How knee replacement works
In a healthy knee joint
The ends of your bones and kneecap are covered in smooth cartilage – tissue that helps your bones glide easily across each other.
In an unhealthy knee joint
The cartilage is worn away, causing damage to the ends of your bones at the joint and making it painful and difficult to move.
Knee replacement surgery
Knee replacement surgery removes your damaged cartilage and the ends of your bones and replaces them with an artificial joint made of metal and smooth plastic, relieving pain and allowing you to move freely again.
The surgery is carried out under a general anaesthetic or a spinal or epidural anaesthetic where you’re awake but can’t feel anything below your waist.
There are two main kinds of knee replacements: total knee replacement surgery and partial knee replacement surgery.
Total knee replacement
Your surgeon will make an incision below your knee and replace both sides of your joint, and sometimes your kneecap.
Partial knee replacement
Your surgeon will replace just one side of your joint and your operation and recovery will usually be faster than with a total knee replacement.
Complex or revision knee replacement
If you have major bone loss, a deformity or ligament weakness, you might need a complex knee replacement. The artificial joint has a longer stem that fixes into your bones, and additional components that can give you more stability. This type of surgery is also sometimes used if you need to have a knee replacement redone.
Advances in surgery
Exciting recent advances mean that surgeons can often operate using smaller incisions, so there’s less impact on your surrounding muscles and tendons and you’ll recover more quickly.
Some of our hospitals use computer-assisted surgery to enable the surgeon to position the replacement more precisely. Some hospitals also use pre-programmable robotic arms to help fit your joint.