Elbow OCD (Osteochondritis Dissecans) on MRI & X-ray: Imaging Findings

Osteochondritis dissecans of the elbow most commonly affects the capitellum of the lateral condyle. During the valgus loading of overhead throwing, the lateral compartment experiences compressive forces between the capitellum and the radial head while the medial compartment is under tension. These repetitive compressive and shear forces disrupt the blood supply to the vulnerable subchondral bone of the capitellum, which has a tenuous end-arterial supply in adolescents. This leads to avascular necrosis of the subchondral bone, subsequent fragmentation, and potential separation of an osteochondral fragment. Gymnasts sustain similar forces through axial compressive weight bearing on the extended elbow.

Elbow OCD lesions are classified as stable or unstable based on the integrity of the articular cartilage overlying the subchondral defect and the presence of fragment displacement. Stable lesions show cartilage continuity over a softened but attached subchondral fragment on MRI, manifesting as subchondral edema and cystic change without full-thickness cartilage breach. Unstable lesions demonstrate a full-thickness cartilage breach, fluid undercutting beneath the fragment on T2-weighted MRI sequences, or a displaced loose body. Stable lesions in athletes with open growth plates are treated non-operatively with rest from overhead activity for 3 to 6 months. Unstable or displaced lesions typically require surgical intervention.

For unstable lesions with an intact, salvageable fragment, internal fixation using headless compression screws or bioabsorbable pins can achieve healing of the fragment to its bed. If the fragment is too comminuted or avascular to fix, arthroscopic removal of loose bodies combined with drilling or microfracture of the exposed subchondral bone can stimulate fibrocartilage fill and restore a functional joint surface. For large defects exceeding 50 percent of the capitellar surface, osteochondral autograft transfer using plugs from the knee or osteochondral allograft transplantation provides hyaline cartilage coverage, with reported good-to-excellent results in skeletally mature patients. Early intervention before skeletal maturity closes is critical to optimizing outcomes.