Partial knee joint resurfacing

What is this procedure?

This picture shows the three compartments of the knee.

The knee joint has three compartments. The medial compartment is part of the joint between the femur (thigh bone) and tibia (shin bone) and is located on the inner aspect of the knee. The lateral compartment is also between the femur and the tibia, but is located on the outer aspect. The third compartment is between the femur and the patella (knee cap). It is known as the patellofemoral compartment and is located at the front of the knee.

Partial knee replacement, also known as unicompartmental knee replacement is where a single compartment (or very occasionally two compartments) are replaced, whilst the rest of the knee is left with the natural cartilage covering.

Who should consider this operation?

In some individuals arthritis affects all three compartments similarly, in others one compartment may be affected much more severely than the others. If you have clinical evidence and symptoms of isolated single-compartment disease then a unicompartmental knee replacement may be suggested.

Preoperative preparation and evaluation?

The surgeon will need to take a history and examine the knee to make the diagnosis. A unicompartmental knee replacement relies on good function in the ligaments and other soft tissues around the knee so these will be assessed clinically.

Xrays can help confirm the diagnosis of unicompartmental knee osteoarthritis, but the only way the surgeon can be sure that there is not arthritis in the other compartments of the knee is to look directly at the cartilage. As part of the preoperative preparation, you will therefore be advised that the surgeon will assess the knee intra-operatively and revert to total knee replacement if the arthritis is more widespread than initially apparent on Xrays.

What happens in the post-operative period?

Depending on the time of day that the surgery is performed you will be encouraged to stand and transfer out of bed either on the same day or the following day. When the wound is dry and physiotherapy goals are achieved you will be allowed home. The time this takes varies from individual to individual but discharge from hospital occurs typically on the third or fourth day post operatively.