Network Meta-analysis: Users' Guide for Surgeons: Part II - Certainty.

In the previous article (Network Meta-analysis: Users' Guide for Surgeons-Part I, Credibility), we presented an approach to evaluating the credibility or methodologic rigor of network meta-analyses (NMA), an innovative approach to simultaneously addressing the relative effectiveness of three or more treatment options for a given medical condition or disease state. In the second part of the Users' Guide for Surgeons, we discuss and demonstrate the application of criteria for determining the certainty in effect sizes and directions associated with a given treatment option through an example pertinent to clinical orthopaedics.