In vitro evaluation of a PEKK and poly-carbonate-urea-urethane implant for the treatment of osteochondral defects

Abstract

Cartilage repair remains a major challenge and treatment of osteochondral defects generally results in inferior quality fibrous repair tissue. This study aims to elaborate on the work of Korthagen et al. who developed a thermoplastic polyurethane and polyetherketoneketone implant to treat osteochondral defects. Although promising results were found, Korthagen et al. encountered difficulties binding the neo-tissue to the elastomer part of the implant. The goal of this study is therefore to test potential solutions to improve cell binding properties of the elastomer in vitro, and to optimize the elastomers mechanical properties to mimic native articular cartilage. The newly produced elastomer showed encouraging cell binding properties with multiple cells types. In addition, 3D printing and punching holes in the elastomer part of the implant both have great potential in creating porosity to physically anchor the neo-tissue. The optimal diameter of vertically aligned punched holes was found to be 319 $\mu$m. Not only provides this diameter optimal circumstances for cartilage to grow into, it also optimizes anchoring potential. Besides that, 3D printing efforts were found to be promising in creating both excellent cell facilitating properties as well as mechanical properties mimicking that of native articular cartilage. Both punched and 3D printed elastomer samples were tested for toxicity and immune response. Both tests delivered excellent results and no sign of toxicity or adverse immune response was detected. These results combined with the excellent cell binding properties of the elastomer strengthens our confidence in favorable future in vivo outcomes.