Femoral surface strain in intact composite femurs: A custom computer analysis of the photoelastic coating technique

Understanding how forces are distributed through the proximal femur has man y clinical applications for surgeons, researchers, and prosthetic designers . A new system for two-dimensional analysis of femoral surface strain was d eveloped and applied to intact composite femurs. The photoelastic coating m ethod was used to resolve the surface strain under axial loading, and strai n analysis was performed using digital imaging of the strain patterns and o riginal computer programs. The technique provides qualitative and quantitat ive data that describes overall femoral surface strains more completely tha n previous point analysis and strain gauge techniques. Results from repeate d testing found the photoelastic process, computer imaging and computer ana lysis of strain areas to be statistically repeatable.