Arthritis in the knee may start in either the medial (inner) or the lateral (outer) compartment. If the arthritis is limited to either of these compartments, an experienced surgeon may be able to offer the patient a partial knee replacement. It is referred to as UKR or uni-compartment knee replacement. It is a much kinder operation for the patient as much of the knee joint is left untouched, and in the correct patient is a superior operation to the total knee replacement (TKR).
The damaged parts of the knee joint are shaped to accommodate the metal prosthesis. Once the bone ends are prepared, the metal parts of the implant are fixed to them with bone cement. A very hard wearing piece of plastic is then placed between the metal parts allowing the joint to move freely.
This is a very successful operation. The chance of the prosthesis surviving for ten years being around 95%. Should the arthritis spread to other parts of the knee, or should the implant fail, it can be replaced by a total knee replacement without too much difficulty.
The advantages of a UKR (partial knee replacement) over a TKR (total knee replacement) are:
- A more ‘natural’ feel of the joint
- Much greater conservation of bone
- Less painful immediately after surgery
- A smaller incision
- Much less blood loss
- A shorter hospital stay (usually no more than two or three days)
The disadvantages of a partial knee replacement:
- Not every patient is suitable
- It should be performed only by experienced surgeons
- In a small number of patients it may need to be converted to a total knee replacement eventually
Mr Prakash’s approach: I do not place an age limit for carrying out this procedure if the patient meets the criteria; my oldest patient was 82 years old when he had it done! I like to perform arthroscopy (keyhole surgery) to make sure that partial knee replacement is the best treatment for the patient, which can then be performed at a later date.