Patient reported outcome measures for ankle instability. An analysis of 17 existing questionnaires.

Background: Patient reported outcome measures (PROMs) are essential for evaluating treatment of ankle instability (AI). The aim was to assess the content validity and the measurement properties of all relevant PROMs for AI.

Methods: Relevant PROMs were identified from PubMed and SCOPUS. The development and validation quality of the PROMs was assessed according to established scientific standards.

Results: Seventeen PROMs and 56 validation studies were analyzed. Content validity, which ensures the PROM measures what is relevant, is obtained by involving target patients in the development process. Only three PROMs identified had some degree of patient involvement (Cumberland Ankle Instability Tool (CAIT), Lower Extremity Function Scale (LEFS), and the Foot and Ankle Ability Measure (FAAM)). Of these, only FAAM was somewhat rigorously validated using modern psychometric validation methods, and exhibited superior measurement properties (construct validity).

Conclusion: No existing PROM is completely adequate to evaluate AI. However, FAAM is the best choice.