Association Between Osteochondritis Dissecans of the Humeral Capitellum and Medial Epicondyle Lesion in Baseball Players

Background: Osteochondritis dissecans (OCD) of the humeral capitellum occurs in adolescent overhead athletes, and medial epicondyle (ME) lesions are also common in this population. Purpose: To evaluate the association between elbow OCD and ME lesions in adolescent baseball players. Study Design: Cross-sectional study; Level of evidence, 3. Methods: This study retrospectively evaluated adolescent baseball players with unstable elbow OCD who underwent surgery between January 2000 and February 2020. Patients were excluded if they had osteoarthritis of the elbow. A total of 139 elbows were included in this study (138 male and 1 female athlete; mean ± SD age, 13.6 ± 1.5 years). The patients were first divided into 2 groups based on OCD location: a central lesion group (72 elbows) and a lateral group (67 elbows). Next, patients were divided according to OCD size into a localized group (56 elbows) and a widespread group (83 elbows). Finally, OCD lesions that were both lateral and widespread were defined as lateral-widespread (60 elbows), resulting in 5 groups. ME apophyseal fragmentation and elongation were evaluated and defined as ME lesions. We then compared the relationship between OCD and ME lesions. Results: Of the 139 elbows, 63 (45.3%) had ME lesions. The prevalence of ME lesion was higher in the lateral group than the central group (56.7% vs 34.7%; P = .009) and higher in the widespread group than the localized group (55.4% vs 30.4%; P = .004). Furthermore, the prevalence ratio of ME lesion was significantly higher in the lateral-widespread group than for other lesions (58.3% vs 35.4%; P = .007). Conclusion: In patients undergoing surgery for capitellar OCD, the presence of ME lesions was more commonly associated with lateral and widespread capitellar lesions when compared with central and localized lesions.