Analysis of wear produced by a 100-station wear test device for UHMWPE with different contact pressures

In orthopaedic tribology, a useful wear test device must produce clinically relevant wear with low variation and have a large capacity for adequate sample sizes and simultaneous testing of several samples. The present study emphasized statistical considerations that are often overlooked. The 100-station SuperCTPOD device was used to study the effect of contact pressure, 0.5–3.0 MPa, on UHMWPE wear with a sample size of 10. The mean wear rate varied from 2.00 to 5.06 mg/10⁶ cycles and the SDs from 0.18 to 0.54 mg/10⁶ cycles. The lowest difference between means was 0.56 mg/10⁶ cycles with ≥ 80% power. The study provided corroborative evidence for the usefulness of the present large capacity wear test system.