Treatment of Lauge-Hansen supination - eversion (SE)4-equivalent ankle fractures is controversial. This retrospective study conducted at a level-I trauma center compared the clinical outcome of nonsurgical vs open management of these fractures. One thousand eight ankle fractures treated between 1998 and 2003 were reviewed. Forty-three patients who met the criteria for a SE4-equivalent ankle fracture were identified. Average patient age of 23 men and 20 women was 42 years (range, 18-84 years). Olerud Molander ankle scores were recorded. Medical records and radiographs of all patients were reviewed. Average follow-up was 20 months. Twenty-six patients were treated nonsurgically, with an average ankle score of 84±4. Seventeen patients treated surgically had an average ankle score of 63±5. The difference is statistically significant (unpaired t test, P=.0035). There was no difference between open vs closed treatment in maintaining a reduction. To investigate the reason for poor results in the surgical group, we sought an association between functional ankle score and common covariables and found that age and preoperative radiographic grading were important variables for ankle score. Patients younger than 30 years had an average ankle score of 85, whereas those older than 50 years had an average score of 61 (P<.001). Type 1 fractures (medial clear space >5 mm in stress view only) had an average ankle score of 89, type 2 (medial clear space >5 mm but <10 mm ) an average score of 76, and type 3 (medial clear space >10 mm or presented with fracture dislocation and/or syndesmosis injury) an average score of 61. Our data support that type 1 and 2 fractures can effectively be treated nonsurgically.