Knee replacement surgery, also known as arthroplasty, involves replacing the damaged or arthritic knee with an artificial prosthesis. Commonly the knee is damaged from arthritis, resulting in pain and restricted movement. Sufferers may also experience swelling or loosening of the knee joint. A knee replacement aims to treat these symptoms, restoring the knee to its original functionality and relieving any associated pain.
The knee joint consists of three bones- the femur (thigh bone), tibia (shinbone) and patella (kneecap). The femur and tibia are connected by tendons and their movement cushioned by cartilage. The patella protects the joint and moves up and down as the leg bends and straightens.
Depending on the area of damage patients may require a total knee replacement or a partial knee replacement. A total knee replacement involves replacing both the tibia and femur with an artificial joint and in some cases resurfacing the patella as well.
There are two types of partial knee replacement- patellofemoral and medial compartment. A patellofemoral knee replacement involves replacing the damaged knee cap and its surrounding cartilage. More commonly a medial compartment knee replacement is required, replacing only the inside part of the knee.
One important benefit of a partial replacement is that it leaves the healthy bone and tissues intact, resulting in a faster recovery time and fewer complications. The disadvantages include a higher risk of revision surgery and sometimes the functionality is not as good as with a total knee replacement.
Sometimes where there is damage to only part of the knee an alternative treatment is partial knee resurfacing. This involves resurfacing the damaged part of the joint with metal, leaving the healthy bone and surrounding soft tissues intact.