Revision total knee replacement is performed when the original primary total knee replacement has worn out or loosened in the bone. Revisions are also carried out if the primary knee replacement fails due to recurrent dislocation, infection, fracture or very rarely, ongoing pain and significant leg length discrepancy.
The revision total knee replacement is a more complex procedure, often because there is a reduced amount of bone to place the new total knee into. Extra bone may be required and this is usually received from a bone bank. Bone bank (allograft bone) is safe and has been irradiated to eliminate any chance of disease transmission. There are also artificial bone substitutes that may be used.
Revision total knee replacement takes longer than a standard total knee replacement and has a slightly higher complication rate. The prosthesis may also not last as long as a primary knee replacement. Surgery is usually performed through the same incision but may need some extension. The risks and complications are similar to standard knee replacement surgery.
As anybody undergoes general or regional anesthesia (epidural anesthesia) there are always risks associated with it. The risks of course are magnified if you have abnormal general medical conditions in addition to your older age, which may have affected the functions of your vital organs such as heart, lungs and kidneys. Therefore a complete evaluation of those systems has to be performed before you are taken to the Operating theatre.
Specific complications relating to knee replacement surgery include the following
- Deep vein thrombosis This is prevented by giving blood thinners and if it occurs it is treated with specific blood thinners.
- Infection The risk of infection is less than 1% and pre-operative antibiotics are given to prevent this from happening.
- Stiffness Occasionally knee replacement may stiffen up particularly in patients who are significantly overweight or have diabetes. Occasionally one will require a manipulation under an anaesthetic should this occur.
- Nerve and vessel damage It is unlikely that any major nerve or vessel will be damaged. It is unlikely that any major nerve or vessel will be damaged. It is, however, very common to have a small area of numbness over the other side of your knee where a superficial skin nerve is always cut during the surgery. This little numb patch is of no significance.
- Prosthesis failure The prosthesis may fail due to the plastic wearing out and it may require revision.
- Reflex sympathetic dystrophy Very rarely a condition can occur where the leg becomes stiff, hypersensitive and painful. This requires specific treatment with a pain management specialist.
- Excessive bleeding around the joint This usually settles but may require drainage.
- Excessive scarring Some skin will scar up significantly (keloid).
- Fluid build-up in the knee joint Occasionally this may occur and require drainage. It is usual for knees to be a little swollen and a little warm.
- Pain with kneeling Kneeling may produce discomfort over the incision site.
A total knee replacement often takes at least six months to settle in