Have you injured your knee or have a long-term knee problem?
The Bupa knee clinic can help you find the information and support you need.
Knee replacement (sometimes called knee arthroplasty) involves replacing your knee joint if it’s painful and has been damaged or worn away, usually by arthritis or an injury.
You will meet the surgeon carrying out your procedure to discuss your care. It may differ from what is described here as it will be designed to meet your individual needs.
Your knee joint is made up by the lower end of your thigh bone (femur) and the upper end of your shin bone (tibia). These normally glide over each other easily because they are covered by smooth cartilage. If your cartilage is damaged by injury or worn away by arthritis, it can make your joint painful and stiff
A new knee joint will usually improve your mobility and reduce pain, although your new knee won’t be able to bend quite as far as a normal knee joint.
Depending on the condition of your knee joint, you may need to have part, or all, of your knee joint replaced. If you have arthritis just in one area of your knee joint, usually the inside part of the joint called the medial compartment, you may be offered a partial knee replacement (called a unicondylar knee replacement). However, a total knee replacement is more common.
Artificial knee parts are almost always made of metal (on the femur side) and plastic (on the tibia side) and a knee replacement can last for up to 20 years.
Your surgeon will usually only recommend that you have surgery if non-surgical treatments, such as physiotherapy and exercise, medicines or using physical aids like a walking stick, no longer help to reduce your pain or improve your mobility.
Alternative surgical procedures include:
You may have already had these procedures before your knee replacement. Your surgeon will explain your options to you.
Your surgeon will explain how to prepare for your operation. For example if you smoke you will be asked to stop, as smoking increases your risk of getting a chest and wound infection, which can slow your recovery.
The operation usually requires a hospital stay of about five days and it's done under general anaesthesia. This means you will be asleep during the operation. Alternatively you may prefer to have the surgery under spinal or epidural anaesthesia. This completely blocks feeling from your waist down and you will stay awake during the operation.
If you’re having a general anaesthetic, you will be asked to follow fasting instructions. This means not eating or drinking, typically for about six hours before a general anaesthetic. However, it’s important to follow your anaesthetist’s advice.
At the hospital, your nurse may check your heart rate and blood pressure, and test your urine.
Your surgeon will discuss with you what will happen before, during and after your procedure, and any pain you might have. This is your opportunity to understand what will happen, and you can help yourself by preparing questions to ask about the risks, benefits and any alternatives to the procedure. This will help you to be informed, so you can give your consent for the procedure to go ahead, which you may be asked to do by signing a consent form.
You may be asked to wear a compression stocking on the unaffected leg to help prevent blood clots forming in your veins (deep vein thrombosis, DVT). You may need to have an injection of an anticlotting medicine called heparin as well as, or instead of, stockings.
A knee replacement usually takes up to two hours.
Your surgeon will make a single cut (10 to 30cm long) down the front of your knee. He or she will move your kneecap to one side to reach the knee joint. Your surgeon will remove the worn or damaged surfaces from both the end of your thigh bone and the top of your shin bone. He or she will usually remove your anterior cruciate ligament and may remove your posterior cruciate ligament. For support, your surgeon won’t remove your collateral ligaments. He or she will shape the surfaces of your thigh and shin bones to fit the artificial knee joint and then fit the new joint over both bones.
Sometimes the back of your kneecap is replaced with a plastic part. This is called patellar resurfacing.
After your surgeon has fitted the new joint, he or she will close your wound with stitches or clips and cover with a dressing. Your surgeon will tightly bandage your knee to help minimise swelling.
You will need to rest until the effects of the anaesthetic have passed. You may not be able to feel or move your legs for several hours after an epidural anaesthetic.
You may need pain relief to help with any discomfort as the anaesthetic wears off.
For the first day or so, you may have an intermittent compression pump attached to special pads on your lower legs. By inflating the pads, the pump encourages healthy blood flow and helps to prevent DVT. You may also have a compression stocking on your unaffected leg. This helps to maintain circulation.
A physiotherapist (a specialist in movement and mobility) will usually guide you daily through exercises to help your recovery.
You will be in hospital until you can walk safely with the aid of sticks or crutches. When you’re ready to go home, you will need to arrange for someone to drive you.
Your nurse will give you some advice about caring for your knee and a date for a follow-up appointment before you go home.
The length of time your dissolvable stitches will take to disappear depends on what type you have. However, for this procedure they should usually disappear in about six weeks. Non-dissolvable stitches and clips are removed 10 to 14 days after surgery.
If you need them, you can take over-the-counter painkillers such as paracetamol or ibuprofen. Follow the instructions in the patient information leaflet that comes with the medicine and ask your pharmacist for advice.
The physiotherapy exercises are a crucial part of your recovery, so it's essential that you continue to do them for at least two months.
You will be able to move around your home and manage stairs. You will find some routine daily activities, such as shopping, difficult for a few weeks. You may need to use a walking stick or crutches for up to six weeks.
You may be asked to wear compression stockings for several weeks at home.
When you’re resting, raise your leg and support your knee to help prevent swelling in your leg and ankle.
Depending on the type of work you do, you can usually return to work after six to 12 weeks.
Follow your surgeon's advice about driving. You shouldn't drive until you are confident that you could perform an emergency stop without discomfort.
Knee replacement surgery is commonly performed and generally safe. However, in order to make an informed decision and give your consent, you need to be aware of the possible side-effects and the risk of complications of this procedure.
These are the unwanted, but mostly temporary effects of a successful treatment, for example feeling sick as a result of the general anaesthetic.
Your knee will feel sore and may be swollen for up to six months.
You will have a scar over the front of the knee. You may not have any feeling in the skin around your scar. This can be permanent, but should improve over two years.
This is when problems occur during or after the operation. Most people are not affected. The possible complications of any operation include an unexpected reaction to the anaesthetic, excessive bleeding or developing a blood clot, usually in a vein in the leg (DVT).
Specific complications of knee replacement are uncommon, but can include those listed below.
The artificial knee joint usually lasts for 20 years, after which you may need to have it replaced.
The exact risks are specific to you and will differ for every person, so we have not included statistics here. Ask your surgeon to explain how these risks apply to you.
For answers to frequently asked questions on this topic, see FAQs.
For sources and links to further information, see Resources.
Read our brochure about musculoskeletal services from Bupa which include treatment by physiotherapists, podiatrists, osteopaths and sports doctors.
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This information was published by Bupa's Health Information Team and is based on reputable sources of medical evidence. It has been reviewed by appropriate medical or clinical professionals. Photos are only for illustrative purposes and do not reflect every presentation of a condition. The content is intended only for general information and does not replace the need for personal advice from a qualified health professional. For more details on how we produce our content and its sources, visit the About our Health Information page.
Publication date: December 2010