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.