Difficulties in classification of malleolar fractures

Abstract

Objective Classification of malleolar fractures are a matter of debate. The Lauge Hansen and the AO-classification are defined as complicated, where the Weber-classification is too simplistic. In trimalleolar fracture is the role and the size of the posterior fragment an additional complicating factor. Material. Methods. Interobserver study: four observers (2 traumasurgeons, 2 radiologists) classified 100 X-rays to the AO-, the Lauge-Hansenand the Danis-Weber classification. In case of a trimalleolar fracture they were asked to measure the size of the posterior fragment. Results Within the Weber classification, there is a lot of discussion whether the fracture is a proximal “Weber B” or a distal “Weber C”. This problem also exists in the AO-classification. In addition, it is not possible to classify the isolated medial malleolus fracture. The biggest problem of the Lauge-Hansen classification is that anamnestic (and in particular radiological) the trauma-mechanism remains unclear. As a result, it is possible to classify identically fractures in different groups. Small posterior avulsion fragments prove difficult to determine on the initial X-ray. Overshadowing of the fibula is the avultion of a very small fragment shows to be limiting factor. Fixation if posterior fragments is, in most literature, dependent on the size if the posterior fragments. Some authors advocate that not only size but most important, the congrunecy of tibiotalar articular surface should be leading in choice of treatment for anatomic restoration. In that case, assessment of size if the posterior fragment is less important where the detection of smaller dislocated posterior fragment is of much more value. Conclusions The ankle X-ray is in most cases a useful tool in detecting clinical relevant fractures of the posterior malleolus however preoperative CT evaluation might be a very useful addition both in pre-operative planning and detection from smaller dislocated posterior fragments.