Gradual degeneration of the cartilage covering the bone ends within joints

  • Rare under the age of 45; increasingly common over the age of 60
  • Twice as common in females
  • Sometimes runs in families
  • Past injuries and being overweight are risk factors

In a joint affected by osteoarthritis, the protective cartilage found at the ends of bones is worn away. As the condition develops, the bone around the affected joint thickens, and bony growths called osteophytes form. If the synovial tissue that lines the joint capsule becomes inflamed, fluid may accumulate within the joint. These changes cause pain, swelling, and stiffness of the joints, reducing their mobility.

Osteoarthritis is most common in weight-bearing joints, such as the knees and hips. However, the hands, feet, and shoulders may also be affected, as may the bones of the neck (see Cervical spondylosis). Nearly everyone has developed a degree of osteoarthritis by the age of 70, but only some people have symptoms. Women are more commonly affected by osteoarthritis than men, and their symptoms are more severe. This form of arthritis sometimes develops in younger people, particularly in those who have had joint injuries.

What are the causes?

There is often no obvious cause for the onset of osteoarthritis, but there are known factors that may increase the risk of developing the disorder. Wear occurs most often in joints that have been damaged by repeated strenuous activity or by repeated minor injuries. For example, the pressure that ballet dancers exert on their feet makes them susceptible to developing osteoarthritis of the ankle. Osteoarthritis is also common in former athletes.

Damage to a joint early in life may lead to osteoarthritis later on. Excessive weight can also increase a person’s risk of developing the condition because of the extra stress it places on the joints. Another risk factor is damage to cartilage caused by another joint disorder, such as septic arthritis. Finally, if a close member of your family has osteoarthritis, you are more likely to develop the condition yourself.

What are the symptoms?

Initially, the symptoms are mild, but they may slowly get worse. Often only one or two joints are badly affected, but sometimes osteoarthritis is more widespread. The symptoms may include:

  • Pain and tenderness that worsen with activity and are relieved by rest.

  • Swelling around the joint.

  • Stiffness lasting a short time after a period of inactivity.

  • Restricted joint movement.

  • Enlarged, distorted finger joints if the hands are affected.

  • Crackling noise (called crepitus) on moving the affected joint.

Referred pain, which is felt in areas remote from the site of damage but on the same nerve pathway as the affected joint, may develop. For example, an arthritic hip may cause referred pain in the knee. The pain may become worse towards the end of the day.

If movement is severely restricted, an affected person may be confined to the home. Lack of mobility may lead to weakness and wasting of muscles and sometimes to weight gain.

Osteoarthritis in a hip joint

In the hip joint seen on the right of this X-ray, the head of the femur (thighbone) has become worn where it fits into the pelvis, causing pain and stiffness.

What might the doctor do?

Your doctor may suspect that you have osteoarthritis from your symptoms, a history of joint problems, and a physical examination. It is often possible to confirm a diagnosis of osteoarthritis, while at the same time ruling out other types of arthritis, by means of blood tests and X-rays.

Osteoarthritis cannot be cured, but with treatment most symptoms can be relieved. Your doctor may recommend that you take paracetamol (see Painkillers) or a nonsteroidal anti-inflammatory drug. If you experience a severe flare-up of pain and inflammation in a single joint, your doctor may inject a corticosteroid drug directly into the affected joint in order to reduce swelling and relieve pain (see Locally acting corticosteroids).

To improve muscle function around joints affected by osteoarthritis, your doctor may refer you for physiotherapy. If osteoarthritis is very severe, surgery may be necessary to repair or replace an affected joint (see Joint replacement).

What can I do?

If you have mild osteoarthritis, you may be able to participate in most everyday activities by adapting your lifestyle (see Living with arthritis). If you are overweight, ask your doctor for dietary advice to enable you to lose weight and reduce further wear on your joints. If possible, take gentle exercise to help to lose weight, maintain muscle tone, and delay the progression of the disease. Supportive shoes with rubber soles will absorb shock and reduce further wear. If you have a painful hip or knee, use a walking stick for support. Massage, warm baths, or a heat pad may ease joint pain and increase mobility.

From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.

The subjects, conditions and treatments covered in this encyclopaedia are for information only and may not be covered by your insurance product should you make a claim.

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