Many types of designs and materials are currently available. The knee joint is divided into three compartments for the purpose of description the medial [inner), the lateral [outer) and the kneecap compartments. Arthritis can affect one or more compartments of the knee joint. When two or all three compartments are damaged by arthritis, your surgeons will usually recommend a Total Knee Replacement.
There are two categories of Total Knee Replacement (TKR)
Fixed Bearing - the plastic cushion in this form of knee replacement is fixed to the metal tray on the tibial side of the knee joint.
Mobile Bearing - the plastic cushion is not firmly attached but is allowed to rotate on the tibial tray. This is a newer type of design. The wear rate of the plastic component is probably lower compared with fixed bearing design. However not all patients are suitable for a mobile bearing TKR.
Unicompartment - If only one compartment is affected by arthritis, your surgeon may recommend a Partial Knee replacement (Unicompartment knee Replacement). In this form of knee replacement, smaller components for the femur and tibia are used and the operation can be performed through a much smaller incision (Minimal Invasive Technique). Because of the less invasive nature of the operation, the recovery period after the surgery is much shorter and blood loss is significantly lower compared with a total knee replacement operation. Most patients are able to return home one or two days after the surgery.
Another advantage of unicompartment knee replacement is that the range of the motion tends to be better than that after a total knee replacement. Unicompartment knee replacements are however less durable than total knee replacements.