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

Objective-To assess the published research base for interventions for osteoarthritis 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 articles were hand searched, and a postal questionnaire was sent to members of the Osteoarthritis Research Society international. All relevant articles were 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 studied (1950-98), with a recent rise in trials of physical therapy, educational interventions, and complementary treatments. However, overall, most research was either drug (59.1%) or surgically (25.6%) related. Most of the studies reported positive results (94%). Research on oral drugs was significantly more likely to provide a positive result than research on any other intervention (p<0.001 by chi(2) test). Commercially funded studies were significantly more likely to produce a positive result than non-commercially funded 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.