The syndrome of osteonecrosis of the femur at the knee presents as
sudden onset of knee pain in elderly patients. It is classically associated
with a subchondral radiolucency and a positive radionuclide bone scan. The
lesion may progress to collapse of the bone. In this report, twelve cases
are described in which the clinical entity of osteonecrosis of the femoral
condyle was diagnosed because the patients had a clinical picture identical
to that of osteonecrosis and also had positive bone scans. However,
roentgenographic changes supposedly diagnostic of the condition were not
seen. In twelve patients, arthrotomy was avoided. They became asymptomatic
and their bone scans returned to normal in a few months.