An investigation into the effect of cyclic loading and frequency on the temperature of PMMA bone cement in hip prostheses.

A titanium alloy hip prosthesis was inserted in a Tufnol tube representing the upper part of the femur. The prosthesis was cemented in the model femur using PMMA bone cement. Five thermocouples were embedded in the bone cement and the assembly was subjected to cyclic loading with a range of 0.3-4.5 kN at a frequency of 6 Hz. Temperature measurements over a 48 hour period indicated that the temperature rise in the bone cement was less than 4 degrees C. It is concluded that such tests can be carried out at 6 Hz without significantly affecting the mechanical properties of PMMA bone cement.