Fracture toughness and compressive properties of cancellous bone at the head of the femur and relationships to non-invasive skeletal assessment measurements

Osteoporosis defines a causal relationship between reduced bone density, reduced mechanical competence of the bone tissue of the sufferers and concomitantly an increased risk of fracture in life. The aims of the present study is: (1) to provide further evidence to support the use of Quantitative Ultrasound (QUS) results from peripheral sites to provide a prediction of the density of the proximal femur; and (2) to provide rational evidence for the well-proven ability of QUS to predict directly 'risk of fracture'. 20 femoral heads were obtained from 15 Caucasian females and 5 Caucasian males undergoing emergency surgery for a fractured neck of femur. QUS investigations of the calcaneus, proximal phalanx, distal radius and mid-shaft tibia were undertaken on the donors with 72 h of surgery. 128 fracture toughness samples and 20 compression cores were manufactured and tested. Significant relationships were found between QUS parameters determined in vivo and the apparent density (g/cm3) of the tissue at the proximal femur and both the fracture toughness and strength determined in vitro from the same donor individual. In this study we relate QUS results obtained in vivo to the actual apparent density of bone tissue from the proximal femur, donated by the same individual, and the fracture toughness and compressive strength. The study demonstrates the ability of QUS investigations at peripheral sites to accurately predict the density of bone from the proximal femur and provides evidence to support the use of QUS to predict the 'risk of fracture' directly.