Osteoarthritis or degenerative joint disease is the most common form of arthritis. The disease initially affects the joint cartilage, causing pain and stiffness in the joints. As a result, joint movement can be restricted or immobilised. The pain also tends to get worse towards the end of the day and with activity.
Osteoarthritis is more common in older people and in those who are overweight and hence place an increased load on weight bearing joints such as the knees, hips and lower back. However there are also variants such as primary or generalised osteoarthritis that are familial and start in the hand joints. In these patients, weight loading does not seem to be a predominant pathogenetic factor.
Therefore it may be better to think of osteoarthritis as a disorder of cartilage metabolism where patients are more prone to cartilage degradation. This is accelerated if they have previous joint injury, joint inflammation or increased weight loading if they are obese. In advanced cases, one can think of the condition as “joint failure” as in any other organ failure.
In the absence of a true disease modifying osteoarthritis drug (DMOAD), management of a patient with osteoarthritis is currently multi-disciplinary and individualised. The first issue is one of diagnosis. The pattern of joint involvement has diagnostic value. In the hands, the joints typically affected are the distal and proximal interphalangeal joints with sparing of the metacarpophalageal joints and the wrists. The knees, spine and hips can also be affected. There is bony rather than synovial swelling and the pain is mechanical in nature. This means that pain is worse with activity and better with rest, which is directly opposite to inflammatory pain. Acute phase reactants are often not raised. X-rays may show narrowed joint spaces with periarticular sclerosis and osteophyte formation.
Weight management is important when weightbearing joints are affected. If the patient gains 1kg of body weight, weight loading can increase by as much as 5kg. The converse is also true. Many patients are able to even discontinue painkillers if they can lose as little as 3kg. Physiotherapy and exercises to strengthen the muscles around the affected joints are very useful in improving joint function. Use of appropriate footwear and walking aids can also make a difference. In those who are severely affected, joint realignment surgery (e.g. osteotomy) or joint replacement can improve the quality of life tremendously in selected patients.
Where pharmacological therapy is concerned, there are three groups of treatments:
The most appropriate medication for pain relief in a patient with osteoarthritis is paracetamol.
Viscosupplementation involves direct injection of hyaluronic acid compounds to increase the viscosity of the cartilage. This works better in milder patients and there is symptom relief for up to a year. It is best reserved for patients who need daily symptom relieving drugs. More severe patients (e.g. badly swollen joints that significantly affect movement) may need surgery. Milder patients may do well with other measures such as weight management and exercise.
There are many supplements on the market which claim to help osteoarthritis. Many of these claims are not backed by clinical trials. Some compounds such as ginger extracts, combinations of Indian herbs and soy extracts have clinical trials which show a mild effect in symptom relief. For glucosamine hydrochloride and chondroitin sulphate, the effects may vary.
The current status of treatment options in osteoarthritis is far from ideal. The best outcome is achieved only with a combination of the sensible use of pharmacological therapy, combined with physiotherapy, weight control and surgery where indicated.