Patellofemoral Joint Replacement - What Exactly is Involved?

The total knee replacement (or arthroplasty) is a very common operation and brings great relief to many sufferers of osteoarthritis. A patellofemoral replacement is a much less common procedure and because of this is more difficult to find information on.

Osteoarthritis is a degenerative joint disease characterized by the loss of articular cartilage and resulting in pain and deformity. The knee is a very common site for osteoarthritis. As this type of arthritis is typical in weight bearing joints, it is most common in the knee between the tibia (shin bone)and the femur (thigh bone). It is not unusual for there to be coinciding patellofemoral arthritic changes when the weight bearing surfaces are worn. This is why the patellofemoral joint is frequently replaced at the same time as the tibiofemoral joint.

What is more unusual is the isolated patellofemoral joint replacement. This is the joint between the femur and the patella (kneecap). It is unusual because the joint is considered minimally weight bearing and as such is usually less affected by years of use. This is why patellofemoral replacements are usually the result of a previous significant event such as a fracture or a long term anatomical difference. This is the reason the main weight bearing surfaces are intact in these cases.

In fitting with modern surgical practice, a patellofemoral replacement only replaces the affected areas. The prostheses used are very different from the traditional total knee replacements. The back surface of the kneecap is replaced along with the groove at the front of the femur, and that is all.

The rehabilitation following the surgery is basically the same as that of a total knee replacement. The time in hospital is often less however as there is less significant bony disruption and potentially less pain.

Because isolated patellofemoral osteoarthritis is usually the result of trauma, those undergoing a replacement tend to be younger. For this reason they have higher physical expectations of their replaced knee and they may not last as long as they would in a more elderly patient.

When health professionals talk of prosthesis failure the usual cause is prosthesis loosening. The materials used today are very resilient and it is not the replacement that usually fails but the junction between the replacement and the bone itself.

One of the key benefits of the patellofemoral replacement is that it does not significantly affect any future total knee replacements. This means that it can be performed in relatively young people and delay the need for total knee arthroplasty.

The ability to operate on younger people adds an extra step in the treatment chain and can result in osteoarthritis sufferers experiencing much less pain in the lead up to a total knee replacement.

The usual recommendations for arthritis sufferers still remain:

Lose Weight if possible
Increase exercise levels
Gain Quadriceps strength
Take appropriate analgesia

Patellofemoral osteoarthritis can be a life changing condition. It is always wise to investigate all non surgical options before going down the surgical route. If you have honestly done everything you can to hold back the pain of patellofemoral arthritis but have been unable to manage it, discuss the surgical options with your Consultant. They will let you know if you are suitable for this kind of surgery.