Comprehensive systematic reviews of results from homogenous or heterogeneous clinical trials, meta-analyses are used to summarize and to interpret studies. Proponents believe that their use can increase study power and improve precision results. Critics emphasize that heterogeneity between studies and bias of individual studies compromise the value of results. The methodology of meta-analyses has improved over time, utilizing statistical analysis to reduce bias and examining heterogeneity. With an increasing trend of meta-analyses in orthopaedic literature, this study aimed to investigate quality and clinical utility of meta-analyses for total knee arthroplasty and total hip arthroplasty.
A systematic review of total knee arthroplasty and total hip arthroplasty meta-analyses in 3 major orthopaedic journals from January 2000 to August 2017 was performed. Three authors independently reviewed eligible meta-analyses. A quality assessment was conducted using the Oxman-Guyatt Index. Reporting quality was assessed using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses). Two high-volume, fellowship-trained, attending surgeons specializing in total hip arthroplasty and total knee arthroplasty independently, in a blinded fashion, reviewed 24 of the highest-scored meta-analyses.
There were 114 studies meeting eligibility criteria, 25 published from 2000 to 2009 and 89 published from 2010 to 2017, a 3.6-fold increase. The mean Oxman-Guyatt Index score was 3.89 points, with 12 high-quality studies, 87 moderate-quality studies, and 15 low-quality studies. The mean PRISMA score for all meta-analyses was 22.2 points, with 79% classified as low to moderate. Only 23 studies listed the Level of Evidence, and 8 were Level-I studies and 9 were Level-II studies. Studies with >15 randomized controlled trials were associated with higher PRISMA and Oxman-Guyatt Index scores. In 12 articles, we were unable to decipher the types of studies included. Only 39.4% of studies showed the risk of bias. Of the 24 studies identified as high quality per the PRISMA statement, 71% were determined to be either clinically unimportant or inconclusive.
The number of total hip arthroplasty and total knee arthroplasty meta-analyses has markedly increased over the past decades. The majority of published meta-analyses from 3 major orthopaedic journals were not performed in accordance with established PRISMA guidelines.
Many published meta-analyses are low to moderate quality, and clinicians should cautiously draw conclusions from poorly executed meta-analyses.