Study on bone mineral density and the ultrastructure of fractured femoral neck in elderly women

Objective To study the ultrastructure and bone mineral density(BMD) of fractured femoral neck in elderly women. Methods From Jan. 1999 to Dec. 2001, in fifty female patients with total hip arthroplasty (THA) due to femoral neck fracture were performed. Age ranged 65～75 years (mean 69.3 years). Hip BMD was measured by DEXA (Double Energy X-ray Absorption, Hologic) within 1 week after fracture. The hip BMD was compared with that of 124 healthy young women and 175 age-matched healthy women. 50 femoral heads were removed during THA and two 1 cm(1 cm×1cm cancellous bones on both sides of the fracture line)were taken for scanning electro-microscopy. Three femoral heads were taken from young women died of accidents as controls. Results Among these, five fractures were due to sprain, thirty-three were from falling, nine from bumping and three from car accident. The hip BMD of these patients was significantly reduced than that of the young healthy women (P0.01). The BMD of femoral neck, intertrochanter and Ward's triangle was less than that of the same aged women, but without statistic discrepancy. The trabeculae of femoral neck in elderly people were destroyed and absorbed. The trabeculae became thinned perforated and even disappeared. Conclusion The reduced BMD of the hip and trabecular resorption and destruction are the pathologic basis of femoral neck fracture in the elderly. Prevention from trauma is a major factor in reducing femoral neck fracture in the elderly.