Institution: Imperial College London
Investigators: Dr Farhad Iranpour-Boroujeni, Professor Justin Cobb
Stream: PhD
Topic: Lower Limbs/Navigation (Knee)
Status: Completed
Knee arthroplasty is one of the most commonly performed operations in the world. Given the scale of intervention at the knee joint, our current understanding of the 3-dimensional shape and motion of the knee joint is limited. The patellofemoral joint in particular, in spite of having major mechanical rules and being a source of complications after total knee arthroplasty, has not received adequate attention.
The purpose of this study was to explore the patellofemoral joint in 3 dimensions, looking at its geometry and motion. This work aimed to establish a relationship between this joint and the tibio-femoral joint. Special 3D software was used to produce accurate and reproducible methods. It was found that the flexion facets of the femoral condyles were spherical. The medial extension facet could be reproducibly described as part of a larger sphere. However, this was not found to be the case laterally. The path of the centre of the patella was circular and uniplanar from full flexion to approximately 16° flexion, after which it deviated laterally towards full knee extension. This path was perpendicular to a newly-defined trochlear axis, which was the line joining the centres of spheres fitted to the articular surfaces of the medial and lateral facets of the trochlea.
The knowledge of the shapes of the surfaces and motion of different compartments of the knee joint and their relationships may help to identify and explain the aetiology of knee joint pathologies. It may also be of use in planning and performing joint reconstruction. These relationships also have implications for the design of unicompartmental and total knee replacements and the rules governing their position.
« Back to research projects
