New bone formation in fractured head of the femur. A study using the scanning electron microscope

Abstract

INTRODUCTION: In senile osteoporosis, thinning and loss of irabeculae in tlie proximal end of ilie lemur leads to hip fractures. New bone formation in ihe form of thickening of remaining irabeculae and microcallus formation around stressed and cracked trabeculae has been demonstrated to occur both before and after fractures. I lowever, formation of an effective trabecular architecture to compensate for lost bone lias not been demonstrated to date. OBJECTIVE: To assess new bone formation in head of Jhe femur associated with hip fracture. METHOD: Femoral heads removed from 22 patients (15 fe¬males 8 males aged from 58 to 82 years) were fro/en and cut into 4 mm thick sections. Macerated specimens were made superficially anorganic by treating them with 1 lydro-gen Peroxide; coated with Platinum and examined under a Scanning Electron M icroscope. RESULTS: Microcallus formation on irabeculae showing different morphological appearance was evident in most specimens. Evidence of bone remodelling was observed on surfaces of these calluses. Irregular deposition of mineral nodules was seen on the fracture face of five specimens indicating that they may have been deposited after the fracture has occurred. The presence of growing trabecular patterns made up of woven bone from ihe remaining irabeculae was observed in six specimens; a phenomenon hitherto not described. Their morphology suggested dial they have been growing before the fracture has occurred. CONCLUSION: The findings suggest a reparalory mechanism resulting in growth of new interconnected trabcculae occurring prior to tlie fracture in a femoral head consequent to bone thinning in senile osteoporosis