OTA 2005 Posters

Scientific Poster #83 Foot & Ankle

Does a Bimalleolar Fracture Predispose Patients to a Poorer Outcome than a Ligamentous Equivalent? A Prospective Evaluation of Two Unstable Ankle Fracture Patterns

Nirmal Tejwani, MD; Toni McLaurin, MD; Gina Aharonoff; Siraj Bhadsavle; Kenneth J. Koval, MD; Kenneth A. Egol, MD (n-all authors);

New York University-Hospital for Joint Diseases, New York, New York, USA

Purpose: This study compares demographics and functional outcome following surgical stabilization between variations of supination external rotation type 4 fractures (OTA 44B2.1/B3.1 medial deltoid rupture with fibula fracture) versus 44B2.2/B3.2/B3.3 (bimalleolar fractures).

Methods: From October 2000 to August 2005, 397 patients who sustained an unstable fracture of the ankle and were treated surgically were entered into a database and prospectively followed. Of these, 233 patients sustained either an OTA type 44B2.2/B3.2/B3.3 fracture (bimalleolar) or an OTA type 44B2.1/B3.1 (lateral fracture with medial deltoid insufficiency and medial widening) fracture pattern. No medial fixation was used in patients with ligamentous injury. All patients followed a similar postoperative protocol consisting of functional bracing for 6 weeks with passive/active ankle motion and nonweight bearing on the injured extremity, and were followed at 3, 6, and 12 months after surgery. Baseline characteristics that were obtained by trained interviewers included: patient demographics, the SFMA, and the presence of depression. Follow-up information included the occurrence of complications or additional surgery, and the AOFAS score. Data were analyzed by contingency table methods (²) or student's t-test to determine predictors of recovering function at 6 months. The following covariables were examined: age, sex, presence of diabetes, and ASA classification. A P value <0.05 was considered significant.

Results: Of the 233 patients analyzed, bimalleolar fractures were more commonly seen in females (OR=2.4; 95% CI 1.4-4.2; P=0.001), patients older than 60 years of age (OR=6.1; 95% CI 2.3-16.3; P<0.001), and patients with ASA grading of 3 or 4 (OR=19.3; 95% CI 2.6-146.0; P=0.004). There was no difference in fracture pattern in patients with diabetes, nor was there any significant difference in length of hospital stay by fracture pattern. 71% of the patients were available at 1 year with completed follow-up information. Using the different components of the AOFAS, patients with bimalleolar fractures showed no difference in pain at 1 year, but were significantly worse for function (P=0.02). Using multiple logistic regression, the poorer functional outcomes were consistent for patients with bimalleolar fractures when controlling for gender, age, and ASA grade (OR=3.4), although this was only of borderline significance (P=0.1).

Conclusion: We found that at 1 year after surgical stabilization of unstable ankle fractures, patients were doing well with most experiencing little or mild pain and few restrictions in functional activities. However, there were significant differences in the patient demographics and functional outcome scores when comparing those with bimalleolar fractures to patients with fibular fractures and medial deltoid injury.

Significance: This is the first study that compares patient outcome following two different variations along the spectrum of Lauge-Hansen ankle fracture patterns. It is important to counsel patients and their families on the expected outcome after injury with regards to functional recovery.