Description of the Simple Ankle Value: A Simplified Patient-Reported Outcome Measure for the Assessment of Ankle and Hindfoot Function

Abstract

Background: The Simple Ankle Value (SAV) is a patient-reported outcome measure (PROM) in which patients grade their ankle function as a percentage of that of their contralateral uninjured ankle. Purpose/Hypothesis: The primary aims of this study were to validate the SAV and evaluate its correlation with other PROMs. It was hypothesized that the SAV would be seen as a valid score that provides results comparable with those of the Foot and Ankle Ability Measure (FAAM) and the European Foot & Ankle Society (EFAS) score. Study Design: Cohort study (Diagnosis); Level of evidence, 2. Methods: Patients seen for an ankle or hindfoot tissue were divided into those treated operatively and nonoperatively. A control group of patients treated for issues outside of the foot and ankle was also created. All patients completed the SAV followed by the FAAM and the EFAS scores. Patients treated operatively completed the questionnaires before surgery and 3 months after surgery. Patients treated nonoperatively completed the questionnaires twice 15 days apart. The correlation between the SAV score, the FAAM score, and the EFAS score was estimated with the Spearman correlation coefficient. Results: A total of 209 patients (79 in the operative group, 103 in the nonoperative group, and 27 in the control group) were asked to complete the questionnaire, and all were included. The test-retest reliability of the SAV was excellent (intraclass correlation coefficient, 0.92; 95% CI, 0.88-0.94). No ceiling or floor effect was reported. Strong correlation was found between the SAV and the FAAM and EFAS scores. The SAV was able to discriminate patients from controls (54.18 ± 21.22 and 93.52 ± 9.589; P < .0001); however, SAV was not able to detect change from preoperative to 3 months postoperative (from 54.18 ± 21.22 to 62.53 ± 20.83; P = .44). Conclusion: Our study suggests that the SAV is correlated with existing accepted ankle PROMs. Further work with this PROM is needed to validate the questionnaire.