title: Supination external rotation ankle fractures: A simpler pattern with better outcomes.
abstract: BACKGROUND
  Rotational injuries are the most common and usually classified as per the Lauge Hansen classification; with the most common subgroup being the supination external rotation (SER) mechanism. Isolated fractures of the distal fibula (SE2) without associated ligamentous injury are usually treated with a splint or brace and the patient may be allowed to weight bear as tolerated. This study reports the functional outcomes following a stable, low energy, rotational ankle fracture supination external rotation (SER2) when compared to unstable SER4 fractures treated operatively.
  
  
  METHODS
  64 patients who were diagnosed and treated nonoperatively for a stable SER2 ankle fracture were followed prospectively. In the comparison group, 93 operatively treated fibular fractures were extracted from a prospectively collected database and evaluated comparison. Baseline characteristics obtained by trained interviewers at the time of injury included: Patient demographics, short form-36, short musculoskeletal functional assessment (SMFA) and American Orthopedic Foot and Ankle Society (AOFAS) questionnaires. Patients were followed at 3, 6 and 12 months postsurgery. Additional information obtained at each followup point included any complications or evidence on fracture healing. Data were analyzed by the Student's t-test and theFisher's Exact Test to compare demographic and functional outcomes between the two cohorts. P < 0.05 was considered to be significant.
  
  
  RESULTS
  The average of patients' age in the stable fracture cohort was 43 versus 45 in the SER4 group. Nearly 64% of the patient population was female when compared with 37% in the operative group. In the SER2 by 6 months all patients had returned to baseline functional status. There were 18 delayed unions (all healed by 6 months). Based on the functional outcome scores all patients had returned to preoperative level. In comparison, SE4 patients had less functional recovery at 3 and 6 months (P < 0.05) based on the SMFA scores and at 3, 6 and 12 months based on the AOFAS (P < 0.001) scores. There was no difference in pain levels between the two groups at all time points. There were three nonunions in the SE4 group and six delayed unions.
  
  
  CONCLUSIONS
  An SER2 ankle fracture is a relatively benign injury with functional limitations resolving by 3 months while the need for surgical fixation in SER ankle fractures appears to affect lower extremity function to a greater degree for a longer time period. Patients should be counseled as to these expected outcomes.
authors.affiliation: Department of Orthopaedics, NYU Langone Medical Center Hospital for Joint Diseases, New York, USA.
authors.forename: Nirmal C
authors.initials: NC
authors.lastname: Tejwani
authors.affiliation: Department of Orthopaedics, NYU Langone Medical Center Hospital for Joint Diseases, New York, USA.
authors.forename: Ji Hae
authors.initials: JH
authors.lastname: Park
authors.affiliation: Department of Orthopaedics, NYU Langone Medical Center Hospital for Joint Diseases, New York, USA.
authors.forename: Kenneth A
authors.initials: KA
authors.lastname: Egol
keywords: Ankle injuries; Fibular fractures; ankle fractures; fibula; fractures; supination external rotation injuries