Are all Weber A ankle fractures benign?

R.J. Gadd, M.B. Davies

Introduction: Ankle fractures are a common injury with an incidence of 168.7/100,000/year. The Danis-Weber classification helps describe fibula fractures and guide treatment. Reports of non-unions in Weber A fractures are extremely rare. We present a case series of large, transverse avulsion type fracture (Weber A, Lauge-Hansen SAD stage 1 injury) which progressed to non-union and required surgical intervention. We aim to determine how commonly these fracture patterns progress to non-union.

Methods: Following initial identification of the injury pattern we searched through theatre and PACS databases to identify all similar ankle fracture non-unions that required surgical intervention. From November 2007 onwards, we also reviewed PACS imaging of all ankle radiographs reported as Weber A fractures or non-unions to try and estimate an incidence.

Results: 116 radiographs were reviewed. 19 patients were found with a fracture pattern similar to our index case. Four patients were identified with an established non-union and required surgery. These cases were dealt with by internal fixation with or without bone graft and all progressed to union.

Discussion: Three of the 4 cases reported a re-injury following their initial management. This could be a factor in the progression to non-union or a response to the already pre-existing condition. A number of theories for the development of a non-union in these cases have been proposed but no definite cause identified. If a symptomatic non-union is diagnosed then in our experience they progress to union following surgical debridement and stabilisation with or without bone graft. This injury pattern should promote thought from the treating clinician and shouldn´t just be dismissed. We recommend no change to treatment applicable to any stable ankle fracture but that patients should be warned of the possibility of symptomatic non-union.