Biological response to wear debris generated in carbon based composites as potential bearing surfaces for artificial hip joints

Abstract

UHMWPE wear particles have been implicated in osteolysis, implant loosening, and long-term failure of total hip arthroplasties in vivo. This study examined four carbon-based composite materials as alternatives for UHMWPE in joint bearings. These materials were HMU-CVD, SMS-CVD, P25-CVD, and CFR-PEEK. New bearing materials should satisfy certain criteria: they should have good wear properties that at least match UHMWPE, and produce wear particles with low levels of biological activity. Of the four materials tested in multidirectional pin-on-plate tribological tests, SMS-CVD, P25-CVD, and CFR-PEEK showed lower volumetric wear factors than UHMWPE. P25-CVD had the lowest wear factor of 0.54 +/- 0.34 x 10(-7) mm(3)/Nm. Analysis of P25-CVD wear particles by transmission electron microscopy showed that the debris was very small, with the vast majority of particles being under 100 nm in size, which was similar in size to metal wear particles. The P25-CVD particles were isolated and cultured with L929 fibroblasts and U937 monocytic cells to assess their effect on cell viability. P25-CVD particles were significantly less cytotoxic (p < 0.01, ANOVA) to both cell types than CoCr metal wear particles. This work suggests that carbon-carbon composite materials may have potential for use in total hip replacement bearings. Of the materials tested P25-CVD had the lowest wear factor, and produced very small wear debris that had minimal cytotoxic effect on L929 and U937 cells in vitro. Therefore carbon-carbon composites, such as P25-CVD, may be important in the development of next-generation implants with lower wear rates and reduced cytotoxic potential.

PEEK biomaterials in trauma, orthopedic, and spinal implants

“…As part of a larger study on composite candidate biomaterials, Howling and coworkers [177] investigated the bioactivity of wear debris generated by a 30% PAN CFR-PEEK composite pins articulating against alumina plates in a bidirectional pin-on-disk tester. The wear particles were extracted from the test fluid and exposed to L929 and U937 cells in an in vitro culture model to evaluate their effect on cellular viability.…”

“…These basic studies established that the friction and wear behavior of PEEK depended not only upon the type and amount of fiber reinforcement, but also the surface roughness of the PEEK surface and the counterface, as well as temperature, sliding speed, and contact pressure. Although an extensive body of tribological literature exists for PEEK and its composites, when we restrict ourselves to conditions relevant to total joint replacement applications, only a limited number of investigations have been reported in the peer-reviewed literature [17,[176][177][178][179].…”

Smart PEEK Modified by Self-Initiated Surface Graft Polymerization for Orthopedic Bearings

“…Considering the results of the wear particle analysis, we expect the biological response of the PMPC-grafted PEEK and CFR-PEEK cups in vivo to be comparable with those of PE or CLPE [12,35]. This is supported by the cell culture experiments performed by Howling et al, who reported that CFR-PEEK wear particles had no cytotoxic effects and could not possibly cause adverse cellular (L929 and U937 cells) reactions [36]. Jones et al reported that wear particles of CFR-PEEK cups exhibited no cytotoxic or mutagenic potential in the Ames test and the evaluation of chromosome aberration in human lymphocytes [12].…”

PEEK (Polyether-ether-ketone) Based Cervical Total Disc Arthroplasty: Contact Stress and Lubrication Analysis

“…Goodman proposed that the immune response to polymer particles is non-specific and macrophage mediated via the production of cytokines [31]. It is widely agreed that UHMWPE wear particles in the size range 0.1 to 1.0 m have been shown to be the most biological reactive [11,32]. Moreover, quantity, composition, and shape of the wear particles all play important roles in determining the host tissue response [33].…”

“…Moreover, quantity, composition, and shape of the wear particles all play important roles in determining the host tissue response [33]. There are plenty of studies [32][33][34] that report on the biocompatibility of PEEK wear debris, however none focus on wear debris generated in cervical TDA. A recent in-vitro wear study pointed out that the wear particle size distribution of a PEEK-on-PEEK cervical disc was from 0.23 to 0.51 m with a mean roundness of 0.5 [30].…”