Knee Osteoarthritis (OA) is a disease that defects knee joint and causes severe pain while walking or sitting. The knee OA can occur due to many symptoms such as rheumatoid, ligament and sport injuries, deterioration of knee ligaments, muscles or deflection of cartilage tissue. OA is a degenerative condition primarily affecting the articular cartilage. Apart from operative and pharmacological therapy, the physical therapy can be used to relieve knee pain by either reducing load or increasing mobility. Knee braces may be used for rehabilitation, to reduce pain, or to prevent injury in either stable or unstable knees. A number of orthosis devices have been developed to help the OA patients and people with knee injuries. However, some of the existing orthoses restrict the movement of the joint and some are not slim enough to be worn under normal clothing. Furthermore, the cost of some of the existing devices (particularly the custom made knee braces) is too high for most patients. In order to design an improved bracing system to help OA patients, a detailed understanding of the mechanical behaviour of knee joint is essential.

This paper presents a study of the behaviour of knee joint and the effectiveness of an unloader knee brace system using the finite element method. Two models (of a healthy knee and an OA knee) are created from CT scans of knee joints. An imaging software is used to construct a 3D finite element mesh from the scanned images. Loading is then applied to the models to mimic stages of a gait cycle. The results are validated against published results from literature. Additional models are developed by including a knee brace system to the knee models to study the effects of the brace in the mechanical functioning of the knee joint. The results show that the developed model can be used to predict the mechanism of load transfer in the knee joint. The results help to improve the understanding of the behaviour of knee joint system which in turn can be used to design appropriate remedial actions for OA patients and those with knee injuries.