Diagnostic Accuracy of Ottawa Knee Rule for Diagnosis of Fracture in Patients with Knee Trauma; a Systematic Review and Meta-analysis

Introduction: In order to improve the efficacy of requesting knee radiography and reduce unnecessary radiation exposure, some clinical decision rules have been proposed for the assessment of knee injuries. Among them, the Ottawa Knee Rule (OKR) was considered as one of the best guidelines with several validation studies. Therefore, in this meta-analysis, we aimed to investigate the accuracy of OKR for diagnosis of fracture in patients presenting with knee trauma. Methods: A systematic search was conducted in PubMed, Web of Science, Scopus, Google Scholar, and EBSCO from inception to September 2022. Quality assessment of the included studies was performed using QUADAS-2 tool. Diagnostic accuracy parameters were analyzed using random-effects model. Statistical analysis was performed using Meta-Disc and Stata softwares. Results: The meta-analysis of the 18 included studies (6702 patients) showed that the pooled sensitivity and specificity of OKR for diagnosis of fractures were 0.98 (95% CI: 0.96-0.99) and 0.43 (95% CI: 0.42-0.45), respectively. The pooled positive likelihood ratio (PLR) and negative likelihood ratio (NLR) were 1.56 (95% CI: 1.39-1.75) and 0.12 (95% CI: 0.05-0.26), respectively. The area under curve (AUC) of the hierarchical summary receiver operating characteristic (HSROC) curve was 0.54. Conclusion: This meta-analysis indicates that OKR has a high diagnostic performance for diagnosis of fracture, with a pooled sensitivity of 98% and a pooled specificity of 43%. These results propose potential effects of OKR on reduction of unnecessary radiography, time spent in emergency departments, and direct and indirect costs, which should be confirmed using high-quality studies in the future.