Core decompression and alendronate treatment of the osteonecrotic rat femoral head: computer-assisted analysis.

Femoral head avascular necrosis is a process leading to femoral head deformity and osteoarthritic changes in the hip joint. Alendronate slows down bone resorption and remodelling in rats, while core decompression hastens the healing processes. We evaluated the influence of daily alendronate treatment on the rat femoral head shape after surgical osteonecrosis with core decompression, compared with controls. No differences were found in shape factor and femoral head height/length ratios. It was concluded that alendronate treatment slows down the process of replacing osteonecrotic bone by new bone and prevents early immature new bone collapse resulting from early revascularization because of core decompression.