Spanish Translation, Cross-Cultural Adaptation, and Validation of the Olerud-Molander Ankle Score (OMAS) for Ankle Fractures

BACKGROUND: The aim of this study was to translate and cross-culturally adapt the Olerud-Molander Ankle Score (OMAS) into Spanish and to assess its reliability and validity. METHODS: The translation and adaptation to develop the Spanish version of the OMAS (OMAS-Sp) was performed according to current international guidelines. The OMAS-Sp was administered to 98 patients with a surgically treated ankle fracture, and it was repeated 7-14 days later to assess construct reliability of each question’s score and the total score. Test-retest reliability and the internal consistency were calculated, and concurrent validity was assessed by comparing the OMAS-Sp with the Foot and Ankle Outcome Score (FAOS). The presence of floor and ceiling effects was also analyzed. RESULTS: Adequate internal consistency was found with a Cronbach α of 0.821. Excellent test-retest reliability was demonstrated with an interclass correlation coefficient for the total score of 0.970 (95% CI 0.956-0.980; P < .001). Spearman correlation coefficients (r’s) between the OMAS-Sp total score and the 5 FAOS subscales ranged from 0.944 to 0.951 (P < .001). No floor or ceiling effects were found. CONCLUSION: The OMAS-Sp demonstrated adequate psychometric properties and is a valid and reliable tool for assessing outcomes in Spanish-speaking patients with surgically treated ankle fractures. LEVEL OF EVIDENCE: Level II, prospective cohort study.