Cross-linked polyethylene in total knee arthroplasty: in opposition.

Overview

Highly cross-linked polyethylene has been used with success in total hip arthroplasty. The reduction of femoral head penetration has been a uniform finding among researchers at 5 to 7 years of follow-up. However, there have also been newly highlighted modes of failure, as increased brittleness of the material can adversely affect the integrity of the acetabular locking mechanism; and some materials can oxidize in vivo, with additional alterations in mechanical properties and early delamination. The mechanics of articulation in a knee arthroplasty are markedly different and will impose more severe stresses on the polyethylene material than hip arthroplasties. Each change that is made to improve polyethylene wear comes with mechanical trade-offs. It is not clear that the gains in wear that have been shown in hips will translate to knees without adverse ramifications from the altered mechanical properties.