PEEK-OPTIMA as an alternative to cobalt chrome in the femoral component of total knee replacement: A preliminary study

摘要

PEEK-OPTIMA (Invibio Ltd, UK) has been considered as an alternative joint arthroplasty bearing material due to its favourable mechanical properties and the biocompatibility of its wear debris. In this study, the potential to use injection moulded PEEK-OPTIMA as an alternative to cobalt chrome in the femoral component of a total knee replacement was investigated in terms of its wear performance. Experimental wear simulation of three cobalt chrome and three PEEK-OPTIMA femoral components articulating against all-polyethylene tibial components was carried out under two kinematic conditions: 3million cycles under intermediate kinematics (maximum anterior-posterior displacement of 5mm) followed by 3million cycles under high kinematic conditions (anterior-posterior displacement 10mm). The wear of the GUR1020 ultra-high-molecular-weight polyethylene tibial components was assessed by gravimetric analysis; for both material combinations under each kinematic condition, the mean wear rates were low, that is, below 5mm(3)/million cycles. Specifically, under intermediate kinematic conditions, the wear rate of the ultra-high-molecular-weight polyethylene tibial components was 0.96 +/- 2.26mm(3)/million cycles and 2.44 +/- 0.78mm(3)/million cycle against cobalt chrome and PEEK-OPTIMA implants, respectively (p=0.06); under high kinematic conditions, the wear rates were 2.23 +/- 1.85mm(3)/million cycles and 4.44 +/- 2.35 mm(3)/million cycles, respectively (p=0.03). Following wear simulation, scratches were apparent on the surface of the PEEK-OPTIMA femoral components. The surface topography of the femoral components was assessed using contacting profilometry and showed a statistically significant increase in measured surface roughness of the PEEK-OPTIMA femoral components compared to the cobalt chrome implants. However, this did not appear to influence the wear rate, which remained linear over the duration of the study. These preliminary findings showed that PEEK-OPTIMA gives promise as an alternative bearing material to cobalt chrome alloy in the femoral component of a total knee replacement with respect to wear performance.