Practical Review of Clinical Research Methodology and Statistics for the Orthopaedic Surgeon.

All orthopaedic surgeons and trainees interact with peer-reviewed literature at some level, from consumer to author. Although orthopaedic practitioners have strong clinical backgrounds and frequently read orthopaedic literature to stay up to date on clinical advances, they often lack formal training or sufficient literacy in clinical research methodology to thoroughly dissect study design and statistics. With an increasing number of orthopaedic surgeons and trainees involved in clinical research, the goal of this review is to provide a concise and pragmatic overview of basic study design and comparative statistical methodology in the context of orthopaedic surgery research. This review discusses first the levels of evidence that can be assigned to a research study and then outlines common comparative study designs seen in orthopaedic literature, their advantages, and statistical considerations for each. Next, statistical versus clinical significance and ways of assessing these findings are reviewed, including the concepts of type I and II error, power, and fragility index. Finally, some common pitfalls in the statistical methodology of orthopaedic research are discussed, including tips and tricks for designing successful clinical research studies.