THE RELATIONSHIP BETWEEN LOADING CONDITIONS AND FRACTURE PATTERNS OF THE PROXIMAL FEMUR

In an attempt to rest the hypothesis of spontaneous hip fracture, seve n pairs of femurs, with ages ranging from 59 to 90, were tested under two loading conditions designed to simulate muscular contraction Simul ated iliopsoas contraction produced femoral neck fractures at an avera ge normalized ultimate load of 5.2 +/- 0.8 times body weight. Simulate d gluteus medius contraction produced sub-/inter-trochanteric fracture s at an average normalized ultimate load of 4.1 +/- 0.6 times body wei ght. The average ultimate load for all specimens was 3040 +/- 720 N. F racture patterns produced by both lending conditions were clinically r elevant. The results from this study suggest that abnormal contraction produced by major rotator muscles could induce hip fracture.