Comparison of wear on articular cartilage from polycarbonate-urethane and other implant biomaterials

Talar replacement procedures offer good clinical outcomes for patients experiencing talar osteonecrosis with collapse. However, there is a potential for cartilage wear as the artificial talus prosthesis articulates against the native articular cartilage (AC) in the ankle joint. Therefore, this study investigated the wear of AC against candidate implant biomaterials with the aim of selecting an appropriate material for use in talar replacement procedures. Cobalt chrome alloy (Co-28Cr-6Mo), titanium alloy (Ti-6Al-4V), ultra-high molecular weight polyethylene (UHMWPE), industrial grade natural polyether ether ketone (PEEK), and polycarbonate-urethane (PCU) were tested against porcine AC submerged in bovine serum using an in vitro customized dual-motion wear testing setup. A total of 43,200 cycles at a frequency of 3 Hz were completed for each test. Both macroscopic and microscopic analyses were used to quantify cartilage wear using the Outerbridge and Osteoarthritis Research Society International (OARSI) clinical grading systems, respectively. In the macroscopic analysis, Ti-6Al-4V demonstrated the most AC wear, followed by Co-28Cr-6Mo, PEEK, UHMWPE, and PCU. In the microscopic analysis, PEEK demonstrated the most AC wear, followed by Ti-6Al-4V, Co-28Cr-6Mo, UHMWPE, and PCU. PCU demonstrated the least amount of AC wear compared to all other biomaterials and showed statistically insignificant differences with the control group (porcine cartilage-on-cartilage) in both macroscopic and microscopic inspections. These results suggest that PCU may be a suitable candidate material for coating talus implants as it demonstrated superior AC wear performance compared to the other biomaterials investigated in this study.