A New Knee Joint

Author:  DAVID P JOHNSON MB ChB FRCS FRCS. MD
Consultant Orthopaedic Surgeon

If you are thinking about having a new knee joint there may be lots of questions on your mind. This booklet aims to provide the most up-to-date information on the options available and to answer the questions which people most often ask.

Do I need a knee replacement?
Over 45,000 knee replacement operations are carried out in England and Wales each year, and the number is increasing. The operation is highly successful for most people, but you will need to consider carefully whether it is right for you at this particular time. You need to weigh up the benefits that a new knee is likely to bring against the risks of having a major operation.

The principal advantages of a knee replacement is in the relief of pain and improvement of functional ability. There may also be a reduction in the swelling of the knee, a correction of deformity or mal-alignment and an increase in the range of knee motion. If you have severe knee pain and serious difficulties in moving about, and if your arthritis is not responding to treatment, then a replacement knee is probably your best option. If your symptoms are still manageable and your medication is effective in relieving pain then you may prefer to wait. In some knees the degree of deformity and bone wear is such that your surgeon may advise an early knee replacement due to increasing technical difficulties encountered with increasing deformity.

Most people who have a total knee replacement are over 60 or over 50 years for a unicompartmental replacement. If you are much younger than this you may want to consider making changes to your lifestyle, such as losing weight or doing more exercise to strengthen your leg muscles in the first instance before reporting to surgery. However, there is some evidence that not leaving the operation too long – until the knee becomes very stiff – leads to a better outcome. If you are under the age of 50 and decide to go ahead with a knee replacement now, you are quite likely to need a repeat operation in later life, and the second or revision procedure may be slightly less successful than the first. If you also have arthritis in your hip, and need a hip replacement, it is best to go ahead with this first and have your knee replacement later. You will need a flexible hip to do the knee exercises required after a knee replacement operation.

What are the risks?
In surgery generally it is thought that a risk of less than 1 in 1,000 (0.1%) is relatively safe. With major surgery like knee replacement the risks are higher than this. Most knee joint operations are problem-free but complications do arise in about 1 in 20 cases (5%), despite precautions being taken to avoid them. These may vary from a degree of stiffness or a minor degree of pain to a serious infection, thrombosis or pulmonary embolism. When complications do happen, most are minor and can be successfully treated. Overall the risk of death, usually due to a heart attack, a stroke, or a blood clot reaching the lungs, is about 1 in 200 (0.5%), but this risk varies between patients. On the whole, a younger patient with no other medical problems will be at lower risk than an older patient with medical problems such as diabetes or heart disease. Your surgeon or anaesthetist will be able to discuss these risks with
you.
DAVID P JOHNSON MB ChB FRCS FRCS. MD
Consultant Orthopaedic Surgeon
www.Bristol-Knee-Clinic.co.uk
boc@orthopaedics.co.uk
© D P Johnson 2008 www.Bristol-Knee-Clinic.co.uk
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