Measurement properties of the most commonly used Foot- and Ankle-Specific Questionnaires: the FFI, FAOS and FAAM. A systematic review.

PURPOSE: In the foot and ankle literature, a wide range of patient-reported outcome measures (PROMs) is used, however, consensus as to which PROMs are preferred is lacking. Selection of a PROM is among other reasons, often based on measurement properties without considering the methodological quality of the studies that evaluate these measurement properties. The aim of current study was first to identify the most frequently used foot and ankle-specific PROMs in recent orthopaedic foot and ankle literature, and second to conduct a systematic review to synthesize and critically appraise the measurement properties of these PROMS.

METHODS: Six PubMed indexed journals focussing on foot and ankle research were screened to identify most commonly used foot and ankle-specific PROMs over a 2 year period (2015-2016). Subsequently, a systematic literature search was performed in PubMed, EMBASE, SPORTDiscus and Scopus to identify relevant studies on their measurement properties. Methodological quality assessment was performed using the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) checklist, criteria for good measurement properties were applied, and a level of evidence was determined for the measurement properties of each domain of the questionnaires.

RESULTS: The three most frequently reported PROMs were the Foot Function Index (FFI), the Foot and Ankle Outcome Score (FAOS) and the Foot and Ankle Activity Measure (FAAM). Among 2046 unique citations, 50 studies were included evaluating these PROMs. Evidence to support the measurement properties of the FFI was mainly lacking due to poor methodological quality. More evidence was available for the measurement properties of the FAOS and the FAAM, but overall evidence supporting all measurement properties is not yet sufficient.

CONCLUSION: The best available evidence retrieved in this review showed that the FAOS and the FAAM are promising outcome measures for evaluation of patients with foot and ankle conditions, but their shortcomings should be taken into account when interpreting results in clinical setting or trials.

LEVEL OF EVIDENCE: I.