Ankle Fracture Stability-Based Classification: A Study of Reproducibility and Clinical Prognostic Ability.

OBJECTIVE: To compare the reproducibility and prognostic capacity of 2 commonly used ankle fracture classifications to the stability-based classification. METHODS: One hundred ninety-three consecutive rotational-type ankle fractures treated during a year at our institution in patients older than 18 years were retrospectively analyzed. Pilon and pathologic fractures were excluded. The fractures were treated by attending physicians who were unaware of the stability-based classification system. Three observers classified injury radiographs using the Lauge-Hansen, Weber/AO, and stability-based classifications systems. Reproducibility (interobserver variation) of each classification system was calculated using kappa statistics. Prognostic values were evaluated by calculating the area under the curve for the receiver-operating characteristic curves (using surgery as the positive outcome). RESULTS: The stability-based and Weber/AO classifications showed better reproducibility [kappa 0.938 (95% confidence interval 0.921-0.952), kappa 0.97 (0.961-0.976)], respectively, than the Lauge-Hansen [kappa 0.74 (0.664-0.795); P < 0.05]. The stability-based classification was more accurate (P < 0.001) in predicting surgical treatment [area under the curve 0.883 (95% confidence interval 0.852-0.914)] compared with the other 2 classifications [0.626 (0.576-0.675) and 0.698 (0.641-0.755)], respectively. CONCLUSIONS: The stability-based classification was both highly reproducible (kappa 0.938) and had superior prognostic capacity to identify patients who needed surgical intervention compared with both the Lauge-Hansen and AO/Weber classification systems. Importantly, there were no patients who were classified as stable who failed nonoperative treatment. This extends earlier studies by directly demonstrating its prognostic advantage to other classification systems.

Clinical utility of a stability-based ankle fracture classification system.

OBJECTIVE: Neither of the ankle fracture classification systems (Lauge-Hansen or Weber) in widespread use today is prognostic. To test the hypothesis that ankle fracture prognosis is dependent on initial biomechanical stability, an alternative classification system created using stability-based treatment criteria was developed on the basis of a structured analysis of the ankle fracture literature. DATA SOURCES: All English-language papers reporting on ankle fractures (searched using the terms "ankle + fracture") published between 1966 and 2005 with available online abstracts via PubMed were screened. STUDY SELECTION: Abstracts were manually screened for inclusion using the following criteria: (1) there were at least 2 groups of patients categorized on the basis of either fracture configuration or treatment and (2) data was reported in sufficient detail to permit interstudy comparisons. DATA EXTRACTION: Each included paper was abstracted into a computerized database for consistent data capture. Data elements included the following: fracture classification, stability definitions, surgical indications, patient follow-up parameters, and outcome measures. Ankle fractures were also stratified into stable and unstable groups using predefined stability criteria, and the outcome measures were re-analyzed. DATA SYNTHESIS: Wilcoxon matched-pairs signed-rank test was used for statistical comparisons, assigning statistical significance to 2-tailed tests with P < 0.05. CONCLUSIONS: The results support the hypothesis that a stability-based ankle fracture classification system can be prognostic. For unstable ankle fractures, the radiographic outcomes were better after surgery, when the decision for surgery was made on the basis of stability (P = 0.0173). Overall, non-operative treatment results were also better with stability-based treatment (P = 0.0299).