Total knee arthroplasty is a widely used and relatively successful procedure, designed to relieve pain and restore function to patients suffering from osteoarthritis. However, satisfaction following the procedure is low. One of the primary sources of pain and a cause of functional limitations following knee arthroplasty is the patellofemoral joint. Reasons for pain in the patellofemoral joint are not well understood but adverse patellofemoral biomechanics are thought to contribute. Many in vitro methods exist for the investigation of patellofemoral joint biomechanics but there is no consistent standard protocol. It is therefore difficult to draw any general conclusions regarding the effect of specific design or alignment factors on the biomechanics of the patellofemoral joint. The present study aimed to improve current understanding of factors contributing to patellofemoral complications. A knee simulator, which was based on the Oxford Knee Rig and included synthetic models for a number of soft tissue and bony structures, was developed. The simulator was demonstrated to provide a simplified but physiologically relevant model of the human knee, which allowed effective assessment of patellofemoral joint biomechanics under physiological loads. The system eliminated the need for cadaveric tissue and therefore demonstrated reduced variability, enabling the efficient assessment of a number of potentially influencing factors. A number of investigations were carried out using the simulator to assess the effect of patella component design and position, and femoral component alignment on patellofemoral biomechanics using the Scorpio NRG system. The results of these studies indicate the benefit of medialisation of the apex of the patella component and warn against excessive femoral component sagittal plane malalignment. However, in general they indicated the relatively forgiving nature of the Scorpio system to malalignment and highlighted that irrespective of alignment and patella component design, pressures in excess of material limits are frequently achieved in deep flexion.