Knee Osteoarthritis (KOA) is considered to be one of the biggest burdens to healthcare. The disease is believed to be a combination of mechanical wear, inflammatory factors and changes in the cellular level. It is estimated that approximately 50% of people over the age of 65 suffer from OA. Because mechanical wear, specifically high stresses in the cartilage have been shown to greatly increase the risk of KOA, several cost-efficient treatment strategies have been proposed. Specifically, because KOA is most common in medial tibial plateau, gait modification strategies to reduce stresses in the medial side have been developed.
Previous studies have shown that it is possible to reduce knee adduction moment i.e. by using a toe-in style in gait. However, it has also been shown that a decrease in adduction moment does not directly translate into reduced stresses in the medial side of the knee.
Because of this, two types of modelling are needed: musculoskeletal (MS) modelling, to determine the forces acting on the knee, and finite element (FE) modelling, to model how those forces translate into stresses in the knee geometry. The advantage of this approach is that it is completely non-invasive.
The primary objectives of this research are:
• Establish a functioning workflow from magnetic resonance images (MRI) via MS modelling to a personalised FE model of the knee. This preliminary model is created of a healthy control subject.
• Apply the workflow to KOA patients and study the effect of gait modification.
This research will be done in close collaboration with Ph. D. students ESR1 and ESR9, who will participate in gathering the data as well as building the knee models. The MS modelling is done in AnyBody software (AnyBody Tehnology, Aalborg, Denmark) and the FE modelling in Abaqus (Simulia, Belgium). The MS model provides the forces and moments that act on the subject’s knee during gait, and will be used as the input for the FE model. Soft tissues are meshed and assigned their respective material models, while bones are defined as rigid structures. The custom material model used for cartilages and menisci has been validated in previous studies vs. experimental results. The final models of knee joints will provide new information of the effect of gait modification on the stresses in medial tibial cartilage.
Impact and Dissemination
Due to the currently untreatable nature of OA, gait modification, if shown successful, could provide a cost-effective method to alleviate the symptoms of KOA patients. Conversely, if shown unsuccessful, the research could focus on other treatment options. The results will be disseminated through publications in respected, peer-reviewed scientific journals as well as conferences.