A review of previous publications on the mechanical complications of cemented total-hip prosthesis femoral component indicates several failure mechanisms. However, the biomechanical significance of the various reported radiographic phenomena has not been clearly assessed with static testing or with computer models.

A new technique was developed to directly measure internal cement strains in a simulated proximal femur with cemented femoral total-hip prostheses. Static experimental testing of a Delrin plastic-bone-analog with a cemented metallic femoral prosthesis indicated highest cement strains in the proximal-medial aspect of the cement sheath, which correlated with highest cement stresses in the same location in a corresponding finite-element analysis computer model. The most noticeable observation from the cyclic testing was the 73% decrease of cement strains in the proximal-medial region after 4.1 million cycles. This time-dependent behavior, that is, creep, may have significance in the failure mechanisms of cemented femoral total-hip replacement components and should be considered in future static or cyclic experimental testing and computer modeling of such prosthetic components.