SLR - February 2018 - Albert A. Elhiani

Impact of Computed Tomography on Operative Planning for Ankle Fractures Involving the Posterior Malleolus

Reference: Donohoe, Steven, et al. “Impact of Computed Tomography on Operative Planning for Ankle Fractures Involving the Posterior Malleolus.” Foot & Ankle International, vol. 38, no. 12, 2017, pp. 1337–1342.

Scientific Literature Review

Reviewed By: Albert A. Elhiani, DPM
Residency Program: Cedars Sinai Medical Center, Los Angeles, CA

Podiatric Relevance: It is important for the podiatric surgeon to understand the nuances in treating ankle fractures. Surgical ankle fractures can have posterior malleolus involvement up to 50 percent of the time. Appreciable disagreement throughout the literature exists on how to manage ankle fractures involving the posterior malleolus. The controversy stems from the fracture complexity and extent of articular involvement. The use of computed tomography (CT) in identifying the complexity of a posterior malleolus fracture is often overlooked and underutilized. Use of preoperative CT can assist in determining operative indications and with surgical planning.  

Methods: A retrospective analysis of radiographs and CT scans from an “ankle fracture registry” was performed at a level I trauma center between 2005 and 2015. Surgical ankle fractures with posterior malleolus involvement that had available plain radiographs and CT imaging were assessed by three fellowship-trained orthopaedic surgeons, two trauma specialists, and one foot and ankle specialist. The panel evaluated 25 plain films and 25 CT images separately in a random order to ensure the images could not be associated with the corresponding CT. Reproducibility was ensured by performing the same task twice at least six weeks apart.

The panel was asked three questions: 1) Is the posterior malleolus fracture simple or complex? 2) Does the fracture require direct visualization and articular reduction? 3) If yes to question 2, then what operative approach and patient positioning would be used at the time of surgery?

Results: The panel was unable to recognize a complex fracture pattern in 8/25 (32 percent) patients using just plain radiographs. The fracture classification was changed in 14/25 (56 percent) cases with the use of CT imaging. The recommendation to directly visualize and reduce the fracture was 21/25 (84 percent) for XR and 23/25 (92 percent) with CT. The panel decided that different patient positioning and a different operative approach were warranted in 11/25 (44 percent) of the cases.

The interobserver and intraobserver correlation coefficient for fracture complexity on XR was 0.20 and 0.52, whereas CT was 0.56 and 0.78, respectively.

The interobserver and intraobeserver correlation coefficient for whether the fracture required direct reduction from XR was 0.47 and 0.85, whereas CT was 0.44 and 0.94, respectively.

Conclusions: The authors of this study conclude that the use of CT in patients with posterior malleolus fractures often changes the surgical plan, patient positioning and surgical indications altogether. It is well known that CT is a superior diagnostic modality that provides the surgeon with more information; however, its use should be judicious. Furthermore, the conflicting literature on how to treat these fractures and the moderate to poor intraobserver correlation coefficients make it even more difficult to determine when CT is truly indicated. Moving forward, I would have a lower threshold in obtaining a CT when posterior malleolus involvement is appreciated and in higher-grade ankle fractures. In treating more complex fractures, I would likely have the patient in a prone position and be more inclined to use second posteromedial incision. 

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