Course of Avascular Necrosis of Femoral Head Without Collapse of Femoral Head at First Examination: Minimum 8-Year Follow-up

Abstract

Disruption of the femoral head contour by collapse of necrotic segments is considered to be an important turning point in the history of avascular necrosis of the femoral head, and in many cases, surgical treatment is required soon after the onset of symptoms. However, in a few cases, conservative treatment is sufficiently effective to avoid surgical procedures for long periods. For patients with early-stage avascular necrosis, it is important to accurately predict its natural course. This article documents the characteristics of patients who can be treated without surgery for long periods. Seventeen hips in 13 patients with avascular necrosis of the femoral head without collapse of the femoral head at first examination were followed for at least 8 years of conservative treatment. Long-term outcomes of hips with avascular necrosis were divided into 3 groups: (1) hips without collapse, (2) hips with progression but cessation of collapse, and (3) hips with progression of collapse. In groups 1 and 2, good clinical results are expected. Hips with femoral head collapse .3 mm at 3 years from the onset of hip pain progressed to osteoarthritis. Our analysis indicated that collapse of the femoral head does not necessarily indicate a poor prognosis, and even after collapse occurs, subsequent cessation of collapse can be expected in a certain percentage of hips.