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Evidence summaries

Pharmacological Therapy in Osteoarthritis of the Knee

Paracetamol, topical capsaicin, intra-articular steroids, intra-articular hyaluronic acid, and NSAIDs are all effective treatments of osteoarthritis of the knee. The long-term prescribing of long-term NSAIDs may not be advantageous in all patients. Level of evidence: "A"

A systematic review 1 including 45 NSAID trials (n=4990), 3 analgesic trials (n=241), 5 steroid trials (n=174), 9 biological agent trials (n=438), and 18 mixed trials (n=1587) was abstracted in DARE. Only randomised controlled trials were included.

NSAIDs were superior to placebo in 8 of 9 trials. Using the author's scoring method, 14 comparisons showed differences in efficacy, with etodolac 600 mg/day superior in 5 of 9 comparisons, 41% of trials reported differences in toxicity; indomethacin and aspirin were found to be more toxic than comparator drugs in 6 and 4 trials, respectively.

Of simple analgesics, glafenine was superior to paracetamol, and paracetamol (4g per day) superior to placebo.

Some (not all) studies suggest that intra-articular steroids are superior to placebo, but only in the short term.

6 of 8 RCTs suggest that biological agents are superior to placebo, but the optimal duration of treatment and route of administration is not clear.

Two relatively large and well-designed trials suggested that acetaminophen was as effective as an NSAID. However, only 35% of patients completed a 2-year study, suggesting that neither drug was satisfactory in the long term.

Topical capsaicin was more effective as placebo as adjunctive treatment.

Intra-articular hyaluronic acid (IA HA) was superior to steroid at 8 weeks, but IA HA and dexamethasone was superior to IA HA alone.

Comment: Studies may have been missed. Confidence intervals are not presented.

Primary/Secondary Keywords