A tribological assessment of a PEEK based self-mating total cervical disc replacement

This paper presents an in-vitro tribological investigation of the PEEK (Poly-ether-ether-ketone) based self-mating articulation of the NuNec® cervical disc replacement. All tests were undertaken using Bose spine simulator. Discs were subjected to wear tests and this involved applying the load and motions given in ISO 18192-1. Wear was determined from the mass loss from the specimens. Testing continued until 5 million cycles had been completed. Disc were subjected to friction tests, before and after the wear testing; each specimen was tested under a constant axial compressive and then subjected to the motions given in ISO 18192-1. Stribeck analysis was used to determine the lubrication regime. The wear rates for the initial phase (0-2 million cycles) and the steady stage (2-5 million cycles) were 4.8±1.5 mg/million cycles and 1.0±0.9 mg/million cycles, respectively. Over the entire test period, the total mass loss was 12.5±0.4 mg. The Stribeck analysis showed that this cervical disc will operate under boundary or mixed lubrication.