INTRODUCTION: The American Orthopedic Foot and Ankle Score (AOFAS) is for many foot and ankle surgeons the gold standard for evaluation of foot and ankle disorders. The score comprises of four different questionnaires depending on which region is evaluated, and covers three different constructs; pain, function and range of motion and alignment. AOFAS however, requires clinical examination, and can therefore not be used as a patient-reported outcome measure (PROM). In contrast, the Self-Reported Foot and Ankle Score (SEFAS) is a PROM that recently has been validated with good results in patients with foot and ankle disorders. The SEFAS contains 12 questions and covers different constructs such as pain, function and limitation of function. The aim of this study was to compare the SEFAS and AOFAS in patients with disorders in the great toe, the hindfoot and ankle, taking psychometric properties for scores into account.PATIENTS AND METHODS: The SEFAS and AOFAS scores were completed by 73 patients with disorders in the great toe and by 89 patients with disorders in the hindfoot or ankle. The time it took to complete the questionnaire was measured in 17 patients. In all patients, construct validity for SEFAS versus AOFAS was estimated by Spearman´s correlation coefficient and we also evaluated if there were any floor and ceiling effects. Test-retest reliability (intra-observer reliability) was measured for SEFAS in 68 patients and for AOFAS in 33 patients with intra-class correlation coefficient (ICC). Inter-observer reliability was calculated in nine patients for AOFAS using ICC. Responsiveness, i.e. the ability of a score to detect changes after a surgical intervention, was estimated by effect size (ES) and standardized response mean (SRM) in 120 patients for SEFAS and in 112 patients for AOFAS.RESULTS: The SEFAS was completed more than three times faster than AOFAS (165 seconds versus 515 seconds). SEFAS had good convergent validity (strong correlation) with AOFAS with a Spearman´s correlation coefficient of 0.64 in patients with great toe disorders and 0.65 in patients with hind foot/ankle disorders. There were no floor or ceiling effects in either of the scores. ICC was in patients with great toe disorders 0.94 (95% CI: 0.87-0.97) for SEFAS and 0.77 (95% CI: 0.39-0.93) for AOFAS, and in patients with hindfoot/ankle disorders 0.92 (95%CI: 0.85-0.95) for SEFAS and 0.52 (95%CI: 0.13-0.77) for AOFAS. ES was 1.4 for SEFAS and 1.8 for AOFAS and SRM 1.4 for SEFAS and 1.6 for AOFAS in patients with great toe disorders. ES was 1.2 for SEFAS and 1.1 for AOFAS and SRM 1.1 for SEFAS and 0.9 for AOFAS in patients with hindfoot/ ankle disorders. Inter-observer reliability was 0.43 (95% CI: 0.0-0.84) for AOFAS.DISCUSSION AND CONCLUSION: In this study there was a strong correlation between SEFAS and AOFAS indicating good construct validity for SEFAS. Both scores had good responsiveness and no floor or ceiling effects. The test-retest reliability was better for SEFAS than AOFAS while the inter-observer reliability was low for AOFAS. Finally, SEFAS was completed three times faster than AOFAS. In conclusion we consider SEFAS at least equal to AOFAS for evaluation of patients with foot and ankle disorders, and as no clinical examination is demanded in SEFAS, it is an ideal instrument for evaluation of clinical patient outcome in national registers.