retracted laterally to expose the fascia of the brachialis. The brachialis fascia is cut, and the muscle is dissected along with the muscle fiber. An 8.0-mm plastic cannula is inserted through the portal. Under the arthroscopic visualization from the anterolateral portal, the tip of the cannula is guided to the region located just above the coronoid fossa. After fully inserting the cannula into the joint, the synovium is removed using a motorized shaver. The coronoid spur is removed using a small chisel and an abrader burr. This portal allows easy removal of the spur at the anteromedial corner of the coronoid process. The spur at the coronoid fossa is removed using an abrader burr. The advantages of this portal are as follows: (1) It allows resection of the spur at the coronoid process as well as the coronoid fossa adequately and easily and (2) it is less likely to harm major neurovascular structures. The following disadvantages should also be taken into account: (1) It is accessible only in the supine position and (2) there is a possibility of lateral antebrachial cutaneous nerve injury. Because the arm-free supine position allows access to the lateral and posterior compartments without postural changes, debridement of these compartments is easily performed using standard lateral and posterior portals.

Abdominal oblique muscle injury is characterized by acute pain and localized tenderness over the lateral trunk. This injury is particularly common among throwing athletes, and usually presents as anterolateral abdominal wall pain. Imaging evidence is scarce in regard to whether oblique muscle injury at its junction with the thoracolumbar fascia can instead present with low back pain. A high school baseball player with unilateral low back pain was referred to us with a different diagnosis. Careful palpation and magnetic resonance imaging guided our care, and the patient returned to high-level competition after 7 weeks of conservative treatment, with no report of recurrence in the subsequent 12 months. Oblique muscle injury at its junction with the thoracolumbar fascia should be added to the differential diagnosis for throwing athletes with unilateral low back pain following a torque movement.

Thoracic ossification of the ligamentum flavum (OLF) is a pathological condition that causes myelopathy, with unilateral lower extremity pain rarely a feature in the presenting complaint. Moreover, most symptomatic cases of thoracic OLF occur in middle-aged men, with younger individuals rarely affected. We present a rare case of severe and chronic unilateral buttock and leg pain mimicking sciatica due to thoracic OLF in a professional baseball pitcher. A 28-year-old, right-handed, Japanese professional baseball pitcher experienced intractable left leg pain with numbness and spasticity. After the initial presentation, extensive testing focusing on lumbar, hip, and pelvis lesions failed to identify a cause for the pain. One year after onset, careful neurological examination showed signs of upper motor neuron disturbance, and thoracic computed tomography and magnetic resonance imaging revealed thoracic OLF at the level of the thoracolumbar junction. After resection of the thoracic OLF, the pain, numbness, and spasticity completely resolved. He resumed full training and was pitching in top condition within four months after surgery. Though rare, thoracic OLF should be considered in the differential diagnosis of lower extremity pain in young athletes, especially amongst high-level baseball pitchers.

Two main causes of gastrocnemius contracture have been considered: 1) congenital deformities in pediatric patients, such as limb-length discrepancy, cerebral palsy, flatfoot, and clubfoot; and 2) secondary conditions such as immobilization for trauma or a nonfunctional limb. Talipes equinus deformity caused by fibrous gastrocnemius contracture after a direct muscle contusion is extremely rare. We describe 2 cases of talipes equinus deformity caused by fibrous gastrocnemius muscle contracture after a direct contusion in football players. Both of the players had a talipes equinus deformity with a severe restriction of ankle dorsiflexion, and a cord-like structure was observed at the proximal part of the lateral gastrocnemius head. Both patients' histological examinations revealed fibrous tendon-like tissue within the structure. After discission of the cord-like structures, the restriction of ankle dorsiflexion was completely resolved, and the patients were able to fully return to playing football without any discomfort in their calves.

Background: Musculoskeletal pain could represent a psychological stressor in adolescent athletes. However, few epidemiological studies have investigated this association. Purpose: To assess the relationship between musculoskeletal pain (shoulder, elbow, wrist, and low back) and psychological stress responses in high school baseball players. Study Design: Cross-sectional study. Methods: Participants comprised male Japanese high school baseball players who had completed a questionnaire as part of their annual medical evaluation in 2016. Experiences of shoulder, elbow, wrist, and low back pain during the previous season were investigated. Pain severity was graded as 1 (mild, playing without interference), 2 (moderate, playing with interference), or 3 (severe, could not play because of pain). The Stress Response Scale–18 was used to measure stress response: low, medium, rather high, and high. Prevalence rates of shoulder, elbow, wrist, and low back pain and their association with psychological stress responses were investigated using univariate and multivariable analyses. Results: A total of 944 players (223 pitchers and 721 fielders) were included in this study. Their mean age was 16.1 ± 0.6 years, and 66% were high school juniors, while 33.6% were seniors. In pitchers, the prevalence rates during the previous year of severe (grade 3) interference with playing because of elbow, shoulder, wrist, and low back pain were 21.5% (n = 48), 19.3% (n = 43), 3.6% (n = 8), and 18.4% (n = 41), respectively, whereas in fielders, the respective prevalence rates were 17.1% (n = 123), 17.9% (n = 129), 6.7% (n = 48), and 19.3% (n = 139). After adjusting for confounding factors (playing on a top-performing team, high school grade level, and all other sites of musculoskeletal pain), the authors found significant associations in pitchers between severe experiences of elbow pain and low back pain and medium to high psychological stress responses (odds ratio, 2.64 [95% CI, 1.32-5.39], P = .006 and odds ratio, 2.32 [95% CI, 1.12-4.89], P = .024, respectively). No significant associations were seen between musculoskeletal pain and psychological stress responses in fielders. Conclusion: In the current study, elbow and low back pain were associated with stronger psychological stress responses compared with other musculoskeletal pain in high school baseball pitchers.

Background Flexor pronator muscles (FPMs) have been reported to act as a dynamic stabilizer against valgus forces in overhead throwing athletes. Several studies have demonstrated the anatomical, biomechanical and clinical effects of the FPMs. However, no studies have investigated the in vivo kinematics of FPMs against the valgus forces on the elbow. The current study aimed to clarify the clinical contribution of the FPMs as a dynamic stabilizer in medial ulnar collateral ligament (MUCL) insufficiency. Methods Eighteen baseball players who suffered from MUCL injury participated in this study. The elbow was flexed to 90 degrees and the forearm was placed in the supinated position. Manual valgus stress was applied to the elbow joint until maximal shoulder external rotation was achieved. The widths of the ulnohumeral joint space were measured using ultrasonography and any changes in the medial elbow pain was recorded before and after isometric forearm pronation. Results All the subjects had MUCL tenderness and felt medial elbow pain when elbow valgus stress was applied. The width of the medial joint space was significantly larger on the injured side compared with the healthy side (5.2±1.0mm vs. 3.5±0.7mm) in elbow valgus stress. During isometric forearm pronation, the width of the medial joint space was significantly decreased (3.4±0.9mm, vs. 2.8±0.9mm) and medial elbow pain had completely diminished. Conclusion Isometric forearm pronation reduces valgus stress induced widening of the medial joint space and medial elbow pain in patients with MUCL insufficiency.

Several guidelines for the prevention of throwing injuries recommend a sufficiently long off-season; however, few studies providing scientific evidence to support these recommendations exist. Our study aimed to clarify the association between off-season duration and throwing elbow injuries among elementary school-aged baseball players.This study enrolled 680 elementary school-aged baseball players who underwent medical checkups. The experience with elbow pain and the off-season duration were investigated via the administration of a self-completed questionnaire. Ultrasonographic assessment of the elbow joint was performed on the day of the medical checkup to assess for morphologic abnormalities.The prevalence of elbow pain and morphologic abnormalities of the medial epicondyle (medial epicondyle lesions) was significantly decreased when the subjects' off-season duration was longer. Multivariate analysis revealed that the risk of elbow pain was significantly lower in the group whose off-season lasted 1 to 2 months (odds ratio [OR], 0.32; 95% confidence interval [CI], 0.15-0.62; P = .0006) and in the group whose off-season lasted longer than 2 months (OR, 0.59; 95% CI, 0.37-0.95; P = .0316). The risk of medial epicondyle lesions was also significantly lower in the group whose off-season lasted 1 to 2 months (OR, 0.39; 95% CI, 0.22-0.67; P = .0005) and in the group whose off-season lasted longer than 2 months (OR, 0.36; 95% CI, 0.23-0.56; P.0001). On the contrary, no significant correlation was found between capitellar osteochondritis dissecans and off-season duration.Off-season duration has a significant correlation with elbow pain and morphologic abnormalities of the medial elbow joint in elementary school-aged baseball players.

Background Various shoulder disorders have been reported to be associated with scapulothoracic joint dysfunction in adult overhead athletes. However, little is known about the prevalence of scapular malalignment and its relationship to shoulder injuries in skeletally immature baseball players. The purpose of the current study was to investigate the prevalence of scapular malalignment in elementary school-aged baseball players, as well as its association with shoulder disorder. Methods One hundred sixty-nine baseball players in higher elementary school grades (aged 11–12 years) were enrolled in this study. Shoulder pain experience pain over the previous one year, as well as other individual and environmental factors were surveyed by a self-completed questionnaire. Scapula malalignment was assessed using still images of both arms both at the side and in an elevated position. The relative position of the dominant scapula to the non-dominant side was assessed by two independent examiners. Results Scapular malalignment was observed in 126 subjects (74.6%), and the dominant scapula tended to deviate inferiorly and medially, as well as tilt anteriorly, compared with the non-dominant side. Forty-four of the 169 subjects (23.8%) experienced shoulder pain over the one year period. The prevalence of shoulder pain was significantly increased with the increasing scapular anterior tilt and the superior shift of the dominant scapula, whereas no significant correlation between shoulder pain and scapular horizontal shift or upward-downward rotation was observed. Conclusion About three-quarters of the elementary school-aged baseball players in the current study presented with scapular malalignment, and those with anterior tilt and superior shift of the dominant scapula were at higher risk of shoulder pain.

Background Reduced core stability is a potential risk factor for low back pain in athletes. However, the association between core stability and low back pain in high school baseball players has not been thoroughly studied. The purpose of this study was to investigate the relationship between core stability and low back pain and its clinical characteristics in high school baseball players. Methods Participants comprised 812 high school baseball players who had undergone annual medical evaluations, comprising a self-completed questionnaire and a physical examination. We investigated the relationships between low back pain during the season and on the day of medical evaluations and core stability using a cross-sectional study design. Core stability was assessed using the Sahrmann core stability test. Results Reduced core stability was confirmed in 358 (44.1%) of all players, 98 (49.5%) pitchers, and 260 (42.3%) fielders. In total, 352 players (43.3%) reported incidents of seasonal low back pain during the previous year. Thirty-five pitchers (17.7%) and 153 fielders (24.9%) reported low back pain on the day of the medical evaluations. No significant associations were seen between low back pain throughout the season and reduced core stability. After adjusting for confounding factors (total amount of practice per week, hamstring tightness and quadriceps tightness) using logistic regression modeling, a significant association between presence of low back pain during lumbar extension movement and reduced core stability was found (odds ratio, 2.57; 95% confidence interval, 1.08–6.62; P = 0.033) in pitchers. Conclusions High school baseball pitchers with reduced core stability showed a higher probability of reporting low back pain during lumbar extension movement. Evaluation of core stability should be considered in high school baseball players, especially in pitchers.

Background Sacroiliac joint (SIJ) dysfunction is a potential source of low back pain (LBP) in baseball players, who are more likely to be affected by loading of the SIJ in the throwing motion. However, the prevalence and characteristics of this condition have not been studied thoroughly. This study aimed to investigate the prevalence and clinical characteristics of SIJ dysfunction among high school baseball players. Methods Participants comprised 891 high school baseball players who had undergone annual medical evaluations (a self-completed questionnaire and physical examination). The prevalence of SIJ dysfunction and associations with the measurements of the flexibility of the spine and lower extremities such as finger-floor-distance, straight-leg-raising angle, heel–buttock-distance, Thomas test, and passive range of motion of the hip were investigated. Results Twenty-two of 891 subjects (2.5%) met our criteria for SIJ dysfunction. Twelve subjects (55%) exhibited throwing arm side symptoms more commonly than in the non-throwing arm side (n = 3, 15%) or bilateral side (n = 7, 32%). Previous episodes of LBP were experienced significantly more frequently among subjects with SIJ dysfunction (n = 19, 86.4%) than among those without (n = 501, 57.7%; P = 0.015). The prevalence of present LBP that interfered with play was significantly higher among subjects with SIJ dysfunction (n = 9, 42.9%) than among those without (n = 118, 21.2%; P = 0.038). The prevalence of SIJ dysfunction as a source of LBP was estimated at 7.1% (9 of 127 subjects). After adjustment for associated factors using a logistic regression model, we observed a significant association between a limitation in hip internal rotation on the throwing arm side and SIJ dysfunction (odds ratio 3.11 [1.30–7.71]; P = 0.0109). Conclusions According to our criteria, the estimated prevalence of SIJ dysfunction among high school baseball players is 2.5%. There was a significant association between a limitation in hip internal rotation on the throwing arm side and SIJ dysfunction.

Both systemic and local factors might influence the development of ossification of the ligamentum flavum (OLF); however, whether specific physical activities play a role in the development of OLF remains unclear. This report presents two cases of thoracic radiculopathy owing to progressive enlargement of thoracic OLF within a few years in Japanese professional baseball pitchers. Two left-handed, Japanese, professional baseball pitchers in their 20s experienced thoracic radiating pain. Mild hypesthesia of the lower thoracic vertebral levels was observed, and an increase in the size of the OLF within a few years was identified in the lower thoracic spine using computed tomography and magnetic resonance imaging. Neither patient exhibited myelopathy and were, therefore, treated conservatively. Both patients were able to return to playing in top condition within 4 months after onset. The findings in these cases suggest that thoracic OLF might increase in size and become exacerbated in certain individuals, such as professional pitchers, who experience repeated, localized, mechanical stress on the thoracic spine, irrespective of age.

Thoracic outlet syndrome (TOS) is one of the common neurovascular disorders of the upper extremities, and the compression or traction of the brachial plexus is the main pathology. We hypothesized that baseball players are more likely to be affected by TOS compared with other overhead-throwing athletes because of strenuous use of their throwing arm. The purpose of this study was to investigate the prevalence and clinical characteristics of TOS in high school baseball players. One thousand two hundred eighty-eight high school baseball players were included in this study. The prevalence of symptomatic TOS and its association to disorders of the upper extremities were investigated. The prevalence of symptomatic TOS was 32.8%. Age- and position-adjusted logistic regression analysis revealed that subjects with symptomatic TOS were at significantly higher risk of shoulder and/or elbow pain (odds ratio [OR]: 1.96, 95% confidence interval [CI]: 1.50 - 2.58) and a higher recurrence rate of shoulder and/or elbow pain during the previous season (OR: 2.38, 95% CI: 1.87 - 3.04). As for physical findings, subjects with symptomatic TOS were also at significantly higher risk of MUCL tenderness (OR: 2.53, 95% CI: 1.83 - 3.50), positive milking maneuver, (OR: 2.63, 95% CI: 1.78 - 3.91), positive subacromial impingement sign (OR: 1.92, 95% CI: 1.20 - 3.07), and positive posterior impingement sign (OR: 2.34, 95% CI: 1.67 - 3.28) compared to the subjects without symptomatic TOS. It is necessary to recognize that TOS is not a rare pathology in overhead-throwing athletes, especially baseball players, and that players with symptomatic TOS are at significantly higher risk of shoulder/elbow pain.

Background: Although tensile force on an immature tibial tuberosity is considered the main cause of Osgood-Schlatter disease (OSD), the relationship between bony maturity and the pathogenesis of OSD remains obscure. Purpose: To survey the bone maturation process of the tibial tuberosity by age and sex and clarify its relationship to OSD. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A total of 731 Japanese basketball players aged 6 to 14 years were enrolled in this study. Ultrasonographic examination was performed in all participants (1462 knees) to evaluate the bony maturity of the tibial tuberosity by use of the Ehrenborg classification. The age- and sex-specific prevalence of each stage was investigated, and the prevalence of symptomatic OSD and its relationship with bony maturity were also assessed. Results: The process of bone maturation occurred 1 to 2 years earlier in female participants compared with male participants. Among female participants, 59.2% were already at the epiphyseal stage (stage E) by 10 years of age, and 47.4% were skeletally mature by 14 years. Among male participants, conversely, only 8.0% were at stage E by 10 years of age, and only 13.8% were skeletally mature by 14 years. The overall prevalence of symptomatic OSD was 6.8% (males, 6.4%; females, 7.2%), and the onset was 1 year earlier in the female participants. The prevalence of symptomatic OSD tended to increase with age and bony maturity, significantly increasing from the cartilaginous stage (stage C) to the apophyseal stage (stage A) (odds ratio, 9.48) and from stage A to stage E (odds ratio, 2.22). Conclusion: The tibial tuberosity matures earlier in female participants. The risk of OSD is greater in stage A than stage C and in stage E than stage A. The risk of OSD increases with age in males but not in females.

Background: Traction apophysitis of medial epicondyle (MEC) lesions and osteochondritis dissecans (OCD) of the capitellum are common elbow injuries in adolescent baseball players. However, the age-specific prevalence of these pathologies and their influence on elbow pain remain unknown. Purpose: To investigate the age-specific prevalence of each MEC lesion and capitellar OCD and to identify the incidence of elbow pain in each condition. Study Design: Descriptive epidemiology study. Methods: Study participants consisted of 4249 baseball players aged 6 to 17 years. A questionnaire was used to assess history of elbow pain, and morphological changes of the elbow joint were assessed using ultrasonography. Results: Regarding MEC lesions, fragmented (FG) and irregular (IR) lesions both reached their greatest respective prevalence at 11 to 12 years of age. After 14 years of age, IR decreased sharply, whereas FG was maintained at approximately 10%. Hypertrophic (HT) lesions increased sharply, reaching over 50% at 16 years of age, while there was a decrease in IR and FG lesions in the same age group. The prevalence of capitellar OCD remained the same (approximately 2%) throughout all ages except for in players aged 7 to 8 years (>7%). Players with MEC lesions had significantly greater prevalence of a history of elbow pain compared with those without (68.0% vs 39.1%) and were at a significantly greater risk for FG lesions (odds ratio [OR], 4.04; 95% CI, 3.16-5.22) compared with IR (OR, 3.22; 95% CI, 2.44-4.27) and HT lesions (OR, 2.03; 95% CI, 1.75-2.36). Players with capitellar OCD also had a significantly greater risk of a history of elbow pain (OR, 2.34; 95% CI, 1.40-4.11). Conclusion: Controlling the amount of practice and its intensity according to the condition of each player in the preadolescent and adolescent periods may be important in accelerating bony healing and decreasing preventable elbow pain in adulthood.

A cohort study. To investigate the association between psychosocial stress and low back pain (LBP)-related interference with daily living among college students. Few longitudinal studies have examined the likelihood of developing LBP in the presence of a designated psychosocial stressor. All participants in the present study were suddenly affected by the Great East Japan disaster after enrolment in our cohort study. The present study was initiated among 95 students at Fukushima Medical University in January 2011. We assessed psychosocial stress in students using the Japanese version of the Perceived Stress Scale (JPSS). Follow-up surveys were conducted in July 2011 and May 2013, analyzing 94 students. Students were then divided into three groups (improved, −19 to −4; Maintained, −3 to +4; Aggravated, +5 to +22) based on the tertile points of JPSS change from baseline to 4 months after the disaster. LBP-related interference with daily living was assessed using the Brief Pain Inventory (BPI) questionnaire. Linear regression modeling was performed with BPI at 4 months after the disaster as the outcome, and JPSS change, sex, history of LBP, baseline physical activity, and baseline BPI as explanatory variables. We found a significant increase in BPI score for the aggravated stress group (β coefficient, +0.79; 95% confidence interval, +0.06–+1.53), compared with the improved stress group. History of LBP and higher physical activity were also significantly associated with BPI. The present study suggests that perceived psychosocial stress induced by the disaster may be associated with LBP-related interference with daily living among college students in Fukushima. Level of Evidence: 3

OBJECTIVES: While several studies have cited a potential association between testosterone deficiency and risk of falls among community-dwelling older men, evidence for such an association is conflicting. Depressive symptoms, which occasionally accompany testosterone deficiency but which are often neglected as associated symptoms, may actually provoke falls independent of or jointly with testosterone deficiency. We examined the association between testosterone levels, depressive symptoms, and falls, and assessed the joint effect of testosterone levels and depressive symptoms on falls among older men. DESIGN, SETTING, AND PARTICIPANTS: Data for this cross-sectional study were obtained from 869 men aged over 60 years who participated in health check-ups conducted in 2010 from 2 Japanese municipalities. Salivary testosterone (sT) levels were measured using an enzyme-linked immunosorbent assay, and depressive symptoms were assessed via the short form of the Center for Epidemiologic Studies Depression Scale. MAIN OUTCOME MEASURES: Self-reported "any fall" over the 1-month period. RESULTS: Among the total of 482 participants analyzed (median age, 70 years), 10.8% reported any fall. On comparison between 90th percentile sT levels and lower levels, our logistic regression model with restricted cubic splines showed that lower sT levels were associated with an increased likelihood of suffering any fall after adjustment for sociodemographic characteristics, comorbidities, and mobility function. For example, 5th percentile sT was associated with any fall [adjusted odds ratio (OR), 4.23; 95% confidence interval (CI), 1.66-10.8]. Depressive symptoms were also strongly associated with any fall [adjusted OR, 3.49 (95% CI, 1.52-8.04)]. We noted no apparent interaction of sT and depressive symptoms with falls (P = .079), suggesting that the joint effect of testosterone deficiency and depressive symptoms on falls was multiplicative. Indeed, compared with a combination of 90th percentile sT values and no depressive symptoms, adjusted OR for any fall in a combination involving 5th percentile sT and depressive symptoms was 14.8-fold (95% CI, 3.76-58.0). CONCLUSIONS: Our findings indicated that both relatively low testosterone levels and presence of depressive symptoms were independently associated with falls among older men. Causality of these associations should be confirmed in future prospective studies. Language: en

The purpose of this study was to anatomically investigate the proximal origin of flexor–pronator muscles (FPMs) and clarify their contribution to dynamic stabilization of the elbow joint during valgus stress. 52 elbows from 26 donated formalin-fixed cadavers were examined. The pronator teres muscle (PT), flexor carpi radialis muscle (FCR), palmaris longus muscle (PL), flexor digitorum superficialis muscle (FDS), and flexor carpi ulnaris muscle (FCU) were identified, and their proximal origin and relationship to the anterior bundle of the medial ulna collateral ligament (AOL) were macroscopically and histologically investigated. The PT, FCR, PL, and FDS converged and formed a common tendon at their proximal origin (the anterior common tendon: ACT). The ACT was attached to the medial epicondyle and the joint capsule, just anterior and parallel to the AOL. The histological morphology of the ACT was quite similar to that of the AOL. The ulnar head of the PT was observed in 48 of 52 elbows (92.3 %), just behind the humeral head of PT. It mainly originated from the anterior edge of the sublime tubercle, while the upper part of ulnar head transitioned directly into the thickened joint capsule just anterior to the AOL. The proximal attachment of the FPMs had a characteristic morphology. According to our results, the ACT and PT might assist the AOL by sharing static and dynamic traction forces applied to the medial elbow joint.

Symptomatic thoracic disc herniation is clinically rare. There are few cases of disc herniation of the thoracic spine in top athletes described in the literature. We herein present a rare case of chest wall pain due to thoracic disc herniation in a professional baseball pitcher. A 30-year-old, left-handed pitcher complained of left-sided chest wall pain in the region of his lower ribs during a game. Neurological examination revealed hypoesthesia of the left side of the chest at the level of the lower thoracic spine. Magnetic resonance imaging (MRI) of the thoracic spine showed a left-sided paramedian disc herniation at the T9-T10 level. The player was initially prescribed rest, administration of pregabalin (150 mg twice a day), and subsequent physical rehabilitation. He was able to resume full training and pitching without medication 6 months after the onset. A follow-up MRI of the thoracic spine showed a reduction in the size of the herniated disc compared to the initial findings. Though relatively rare, thoracic disc herniation should be considered in cases of chest wall pain in athletes.

There is little evidence regarding long-term outcomes of locomotor dysfunction such as cardiovascular events, quality of life, and death. We are conducting a prospective cohort study to evaluate risk of cardiovascular disease, quality of life, medical costs, and mortality attributable to locomotor dysfunction. The present study determined baseline characteristics of participants in the Locomotive Syndrome and Health Outcome in Aizu Cohort Study (LOHAS).Cohort participants were recruited from residents between 40 and 80 years old who received regular health check-ups conducted by local government each year between 2008 and 2010 in Minami-Aizu Town and Tadami Town in Fukushima Prefecture, Japan. Musculoskeletal examination included assessment of physical examination of the cervical and lumbar spine, and upper and lower extremities and of physical function, such as grasping power, one-leg standing time, and time for the 3-m timed up-and-go test. Cardiovascular risk factors, including blood pressure and biological parameters, were measured at annual health check-ups. We also conducted a self-administered questionnaire survey.LOHAS participants comprised 1,289 men (mean age 65.7 years) and 1,954 women (mean age 66.2 years) at the first year. The proportion of obese individuals (body mass index 25.0 kg/m(2)) was 31.9% in men and 34.3% in women, and 41.0% of participants reported being followed up for hypertension, 7.0% for diabetes, and 43.6% for hypercholesterolemia. Prevalence of lumbar spinal stenosis was 10.7% in men and 12.9% in women, while prevalence of low back pain was 15.8% in men and 17.6% in women.The LOHAS is a novel population-based prospective cohort study that will provide an opportunity to estimate the risk of cardiovascular disease, quality of life, medical costs, and mortality attributable to locomotor dysfunction, and to provide the epidemiological information required to develop policies for detection of locomotor dysfunction.

Study design Controlled, interventional, animal study. Objective To examine the involvement of high-mobility group box 1 (HMGB1) in the neuropathic pain state induced by the application of nucleus pulposus onto the dorsal root ganglion (DRG) and to investigate the effect of HMGB1 neutralization antibody in the pathogenesis. Summary of background data HMGB1 is a potent proinflammatory mediator when present extracellularly, and anti-HMGB1 neutralization antibody inhibits inflammation, cytokine expression, and macrophage activation. Methods Thirty-nine adult female Sprague-Dawley rats (200-300 g) were used. The left L5/6 facet joint was removed, and the L5 DRG was exposed. Nucleus pulposus harvested from the tail was applied to the left L5 DRG. Then, 400 μg of anti-HMGB1 neutralization antibody was administered intraperitoneally after surgery. Behavioral testing using von Frey hairs was performed to investigate the mechanical withdrawal threshold. Neuronal damage was investigated by counting the number of activating transcription factor 3 (ATF3) neurons. The expressions of tumor necrosis factor-α (TNF-α) and HMGB1 were measured by double-labeled immunohistochemistry and immunoblotting. Results Immunoblotting of harvested nucleus pulposus revealed HMGB1 in the nucleus pulposus. Double-labeled immunohistochemistry revealed that macrophages in the applied nucleus pulposus expressed HMGB1 and TNF-α. Administration of anti-HMGB1 neutralization antibody significantly reduced the TNF-α expression in the DRG and improved the pain-related behavior from day 2 to day 14. Conclusion HMGB1 appears to play an important role in the development of pain-related behavior induced by the application of nucleus pulposus onto the DRG. HMGB1 from applied nucleus pulposus and actively secreted from macrophages would act as a proinflammatory mediator together with proinflammatory cytokines. HMGB1 blocking therapy might become a new treatment method for neuropathic pain.

STUDY DESIGN Controlled, interventional, animal study. OBJECTIVE To observe the reaction of glial cells and endoneurial macrophages in the dorsal root ganglion (DRG) after application of nucleus pulposus (NP) and investigate whether activated DRG glial cells play a role in the pathogenesis of neuropathic pain. SUMMARY OF BACKGROUND DATA Peripheral nerve injury activated DRG and spinal cord glial cells and several cytokines and neurotrophins released from these activated glial cells might induce pain hypersensitivity. METHODS Adult male Sprague-Dawley rats were used. NP harvested from the tail was applied to the left L5 DRG. Behavioral testing was performed to investigate the mechanical withdrawal threshold. The numbers of activated satellite glial cells and endoneurial macrophages were counted, and the expressions of tumor necrosis factor-alpha (TNF-alpha) and glial cell-line derived neurotrophic factor (GDNF) were examined by double-labeled immunohistochemistry and immunoblotting. RESULTS The mechanical withdrawal threshold was significantly decreased for 28 days and then gradually recovered (P < 0.05). Long-term activation of endoneurial macrophages and satellite glial cells in the DRG was observed, and the reactions of these cells correlated well with pain-related behavior. TNF-alpha was expressed in both endoneurial macrophages and activated satellite glial cells, and TNF-alpha expression was significantly increased in the early stage (P < 0.05). Activated satellite glial cells also expressed GDNF, and its expression was significantly increased and persisted for 28 days (P < 0.05). CONCLUSION Activation of DRG glial cells and endoneurial macrophages plays an important role in the pathogenesis of the neuropathic pain state. TNF-alpha actively released from activated glial cells and endoneurial macrophages in the DRG might initiate and maintain the neuropathic pain together with TNF-alpha derived from the applied NP. In the recovery phase, persistent expression of GDNF from activated satellite glial cells might play an important role to restore the function of damaged neurons and recover from neuropathic pain.

Objectives: Scapular dyskinesis, defined as an alteration in scapular position and motion, has been suggested as a risk factor for upper extremity injuries. Assessing scapular asymmetry is a simple and easy way to identify scapular dyskinesis that is typically associated with throwing-related injuries. Despite the large number of investigations identifying scapular asymmetry in patients with shoulder pathology, little research has examined the incidence of scapular asymmetry and its association with shoulder injury in young, skeletally immature baseball players. The purpose of this study was to determine the incidence of scapular asymmetry in juvenile baseball players and investigate its association with shoulder injuries. Methods: Two hundred and twenty-three juvenile baseball players aged 9-12 years were included in this study. Each participant submitted a self-completed questionnaire and underwent a physical examination and an imaging assessment of scapular asymmetry. Questionnaire items included the subject's sex, age, position, years of baseball experience, practice frequency and duration, and shoulder pain during throwing over the past 1 year. Tenderness of the proximal humeral epiphysis and pain during maximum external rotation were also assessed on the physical examination. Digital photos of each participant's upper body were taken from behind, first with their arms held straight out to the sides and then with their hands in the air. Scapular asymmetry was evaluated using a computerized image analysis system (Image J version 1.33u; National Institute of Mental Health, Bethesda, MD, USA). Inter- and intra-observer reliability for scapular asymmetry was 0.65 and 0.77, respectively. All analyses were conducted using JMP 10 (SAS Institute, Cary, NC, USA) and p values Results: Fifty-three of the 223 subjects had experienced shoulder pain while throwing in the past 1 year. Of these 53 symptomatic subjects, 28 (52.8%) had experienced shoulder pain twice or more in that year, whereas 42 (79.2%) had some kind of throwing disability. The incidence of shoulder pain significantly increased with age and was significantly higher in pitchers than in players of other positions. There was no significant association between shoulder pain and years of baseball experience or amount of practice. Scapular asymmetry was observed 171 (76.7%) subjects. The scapula of the throwing side tended to tilt anteriorly, deviate inferiorly and medially, and rotate downwardly in both the arms at side and hands up positions compared with the scapula on the non-throwing side. Age- and position-adjusted logistic regression analysis revealed that scapular superior deviation and anterior tilting significantly increased the risk of shoulder pain as evidenced by odds ratios (95% confidence interval) of 2.41(1.17-4.98) and 2.36 (1.20-4.67), respectively. Conclusion: Our study demonstrated that approximately three-quarters of juvenile baseball players under the age of 12 years already had scapular asymmetry and that 24% experienced shoulder pain. Scapular superior deviation and anterior tilt, which might be induced by tightness of the pectoralis minor muscle, leads to increased rotational torque at the proximal humeral epiphysis by restricting the scapular posterior tilt during late cocking to the acceleration phase.

Flexor pronator muscles (FPMs) play a key role in stabilizing the elbow joint against valgus forces. However, no studies have investigated the in vivo kinematics of FPMs against these forces on the elbow. This study aimed to clarify the in vivo contribution of each FPM as a dynamic stabilizer in a clinical situation.Twelve healthy volunteers participated in this study. Verbal informed consent was obtained from all subjects. The elbow was flexed to 90 degrees, and the forearm was placed in the neutral position. Manual valgus stress was applied to the elbow joint until maximal shoulder external rotation was achieved. The width of the ulnohumeral joint space and the ulnar shift of the sublime tubercle were measured before and after isometric contraction of FPMs using ultrasonography.The horizontal distances were decreased 1.1±0.6 mm after forearm pronation, 0.6±0.5 mm after wrist palmar flexion, 0.1±0.4 mm after wrist ulnar flexion, and 0.2±0.5 mm after finger flexion. Significant changes were observed during forearm pronation, wrist palmar flexion, and finger flexion but not during wrist ulnar flexion (p

Background Kyphosis is a cause of scapular dyskinesis, which can induce various shoulder disorders, including subacromial impingement syndrome (SIS). This study aimed to clarify the impact of kyphosis on SIS with use of cross-sectional data from the Locomotive Syndrome and Health Outcome in Aizu Cohort Study (LOHAS). Methods The study enrolled 2144 participants who were older than 40 years and participated in health checkups in 2010. Kyphosis was assessed by the wall-occiput test (WOT) for thoracic kyphosis and the rib-pelvic distance test (RPDT) for lumbar kyphosis. The associations between kyphosis, SIS, and reduction in shoulder elevation (RSE) were investigated. Results Age- and gender-adjusted logistic regression analysis demonstrated significant association between SIS and WOT (odds ratio, 1.65; 95% confidence interval, 1.02, 2.64; P

Objectives: Apophysitis of humeral medial epicondyle, often referred to as “Little Leaguer’s Elbow, is one of the major throwing injuries in juvenile baseball players as common as osteochondritis dissecans of humeral capitellum. Repetitive valgus stress to the skeletally immature elbow can result in fragmentation, hypertrophy, or separation of the medial epicondyle apophysis, and these injuries may induce elbow pain and adversely influence on elbow function and throwing performance. Although several reports have described various morphological variations of the medial epicondyle apophysis, little is known about the natural course and clinical significance of these variations. The purpose of this study was to investigate the prevalence of these variations in each age group and clarify the association with elbow pain using the large epidemiologic data from medical check-ups of juvenile baseball players. Methods: Of 3,626 juvenile baseball players aged 6 to 17 years, 2,926 players were enrolled in this study. Experience of elbow pain was rated by self-completed questionnaires. Ultrasonographic assessment was used to assess the morphological variations of the antero-inferior medial epicondyle (MEC) and humeral capitellum. Regarding MEC lesion, enthesis of medial ulnar collateral ligament (MUCL) was classified into four types: normal, irregular (IR), fragmentation (FG), and hypertrophy (HT). Osteochondral lesion (OCL) of humeral capitellum was judged by the irregularity or fragmentation of subchondral bone. The prevalence of these lesions was investigated in each age group and evaluated the influence on elbow pain using multivariable logistic regression analysis. Results: The overall prevalence of MEC lesions and capitellum OCL was 49.9% (IR:6.7%, FG:11.7%, HT:31.5%) and 2.1%, respectively. The prevalence of IR and FG gradually increased until reaching its highest at 11-12 years of age. At 12-17 years of age, the prevalence of IR was decreased with age, whereas that of FG persisted at approximately 10% after a temporally decrease. Conversely, the prevalence of HT increased while those of IR and FG simultaneously decreased (Figure 1). Age- and position adjusted multivariable analysis revealed that the presence of MEC lesions were high risk of elbow pain, and significantly higher risk for FG (odds ratio [OR]: 4.25, 95% confidence interval [CI]: 3.23-5.62) compared to IR (OR:3.17, 95%CI:2.31-4.39) and HT (OR:2.12, 95%CI:1.76-2.55). Capitellum OCL of was also significantly high risk of elbow pain (OR:,2.69, 95%CI:1.42-5.45) (Table 1). Conclusion: Our study demonstrated that morphology of MEC apophysis in juvenile baseball player varied with age. As the presence of FG was a significantly high- risk factor for elbow pain as compared to HT, appropriate management of “Little Leaguer’s Elbow” in the preadolescent period might be quite important to accelerate the bony healing of medial epicondyle apophysitis and decrease preventable adulthood elbow pain.

Some patients with rotator cuff tear have shoulder stiffness preoperatively. Concomitant preoperative shoulder stiffness may affect postoperative outcomes of arthroscopic sub- acromial decompression (ASD) for rotator cuff tear. The purpose of this study was to compare postoperative outcomes for ASD between rotator cuff tear patients with and without preoperative shoulder stiffness and to analyze the serial change in functional scores, range of motion (ROM), and pain intensity of the 2 groups after operation. 60 shoulders of 58 patients who underwent ASD for rotator cuff tear were studied. Arthroscopic release was performed for the stiffness group. The results were assessed before sur- gery and 1, 3, 6, 12 and 24 months after surgery, and the results in the stiffness group and non-stiff- ness group were compared. No differences in serial changes for postoperative outcomes of ASD were seen in terms of the Japanese Orthopaedic Association shoulder scoring system (JOA scores) and the visual analog scale (VAS scores) for pain at night and pain during motion between the stiffness group and non-stiffness group. However, compared to the non-stiffness group, forward flexion and abduction angles were significantly smaller for the stiffness group at 1 and 3 months after surgery. External rotation and internal rotation angles were significantly smaller at 1 month after surgery for the stiffness group than for the non-stiffness group. Preoperative shoulder stiffness does not affect improvement of postoperative JOA scores and VAS scores of ASD. When measured 6 months after surgery, ROM in the stiffness group and the non-stiffness group was similar.

STUDY DESIGN The effect of an EP1 receptor antagonist on pain-related behavior induced by nucleus pulposus (NP) applied to the dorsal root ganglion (DRG) in rats was investigated. OBJECTIVE We investigated pain-related behavior, the amount of prostaglandin E2 (PGE2), and neural damage to the DRG after application of NP to the DRG after administration of an EP1 receptor antagonist. SUMMARY OF BACKGROUND DATA PGE2 induces mechanical allodynia and hyperalgesia, which are mediated by PGE2 receptors. EP1 is one of the PGE2 receptor subtypes. An EP1 antagonist reduces hyperalgesia, allodynia, and c-fos expression in the rat chronic nerve constriction model. METHODS Sprague-Dawley rats (n = 103) were used. Animals receiving NP were divided into three experimental groups (n = 12 in each group): saline, high-dose (5 mg/kg) EP1 receptor antagonist (RA), and low-dose (2.5 mg/kg) EP1-RA (orally once daily for 5 days). Animals in the sham group did not receive NP. Von Frey tests were used for pain-behavior testing. The amount of PGE2 in DRG and the number of activating transcription factor-3 (ATF3) immunoreactive positive cells were compared among groups. RESULTS The mechanical thresholds in the three groups decreased 7 days after surgery (just before treatment). The threshold in both the high- and low-dose EP1-RA groups increased at 11 days (5 days after treatment) and continued for 14 days. The thresholds in both the low- and high-dose EP1-RA groups increased significantly compared with the saline group (P < 0.05). The amount of PGE2 was significantly increased in the NP group compared with the sham and naive animals after application of NP. ATF3 expression was increased by NP but was not increased after administration of the EP1-RA. CONCLUSION An EP1 receptor antagonist improves pain-related behavior in the rat model and might be a potential agent to improve pain-related behavior in patients with lumbar disc herniation.

生着不全の同種骨髄移植後(BMT)にみられた急性移植片対宿主病(GVHD)を経験したので報告する.骨髄の生着不全は比較的稀であり,一般的にGVHDは生着がみられてから発症するが,今回の症例では生着のみられないまま,右季肋部痛と黄疸を伴った肝障害で発症した.臨床所見は肝中心静脈閉塞症と考えられるものであったが,組織学的な検索では肝GVHDであった.従って,BMT後生着のみられない場合でも,肝障害のみられる場合には,肝GVHDの可能性を考慮する必要がある.

The purpose of this study was to clarify the mechanism of tendon regeneration by investigating macroscopically, histologically, and biomechanically.Fifty, adult, female Sprague-Dawley rats were used. The Achilles tendon in the left hind limb was removed totally by use of the tendon-stripping device. Rats were killed at 2, 7, 30, 90, and 180 days after surgery, and the regenerate tendons were dissected. Contralateral Achilles tendons were used as normal controls. Gross anatomic changes, microscopic remodeling, and recovery of biomechanical properties of regenerate tendons were investigated. The expressions of type I collagen, type III collagen, and transforming growth factor β1 were also investigated by immunohistochemistry.The regenerate tendons formed in all specimens. In the early phase, hematoma and soft granulation tissue were observed at the harvest defect. These gradually matured with time, and the microscopic structure became quite similar to normal at 180 days after surgery. These findings occurred uniformly along the entire length of the regenerate tendon. However, the biomechanical properties were significantly inferior to the normal tendons (P.05). Transforming growth factor β1 was well co-localized with inflammatory cells and fibroblasts in the regenerate tendons. The type I-type III collagen ratio in the regenerate tendon was significantly decreased in the early phase (P.05) but gradually increased with time.Tendon regeneration and maturation occurred uniformly along the length of regenerate tendons. The hematoma that initially occupies the harvest defect acted as a scaffold for fibroblast precursor cells from the surrounding peritendinous tissue and tendon sheath. The mechanical properties of regenerate tendon were significantly inferior to contralateral control even at 180 days after surgery, and the alteration of the collagen composition would have an influence on mechanical properties of regenerate tendon.Clinicians should be cautious about using reharvested hamstring tendons for ligament reconstruction surgery.

We report a case of meralgia paresthetica occurring in an amateur baseball pitcher who experienced inguinal pain and dysesthesia in the anterolateral thigh during pitching practice. The lateral femoral cutaneous nerve was pushed up by the iliac muscle to the inguinal ligament at the sharp ridge of its fascia and ensheathed in the tendinous origin of the sartorius muscle. Neurolysis of the lateral femoral cutaneous nerve and partial dissection of the inguinal ligament and sartorius muscle promptly relieved the symptoms and the patient resumed pitching 1 month later. These anatomic variations of the lateral femoral cutaneous nerve in the inguinal region might render the nerve susceptible to compression and irritation, and repetitive contraction of inguinal muscles during throwing motion might induce and exacerbate the neuropathy of the lateral femoral cutaneous nerve.

[Objectives] To examine the association between overactive bladder (OAB) symptom severity and falls and the contribution of OAB symptoms to falls in a community-dwelling population. [Design] Cross-sectional study. [Setting] 2 Japanese municipalities. [Participants] A total of 2505 residents aged over 40 years, who participated in health check-ups conducted in 2010. OAB symptom assessed via overactive bladder symptom score (OABSS) was divided into six categories based on distribution and Japanese clinical guidelines. Mobility problems and depressive symptoms were assessed via the Timed Up and Go test and the short form of the Center for Epidemiologic Studies Depression Scale, respectively. [Primary outcome measures] Self-reported any fall and frequent fall (≥2) over the 1-month period. Independent contributions to any fall and frequent falls were assessed via logistic regression to generate population-attributable fractions (PAFs), assuming separate causal relationships between OAB symptoms, mobility problems and depressive symptoms and any or frequent falls. [Results] Among the total 1350 participants (mean age: 68.3 years) analysed, any fall and frequent falls were reported by 12.7% and 4.4%, respectively. Compared with no OABSS score, moderate-to-severe OAB and mild OAB were associated with any fall (adjusted ORs 2.37 (95% CI 1.12 to 4.98) and 2.51 (95% CI 1.14 to 5.52), respectively). Moderate-to-severe OAB was also strongly associated with frequent falls (adjusted OR 6.90 (95% CI 1.50 to 31.6)). Adjusted PAFs of OAB symptoms were 40.7% (95% CI 0.7% to 64.6%) for any fall and 67.7% (95% CI −23.1% to 91.5%) for frequent falls. Further, these point estimates were similar to or larger than those of mobility problems and depressive symptoms. [Conclusions] An association does indeed exist between OAB symptom severity and falls, and OAB symptoms might be important contributors to falls among community-dwelling adults. Further longitudinal studies are warranted to examine whether or not OAB symptoms predict risk of future falls and fall-related injuries.