What is a Total Knee Replacement?
A joint is a point of contact between two bones, allowing movement and providing support. A total knee replacement is the surgical procedure for the replacement of a diseased or damaged knee joint with one made from artificial material.
The knee is the joint formed where the femur (thigh bone) meets the tibia (shinbone). The ends of the bones are covered with cartilage, which acts as a cushion and allows for smooth, gliding movement. The patella (kneecap) is a small bone which runs in a groove on the femur. The function and stability of the knee depends on muscles and ligaments. Flexion (bending) and extension (straightening) are the principal movements of the knee. Knee replacement surgery has become more common, due to advances in the types of implants and materials. The operation can greatly improve quality of life because of pain reduction, increased mobility and the correction of deformity.
What does a Knee Replacement entail?
You will be seen by the surgeon before the operation. They will take this opportunity to draw (mark with a pen) on your leg. This is to make sure the correct leg is operated on. If you have any questions, this might be a good time to ask them.
An anaesthetic will be administered in theatre. This may be a general anaesthetic (where you will be asleep) or a local block (e.g. where you are awake but the area to be operated is completely numbed). You must discuss this with the anaesthetist.
A tight inflatable band (a tourniquet) may be placed across the top of the thigh to limit the bleeding. Your skin will be cleaned with anti-septic solution and covered with clean towels (drapes). The surgeon will make an incision (a cut) down the middle of the knee. The knee capsule (the tough, gristle-like tissue around the knee) which is then visible can be cut and the knee cap (patella) pushed to one side. From here, the surgeon can trim the ends of the thigh bone (femur) and leg bone (tibia) using a special bone saw. Some surgeons also remove the underside of the knee cap.
Using measuring devices, the new artificial knee joints are fitted into position. The implants have an outer alloy metal casing with a “polyethylene” bearing which sits on the tibia. A polyethylene button is sometimes placed on the underside of the knee cap.
Objectives of a Knee Replacement
The objective of knee replacement surgery is to improve quality of life. It has a high success rate and dramatically improves the quality of life by reducing pain, improving mobility and correcting deformities.