What is a knee replacement?
Knee replacements can be made from a number of different materials, including metal, plastic or ceramic. They are used to replace a worn knee joint.
Why would a knee replacement be needed?
Rarely, these are performed for reasons such as trauma (eg car accidents) or bone cancer. Usually, though, knee replacements are performed because of wear and tear caused by osteoarthritis. This may arise from trauma caused many years ago, although often no cause can be found. Rheumatoid arthritis can also cause inflammation and damage to the knee joint. The damage to the joint leads to pain, stiffness, and reduced mobility. A successful knee replacement should reduce the pain and increase mobility.
Are there any alternatives to knee replacement surgery?
Generally, your specialist will only perform a knee replacement when all other options have been used and surgery is really necessary.
Such options include painkillers, using a walking stick, physiotherapy, and steroid injections into the joint. As the arthritis worsens, these become less effective and knee surgery may eventually be needed.
How is a knee replacement performed?
The surgery may be performed under general anaesthesia or regional anaesthesia (an injection makes the body go numb from the waist or hip downward).
A cut is made in front of the knee, and the damaged joint surfaces are removed. The replacement joint is then inserted; the parts are held firmly in place with special cement or adhesives, and the wound is then stitched closed.
What happens after the operation?
You will be encouraged to walk soon after the operation, often the next day. Your physiotherapist will help you to mobilise and strengthen the knee, using crutches or a frame at first.
You will usually be able to go home after about 4 to 7 days. Your specialist and physiotherapist will be able to guide you as to how much exercise you can do with the new knee. You should check with your specialist and insurance company before starting to drive again. Whilst your new knee will often give a good range of movement, it may never feel as good as a normal knee.
A knee replacement lasts for about 10 years; it will last longest if you follow the advice of the physiotherapist, maintain regular activity and have a healthy body weight.
What are the risks of knee replacement surgery?
Infection - this can lead to loosening of the replacement, which may need antibiotics or even further surgery.
Loosening - even without infection, the replacement can loosen, which may need further surgery.
Damage to nerves - this is quite uncommon, but can lead to numbness or weakness in the leg or foot.
Blood clots in the legs - clots in the calf (deep vein thrombosis / DVT) occurs in about 1 in 11 hip replacements. These can usually be treated with medication, but a DVT can (rarely) move to the lungs. This can cause breathing difficulty, or even be life threatening.
Stiffness - it is quite common to have a degree of stiffness in the knee, which can often be improved with physiotherapy. Occasionally, a short procedure may be needed to stretch the knee joint under anaesthesia to improve movement.
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You may also be interested to read our articles on arthroscopy or hip replacement
Any procedure involving skin incision can also result in unfavourable scarring, wound infection, or bleeding. This list of risks is not exhaustive, and you should discuss possible complications with your specialist. Whilst these risks will seem very worrysome, and indeed can be serious, it should also be borne in mind that many people have no postoperative problems whatsoever.
The information provided is as a guide only and you should discuss matters fully with your specialist before deciding if this is the right procedure for you. Please also read our disclaimer