Patellofemoral Replacement

What is it?

The knee is made up of the main joint between the femur (thigh bone) and tibia (shin bone) as well as the patellofemoral joint between the femur and the patella (knee cap). Often, when there is arthritis involving the patellofemoral joint, the main knee joint is also affected. Occasionally, however, there can be significant arthritis under the knee cap but the main joint is normal. In this situation, a patellofemoral joint replacement might be an option. It aims to replace the undersurface of the patella and the groove in the femur that the patella sits in but does not change the main joint.

How is it performed?

Under an anaesthetic, a large incision is made in the front of the knee and the knee joint is exposed. The groove in the femur (trochlea groove) is reshaped and a metal replacement is cemented in place. The undersurface of the patella is then cut flat and a plastic button is cemented onto it. The plastic button can then glide up and down in the metal groove.

How long is the recovery process?

After the operation you will stay in hospital for about three nights. Most people would be discharged home but sometimes a week or two of rehabilitation in a hospital is required. As with most knee surgery, the knee takes a long time to recover from this operation. It can be 6 months before the knee is really comfortable. Physiotherapy is very important as it helps with regaining range of movement and strength at the knee.