1: J Trauma  1992 Jan;32(1):65-70 Examination of the pathologic anatomy of ankle fractures.Michelson JD, Magid D, Ney DR, Fishman EK.Department of Orthopaedic Surgery, Johns Hopkins Medical Institutions,Baltimore, Maryland 21205.A prospective study of the translational and rotational displacement of thelateral malleolus in ankle fractures was carried out utilizing roentgenographictechniques. Twenty-six ankle fractures in 25 patients were studied using bothroutine plain films and CT scanning with two- and three-dimensional multiplanarreconstruction. Eighty-one percent were Lauge-Hansen supination-externalrotation type injuries. Overall, 21 fractures did not involve the medialmalleolus. Initial talar shift was less than or equal to 2 mm in 15 fractures.Although all patients exhibited external rotation deformities of the lateralmalleolus on plain films, only one fracture was found to possess any degree ofexternal rotation relative to the talus. The proximal fibula was seen on CTscans to have increased internal rotation with respect to the tibia in 19 cases.One patient had a slightly externally rotated proximal fibula; the remainderappeared normally aligned. The displacements measured by the CT scans at thetalofibular articulation were compared with the standard plain filmmeasurements. The displacements at the distal lateral malleolus wereconsistently overestimated by the plain roentgenograms, presumably because thecapsular and ligamentous attachments to the distal fibula limit malleolardisplacement. The talocrural angle, determined on both plain films and CT scans,was also not found to be a sensitive measure of fibular shortening nor of theseverity of the fracture. The results of this study suggest that, in an isolatedlateral malleolar ankle fracture, the apparent external rotation of the fracturefragment is relative only to the proximal fibula and is not associated withderangement of the talofibular articulation. Based on these mechanicalconsiderations, surgical intervention for such fractures may not be necessary.This hypothesis is consistent with previous long-term clinical studies.PMID: 1732577 [PubMed - indexed for MEDLINE]