Machiko Hiramoto

Prevalence and Clinical Characteristics of Osteochondritis Dissecans of the Humeral Capitellum Among Adolescent Baseball Players

Background: The prevalence and clinical characteristics of osteochondritis dissecans (OCD) of the humeral capitellum among adolescent baseball players are unknown. Purpose: To determine the OCD prevalence in adolescent competitive baseball players and to investigate the clinical characteristics of these patients. Study Design: Cross-sectional and case-control study; Level of evidence, 3. Methods: A total of 2433 baseball players (mean age, 14.5 ± 1.5 years) belonging to junior high school and high school baseball clubs were enrolled. Players completed a questionnaire, and the elbow of each player’s throwing arm was assessed by ultrasonography. Participants with abnormal results on ultrasonography were further examined through radiographic study. The OCD lesions were classified into stages based on radiographic results, and demographic data were compared between players with and without OCD lesions. Results: Osteochondritis dissecans of the humeral capitellum was found in 82 (3.4%) elbows by ultrasonography. Players with an OCD lesion began playing baseball at an earlier age (P = .016), had a longer duration of competitive play (P = .0013), and had experienced more present (P = .0025) and past (P < .0001) elbow pain compared with players without a lesion. There were no differences between the 2 groups in the position played (P = .26). Sixty-eight patients underwent further radiographic examination for OCD (radiography, computed tomography, magnetic resonance imaging). Of these players, 10 (14.7%) were classified as having stage I OCD (radiolucent stage); 26 (38.2%), stage II (fragmentation stage); 9 (13.2%), stage III (loose body stage); 9 (13.2%), stage IV (residual stage); and 14 (23.5%), stage V (postoperative stage). Conclusion: The prevalence of OCD of the humeral capitellum, including latent cases, was 3.4% among adolescent baseball players. Players with OCD lesions began playing baseball at earlier ages, had played for longer periods, and had experienced more elbow pain. The player’s current baseball position may not be related to the existence of OCD lesions in adolescents.

The laterality of physical function in high school baseball players with shoulder or elbow injury: Comparison of laterality with positive group and negative group.

[Purpose] The purpose of this study was to investigate the laterality of flexibility and muscle strength in high school baseball players with shoulder or elbow injury. [Methods] Subjects were 76 high school baseball players participated in the medical check in Kyoto. Measurement outcomes were judgment of elbow and shoulder injury, range of motion, and muscle strength. Laterality of flexibility and muscle strength was calculated by subtracting non-throwing side from throwing side. Student T-test was used to analyze difference positive and negative group with each injury. The significance level was set at 5%. [Results] Laterality of shoulder internal rotation angle in positive group with shoulder injury was lower compared to negative group (p<0.05). Laterality of shoulder external rotation angle in positive group with elbow injury was lower compared to negative group (p <0.05). [Conclusion] It was suggested that the analysis of laterality in shoulder rotation angle might be helpful to predict shoulder or elbow injury in high school baseball players.