77. AN OBSERVATIONAL STUDY OF FUNCTIONAL OUTCOME SCORES IN FOOT AND ANKLE TRAUMA

Abstract

Purpose: Identifying optimal treatment strategies in patients with traumatic foot and ankle injuries has been hampered by the variety of different measurement tools and lack of validation of generic and foot-specific functional measures. It remains plausible that the choice of functional outcome measure may influence our ability to accurately measure treatment effects. This prospective observational study aims to correlate the scores across six functional outcome measures in patients with traumatic foot and ankle injuries and to examine agreement of scores and patients’ subjective health status.

Method: Patients with traumatic foot or ankle injuries completed two generic, the SF-12 Health Survey and the Short Musculoskeletal Functional Assessment (SMFA), and four specific health outcome measures, the Foot Function Index (FFI), Foot and Ankle Ability Measure (FAAM), American Academy of Orthopedic Surgeons (AAOS) Foot and Ankle Questionnaire and the American Orthopedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Scale, at a single follow-up visit. Raw scores were calculated and used to assign patients to a categorical functional level (excellent, very good, good, fair or poor). Agreement between the assignments was assessed and Pearson correlation co-efficients were calculated for each pair of outcome scores. Statistical significance was determined using an α of 0.05.

Results: 52 patients (mean age 43.3 ± 16.8 years) were enrolled at a mean follow-up of 15.5 months. All correlations except for that between the AOFAS ankle-hindfoot scale and the mental component of the SF-12 were statistically significant. The strongest correlations were found between the SMFA, FFI, AAOS Foot and Ankle Questionnaire and the FAAM. Despite significant correlation between scores and patients’ subjective functional outcome, there was minimal agreement between assigned categorical functional levels.

Conclusion: The high correlations between scores on the generic and foot-specific functional measures suggest that it is likely unnecessary to use more than one instrument when examining functional outcome in patients with traumatic foot and ankle injuries. Generic tools also appear to function as well as specific scores in this population. However, assignment of patients to a categorical functional level based on raw outcome scores must be performed with caution as the results obtained may not accurately reflect functional outcome.