Performed by – Khalid Al-Hourani, Alastair Davidson, Reza Mansouri, Zuhair Nawaz, Andrew Perry, James Singleton

Patello Femoral replacement (PFA) is performed for arthritis affecting the patella ie the kneecap and the front of the knee that it rubs against as the knee bends. In about 10% of arthritis patients the majority of their knee symptoms are coming from a worn kneecap. These people suffer from pain when crouching, climbing and descending stairs, walking up slopes and getting out of low chairs. Patients with this condition are usually able to walk well on the flat and still have a good range of movement of the knee, which would be reduced with a total knee replacement. Initially Patello Femoral Arthritis can be treated with painkillers, anti-inflammatories, physiotherapy and in the earlier stages, arthroscopy (keyhole surgery) but as the knee progressively wears, joint replacement surgery may be required to relieve the pain and improve function and mobility. If the majority of the joint is free from arthritis (or displays minimal symptoms) it may be possible to replace the back of the patella and the front of the femur (thigh bone) to provide relief. If other parts of the knee are also affected a total knee replacement is the better option.

What happens in surgery?
The surgery involves removing a small thickness of the damaged bone from the front of the femur (thigh bone) and the back of the patella (kneecap). The Patello Femoral replacement fits inside the space and is fixed to the bone with cement. The operation takes about an hour and involves a 15cm incision over the front of the knee and through the quadriceps muscle.

The component parts of the PFR
The Patello Femoral Replacement comes in two parts. The Femoral component is made of metal and is highly polished. The back of the patella is covered with a plastic button, which sits in a shallow groove on the front of the metal femoral component. Essentially a Patello Femoral Replacement is the front part of a Total Knee Replacement, but leaves the unworn cartilage over the rest of the joint intact.

After a Patello Femoral replacement
With the aid of a physiotherapist you will get out of bed and begin to exercise your new knee replacement. With perseverance, you should be able to climb stairs by day 2 and go home on day 3, although you may need another day if still stiff. It is very important to continue attending regular physiotherapy as an outpatient as well as diligently working on your stretches and range of movement exercises at home to get the best result. This can be achieved with one of our recommended group of physiotherapists or one closer to your home. For most people it will take around 6 weeks to be walking reasonably with only one stick, at which time you can return to driving a manual car. After three months you should be able to walk well without pain, be back to normal daily activities and be capable of a range of movement with your new knee from 0 degrees to 120 degrees. However, this range of movement may not be as good as it was before surgery and you may not be able to kneel after your Patello Femoral Replacement, although you will not damage the knee if you do. It is important to remember that an artificial knee is not a normal knee but that this will feel much more normal than a total knee replacement. You should be able to return to all your normal daily activities and sports such as golf, tennis, bowls, cycling, swimming.

Lifespan of the PFR
Studies suggest that a Patello Femoral Replacement has around an 85% probability of lasting for 10 years after surgery. It is frequently done in a younger age group, such as patients aged 50 or over, as it is relatively easy to convert to a TKR if it wears out. It is performed less often in older patients as they frequently have osteoarthritis that affects the rest of the knee as well, making a TKR a better option.