Joint replacement

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Joint replacement is a surgical procedure to replace worn out joints with a prosthetic implant made from metal, ceramic and hard plastic. Hip and knee replacements are the most commonly performed joint replacement procedures, with a high success rate. They normally result in long-term relief from pain and improved mobility. Latest statistics from NHS England suggest that joint replacements procedures are continuing to rise, up to around 2.35 million in 2016/17.

Prosthetic implants normally last 15-20 years but over time they can wear and become loose. They may also become infected. If this happens, revision joint replacement surgery may be necessary to replace the worn out or infected implant.

Who might need it?

Joint replacement surgery is for people with severe hip or knee pain, due to conditions like osteoarthritis, rheumatoid arthritis or injury. Normally, it is only recommended once other less invasive procedures, such as painkilling injections or joint resurfacing have ceased to work effectively or been discounted by your surgeon. You may be offered a total or partial joint replacement, depending on the extent of damage to your joint.

Cartilage lining the joint helps it to move smoothly however if it becomes damaged or worn, the bone underneath may be exposed and the joint can become inflamed, sore and stiff. This may make it difficult to walk, leading to mobility issues. Severe joint pain can have a significant impact on a person’s quality of life and may lead to depression.

Revision joint replacement surgery is for people who previously had a prosthetic implant that has started to wear out. It is a more complex procedure than a normal joint replacement with a greater risk of complications.

What to expect

Prior to surgery you may be asked to make some lifestyle changes to reduce the risk of complications. If you smoke, you will need to stop smoking as it can increase the risk of infection and slow your recovery. If you are overweight, losing weight could help to reduce strain on your new joint and reduce the risk of complications.

Joint replacement is a major surgical procedure and you will undergo extensive tests to ensure you are well enough. These include blood tests, urine tests, X-rays and an electrocardiogram to check the health of your heart. You may need to make some simple adaptations to your home prior to surgery, such as removing trip hazards and ensuring you have appropriate chairs to avoid putting strain on your new joint.

Knee and hip replacement surgery is generally performed under general anaesthetic, which means you will be asleep throughout the procedure, or you may be given an epidural which numbs you from the waist down. If you have a general anaesthetic, you will not be able to eat or drink for several hours beforehand.

In hip replacement surgery, an incision of around 20-30cm is made along your hip and thigh. The surgeon will cut away worn parts of the joint and position an artificial implant in its place. The ball at the top of your thighbone will be removed and an artificial one on a stem attached to the bone. The implant may either be fixed in place with bone cement or it may be left uncemented and given a special coating to encourage new bone to grow around it. The incision will then be closed with stitches or clips and covered with a dressing. In some cases, it may be possible to have keyhole hip replacement surgery. Your surgeon will discuss this with you as it is not suitable for everyone.

There are two types of knee replacement – total and partial. In partial knee replacements, only part of the knee is damaged (normally the inside) and will be replaced with an artificial implant. Most knee replacements are either carried out under general anaesthetic or epidural which numbs you from the waist down. An incision is made down the front of the knee and the damaged sections are cut away. The artificial joint is inserted and the surfaces of the thigh and shinbones are shaped around it. In some cases, an artificial kneecap may be fitted (patellar resurfacing). The incision is closed with stitches or clips.

Immediately after surgery you will be moved to the recovery area and monitored while you recover from the anaesthetic. A physiotherapist will normally visit you after your operation and recommend exercises to build strength and flexibility in your new joint. You will normally stay in hospital for four to eight days.

During hip or knee revision replacement, the artificial joint will be removed and the surgeon may need to reconstruct some of the surrounding bone, which can make this a more lengthy surgical procedure.


As with all types of surgery, there are some risks to hip and knee replacements. These include:

  • Soreness and swelling at the surgery site which may last for several weeks.
  • Infection of the wound or joint which may be treated with antibiotics.
  • Blood clot which can travel to the lung, resulting in serious complications. You will be given compression stockings and blood-thinning medication to help prevent blood clots.
  • Dislocation of the hip or knee joint.
  • Nerve damage.
  • Stiffening due to scar tissue. This will normally be treated with physiotherapy.
  • Artificial joint wearing out. This is a longer-term risk that may require revision joint replacement surgery.


Hip and knee replacements are common procedures that generally result in excellent outcomes for patients. Among the benefits are:

  • Joint pain is alleviated, or significantly reduced allowing to lead a full life again.
  • Mobility is improved so you can enjoy many of the activities you did before you developed arthritis.
  • Improved quality of life.

Hip and knee revision surgery is not always as successful as the original joint replacement.


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