OSTEOARTHRITIS

“Despite the efficacy of exercise, the majority of patients with OA knee receive little or no advice.”

ically to identify patients who need urgent and aggressive treatment to pre- vent joint damage.

It is important to explain that symptoms will fluctuate but very few people are severely disabled by OA, a walking stick can help unload the joint - this should be used in the hand contralateral to the affected knee. Wearing flat, soft-soled shoes (eg. good quality trainers) or cush- ioned insoles can significantly reduce the impact of walking and minimise jarring of the joint. Patients with patellofemoral OA may benefit from medial taping of the knee. In more severe cases the help of an occupational therapist or physiotherapist way be needed to provide appropriate aids

MEDICATION IN OA

1 Analgesics Paracetamol at maximal dosage (4g in 24 hours) is a sensible first line therapy for the pain of OA and will be sufficient to control symptoms in about half of patients. Combination preparations of paracetamol with dextropropoxyphene or with codeine are of similar efficiency but side effects may restrict use.

2 COX inhibition Selective cyclo-oxygenase (COX) inhibition is the latest con- cept in non-steroidal anti-inflammatory (NSAID) therapy. They inhibit to various degrees the activity of the COX enzymes. Whilst inhibition of COX-2 enzymes (which are pro- duced in response to inflammation) seems to produce anal- gesic effects, COX-1 appears to have a beneficial physiologi- cal role with protective effects on the lining of the stomach and a role in normal renal function. For this reason pharma- ceuticals which selectively inhibit the COX-2 enzyme should control the inflammation while leaving the more beneficial COX-1 enzyme active. Etodolac (Lodine) and meloxicam (Mobic) have some COX selectivity with good gastric tolera- bility which is often the primary concern relating to NSAID use. A highly selective COX-2 inhibitor Rofecoxib (Vioxx) has recently been launched in the United Kingdom and celecoxib (Celebrex) manufactured by Searle is awaiting licence approval from the European regulating authorities. These have a potentially huge role in preventing morbidity and in reducing the 2000 plus deaths a year caused by gastric haemorraging.

3 Topical NSAIDS Topical NSAIDs are now widely used in the treatment of OA and their efficacy has been confirmed in a recently published

and appliances.

Knee OA is more common in obese patients and the incidence increases with the degree of obesity.

ment, weight loss makes the surgical pro- cedure safer and speeds up postoperative recovery and mobilisation.

Obesity Large population studies have now demonstrated that obesity precedes OA. Data also suggests that losing weight may slow or prevent the onset of disease and is also beneficial in secondary prevention. Losing only a few kilograms can have sub- stantial effects on symptoms. In over- weight patients facing knee joint replace-

Symptoms of OA are often episodic and if NSAIDS are used their requirement should be reg- ularly reviewed especially in elderly patients who are at risk of gastrointestinal complica- tions. There is no convincing evidence that these drugs affect the progression of OA in humans.

Additional treatment options Total knee replacement is now producing similar results to total hip replacement in

study. A systematic review of 86 randomised controlled trials involving over 10,000 patients showed topically applied NSAIDs have a genuine analgesic effect separate from any benefit achieved by the tactile stimulation of rubbing. Systemic side effects are greatly reduced with topical NSAIDs compared with oral. Capsaicin (Zacin) cream is available for osteoarthritis. This contains the same molecule extracted from chillies that has been used successfully in pain clinics. It can provide additional pain relief without the risk of sys- temic toxicity or drug interaction.

4 Joint injections In patients with arthritic knees, injections of appropriate steroids, eg hexacetonide, can give short-term relief. Recently new formulations of sodium hyaluronate such as Synvisc and Hyalgan have become available for use in osteoarthritis of the knee. The injections need to be given weekly for three to five weeks. Clinical trials have confirmed that patients derive symptomatic benefit with reduction of pain and stiffness that can last many months after a course of injections. It is likely that these drugs have an effect on the cellular processes rather than merely acting as a mechan- ical lubricant. This may be useful for patients awaiting knee replacement, those unfit for surgery, or those symptomatic despite other medication.

5 Chondrocyte transplants Specialised centres are currently working on techniques for resurfacing localised areas of cartilage damage. These include chondrocyte transplantation in which joint cartilage is har- vested arthroscopically and grown in tissue culture for subse- quent implantation. Another technique is ‘mosaicplasty’ - cylindrical plugs of articular cartilage and underlying bone are removed from the non-load bearing margins of the knee and inserted into holes drilled in the damaged area.

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