A five-station hip joint simulator

Abstract

A five-station hip joint wear simulator was designed and built which featured simplified motion and loading. An elliptical wear path was produced using approximately sinusoidal motion in the flexion/extension and internal/external rotation axes and the dynamic loading approximated to a square wave. Five 28 mm diameter zirconia femoral heads articulated against ultra-high molecular weight polyethylene acetabular cups in 25 per cent bovine serum for 5 × 10⁶ cycles. Gravimetric wear measurement was used with moisture absorption compensation using a dynamically loaded soak control. With motion of physiological magnitude, the mean acetabular cup wear rate was 52.2 mm³/10⁶ cycles which is comparable with a number of clinical studies.