A SCANNING ELECTRON-MICROSCOPIC STUDY OF TRABECULAE IN OSTEOPOROTIC FEMORAL-HEAD

Objective. To investigate osteoclastic resorption in trabeculae of ost eoporotic femoral head. Methods. Osteoporotic femoral heads were colle cted from 7 aged women with an average age of 72.4 years, who underwen t endoprosthetic replacement for intracapsular hip fracture. Femoral h ead trabeculae from 3 young adults killed in traffic accidents served as control. The two types of specimens were processed and studied unde r scanning electron microscope. Results. The trabeculae of femoral hea d formed round or roundish arch structure. The columnar trabeculae of femoral head in the aged women showed overt osteoclastic resorption, m anifested in thinning, tapering and perforation, resulting in formatio n of icicle-like trabeculae, which then became rounded, lost height an d eventually turned into small tubercle. As a result, the inter-trabec ular space enlarged markedly. Under high magnification, the trabeculae could be discerned oval, narrow oval or spindle-shaped. Howship resor ption lacunae, which varied in size, depth and content, but all reveal ed punched-out margin. During bone resorption, the inorganic and organ ic components were successively resorbed. In the Howship lacunae and s urrounding areas, newly formed collagen fibrils and bone tissues emerg ed, signifying reversal and new bone formation phases after bone resor ption phase. Conclusion. Osteoclastic resorption markedly compromises the structural integrity and strength of the trabeculae of the arch st ructure of the femoral head in the aged women.