SLR - April 2018 - Spruha Magodia

Effect of Posterior Malleolus Fracture on Syndesmotic Reduction: A Cadaveric Study

Reference: Fitzpatrick E, Goetz JE, Sittapairoj T, Hosuru Siddappa V, Femino JE, Phisitkul P. Effect of Posterior Malleolus Fracture on Syndesmotic Reduction: A Cadaveric Study. J Bone Joint Surg Am. 2018 Feb 7; (100:3):243–248.

Scientific Literature Review

Reviewed By: Spruha Magodia, DPM
Residency Program: Temple University Hospital, Philadelphia, PA

Podiatric Relevance: Management of rotational ankle fractures is a common and challenging aspect of foot and ankle surgery. Syndesmotic reduction poses a significant challenge in rotational ankle fractures. Posterior malleolus fractures are commonly associated with syndesmotic injury, and studies have demonstrated that fixation of the posterior malleolus leads to greater stability of the syndesmosis. A key factor is posterior malleolus fragment size: different size fragments provide different qualities in reduction. The authors conducted this cadaveric study to analyze how the quality of anatomic reduction of the syndesmosis is affected by posterior malleolus fracture size. The authors hypothesized that a malreduction of the posterior malleolus fracture results in malreduction of the syndesmosis itself.

Methods: Nine cadaveric specimens with intact proximal tibiofibular joints were obtained. CT scans were taken to determine a baseline condition to ensure equivalent orientation. A Lauge-Hansen SER IV injury was then created by releasing the AITFL, deltoid ligaments and interosseous membrane 10 mm above the joint line. A saw blade and osteotome were used to create the fractures. The specimens were divided into small and large posterior malleolus fractures. Clamp reduction of the syndesmosis and fracture fragment was performed. CT imaging was used to assess the level of reduction in the antero-posterior and medial-lateral direction.

Results: In the unreduced, anatomically reduced and malreduced small posterior malleolar fracture, a slight anterior shift of the fibula was noted. In the large fracture subset, fibular shift was noted during both unreduced and malreduced fractures but not in the anatomically reduced group. Significant lateral displacement of the fibula was noted in a malreduced fracture compared with unreduced fractures and anatomically reduced fractures.

The authors of this study state that the relationship between syndesmotic reduction and posterior malleolar fracture has not been studied, and they conclude that malreduction of the posterior malleolus leads to malreduction of the syndesmosis, thus increasing the chance of posttraumatic arthritis and poor clinical outcomes. They state that fixation of all posterior malleolus fractures should be considered, regardless of size. It will behoove the podiatric surgeon to bear in mind the consequence of any size posterior malleolar fracture when managing ankle fractures.

Educational Opportunities