Wear Rate, Particle Morphology, and Biocompatibility of Polyether-Ether-Ketone Femoral Heads Against Highly Cross-Linked Polyethylene Acetabular Cups in Hip Prosthetic Couples

Abstract

Biological reactions to wear particles from artificial joint prostheses can lead to osteolysis, ultimately resulting in aseptic loosening and implant failure, which affect the longevity of the prosthesis and the patient's quality of life. Polyether-ether-ketone (PEEK) has emerged as a key area of research in orthopedic implant materials due to its excellent wear resistance and biomechanical compatibility with human bone tissue. In this study, we conducted a 10-million-cycle simulator wear test on hip artificial joints with polyetheretherketone-on-highly cross-linked polyethylene (PEEK-on-HCLPE) bearing couplings for the first time. The results indicated the total wear loss of the highly cross-linked polyethylene (HCLPE) liners was 34.03 ± 3.2 mg (~2.96 mg/MC or 3.18 mm³/MC after linear fitting). The physicochemical properties of the mixed particles indicated a predominant particle size distribution ranging from 0.1 to 0.5 μm. Pure PEEK or HCLPE particles with the similar size range (maximum size: 0.5 μm) were generated by an EXAKT grinding system, followed by vacuum filtration with precision pore—size membranes for the biocompatibility experiments. In vitro immunological assays showed that 0.1 to 0.5 μm PEEK particles may induce a relatively weaker immune inflammatory effect than 0.1 to 0.5 μm HCLPE particles. In conclusion, the PEEK-on-HCLPE bearing couple has been demonstrated to have acceptable biosafety and a wear rate suitable for use as a potential hip replacement implant.