Abstract
Unicompartmental knee replacement (UKR) is an established and effective treatment for early unicondylar osteoarthritis of the knee. However good results will only be achieved with a UKR if appropriate implants, indications and surgical techniques are used.
There are now many UKR available. The majority have been introduced recently and have no published clinical results, as a result it is not clear how well they will function. Wear is a potential problem with UKR because of thin polyethylene and small contact areas. To minimise wear we use a device with a fully congruous unconstrained mobile bearing, the Oxford UKR.
The indications for UKR are confusing. The Oxford UKR is recommended for medial compartment osteoarthritis with full thickness cartilage loss and a functionally intact Anterior Cruciate Ligament. The Varus deformity should be correctable and there should be full thickness cartilage in the lateral compartment. It is appropriate for about one in four osteoarthritic knees needing replacement. With fixed bearing devices, because of problems with wear, the indications are narrower and contraindica–tions include young patients and damage to the Patello-femoral joint. These devices can however be used in the lateral compartment. There is currently a vogue to consider UKR as a pre-TKR. Under these circumstances the indications are relaxed and worse results are achieved.
UKR are now routinely implanted through a minimally invasive approach, which decreases morbidity and aids recovery. There is concern that the small incision will compromise implantation. The techniques used range from free hand with a burr to sophisticated instrumentation. We use a mill to precisely restore ligament balance and function to normal and have shown that, with this instrumentation, the device can be implanted as precisely through a short incision as through a standard one.
If appropriate implants, indications and surgical techniques are used then UKR achieve better short term functional results than both HTO and TKR, and they can achieve a long term survival that is similar to TKR and better than HTO.
Under these circumstances we believe that UKR is the treatment of choice.
Theses abstracts were prepared by Professor Dr. Frantz Langlais. Correspondence should be addressed to him at EFORT Central Office, Freihofstrasse 22, CH-8700 Küsnacht, Switzerland.
