Influence of contact pressure, cross-shear and counterface material on the wear of PEEK and CFR-PEEK for orthopaedic applications

Abstract

Total joint replacement is a successful surgical intervention for the treatment of the degeneration of many joints, particularly the hip and knee. As the demand for joint replacement grows, and the life expectancy of the population increases, the performance requirements of these implants also changes. New materials, to improve longevity and enhance performance have been explored including PEEK and CFR-PEEK.This study investigated whether CFR-PEEK and PEEK were appropriate materials for total joint replacement by examining wear performance in simple configuration studies articulating against cobalt chrome under a range of cross-shear and contact pressure conditions. Simple geometry pin on plate studies were conducted for one million cycles for each test condition, with the contact pressure and cross-shear conditions representing a range in which the material may need to operate in-vivo.The wear factor for PEEK was significantly higher than CFR-PEEK and conventional polyethylene under all test conditions. Both PEEK and CFR-PEEK wear were influenced by contact pressure, with the highest wear factors for both materials measured at the highest pressure conditions. PEEK appeared to have a cross-shear dependent wear response, but this was not observed for the CFR-PEEK material.This study has further characterised the wear performance of two materials that are gaining interest for total joint replacement. The wear performance of the PEEK material showed poorer wear performance compared to polyethylene when articulating with a metal counterface, but the performance of the CFR-PEEK material suggested it may provide a suitable alternative to polyethylene in some applications. The wear performance of CFR-PEEK was poorer than polyethylene when it was used as the plate, when there was translation of the contact zone over the surface of the CFR-PEEK plate. This has implications for applications in low conforming contacts, such as lower conformity knee replacement.

Wear properties of poly‐ether‐ether‐ketone bearing combinations under zero and cross shear kinematics in total knee arthroplasty

“…This difference suggests that a hard counter face 225 bearing material directly effects the CS dependency and wear factor of PEEK-OPTIMA 226 bearings. This confirms the effect reported by Brockett et al 21 . There was no significant CS 227 dependency observed for PEEK-OPTIMA pins when articulating on the PEEK-OPTIMA 228 counter face lubricated with a proteinaceous fluid (BCS) in this study, which is a similar 229 characteristic to the results reported by Baykal et al 20 for the all-polymer, PEEK-OPTIMA 230 and polyethylene bearing combinations, and those reported by Laux and Schwartz 31 under dry 231 lubricated conditions, however, at a lower contact pressure of 1.1 MPa.…”

“…Brockett et al 21 who found a wear factor of (1.76 ± 2.29) x 10 -6 mm 3 /Nm for PK-on-M under 240 zero CS conditions, with an increase to (7.29 ± 2.18) x 10 -6 mm 3 /Nm when CS was applied. 241…”

“…A study by Baykal et al 20 investigated the effect of CS on PEEK on highly cross-linked 80 polyethylene (PK-on-HXLPE) and HXLPE-on-PK using a pin-on-disc test rig, with alpha calf 81 serum as the lubricant, and found that the wear rate of PK-on-HXLPE was not affected by the 82 introduction of CS. A more recent PK-on-CoCr pin-on-plate (PoP) study by Brockett et al 21…”

PEEK Composites as Self-Lubricating Bush Materials for Articulating Revolute Pin Joints

“…Most of the work relating to PEEK composites has been conducted in the lab using standard tribo-meters. For engineering use, some research has been carried out where PEEK composites form the tribological component, including ball bearings [8,24], thrust bearing [25], orthopaedic device [26] and crank shaft bush on the robot joint [27]. There is no work conducted towards journal bearing bushes made of PEEK composites.…”

Polyether ether ketone (PEEK) and its 3D printed implants applications in medical field: An overview

“…This technology is rapidly growing to fabricate patient-specific implants of bone, https://doi.org/10.1016/j.cegh.2019.01.003 Received 4 November 2018; Received in revised form 17 December 2018; Accepted 3 January 2019 prosthetic, heart and its components. 8,9 In medical, the main aim is to maximise the power-to-weight ratio and create development and innovation by using the high-performance material. PEEK is a high-performance polymer which used for manufacturing of medical implants and devices which has a high capability of load bearing.…”