Osteochondritis dissecans of the humeral capitellum. Diagnosis and treatment.

Elbow pain seen in the at-risk athlete, such as a baseball player (in particular, a pitcher) or gymnast, should raise suspicion for OCD. OCD of the humeral capitellum remains a difficult problem to treat. Once radiographic changes are obvious, long-term studies suggest that half of affected individuals will be symptomatic. Currently, the key to successful treatment is early detection. Gymnasts, in general, fare worse in returning to sport. The reason is not entirely clear but is likely related to the amount of force directed across the elbow and the nature of the sport. Pitchers sometimes can be returned, but to another position. Radiographs remain the screening test of choice but can give the surgeon a false sense of security, because changes early in the disease process may not be obvious radiographically. Views at 45 degrees flexion and contralateral elbow views are helpful. The advent of MR imaging now allows the practicing orthopaedic surgeon to assess very early lesions effectively that might otherwise be underappreciated on radiographs. With more advanced lesions, radiographic findings are more obvious and demonstrate the more classic capitellar fragment with a surrounding zone of lucency. MR imaging is this setting is helpful in assessing the overlying articular cartilage and, hence, the stability of the fragment. In the absence of obvious loose bodies or mechanical symptoms, rest is the first step in treatment. If symptoms persist, then operative intervention is indicated. About half of these patients heal with nonoperative treatment. Pretreatment assessment of fragment viability has not traditionally been incorporated into the treatment algorithm. Recent anecdotal evidence suggests that stability and viability of a fragment can be assessed using intravenous contrast. Knowledge of the fragment viability could allow those lesions likely to heal without surgical intervention to be distinguished from those requiring surgical intervention. The procedure should be chosen based on the size of the lesion and the integrity of the subchondral bone. Subchondral drilling and microfracture can only resurface defects and cannot reconstitute subchondral bone. Autologous chondrocyte implantation has limited ability to address subchondral bone loss, whereas autograft and allograft osteochondral transplantation can restore subchondral bone. Most authors would agree that there is no role currently for reduction and fixation of long-standing, free loose bodies. No consensus exists regarding acute dislodging of an in situ loose fragment. Long-term results after radiographic changes are present suggest a degenerative course in about half the patients. Whether the newer techniques of cartilage resurfacing will significantly impact the natural history of this process remains to be seen.