Researchers and clinicians measuring outcomes following total ankle replacement (TAR) are challenged by the wide range of outcome measures used in the literature without consensus as to which are valid, reliable, and responsive in this population. This review identifies region- or joint-specific outcome measures used for evaluating TAR outcomes and synthesises evidence for their measurement properties.

A standard search strategy was conducted of electronic databases MEDLINE, EMBASE and CINAHL (to June 2015) to identify foot/ankle measures in use. A best evidence synthesis approach was taken to critically appraise measurement properties [COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN)] of identified measures. The review was restricted to English publications and excluded cross-cultural adaptations. Measurement properties collected from each article were coded for validity, reliability, responsiveness, or interpretability. Clinimetric evidence exists for identified measures tested in non-TAR populations, but were not the focus of this review.

The search identified 14 studies to include in the best evidence synthesis with 32 articles providing clinimetric evidence for eight of the measures (one CBO, seven PRO), however only five measures were tested in a TAR population (Foot Function Index, Ankle Osteoarthritis Scale, American Orthopaedic Foot and Ankle Society Ankle-Hindfoot Scale [AOFAS], Foot and Ankle Outcome Score, Self-Reported Foot and Ankle Score). Five studies provided clinimetric evidence in a TAR population and their methodological quality was assessed: (1) Validity—two good quality studies examining different measures provide moderate evidence supporting construct validity (FFI, AOS, AOFAS self-reported items; SEFAS); (2) Reliability—two good quality studies examining different measures provide moderate evidence supporting internal consistency and test-retest reliability (FFI, AOS, AOFAS self-reported items; FAOS, SEFAS); (3) Responsiveness—three poor quality studies, thus unknown evidence for responsiveness; (4) Interpretability—two studies provide interpretability values (AOS, FFI, AOFAS self-reported items; AOS).

This review offers a basis for choosing the most appropriate instrument for evaluating TAR outcomes. Numerous outcome measures were identified with evidence supporting their use in populations with various foot/ankle conditions, but none have strong evidence supporting use in a TAR population. Measures must have adequate clinimetric properties in all patient groups in which they are applied. Evidence supporting or critiquing an instrument should not be based on studies with poor quality methodology, as identified by this review. Further testing in a TAR population would benefit identified measures with emphasis on adequate sample sizes, testing a priori hypotheses, and evaluating their content validity for a TAR population.

Purpose: The objective of this study is to compare items from patient-reported questionnaires measuring musculoskeletal outcomes with items generated by pre-and post-operative ankle arthrodesis and arthroplasty patients using the Patient-Specific Index (PSI-P). The International Classification of Functioning, Disability and Health (ICF) was used as an external reference.

Method: A literature review identified six questionnaires that assess lower extremity outcomes (AAOS, patient-reported portion of AOFAS, FFI, LEFS, SMFA, WOMAC). Surgical patients (n=142) from an orthopaedic surgeon’s practice completed the patient-selected items from PSI-P. Items from questionnaires and PSI-P were coded by three reviewers and linked to the ICF. The ICF is divided into four components (Body Functions and Structures, Activities and Participation, Environmental Factors, and Personal Factors) which are then further divided into second level categories. A higher number of second level categories would indicate a questionnaire that captures a broader range of experiences.

Results: Patient’s responses from PSI-P identified 690 meaningful concepts that were linked to 45 second level ICF categories. Most PSI-P responses fell into Activities and Participation (60.6%) and Body Functions and Body Structures (35.2%) including the second level categories Walking (19.1%), Pain (16.5%), and Recreation and Leisure (15.4%). There was no statistical difference between arthrodesis and arthroplasty patients nor between pre-operative versus postoperative patients in terms of the proportion of patient responses that fell into each ICF component. A total of 237 meaningful concepts were identified in the 6 questionnaires studied and linked to 38 second level ICF categories. Overall, SMFA addressed the most number of second level categories and had the closest proportion of Body Function (23.0%) and Activities and Participation (68.9%) concepts as compared to PSI-P. The patient-reported portion of AOFAS addressed the fewest categories. LEFS only contained items from Activities and Participation. AAOS was the only questionnaire to address the issue of ‘swelling’, though it represented 4.9% of all PSI-P responses.

Conclusion: Questionnaires differ largely in their content and no single questionnaire captured all of the concerns identified by PSI-P. This analysis will guide us in the development of a new and more comprehensive instrument for evaluating ankle outcomes following fusion or replacement.