Arthritis: Knee replacement surgery

Who needs knee replacement surgery?

You may want to consider knee replacement surgery if you have a stiff, painful knee that prevents you from performing even the simplest of activities, and other treatments are no longer working.

What happens during knee joint replacement surgery?

Once you are under either a general anaesthesia (meaning you are temporarily put to sleep) or a spinal or epidural anaesthesia (meaning you are numb below the waist), a 10-30cm incision is made in the front of the knee. The damaged part of the joint is removed and the ends of the thigh bone and shin bone are then shaped and cleaned to hold a metal or plastic artificial joint. The artificial joint is attached to the thigh bone and shin bone either with cement or a special material. When fitted together, the attached artificial parts form the joint, relying on the surrounding muscles and ligaments for support and function.

What are recent advances in knee joint replacement surgery?

Minimally invasive surgery (MIS) has the potential to revolutionise knee replacement surgery as well as many other fields of medicine. Its key characteristic is that it uses specialised techniques and instrumentation to enable the surgeon to perform major surgery without making a large incision.

MIS knee joint replacements require a much smaller incision, just 7-12cm, as opposed to the standard 10-30cm incision. The smaller, less invasive approach results in less tissue trauma by allowing the surgeon to work between the fibres of the quadriceps muscles instead of requiring an incision through the tendon. This may also lead to less pain, decreased recovery time and better motion due to less scar tissue formation.

Currently this less invasive procedure is performed by only a small percentage of orthopaedic surgeons. Since this type of surgery is still relatively new, research has been initiated to determine how the immediate and long-term results will compare to traditional surgery.

What happens after the surgery?

The average hospital stay after knee joint replacement is usually three to five days. The vast majority of people who undergo knee joint replacement surgery experience a dramatic improvement. This improvement is most notable one month or more after surgery. The pain caused by the damaged joint is relieved when the new gliding surface is constructed during surgery.

After knee joint replacement, people are standing and moving the joint the day after surgery. At first, you may walk with the help of parallel bars, and then a walking device such as crutches, walker, or cane is used until your knee is able to support your full body weight. After about six weeks, most people are walking comfortably with minimal assistance. Once muscle strength is restored with physiotherapy, people who have had knee joint replacement surgery can enjoy most activities - your doctor or physiotherapist will advise you about which activities are suitable for you.