Unicompartmental (partial) knee replacement
There are three compartments of the knee – the inner (medial), the outer (lateral) and the kneecap (patellofemoral). If arthritis affects only one side of your knee – usually the inner side – it may be possible to have a half-knee replacement (sometimes called unicompartmental or partial replacement). Because this involves less interference with the knee than a total knee replacement, it usually means a quicker recovery and better function.
Partial knee replacements can be carried out through a smaller cut (incision) than a total knee replacement, using techniques called reduced invasive or minimally invasive surgery. A smaller incision may further reduce the recovery time.
Partial knee replacement isn’t suitable for everyone because you need to have strong, healthy ligaments within your knee. Sometimes this won’t be known until the time of surgery.
Research shows that people who have partial knee replacements are more likely to have the knee revised than people who have a total knee replacement – about 1 person in 10 needs further surgery after 10 years. Even though the operation involves less interference with the knee it is often a more complex operation than total knee replacement. Your surgeon may therefore prefer to offer you a more predictable total knee replacement.
Partial knee replacement can be considered at any age. For younger people, it offers the opportunity to preserve more bone, which is helpful if you need revision surgery at a later stage. For older people, partial knee replacement is a less stressful operation with less pain and less risk of bleeding. The outcome of the surgery, however, depends on the type of arthritis, rather than your age.