Osteochondritis Dissecans of the Capitellum

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Osteochondritis dissecans (OCD) of the capitellum occurs when a segment of the lateral femoral condyle equivalent in the elbow — the capitellum — loses its blood supply, undergoes necrosis, and may form a loose fragment within the joint. It most commonly affects adolescent throwers (especially baseball players) and gymnasts aged 10–17, due to repetitive compressive and rotational forces on the lateral elbow. Early detection and treatment are critical to prevent loose body formation, permanent cartilage damage, and early arthritis.

Lateral elbow pain and swelling in a young athlete, with limited extension. X-rays may show a radiolucent lesion on the capitellum. MRI evaluates stability — fluid behind the fragment on T2 indicates an unstable lesion. CT arthrography characterizes the fragment for operative planning.

Unstable lesions, loose bodies in the joint, and stable lesions that fail to heal with non-operative management require surgery.

External patient-education references and related OSI pages for additional background:

• Britannica — Joint (anatomy)
• AAOS OrthoInfo — patient education library
• OSI glossary — orthopedic terminology in plain language