Nowadays, systematic literature reviews/meta-analyses of clinical trials are considered the best evidence in clinical research; thus, if performed appropriately, they can save resources by avoiding the development of unnecessary clinical trials. Nevertheless, to carry out a systematic literature review /meta-analysis, researchers must deeply understand its methodology. This narrative review aims to act as a learning tool for new researchers to perform systematic literature reviews/meta-analyses for categorical variables, addressing this matter in a step-by-step fashion using STATA 17. Readers must understand that the scope of this topic is much broader. Therefore, concepts such as meta-analysis for numerical outcomes or meta-analysis for survival analysis are not addressed. The authors hope that the information presented in this manuscript serves as pillars to enhance research worldwide, especially in places where formal research training is uncommon. If readers want to extend their knowledge regarding this subject, we recommend reading the "The Cochrane Handbook for Systematic Reviews of Interventions and the Center for Reviews and Dissemination" or the book "Finding What Works in Health Care: Standards for systematic reviews.

Scaphoid fractures are the most prevalent type of carpal bone fractures. High-spatial-resolution sonography detects direct signs of scaphoid fractures such as scaphoid cortical disruption; nevertheless, indirect signs such as radiocarpal effusion and scapho-trapezium-trapezoid effusion can also be visible. The diagnosis is performed when both direct and indirect signs of scaphoid fracture are presented. The presence of indirect signs alone is not enough to complete the diagnosis, for which more advanced imaging modalities are usually required. Here, we review the anatomy of the scaphoid, the clinical manifestations of scaphoid fractures, as well as ultrasonographic findings and differential diagnosis.