Difference between Uni & Total Knee Replacement


RWN’s view

These are both major operations which require a metal implant to be inserted into the knee. It is an operation which can result in complications, but in the majority of patients who undergo this operation they will achieve satisfactory relief of their knee pain.

Approximately 20% of patients presenting with knee arthritis who require knee replacement surgery will be suitable for a unicompartmental arthroplasty. The main advantages of a unicompartmental replacement is that it is a less invasive operation, performed through a smaller incision, resulting in less swelling and bruising of the knee. For this reason, patients recover more quickly after the surgery and re-establish a better range of knee movement compared to total knee replacement. Overall, knee function is better but there are risks of failure, mainly due to persistent knee pain, or the development of arthritis in the other compartments of the knee. If this situation arises, a total knee replacement will be required.

Unicompartmental arthroplasty has an important role in the management of knee arthritis but the knee must be carefully assessed to make sure that it is suitable for a unicompartmental replacement, rather than a total knee replacement.

A total knee replacement is possibly a more predictable operation, in terms of pain relief, however, the knee function after a total knee replacement is less satisfactory compared to a unicompartmental arthroplasty. The main difference is that the range of knee movement is usually more limited and it is generally accepted that the range of movement that was present before the operation will be the range of movement that is achieved after a total knee replacement.

Overall, approximately 80% of patients are satisfied with the outcome of their total knee replacement.

How long will a knee placement last?

Modern designs of knee replacement, in the hands of an experienced knee replacement surgeon can be expected to last well over 10 years, with approximately 85% of implants still functioning well at 15 years.