How to conduct a meta-analysis in hand surgery. Part I: principles and procedures

Meta-analysis (MA) is a fundamental statistical tool for combining the results of different studies to obtain potentially high-level evidence that can be implemented in clinical practice. Although its use in clinical research is increasing, MAs are still relatively rare in hand surgery. Therefore, it should be important for every hand surgeon to not only know how to interpret a MA, but also how to perform one. The purpose of this first of a two-part article is to introduce the principles of MA and describe the main models and methods used to pool effect estimates.