The wear performance of PEEK-OPTIMA based self-mating couples

Abstract

Polymer-on-polymer wear couples have had limited investigation for use in orthopaedic implants but may provide engineers with new approaches for the design of medical devices such as in spinal arthroplasty or small joints of the extremities. In this study, the wear performance of polyetheretherketone (PEEK-OPTIMA) against itself, carbon fibre reinforced PEEK-OPTIMA (CFR-PEEK) against CFR-PEEK and alternative non-reinforced polyketones such as polyetherketoneetherketoneketone (PEKEKK) and polyetherketone (PEK) against themselves were investigated on a multidirectional pin-on-plate machine. PEKEKK against itself gave the highest wear. Whilst PEK/PEK gave lower wear factors than PEEK-OPTIMA/PEEK-OPTIMA, CFR-PEEK (both Pitch and PAN-based) against itself gave even lower wear. The PAN-based CFR-PEEK combination gave the lowest wear of all material combinations reported here. The average steady-state wear factor was found to be 5.44×10−6mm3N−1m−1 for the PEKEKK/PEKEKK samples. This compares with the average steady-state wear factors of 0.300, 0.921, 1.64 and 4.5×10−6mm3N−1m−1 for the CFR-PEEK PAN against itself, the CFR-PEEK Pitch against itself, PEK against itself and the PEEK-OPTIMA coupling respectively. Standard PEEK-OPTIMA against itself is currently used in a disc arthroplasty system which is undergoing clinical trials and it is possible that these material combinations may perform well in other prosthetic joints.