Thermoelastic femoral stress imaging for experimental evaluation of hip prosthesis design

An experimental system using the thermoelastic stress analysis method and a synthetic femur was utilized to perform reliable and convenient mechanical biocompatibility evaluation of hip prosthesis design. Unlike the conventional technique, the unique advantage of the thermoelastic stress analysis method is its ability to image whole-surface stress (Delta(sigma(1) + sigma(2))) distribution in specimens. The mechanical properties of synthetic femurs agreed well with those of cadaveric femurs with little variability between specimens. We applied this experimental system for stress distribution visualization of the intact femur, and the femurs implanted with an artificial joint. The surface stress distribution of the femurs sensitively, reflected the prosthesis design and the contact condition between the stem and the bone. By analyzing the relationship between the stress distribution and the clinical results of the artificial joint, this technique can be used in mechanical biocompatibility evaluation and pre-clinical performance prediction of new artificial joint design.