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.