Epidemiology of research into interventions for the treatment of osteoarthritis of the knee joint

Objective-To assess the published research base for interventions for osteo arthritis of the knee, and to identify areas in need of further research. Methods-Literature searches were conducted on electronic databases (Medline , Embase, ISI, and Cochrane library), bibliographies of existing review art icles were hand searched, and a postal questionnaire was sent to members of the Osteoarthritis Research Society international. All relevant articles w ere copied and searched for treatment type, study methodology, statistical results, conclusions, funding source, researcher affiliations, and year of publication, using a predetermined data extraction form. Results-There have been marked changes in the literature over the period st udied (1950-98), with a recent rise in trials of physical therapy, educatio nal interventions, and complementary treatments. However, overall, most res earch was either drug (59.1%) or surgically (25.6%) related. Most of the st udies reported positive results (94%). Research on oral drugs was significa ntly more likely to provide a positive result than research on any other in tervention (p<0.001 by chi(2) test). Commercially funded studies were signi ficantly more likely to produce a positive result than non-commercially fun ded research (p=0.0027 by chi(2) test). Conclusions-Analysis of time trends indicates that the research agenda does shadow changes in consumer demands. However, there are significant gaps in the research base that need to be considered.