Medical management of osteoarthritis

Patient education (table 1)

A meta-analysis of 10 trials that contrasted patient education with the therapeutic effects of non-steroidal anti-inflammatory drugs confirmed a significant beneficial effect of education on joint pain but not on disability.8 The method was only around 20% as effective as non-steroidal anti-inflammatory drugs, but there was some evidence for a synergistic effect of both interventions. Any member of the care team may provide education in several forms (for example, literature, audiocassette, computer); available packages explain the disease and its management, emphasising the role of weight reduction and exercise. There is now strong evidence that formal patient education should form part of the management of osteoarthritis.

Social support (table 1)

In patients with osteoarthritis of the knee controlled studies have shown that regular telephone contact from a healthcare worker produces significant improvement in pain and functional status.9 Furthermore, education of family members can improve their ability to provide social support, which also benefits the patient.6 These specific effects complement the generally observed improvements in wellbeing and reduced use of health care associated with social support networks.

Physical therapy

Physical therapy is a mainstay of the treatment of osteoarthritis. Two main approaches are used by physiotherapists: muscle strengthening programmes specific for certain joints and general aerobic conditioning (table 2). Both of these regimens have been clearly shown to improve pain and disability in osteoarthritis of the knee.15 A single study has shown that the technique of medial taping in patellofemoral osteoarthritis reduces pain.16 Physical measures such as diathermy and ultrasound have limited value.15 In contrast, three trials of trancutaneous electrical nerve stimulation (TENS) suggest modest pain relief when compared with placebo stimulation.15 It is estimated that osteoarthritis constitutes 50% of the workload of traditional acupuncturists. The use of acupuncture is supported by case series and uncontrolled studies, but trials that have compared random needling with acupuncture have failed to show measurable benefit for true acupuncture.17 Ideally, all newly diagnosed patients with osteoarthritis of the hip or knee should be seen by a physiotherapist.

Occupational therapy

Although occupational therapy provides a means of educating patients and social support, there are few evaluations of specific interventions such as the provision of walking aids, orthoses, and splints in controlled studies. In a single trial of patients with osteoarthritis of the hand the combination of a hand exercise programme, provision of splintage, and non-steroidal anti-inflammatory drugs improved disability in 49% of treated patients, but the study could not dissect the relative benefits of occupational therapy from those of the drugs.18 Despite the absence of formal controlled trials of many occupational therapeutic interventions, there is ample historical and anecdotal evidence of their effectiveness in clinical practice. The precise indications for referral to occupational therapy in patients with osteoarthritis remain to be delineated.

Analgesics, non-steroidal anti-inflammatory drugs, and cyclo-oxygenase-2 (COX-2) inhibitors

The evidence supporting use of analgesics and non-steroidal anti-inflammatory drugs in osteoarthritis was recently reviewed.19 Paracetamol is safe and effective. There is a slight benefit from the addition of dextropropoxyphene, but this is counterbalanced by the broader range of adverse effects. Several short term studies (under six months) have shown that non-steroidal anti-inflammatory drugs are more effective than placebo in reducing pain and improving function, but there have been few studies that have lasted longer than two years.20 Inference from these is difficult as adherence rates with non-steroidal anti-inflammatory drugs are poor because of adverse effects, while those with paracetamol are poor because of suboptimal pain relief. As many as 20-30% of all admissions to hospital and deaths from peptic ulcer disease in elderly people may be related to use of non-steroidal anti-inflammatory drugs.21 There is evidence that misoprostol and proton pump inhibitors reduce the risk of serious upper gastrointestinal injury induced by non-steroidal anti-inflammatory drugs. Adjunctive use of H₂ blockers has been shown only to reduce the incidence of duodenal ulceration. The cost utility of prophylactic use of any of these agents, however, is controversial.20 It is recommended that non-steroidal anti-inflammatory drugs are initiated only after consideration of side effects and counselling of the patient; the prescription should be reviewed every six months.

Cyclo-oxygenase, an enzyme involved in the conversion of arachidonic acid to prostaglandins, exists in two isoforms: COX-1, a constitutive isoform, predominates in the stomach and produces cytoprotective prostaglandins, while COX-2, an inducible isoform predominantly involved in the inflammatory cascade, gives rise to articular pain, swelling, and stiffness. Novel therapeutic agents have been developed that act as specific inhibitors of the cyclo-oxygenase-2 isoform (COX-2 inhibitors). Although published data on these drugs remain scarce,22 trials have shown similar efficacy to that of non-steroidal anti-inflammatory drugs in the treatment of osteoarthritis but with gastrointestinal toxicity comparable with that of placebo. The early evidence points towards greater safety than non-steroidal anti-inflammatory drugs alone, but comparisons are not yet available with combinations of non-steroidal anti-inflammatory drugs and cytoprotective therapy. A meta-analysis of all eight double blind, randomised, controlled trials of rofecoxib, published after completion of our literature search, suggested a relative risk of 0.51 for serious clinical upper gastrointestinal events among users of the COX-2 inhibitors when compared with conventional non-steroidal anti-inflammatory drugs.23 These drugs may be widely prescribed for patients with osteoarthritis (and are licensed for this indication), but the most cost effective strategy for their use is far from clear; non-selective non-steroidal anti-inflammatory drugs with or without co-prescription of cytoprotection may still have a role.

Topical treatment

Topical treatment is an additional option for patients with osteoarthritis who have inadequate pain relief or who cannot tolerate systemic therapy. The two best evaluated topical agents in the treatment of the disorder are non-steroidal anti-inflammatory drugs and capsaicin. A recent meta-analysis concluded that 65% of patients allocated to active treatment with topical non-steroidal anti-inflammatory drugs had a good response compared with only 30% of patients receiving placebo.24 Although the component trials were often small and of variable quality there is reasonably strong evidence to conclude that topical non-steroidal anti-inflammatory drugs are effective and safe for patients with osteoarthritis.

Capsaicin is a naturally occurring compound that reversibly depletes the stores of the neurotransmitter substance P from sensory nerve endings; it thereby attenuates the transmission of painful stimuli from the peripheral nerve fibres to higher centres. A meta-analysis of the three placebo controlled trials of capsaicin in osteoarthritis reported that the agent is well tolerated and has significantly greater analgesic effects than placebo.25

Intra-articular therapy

Chondroprotective agents

All the pharmacological interventions described hitherto aim to relieve pain and thereby improve function in osteoarthritis. To date, no measures have been convincingly shown to modify the rate of structural change in cartilage or subchondral bone, which constitute the underlying disease process. Several putative chondroprotective agents or ones that may modify structure have been proposed, including chondroitin and glucosamine compounds, other glycosaminoglycan derivatives found in mammalian articular cartilage, and tetracycline. Clinical trials provide some justification for the use of chondroitin and glucosamine preparations but only for their analgesic or anti-inflammatory effects.40 The issue as to whether glucosamine sulphate is capable of attenuating cartilage loss in patients with early knee osteoarthritis is currently under investigation.