Effects of Walking Gait on Ultra-High Molecular Weight Polyethylene Damage in Unicompartmental Knee Systems

There is increasing, renewed interest in the use of unicompartmental knee replacement as the treatment of choice for isolated compartment disease, although there is debate regarding its role as a temporizing or definitive procedure. The popularization of mini-incision surgery with claims of reduced pain, shorter hospitalization, more rapid rehabilitation, more normal knee function, and decreased cost are positive arguments for the procedure. However, the damage observed in retrieved ultra-high molecular weight polyethylene components is the result of high cycle fatigue loads, which act on the polymer insert during daily walking. This suggests that there is a material limitation to the use of these components.