The treatment of osteonecrosis of the medial femoral condyle.

Osteonecrosis of the medial femoral condyle presents as a sudden onset of pain on the medial side of the knee. This is associated with a positive bone scan and, frequently, a radiolucent lesion in the subchondral zone. In a review of 79 patients with this disease, performed to establish guidelines for treatment, the patients are divided into three groups according to clinical course and size of the lesion. Group I patients have typical clinical presentation and positive bone scans, but lack radiologic evidence of the lesion. Group II patients have small lesions, with an average diameter of 32% of that of the medial femoral condyle. Group III patients have large lesions, all with diameters greater than 50% of the diameter of the condyle. Patients in Groups I and II obtained relief of pain with conservative treatment; the lesion stabilizes; surgery should be avoided until late degenerative changes become symptomatic. The joints of Group III patients will all collapse rapidly; surgical treatment prior to the development of fixed deformity is advisable.