Causes of osteoarthritis

It’s estimated that about eight and a half million people in the UK have osteoarthritis and that about one million of these request treatment. Among the over-65′s, 10 per cent are disabled by their osteoarthritis.

Osteoarthritis (OA) can be divided into primary OA where the joint was previously healthy and secondary OA which follows either a congenital deformity of bones or joints, or an injury. There is no single cause of OA, but several factors seem to increase the likelihood of getting the disease:

*Age – osteoarthritis becomes more likely with increasing age and is less common before the age of 40.

*Genetics – there may be a genetic link showing the tendency to run in families, but OA is not directly inherited.

*Gender – osteoarthritis is more common in women.

*Weight – being overweight or obese increases the risk of osteoarthritis, particularly of the knee.

*Injury – an injury to the bone or ligaments , fracture, infection, operation, earlier disease or repeated strain at a joint may lead to osteoarthritis later in life.

Effects of osteoarthritis

In osteoarthritis, the smooth cartilage that takes the strain in a normal joint becomes rough, brittle and weak. To compensate, the bone beneath thickens and spreads out, forming knobbly outgrowths (osteophytes). The dynamics of the joint changes, which can cause further damage. The synovial membrane surrounding the joint thickens and the fluid-filled space within it becomes smaller. There is often inflammation.

As osteoarthritis gets worse, bits of cartilage may break away from the bone, causing the bone ends to rub together and the ligaments to become strained. This causes a lot of pain, changes the shape of the joint and can reduce the range of movement, which along with the swelling and stiffness can severely reduce mobility and dexterity.

Osteoarthritis is most common in the hands, knees, hips and feet. Some people also develop it in the back and neck.

Symptoms of osteoarthritis

Osteoarthritis develops differently from person to person. The condition typically causes joints to become stiff and painful, either at rest or on movement. There can be marked swelling around the joint, although not usually with any redness, and tendons attached to the joint may also be affected, causing local pain, reduced muscle power and reduced mobility. Sometimes pain is ‘referred’ down the bone to the next joint along.

Occasionally there are no symptoms, but OA changes are found co-incidentally on X-ray.

It usually develops slowly and the changes can be so gradual that people hardly notice them. The condition usually settles down after a number of years and, although the joints may have a knobbly appearance, they may become less painful.

Treatment

There are a variety of treatments and supportive aids, which will depend on which joint is affected and how severe it is:

*Lifestyle changes such as weight management and exercise may prevent further deterioration.

*Orthotic devices such as insoles and braces may help.

*Analgesia – pain relief in the form of tablets, creams and patches may give relief. Painkillers such as paracetamol and codeine, as well as the non-steroidal anti-inflammatories (NSAIDs) such as ibuprofen or diclofenac may be tried as tablets or creams.

*Capsaicin cream, made from chilli peppers, can be useful, possibly by blocking pain signals down the nerves from the joints.

*Steroids as tablet courses or injections occasionally have a role in management of acute flares of inflammation in certain joints.

*Physiotherapy.

*Occupational therapy.

*Local heat and massage gives relief for some people.

*Walking aids such as stick, tripods and zimmer frames for those who otherwise are less mobile.

*Food supplements – the use of glucosamine and chondroitin are still controversial, with some studies suggesting a benefit and others not. A large study, published in the British Medical Journal (BMJ) in 2010, analysed 10 research trials involving over 3,800 patients with knee and hip OA using glucosamine and chondroitin supplements, but concluded that the supplements appeared to be no better than a placebo.

*Other treatments such as hyaluronic acid injections into joints have yet to show any clinical benefit in trials.

*Surgery may be an end-point treatment for OA, with either joint replacement or, in some of the smaller joints, ‘arthrodesis’ (where the joint is permanently fused) offering an answer to chronic pain or reduced mobility. However as with any operation, although surgery is now commonplace and usually effective, it is not without some risks.