Six Meta-analyses on Treatments for Femoroacetabular Impingement Syndrome in a Year and Readers Are None the Wiser: Methods Advice for Researchers Planning Meta-analysis of Data From Fewer Than 5 Trials.

In 2020, 6 meta-analyses comparing arthroscopic hip surgery to physical therapy were published. All included the same 3 randomized controlled trials, and none used methods suitable for the analysis of fewer than 5 studies. When there are fewer than 5 studies and heterogeneity, a random-effects model with the Hartung-Knapp-Sidik-Jonkman adjustment for a maximally conservative estimate should be employed; if reliable prior information is available, a Bayesian random-effects meta-analysis should be employed. Our re-analysis, which employed the appropriate model, found that there is currently insufficient evidence to conclude that surgery is superior to physical therapy for femoroacetabular impingement (FAI) syndrome. Further randomized controlled trials are required to resolve the clinical question of what the best treatment approach is for FAI syndrome. We provide readers with tools to conduct appropriate meta-analysis of fewer than 5 trials. .