Implications of a polymer meniscus implant on knee tribology

Meniscal lesions are one of the most frequent knee injuries. The menisci support articular cartilage throughout its main functions in the knee joint, i.e. providing lubrication and load distribution. A malfunctioning meniscus changes the load distribution on the articular cartilage, resulting in degenerative arthritis. Considering the currently available treatments, replacing an injured meniscus with a meniscus implant is a promising solution. The work in this thesis was carried out within the scope of the TRAMMPOLIN project, which aimed to develop an anatomically shaped, permanent meniscus implant. The goal of this thesis was to evaluate the changes in tribology (friction and wear) of the articular cartilage when the meniscus is replaced with a permanent polymer material. To do so, the tribology of different biomaterials and surfaces in the presence of different (lubricant) molecules was studied in vitro both at nano-and macro-scale. In addition, the involved molecules and mechanisms were studied as well. The nanoscopic approach—through the use of quartz crystal microbalance with dissipation and atomic force microscopy with colloidal probe—provided fundamental information on the adsorption mechanism of the molecules and the consequent boundary lubrication. The macroscopic approach—using a tribometer device—provided a wider overview of the lubrication mechanisms on the substrate and revealed that boundary lubrication and interstitial fluid pressurization and weeping lubrication are the operative lubrication mechanisms.