Prevention of distortion of vascular deprivation-induced osteonecrosis of the rat femoral head by treatment with alendronate

In animals with a disrupted blood supply and drainage of the femoral head, the dead epiphyseal bone undergoes osteoclastic osteolysis and is replaced by newly synthesized, immature, and weak bone, which cannot withstand the daily loads and, therefore, the articular surface caves in. Female Sprague–Dawley rats with interrupted blood circulation of the femoral head were treated with alendronate and compared to controls. There was no distortion of the femoral heads in the alendronate-treated animals. Alendronate medication interferes with osteoclastic activities, slowing down bone turnover. These observations verify our hypothesis that osteoclastic activity is detrimental to the conservation of a hemispherical femoral head because of the rapidly occurring replacement of the dead by living tissues. Hence, halting the activities of the osteoclasts by alendronate stops the hasty new bone formation which is responsible for early femoral capital disfigurement.