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.

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.

Epidemiological Study of Lumbar Spinal Stenosis Symptoms: 10-Year Follow-Up in the Community.

BACKGROUND: Lumbar spinal stenosis (LSS) is one of the important health problems in an aging society because it can significantly impair quality of life (QOL) and active daily living (ADL). However, the natural history or long-term change of LSS symptoms is still unclear. The purpose of this study was to clarify the 10-year course of lumbar spinal stenosis (LSS) symptoms in community-dwelling residents of more than 1000 people with prospective data collection. METHODS: A total of 1149 subjects were analyzed for the time course of LSS symptoms for ten years. LSS symptoms were assessed using a questionnaire specially designed and validated to detect LSS symptoms without image information such as magnetic resonance imaging. RESULTS: The prevalence of positive LSS symptoms was about 16% in the initial survey and 10-year follow-up. Of the subjects who were LSS positive at the initial survey, 40% showed positive LSS symptoms at follow-up and 60% switched to negative LSS symptoms. According to the multivariable logistic regression analysis, severe depression and positive LSS symptoms were extracted as predictors of the presence of LSS symptoms after a 10-year follow-up. CONCLUSION: The statistical predictor of the presence of LSS symptoms at 10 years was the presence of LSS symptoms at the initial survey; however, 60% of those who were positive for LSS symptoms at the initial survey were not determined to have LSS symptoms at the 10-year follow-up. This was the same result as at the 1-year and 6-year follow-up.

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 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.

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.

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.

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.

Association Between Musculoskeletal Pain and Psychological Stress Responses in High School Baseball Players: A Cross-sectional Study.

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.

Arthroscopic Elbow Debridement Using Anterocentral Transbrachialis Portal.

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.

Human case of Onchocerca dewittei japonica infection in Fukushima, Northeastern Honshu, Japan.

A 73-year-old man living in Kawamata-machi, Fukushima Prefecture, Northeastern Honshu, Japan, visited a hospital with complaints of a subcutaneous swelling that had developed on the back of his left hand. The nodule was surgically removed from the vagina fibrosa tendinis of his left forefinger. Based on the histopathological characteristics, the causative agent of this nodule was identified as a female Onchocerca dewittei japonica (Spirurida: Onchocercidae). The species identification was confirmed by cox1 gene sequencing of the worm tissues from paraffin-embedded sections of the nodule. Although 11 cases of zoonotic onchocercosis have previously been recorded in Kyushu and Western Honshu, Japan, the present findings represent the first human case of infection with O. dewittei japonica in Northeastern Honshu, Japan.

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.

Bony Maturity of the Tibial Tuberosity With Regard to Age and Sex and Its Relationship to Pathogenesis of Osgood-Schlatter Disease: An Ultrasonographic Study.

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.

Age-Specific Prevalence and Clinical Characteristics of Humeral Medial Epicondyle Apophysitis and Osteochondritis Dissecans: Ultrasonographic Assessment of 4249 Players.

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.

Psychosocial Stress After a Disaster and Low Back Pain-Related Interference With Daily Living Among College Students: A Cohort Study in Fukushima.

STUDY DESIGN: A cohort study. OBJECTIVE: To investigate the association between psychosocial stress and low back pain (LBP)-related interference with daily living among college students. SUMMARY OF BACKGROUND DATA: 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. METHODS: 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. RESULTS: We found a significant increase in BPI score for the aggravated stress group (ß 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. CONCLUSION: 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.