Abstract
Ultra-high molecular weight polyethylene (UHMWPE) is the sole polymeric material currently used for weight-bearing surfaces in total joint arthroplasty. However, the wear phenomenon of UHMWPE in knee and hip prostheses after total joint arthroplasty is one of the major restriction factors on the longevity of these implants. In the microscopic surface observation of the virgin knee prosthesis, microscopic machining grooves caused by the machining process were observed on the surface of the UHMWPE tibial insert. The authors focused on the machining grooves as a factor influencing the wear mechanism of UHMWPE. The 3D microscopic surface profile measurement and reproduction of the surface of the UHMWPE tibial insert were performed to produce finite element models of the machining grooves based on actual measurement data. Elasto-plastic finite element contact analyses between UHMWPE microscopic surface model with machining grooves and the metallic femoral component were also performed to investigate the mechanical state and wear behavior of UHMWPE surface zone with the machining grooves. The analytical findings of this study suggest that the machining grooves of the UHMWPE tibial insert are one of the important factors influencing the microscopic failure and/or microscopic wear behavior of the UHMWPE tibial insert in the knee prosthesis after total knee replacement.
