Radiographic knee osteoarthritis severity has no impact on fall risk: the locomotive syndrome and health outcomes in the aizu cohort study (LOHAS): a cross-sectional study.

BACKGROUND: To investigate factors that have an impact on the risk of falls and determine whether radiographic knee osteoarthritis (KOA) is a factor involved in falls independent of knee pain, psychological factors, and physical function. METHODS: A cross-sectional analysis was conducted on 1083 subjects for the 2009 Locomotive Syndrome and Health Outcomes in the Aizu Cohort Study (LOHAS). A logistic regression analysis was performed to examine the relationship between radiographic KOA and fall history. RESULTS: Fall history was significantly associated with the severity of knee pain. Compared to subjects with no knee pain, the odds ratio (OR) was 1.53 times higher in the subjects with mild knee pain (95% confidence interval [CI]: 1.04-2.25), 1.69 times higher in those with moderate knee pain (95%CI: 1.03-2.79), and 2.98 times higher in those with severe knee pain (95%CI: 1.67-5.30). In subjects with depression, the OR was 1.91 (95%CI: 1.25-2.92), and in those with decreased mobility, the OR was 1.70 (95%CI: 1.08-2.69). Age, gender, knee crepitus, BMI, OLST, and sleeping pill use were not significantly associated with fall risk. In a multivariate analysis, radiographic KOA severity was not significantly associated with fall risk (OR 0.81, 95%CI 0.44-1.50 in mild OA; OR 1.10, 95%CI 0.57-2.14 in severe OA). CONCLUSION: Knee pain, decreased mobility, and depression, but not the radiographic KOA severity, were significantly associated with a fall risk. Regardless of the individual's radiographic KOA severity, the risk of falls may be reduced by treating his/her knee pain, mobility problems, and/or psychological factors.

Impact of low back pain experience on future occurrence of shoulder pain in adolescent baseball players: A 1-year prospective cohort study.

BACKGROUND: Low back pain can affect musculoskeletal problems of the upper limb in adolescent overhead athletes. However, few epidemiological studies have examined this causal relationship. This prospective cohort study aimed to investigate the relationship between baseline low back pain experience and the occurrence of future shoulder and elbow pain among high school baseball players. METHODS: Participants comprised 383 high school baseball players from 43 high school baseball teams who had undergone baseline medical evaluations (a self-completed questionnaire and physical examination). The occurrence of shoulder and elbow pain during a 1-year follow-up and associations with baseline low back pain (positive subjective symptom during the last year at baseline) adjusted for flexibility of the scapulo-thoracic region, shoulder, and lower extremities, such as straight-leg raise angle (hamstring tightness), Thomas test (iliopsoas tightness), heel-buttock-distance (quadriceps tightness) and passive range of motion of the hip were investigated using multivariable analysis. RESULTS: A total of 307 players (80.2%) participated in the 1-year follow-up survey, with shoulder and elbow pain reported in 75 players (24.4%) and 119 players (38.8%), respectively, during follow-up. After adjusting for factors associated with shoulder pain using logistic regression modeling, significant associations between LBP experienced during the last year at baseline (odds ratio, 2.18; 95% confidence interval, 1.23-3.87; P = 0.0078) and new-onset of shoulder pain were noted. CONCLUSIONS: Baseline low back pain impacted future shoulder pain in high school baseball players during the 1-year follow-up. Management of shoulder pain warrants careful attention to low back pain.

The role of the flexor pronator muscles as dynamic stabilizers against elbow valgus stress in patients with medial ulnar collateral ligament insufficiency.

BACKGROUND: The flexor pronator muscles (FPMs) have been reported to act as dynamic stabilizers against valgus forces in overhead-throwing athletes. Several studies have demonstrated the anatomic, biomechanical, and clinical effects of the FPMs. However, no studies have investigated the in vivo kinematics of the FPMs against the valgus forces on the elbow. This study aimed to clarify the clinical contribution of the FPMs as dynamic stabilizers in medial ulnar collateral ligament (MUCL) insufficiency. METHODS: Eighteen baseball players with MUCL injury participated in this study. The elbow was flexed to 90°, 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 width of the ulnohumeral joint space was measured using ultrasonography, and any changes in medial elbow pain were 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 than on the healthy side (5.1 ± 1.0 mm vs. 3.2 ± 1.0 mm) with elbow valgus stress. During isometric forearm pronation, the width of the medial joint space was significantly decreased (3.1 ± 0.9 mm vs. 2.6 ± 1.0 mm) 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.

Clinical characteristics of early-stage lumbar spondylolysis detected by magnetic resonance imaging in male adolescent baseball players.

BACKGROUND: 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. METHODS: 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. RESULTS: 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). CONCLUSIONS: 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.

Influences of limited flexibility of the lower extremities and occurrence of low back pain in adolescent baseball players: A prospective cohort study.

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.

The prevalence and clinical characteristics of sacroiliac joint dysfunction in adolescent baseball players.

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.

Associations between core stability and low back pain in high school baseball players: A cross-sectional study.

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.

Talipes Equinus Deformity Caused by Fibrous Gastrocnemius Muscle Contracture After Direct Contusion in Football Players: Report of Two Cases.

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.

Sufficient duration of off-season decreases elbow disorders in elementary school-aged baseball players.

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSION: Off-season duration has a significant correlation with elbow pain and morphologic abnormalities of the medial elbow joint in elementary school-aged baseball players.

The prevalence of scapular malalignment in elementally school aged baseball player and its association to shoulder disorder.

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.

Association between kyphosis and subacromial impingement syndrome: LOHAS study.

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 < .05), whereas there was no significant association between SIS and RPDT. Multivariable logistic regression analysis demonstrated no significant association between SIS and both WOT and RPDT, whereas there was significant association between SIS and RSE. CONCLUSION: RSE plays a key role in the development of SIS, and thoracic kyphosis might influence the development of SIS indirectly by reducing shoulder elevation induced by the restriction of the thoracic spine extension and scapular dyskinesis.

The proximal origins of the flexor-pronator muscles and their role in the dynamic stabilization of the elbow joint: an anatomical study.

PURPOSE: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Surgical management for refractory medial epicondylitis based on the anatomical characteristics of flexor pronator origin: surgical results of 8 cases and review of the literature.

Background: This case series aimed to introduce surgical management for refractory medial epicondylitis based on the anatomical characteristics of the flexor pronator origin and present the surgical results. Methods: Ten elbows from 8 patients (2 males and 6 females; mean age 50.2 years) were included in this case series. All patients underwent resection of the degenerated anterior common tendon and repair using suture anchors. Ulnar neuritis was observed in 9 elbows of 7 patients who underwent the relevant additional surgery. Results: Medial elbow pain was resolved in all patients, and pain provocation tests (wrist flexion test and forearm pronation test) were negative postoperatively. The mean Patient-Rated Elbow Evaluation (Japanese version) score was significantly improved from 79.6 ± 7.7 (range, 64.3-92) preoperatively to 8.4 ± 15.2 (range, 0-50) at the final follow-up. Conclusion: Angiofibroblastic tendinosis of the anterior common tendon might be an essential pathology of medial epicondylitis, and anterior common tendon resection and repair could be the most appropriate treatment for medial epicondylitis.

Rib stress fracture in a female athlete caused by bouncing the barbell in bench press exercise: A case report.

Rib stress fractures can occur in sports involving repetitive trunk muscle contractions. Few documented cases show rib fractures from repetitive upper-limb training. This report presents a case of a rib stress fracture from micro blunt trauma during bench press exercises. The patient was a 24-year-old elite female sprinter with a history of left navicular stress fracture and secondary amenorrhea treatment a year prior. She modified her bench press technique to involve bouncing the barbell on her rib cage. Within weeks, she experienced anterior chest pain, exacerbated by sneezing. Computed tomography revealed a fifth rib fracture with callus formation. After refraining from bench presses for 4 weeks, her chest pain subsided, allowing her to resume upper-limb training. When athletes performing bench press exercises experience chest pain, rib fractures should be considered, even without acute trauma. Additionally, research on the safety of the bouncing bench pressing technique is required.

Potential influencing factor on health-related quality of life in Japanese with knee osteoarthritis: the Locomotive syndrome and Health outcome in Aizu cohort Study (LOHAS).

PURPOSE: Several studies have investigated the factors that influence health-related quality of life in patients with knee osteoarthritis (KOA). This study aimed to identify and investigate the degree of involvement of potential factors influencing health-related quality of life (HRQOL) in an aged population with or without KOA. METHODS: This multi-centered study included 651 participants who underwent health checkups in rural areas of Japan in 2010. The association between three component summary score of short-form 12 (physical component summary; PCS, mental component summary; MCS, and role-social component summary; RCS) and covariates were investigated using multiple linear regression model and calculated the scaled estimated regression coefficient. RESULTS: Decreasing mobility, severity of knee pain, high pain-related self-efficacy (PSE), older age, high functional self-efficacy (FSE), and female gender had significant effect on PCS (p < 0.05). However, radiographic KOA had no influence on PCS. Presence of depression and body mass index had a significant influence on the MCS (p < 0.05). Decreasing mobility, presence of depression, PSE and older age had significant influence on the RCS (p < 0.05). CONCLUSION: Our study results showed that physical, mental, and role/social QOL were affected by different influencing factors. Physical QOL was strongly influenced by subjective pain, physical performance, and self-efficacy, whereas radiographic KOA had no such effect. Depressive mood is associated with both mental and role/social QOL. The role/social QOL was predominantly affected by physical function and pain-related self-efficacy. Taking measure to improving functional ability and mental status might be the key factor to improve HRQOL in patient with KOA. LEVEL OF EVIDENCE: Level 3: Epidemiologic cross-sectional study (prognostic study).

Age-Related Differences in the Limited Range of Motion of the Lower Extremity and Their Relation to Low Back Pain in Young Baseball Players: A Cross-Sectional Study of 1215 Players.

BACKGROUND: Age-related differences in the limited range of motion of the lower extremities and their relationship with low back pain in juvenile athletes have not been well assessed. This study investigated the relationship between low back pain and limited range of motion of the hip and knee in young baseball players during the baseball season. RESULTS: Participants comprised 1215 baseball players (216 pitchers, 999 fielders) aged 6-16 years who underwent medical checkups (self-completed questionnaire and physical examination). Of the 1215 players, 255 (21.0%) experienced seasonal low back pain requiring rest during the previous year. The prevalence of low back pain and a positive Thomas test, straight-leg-raising test, and heel-to-buttock test increased with age. Univariate analysis revealed that a positive heel-to-buttock test in both the throwing and non-throwing arm sides in the 11-12 age group and a positive Thomas test in the throwing arm side in the 13-14 age group were associated with seasonal low back pain (P = 0.0051, P = 0.021, and P = 0.048, respectively). Multivariate analysis, adjusted for factors associated with low back pain, showed significant associations between the positive heel-to-buttock test (odds ratio 1.75, 95% confidence interval 1.11-2.79; P = 0.016) and low back pain in players aged 11-14 years. CONCLUSIONS: A positive heel-to-buttock test is potentially associated with low back pain among juvenile baseball players. Particular attention should be paid to the limited range of motion of the knee joint and tightness of the quadriceps femoris muscle among baseball players with low back pain aged 11-14 years.

A muscle-preserving, spinous process-splitting approach for ossification of the ligamentum flavum in the thoracic spine in professional athletes: a report of three cases.

A muscle-preserving, spinous process-splitting approach may be a less invasive approach to conventional laminectomy in patients with thoracic ossification of the ligamentum flavum. Few reports have discussed the usefulness of this procedure for thoracic lesions in professional athletes who need highly active thoracic spinal function after surgery. The treatment of thoracic ossification of the ligamentum flavum using a spinous process-splitting approach in 3 professional athletes is presented. In all three cases the patients could return to play within 3 months after surgery without complications, and in two of the cases, there was no spinal deformity or local recurrence of ossification of the ligamentum flavum at the final follow-up at least 8 years after surgery. The spinous process-splitting approach could be a safe procedure for multi-level and all other forms of ossification of the ligamentum flavum and is less invasive to the paraspinal muscles, relieves back symptoms, and restores function for athletes.

Locomotor dysfunction and risk of cardiovascular disease, quality of life, and medical costs: design of the Locomotive Syndrome and Health Outcome in Aizu Cohort Study (LOHAS) and baseline characteristics of the study population.

BACKGROUND: 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). METHODS: 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. RESULTS: 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. CONCLUSION: 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.

The influence of chronic medial epicondylar apophysitis on medial ulnar collateral ligament insufficiency-: a retrospective cohort study.

Background: This study aimed to investigate the effect of chronic traction apophysitis of the medial epicondyle (MEC) on medial ulnar collateral ligament (MUCL) insufficiency in high school baseball players. Methods: In this retrospective cohort study, 3034 of 6069 high school baseball players were enrolled. A self-reported questionnaire was distributed to investigate past history of elbow pain and elbow pain during the previous season. Physical examinations to assess tenderness on the MUCL and the elbow valgus stress test (EVST) were performed. Ultrasonography was performed to determine the presence of morphological abnormalities of the anteroinferior aspect of the MEC (MEC lesions). Results: Participants with MEC lesions had a significantly higher prevalence of past history of elbow pain, elbow pain during the previous season, MUCL tenderness, and positive EVST than those without MEC lesions (P < .05). Multivariate logistic regression analysis revealed that the participants with the fragmented type had the highest risk of past history of elbow pain (odds ratio [OR] = 3.94), elbow pain during the previous season (OR = 2.27), positive EVST (OR = 3.49), and the second highest risk of MUCL tenderness (OR = 2.01) followed by the irregular type (OR = 2.31). Participants with the hypertrophic type had the lowest risk of past history of elbow pain (OR = 2.08), elbow pain during the previous season (OR = 1.42), MUCL tenderness (OR = 1.09), and positive EVST (OR = 1.47). Conclusion: The presence of chronic non-healed traction apophysitis of the MEC in high school baseball players presented a significantly high risk of elbow pain and MUCL insufficiency.

The process of tendon regeneration in an achilles tendon resection rat model as a model for hamstring regeneration after harvesting for anterior cruciate ligament reconstruction.

PURPOSE: The purpose of this study was to clarify the mechanism of tendon regeneration by investigating macroscopically, histologically, and biomechanically. METHODS: 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 ß1 were also investigated by immunohistochemistry. RESULTS: 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 ß1 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. CONCLUSIONS: 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. CLINICAL RELEVANCE: Clinicians should be cautious about using reharvested hamstring tendons for ligament reconstruction surgery.