Cancellous bone and mechanical strength of the femoral neck.

Twenty pairs of dried macerated femora were submitted to progressive, physiologically oriented loading. The aim of this work was to determine the role of trabecular bone, the importance of the bone mineral density of the femoral shaft, and the importance of the Singh index in the mechanical strength of the femoral neck. By means of an original technique, the influence of both the principal tensile and secondary compressive trabecular groups on the mechanical strength to bending stress has been demonstrated. The artificial destruction of these trabecular groups is responsible for a loss of strength of more than 50% in varus angulation while it has practically no effect in valgus angulation. On the other hand, the mechanical strength of the femoral neck is better correlated with the bone mineral density of the femoral shaft (r = 0.74) than with the Singh index (r = 0.50) or with age (r = 0.15).