Analysis of run-in-stage wear behavior and contact mechanics of metal-on-metal hip joint bearings with different radial clearances

We systematically elucidate the effects of radial clearance on the wear behavior of hip joint prostheses bearings during run-in-stage. The results indicated that bearings with smaller radial clearances exhibited lower wear rate and less abrasive wear characterized by mild surface roughness and sphericity. The contact mechanics and lubrication regime of MOM bearings with different radial clearances were also analyzed, indicating that bearings with radial clearance of ≤20μm was more beneficial for small contact pressures even the enlarged clearance made the bearings operate under a full-fluid-to-mixed lubrication during wear. The agreement between the experimental results of wear rate (mm3/Mc) and contact mechanics and lubrication analysis indicated that the radial clearance significantly affected the wear behavior of the MOM bearings.