Retrieval Analysis of Contemporary Knee Implants

Total knee arthroplasty (TKA) is a successful treatment for end-stage osteoarthritis. However, 20% of TKA patients remain unsatisfied due to poor knee function, defined as pain and functional difficulties assessed using disease-specific patient-centred pain outcome measures. The thesis aims to understand the multifactorial root cause of TKA implant failure. Aseptic loosening is one of the major complications that lead to knee implant replacement. The potential root cause of aseptic loosening is implant-cement-bone interface failure. The thesis is the first study that analysed a large sample group of 175 retrieved cemented TKA tibial tray components of 8 different designs. The surface depth and implant weight have been found to significantly (p<0.001) influence macroscopic bone cement adhesion to the tibial trays. Furthermore, the correlation between microscopic and macroscopic cement adhesion was investigated. The microscopic features were analysed using microscopic photogrammetry, profilometry, Fourier transform infrared spectroscopy, and scanning electron microscopy. Implants with a rougher surface (Ra > 0.60 μm) showed a significant difference (p