Maximizing ultra high molecular weight polyethylene performance in total knee replacement

The etiology of polyethylene wear following TKR is multifactorial. Factors such as surgical technique, patient selection, and choice of implant design directly impact the polyethylene wear rate. Surgical technique is directly associated with polyethylene wear; particularly the thickness of the polyethylene insert, the postoperative mechanical axis of the limb, and the alignment of the tibial component in the coronal plane. Patient selection is an important determinant of polyethylene wear, as patient body weight and activity level have been shown to correlate with wear rate. Prosthetic design plays a role in polyethylene wear as femoral-tibial contact areas, peak contact forces, and surface topography of the polyethylene are important considerations. The method by which the polyethylene is manufactured and the method of sterilization are also important determinants of polyethylene wear. Wear of polyethylene is one source of particulate debris following TKR. Phagocytosis of the particulate debris by macrophage occurs at the prosthesis-bone interface. The macrophage produces inflammatory mediators in response to the particulate debris. Inflammatory mediators act at the failed interface to effect bone resorption and produce osteolysis. In summary, the surgeon can play a major role in maximizing polyethylene performance in TKR by understanding the multiple factors that contribute to polyethylene wear and taking steps to lessen their effect.