A person experiencing pain going up and down stairs, may be suffering from arthritis of the front of the knee (which in medical terms is known as the patello-femoral or PFJ) compartment. Such a problem is fairly common. Although other surgical procedures may be performed to off-load this part of the joint, none give the patient relief from pain as consistently as replacement of this part of the joint. The patient is freed from the pain of their condition promptly after surgery. Full range of movement is achieved without too much trouble, and patients are able to negotiate stairs normally.
In this procedure, the damaged part of the joint is prepared to accept the prosthesis. The replacement for the removed kneecap is made of plastic, while that for the thigh bone is made of metal. Bone cement is used to fix the prosthesis in place.
There is greater than 90% chance of survival of the prosthesis for ten years. If arthritis develops in the remaining (natural) part of the knee, or if the prosthesis fails, it can be removed and replaced with a standard total knee replacement without too much technical difficulty.
The advantages of a PFJ replacement are very similar to that of UKR:
- A ‘natural’ feel of the joint
- Much greater conservation of bone
- Prompt relief of pain
- Much less blood loss
- A shorter hospital stay (usually no more than two or three days)
The disadvantages of a PFJ replacement:
- Suitable only for selected patients
- Should be performed only by experienced surgeons
- It may need to be converted to a total knee replacement eventually
Mr Prakash’s approach: I encourage my patients to lose weight if they are overweight, as this will increase the life span of the replaced joint. To ensure the suitability of the patient for PFJ replacement, I like to perform arthroscopy (keyhole surgery) initially; the PFJ replacement may then follow later. I also try and preserve the patella and not replace it, instead replace only the trochlea which is the area where the patella sits.