An evaluation of the Weber classification of ankle fractures

Abstract

This retrospective study over a 3 year follow-up was designed to establish the significance of the Weber classification of ankle fractures with regards to functional and radiographic outcome. One hundred and seven patients were available for follow-up, of which 88 ankles could be classified with the Weber system. Medial malleolar fractures alone and pilon fractures could not be classified with this system. A correlation was found between the type of Weber fracture and the overall ankle score. This held true for unimalleolar fractures alone. More complex bimalleolar and trimalleolar fractures did not follow this convention. Logistical regression analysis was used to evaluate other predictors of outcome. Bimalleolar and trimalleolar fractures were statistically significant predictors of a poorer outcome (P=0.033, P=0.021). The initial degree of displacement was also determined to be a predictor of outcome (P=0.0133) as was the operative reduction (P=0.0113). Using linear regression, older age (>62 years) was also established as a predictor of a poorer outcome (P<0.05). The Weber classification was found to be a predictor of outcome in unimalleloar ankle fractures and not for multimalleolar fractures. We have identified further predictors of a poorer outcome in ankle fractures as the degree of initial injury, the number of malleoli fractured and older age. These factors were found to have greater significance in predicting outcome than the level of fibular fracture alone. We have identified a deficiency of the Weber system in excluding these criteria and have addressed this by modifying the existing system to include the number of malleoli involved, thus providing a more useful prognostic tool.

Introduction

Malleolar fractures of the ankle are common injuries1, 2. Various classification systems exist to describe these injuries, including those of Lauge Hansen[3]and Müller. Although these systems are useful, the complex nomenclature of the numerous subgroups has precluded them from widespread use[4]. Perhaps the most common ankle classification used is that of Weber, which is based on the level of the fibular fracture relevant to the tibio-fibular syndesmosis[5].

Whilst the treatment of ankle fractures is based largely on radiographic findings, effective strategies for treating ankle fractures will require a classification system that is not only descriptive, but can aid in predicting the outcome following treatment modalities. The purpose of this study was to evaluate the Weber classification as a prognostic indicator in terms of functional and radiographic outcome.