National arthroplasty registers are often cited as examples of a non-randomized design that have made an essential contribution to advances in assessing arthroplasty procedures. We aimed to compare national registers to randomized controlled trials (RCTs) and meta-analyses in the field of arthroplasty in terms of scientific production and impact.
We systematically searched Medline via PubMed and the registers' websites to select all articles from national registers, RCTs and meta-analyses assessing hip and knee arthroplasty. The scientific production and impact were evaluated by number of publications, number of citations (total and the 3-year citation counts), and information on the 2008 journal impact factor (IF), for each design and identified articles. We also contacted representatives of all the selected registers to determine the availability of the data for external research projects.
We retrieved information on 13 active national hip or knee arthroplasty registers; for 9, data were available for research projects under specific conditions. Overall, 190 publications in peer-reviewed journals resulted from national arthroplasty registers, 476 from RCTs, and 40 from meta-analyses. We found 4,112 citations for national register reports, 7,328 for RCT reports and 552 for meta-analysis reports. The median [interquartile [IQR] range] number of citations for register, RCT and meta-analysis reports in the 3-year period after publication was 3.5 [1.0-6.0], 2.0 [1.0-6.0], and 2.5 [0.5-7.5], respectively.
Publications from national registers may have the highest impact among the 3 designs in terms of median citation counts, but data from RCTs remain the most productive evidence in the arthroplasty field. Because of the number of patients recruited by registers, the quality of data collected, and the potential availability of data, scientific production and impact from national registers should be improved.