A five-station hip joint simulator

A five-station hip joint wear simulator was designed and built which featur ed simplified motion and loading. An elliptical wear path was produced usin g approximately sinusoidal motion in the flexion/extension and internal/ext ernal rotation axes and the dynamic loading approximated to a square wave. Five 28 mm diameter zirconia femoral heads articulated against ultra-high m olecular weight polyethylene acetabular cups in 25 per cent bovine serum fo r 5 x 10(6) cycles. Gravimetric wear measurement was used with moisture abs orption compensation using a dynamically loaded soak control. With motion o f physiological magnitude, the mean acetabular cup wear rate was 52.2 mm(3) /10(6) cycles which is comparable with a number of clinical studies.