Total knee replacement is a reliable operation for patients with arthritic pain that they cannot mange and whose quality of life is deteriorating. It is less reliable for patients who have little pain but whose physical activities are restricted e.g. sport. It carries a complication rate of 1-4% from stroke, heart attack, VTE (venous thromboembolism) and infection. A more worrying figure is that up to 20% still have knee pain one year or more following surgery. However, the majority of patients will be free from pain, have a good range of movement and be able to walk as far as they want. It often takes 3-6 months to recover from a knee replacement.
If a patient has arthritis that is confined to just one side of the knee (usually the inside or medial side), it may be possible to replace that compartment only, leaving the rest of the knee and the important cruciate ligament undisturbed.
This means the knee joint moves more naturally than following a total knee replacement and it may feel completely normal to the patient.
The patellofemoral joint (that is the kneecap and its grove on the femur) can also be replaced, but the results are not as good as Uni-compartmental replacement for the medial and lateral side of the knee and are, therefore, usually best addressed with by total knee replacement.