Effects of femoral head diameter on the predicted acetabular cup wear volume of CP-Ti and UHMWPE hip implants

Abstract

Numerical investigation is a method capable to study the expensive and long-time duration wear problems in biotribology. The technique has been used to predict the wear of hip implants specially those made from metal on polymer biomaterials. This research studied the effect of commercially pure titanium (CP-Ti) femoral head diameter on the wear volume of ultra-high molecular weight polyethylene (UHMWPE) acetabular cup. Diameter variations are 22 mm, 28 mm and 32 mm. Hip implant models were created and the numerical approximations conducted with the finite element method. Wear calculations used a nonlinear load and contact area mathematical model. A Python script was developed to proceed the calculations. Accurate wear predictions can be obtained with the use of fine elements those maximum contact loads are closer to the physiological load. Verification with experimental data on the 32 mm femoral head model shows a good agreement with error rates below 1%.