Level 2: Mid-level evidence
Advice to use a topical nonsteroidal anti-inflammatory drug (NSAID) and advice to use an oral NSAID appear to have similar effects on chronic knee pain at one year, based on a non-placebo-controlled randomized trial (BMJ. 2008;336: 138-142). Patients older than 50 years with knee pain (N=282) were randomized to advice to use topical NSAID vs. advice to use oral NSAID, preferably ibuprofen. Follow-up questionnaires were completed by 93%-94% at three months, 88%-90% at six months, 88% at 12 months, and 58%-64% at two years. There were no differences in pain, stiffness, or difficulty in functioning on global Western Ontario and McMaster University Osteoarthritis index (WOMAC) scores between groups at three, six, or 12 months. At 24 months, there were no significant differences between groups except that pain score was better with oral NSAIDs (by six points on a 100-point scale, with borderline statistical significance).
Comparing oral vs. topical ibuprofen at one year, 92% vs. 37% had a prescription for an oral NSAID and 5% vs. 83% had a prescription for a topical NSAID. Oral ibuprofen was associated with more frequent respiratory adverse effects (17% vs. 7%, NNH 10) and greater change in serum creatinine (2.4 µmol/L vs. -1.3 µmol/L [0.032 mg/dL vs. -0.017 mg/dL]). Fewer patients in the oral NSAID group changed mode of treatment because of inadequate pain relief (13% vs. 23%, NNT 10), but 11% vs. 1% changed mode of treatment because of adverse effects (NNH 10). However, without placebo control or a non-medication advice group, this trial does not directly show that either advice had efficacy.