Clinical course and roentgenographic changes of osteonecrosis in the femoral condyle under conservative treatment.

The history of osteonecrosis in the femoral condyle of the knee was observed in 15 knees in 14 patients, averaging 62.8 years in age (range, 23-79 years). There were nine women and five men. The average follow-up period was 4.9 years (range, one to 12 years). Spontaneous osteonecrosis was found in 11 patients and steroid-induced osteonecrosis in three. The medial femoral condyles were involved in 13 knees and the lateral femoral condyles in two. The maximum width of the lesion was measured on anteroposterior roentgenograms and an osteonecrotic lesion less than 10 mm wide was rated as small. Cases of small osteonecrotic lesions displayed no remarkable changes with respect to stages and limb alignment. The average size of the steroid-induced osteonecrotic lesions was significantly larger than that of the spontaneous type. The size of the osteonecrotic lesions at the follow-up examination was compared to that observed at the initial diagnosis in 12 knees. Eight of these lesions displayed increases in dimension of more than 18% over the initial size at diagnosis.