Unicompartmental Knee Replacement
The knee joint is divided into three compartments. The medial compartment, the lateral compartment and the patellofemoral compartment. A unicompartmental (partial) knee replacement is a prosthesis which replaces only one compartment of the knee. This is usually the medial compartment.
In a standard total knee replacement all three compartments are generally replaced. In a number of patients the arthritic process only affects the medial compartment. Provided certain conditions are fulfilled it may be more appropriate to undertake a partial knee replacement instead. This involves resurfacing the diseased medial compartment with metal components and placing a mobile, wear resistant, plastic bearing between the metal components
What are the advantages of unicompartmental (partial) knee replacement?
Because the partial knee replacement requires a smaller approach to the knee and removes less tissue there are a number of advantages. These include less pain after surgery and a more rapid recovery. Because this procedure preserves more of the natural joint and ligaments this results in a more natural motion (compared to total knee replacement) and potentially better function.
What are the risks of Partial Knee Replacement Surgery?
The risks of this procedure are small and are similar to those of a total knee replacement. These include infection, thromboembolism, stiffness, injury to nerves or blood vessels, ligament damage and loosening of the prosthesis. In addition there is a small risk of bearing dislocation. All of these risks are small but if they were to occur it may be necessary to revise the prosthesis to a standard total knee replacement.
What sort of knee replacement would be best for me?
The most commonly used unicompartmental (partial) knee replacement is the ‘Oxford’ knee. In order for this prosthesis to be used successfully a number of criteria need to be fulfilled. These include good preservation of the other compartments of the knee, minimal fixed deformity of the joint, intact ligaments and the absence of an inflammatory type of arthritis. It is also preferable that the arthritic pain is well localised to the medial (inner) aspect of the knee joint. If these criteria are not fulfilled then a standard total knee replacement would be the preferred option.
Your surgeon will be able to guide you as to which type of knee replacement would be most suitable for your individual circumstances.