ARE HIP-FRACTURES CAUSED BY FALLING AND BREAKING OR BREAKING AND FALLING - PHOTOELASTIC STRESS-ANALYSIS

The distribution of stress in the heads of femurs has been assessed us ing an engineering technique known as photoelastic stress analysis. Th e aim of the investigation was to locate and evaluate the probable sit es of stucture failure in femurs with various axes of loading. The ana lysis shows that the maximum stress in the upper femur occurs in the c ervical region during vertical loading. Lateral loading does not produ ce significant stress patterns at the sites of extracapsular hip fract ure. It is concluded that cervical hip fractures in individuals suffer ing from osteoporosis result from a combination of fatigue damage and axial muscular compression, rather than forces generated by a fall. Th is has significance for the medico-legal interpretation of the cause o f death following femoral neck fracture.