Influence of bone properties in the biomechanical response of knee cartilage: a finite element study

Abstract

Osteoarthritis of the knee is a very prevalent, progressive disease which affects a lot of people nowadays. Its symptoms include pain and swelling of the joint, which can be treated by conservative treatments, like anti-inflammatories or physical therapy, or non-conservative, more invasive techniques like knee arthroplasty. To study the pathology, in-silico models can be used. Currently, most of the 3D Finite Element models available in the literature consider the bones as rigid bodies. This fact results in a null load absorption by the bone, transmitting the full load to the cartilage. In the actual joint, bones act as load absorbers, decreasing the load applied to the articular cartilage. This difference, although might result in small errors of 2-3%, can suppose a big change in cell behaviour. Hence, the aim of this study is to implement bone structures in a knee model and evaluate the influence of bone properties on knee cartilage biomechanical response on healthy patients, hypothesising that bone does affect on the cartilages biomechanical response. Structural bone meshes were created and implemented into a representative model of the joint, including the femur and the tibial articular cartilages. The simulations of the rigid body and deformable models resulted in our confirmed hypothesis. The inclusion of bone, indeed, made the pressure on the cartilage lower, deforming itself and absorbing part of the load. In conclusion, in this project we demonstrated how, with the introduction of bone, using structural meshes, and bone properties in a knee joint model, bone properties should indeed be included in a full knee finite element model for better interpretation of the load scenarios in articular cartilage, which might provide valuable data to the clinician for the evaluation and prevention of knee osteoarthritis.