Describing randomization in trials included in systematic reviews in orthopaedic surgery

Aims Systematic reviews of randomized controlled trials (RCTs) are the highest level of evidence used to inform patient care. However, it has been suggested that the quality of randomization in RCTs in orthopaedic surgery may be low. This study aims to describe the quality of randomization in trials included in systematic reviews in orthopaedic surgery. Methods Systematic reviews of RCTs testing orthopaedic procedures published in 2022 were extracted from PubMed, Embase, and the Cochrane Library. A random sample of 100 systematic reviews was selected, and all included RCTs were retrieved. To be eligible for inclusion, systematic reviews must have tested an orthopaedic procedure as the primary intervention, included at least one study identified as a RCT, been published in 2022 in English, and included human clinical trials. The Cochrane Risk of Bias-2 Tool was used to assess random sequence generation as 'adequate,' 'inadequate,' or 'no information'; we then calculated the proportion of trials in each category. We also collected data to test the association between these categories and characteristics of the RCTs and systematic reviews. Results We included 917 unique RCTs. We found that 374 RCTs (40.8%) reported adequate sequence generation, 61 (6.7%) were inadequate, 410 (44.7%) lacked information, and 72 (7.9%) were observational studies incorrectly included as RCTs within the systematic review. Publication year, an author with statistical or epidemiological qualifications, and journal impact factor were each associated with adequate randomization. We found that 45 systematic reviews (45%) included at least one inadequately randomized RCT or an observational study incorrectly treated as a RCT. Conclusion There is evidence of a lack of random allocation in RCTs included in systematic reviews in orthopaedic surgery. The conduct of RCTs and systematic reviews should be improved to minimize the risk of bias from inadequate randomization in RCTs and mislabelling of non-randomized studies as RCTs.