If a partial knee replacement is no longer possible (the damage to the joint surface is too great), the knee joint surface is replaced completely with an "artificial knee joint". This means that the worn ends of the bones are replaced with metal and plastic parts.
With a total knee replacement, the choice of method used to connect the upper and lower leg components, is most important. There are two prosthesis options for this, "fixed bearing" and "mobile bearing". The mobile bearing prosthesis uses a moving "meniscus" disc, more closely resembling the natural structure of the knee.
In knee replacement surgery, a damaged knee is replaced with an "artificial knee joint". The worn ends of the bones are replaced with metal and plastic parts. Such a prosthesis is necessary when the articular cartilage becomes severely damaged or worn away. The levels of pain and discomfort in the knee are high and the knee joint ceases to function properly i.e. where there is a reduction in the range of motion in the joint, or in cases where the knee joint has become malpositioned.
The surgeon makes a cut down the front of the knee. Damaged cartilage is removed, and the damaged ends of the bones are cut away. In order to be able to preserve as much of the bone as possible, the metal surface is manufactured to dimensions according to the sex and body size of the patient. The ligaments, which are of great importance, are retained to give the joint its necessary stability following the operation and to allow more natural movement of the knee.
As with any operation, knee replacement surgery carries certain risks. The most common general risks are infection of the wound, blood clots or deep vein thrombosis, unexpected bleeding and excess scar tissue restricting the movement of the knee.
Infection around the implant is usually treated with antibiotics. If this treatment is unsuccessful, and only then, it may be necessary to remove the implant until the joint has completely healed up, replacing it at a later date.
The day after the operation, the knee joint is gently mobilized by means of a continuous passive motion device (CPM). On the second day, intensive physiotherapy begins. The patient is taught to walk with forearm crutches, this means that on leaving hospital (after seven to ten days), he should be able to climb stairs.
Immediately after hospitalization, a three- to four-week rehabilitation program takes place, either as an outpatient or in a rehabilitation centre.