Medical Information

Explore detailed information about a range of joint problems and treatments, including medications, surgery, physiotherapy and rehabilitation. Reading this will help you understand more about your own condition. There is also a glossary with explanations of many medical terms used in orthopaedics. You can find out even more by following the links page to other related websites, journals or professional medical associations.

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Rheumatoid Arthritis

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

Rheumatoid arthritis
This booklet aims to help people who have rheumatoid arthritis, and their families and friends. Rheumatoid arthritis is a complicated disease which varies a great deal from person to person, so a short booklet like this cannot tell you everything about it, but it will help you to understand rheumatoid arthritis – how it develops, and how to deal with it.

What is rheumatoid arthritis?
Rheumatoid arthritis is a disease in which the joints in the body become inflamed.

To understand how rheumatoid arthritis develops you need to understand how a normal joint works. A joint is where two bones meet. Most of our joints are designed to allow the bones to move in certain directions. For example, the knee is the largest joint in the body, and also one of the most complicated because it has many important jobs. It must be strong enough to take our weight and must lock into position so we can stand upright, but it also has to act as a hinge so we can walk. It must withstand extreme stresses, twists and turns, such as when we run or play sports.

The end of each bone is covered with cartilage which has a very smooth slippery surface. The cartilage allows the ends of the bones to move against each other almost without friction. It also acts as a shock absorber. The joint is surrounded by a membrane (the synovium) which produces a small amount of thick fluid (synovial fluid). This fluid acts as a lubricant to keep the cartilage slippery and help the joint to move smoothly. The synovium has a tough outer layer of ligaments called the capsule which holds the joint in place and stops the bones moving too much.

Inflammation takes place within the synovium. The result is very similar to inflammation which you may have seen taking place within your eye – it goes red, it swells, it ‘cries’, and it hurts. The redness is caused by the flow of blood increasing. As a result, the inflamed joint may feel warmer than usual. The swelling is caused by a build-up of fluid and cells in the synovium. When a joint ‘cries’ it produces excess fluid – not tears but synovial fluid – which remains inside the joint, resulting in swelling. The joint hurts for two reasons:

Nerve endings are irritated by the chemicals produced by the inflammation.
The capsule is stretched by the swelling in the joint.

How does rheumatoid arthritis affect different people?
Our bodies normally produce inflammation to destroy things, such as bacteria, which cause illness. We do not know what sets off the inflammation in rheumatoid arthritis, but the result is the same – unfortunately, in this case it is not bacteria or other harmful substances which are attacked but the tissues in the joints. The inflammation in rheumatoid arthritis causes damage to the cartilage and sometimes to the bone itself. It may also damage any ligaments within the joints.

The extent to which this happens varies a great deal from person to person. Some people have little or no damage to the joints, or suffer only very minor damage to a few joints. Most people with rheumatoid arthritis have some damage in a number of joints, and a few – about 5% of those with rheumatoid arthritis – have quite severe damage in a lot of joints.

Link – http://www.arc.org.uk/arthinfo/patpubs/6033/6033.asp

Editor: David P Johnson MD.
St Mary’s Hospital. Clifton Bristol. BS8 1JU.
Web site: www.orthopaedics.co.uk
boc@orthopaedics.co.uk
© OrthopaedicsOpinionOnline 2011 www.OrthopaedicOpinionOnline.co.uk

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