Evaluation of the validity of the Foot Function Index in measuring outcomes in patients with foot and ankle disorders.

Background: There is uncertainty regarding which outcomes tools should be used to report the results of treatment for patients with foot and ankle disorders. This study evaluates the validity of the Foot Function Index (FFI) by examining its level of correlation to the Medical Outcomes Study Short Form-36 (SF-36). The SF-36 is an extensively validated outcomes tool that has been used as a benchmark in examining the validity of several orthopaedic outcomes tools.