To evaluate the longterm efficacy of topical therapies for pain control in primary knee osteoarthritis (OA).
Systematic literature search was carried out from January 1, 1966, to December 31, 2004, in Pubmed, Medline, Embase, and Cochrane database. Manual searches of related journals in the National Medical Library (New Delhi, India), the library of our institute, and conference abstracts were also carried out. We included randomized controlled clinical trials of 4 weeks or more comparing any topical nonsteroidal antiinflammatory drug (NSAID) with placebo or vehicle. Effect size for pain control was estimated.
Out of 172 citations, 4 studies fulfilled all the specified criteria. Four of them compared topical NSAID with placebo or vehicle. Pooled effect of topical NSAID measured at 4 weeks or beyond was superior to placebo/vehicle in pain relief (mean effect size -0.28, 95% CI -0.42 to -0.14).
Topical NSAID are effective for pain relief in knee OA for a longer duration; however, this may not hold true for all the preparations.