Knee Arthroplasty, otherwise known as Total Knee Replacement, is a surgical procedure that replaces an arthritic knee joint with an artificial joint. The aim is to take away pain, restore function and preserve anatomy.
A typical knee replacement replaces the ends of the femur (thigh bone) and tibia (shin bone) with a plastic prosthesis. The patella (knee cap) is usually replaced as well. The prosthesis replicates the knee’s natural ability to roll and glide smoothly as it bends.
The knee is the largest joint in the body and consists of the lower end of the thigh bone (femur), which rotates on the upper end of the shin bone (tibia) and the knee cap (patella), which slides in a groove on the end of the femur. Large ligaments attach to the femur and tibia to provide stability. The long thigh muscles give the knee strength.
The joint surfaces where these three bones touch are covered with articular cartilage, a smooth substance that cushions the bones and enables them to move easily and smoothly.
All remaining surfaces of the knee are covered by a thin, smooth tissue liner called the synovial membrane. This membrane releases a specialised fluid that lubricates the knee and in a healthy knee reduces friction to nearly zero.
In a healthy knee all of these components work in harmony. But disease or injury can disrupt this and result in pain, muscle weakness and reduced function.
In an arthritic knee the components no longer function at their optimum level which restricts movement and interferes with day to day activities.
In an arthritic knee the following is often found:
The combinations of these factors make the arthritic knee stiff and limit activities due to pain or fatigue.
Total Knee Replacement Surgery is usually recommended for older patients who suffer from pain and loss of function from arthritis and after other conservative methods of intervention have failed.
Most patients who have a total knee replacement are aged between 60 to 80 years, but each patient is assessed individually and patients as young as 20 or as old as 90 are occasionally operated on and with good results.
Benefits of Knee Arthroplasty
The benefits following surgery are the relief of symptoms of arthritis. A total knee replacment can result in the reduction or complete disappearance of: