SLR - December 2015 - Jennifer Seifert

Title: Dislocation is a Risk Factor for Poor Outcome after Supination External Rotation Type Ankle Fractures

Sculco PK, Lazaro LE, Little MM, Berkes MB, Warner SJ, Helfet DL, Lorich DG. Dislocation is a Risk Factor for Poor Outcome after Supination External Rotation Type Ankle Fractures. Arch Orthop Trauma Surg. 2015 Oct 27.

Scientific Literature Review

Reviewed By: Jennifer Seifert, DPM
Residency Program: NewYork-Presbyterian/Queens

Podiatric Relevance: Ankle fractures are the most frequently encountered surgical fractures and represent 10 percent of all traumatic fractures. Traditionally, the Lauge-Hansen classification is the most widely used; with supination external rotation (SER) type ankle fractures being the most common. In SER IV type ankle fractures or the equivalent, both fracture patterns require surgical intervention, as the ankle is unstable and can potentially dislocate. The objective of this study was to evaluate the effect of dislocation in SER IV ankle fractures, specifically to evaluate if dislocation increases the risks of wound complication, articular mal-reduction, or functional outcomes.  It is important for the podiatric surgeon to understand the differences in outcome when facing an unstable, possibly dislocated ankle.

Methods: From a prospective trauma registry, 178 SER IV ankle fractures treated by a single surgeon were identified. All patients included in the study had a minimum of one-year follow up, Foot and Ankle Outcome Scores, and complete radiographic imaging. All patients were treated with open reduction with internal fixation through a posterior-lateral approach and received intraoperative antibiotics. CT scans were completed post operatively to assess the accuracy of reduction, both articular and syndesmotic. Standard post-operative protocol was followed. The outcome measures were the FAOS, ankle motion compared contra-laterally and wound complications.

Results: Out of the 178 ankles, 108 met all of the inclusion criteria, with a mean follow-up of 21 months. Tri-malleolar injury was the most common type of SER IV ankle fracture with 43 percent non-dislocated versus 54 percent in the dislocation group. There were significantly more open fractures in the dislocation group (11 percent) when compared to the no dislocation group (1 percent), with no significant difference in wound complications or infection.  The risk of articular malreduction was higher in fracture-dislocation patients (20 percent) compared to the non-dislocated patients (3 percent) (p=0.005). On FAOS, a fracture-dislocation patient had more pain and impacted their activities of daily living, but was not statistically significant. Range of motion testing at final follow-up showed a significantly lower range of motion when compared to the contralateral ankle in the fracture-dislocations patients in all motions but dorsiflexion.

Conclusion: When facing a SER type IV fracture, either dislocated or not, it is important to treat the initial injury appropriately. Historically, dislocated ankles have more wound complications, which may have been avoided in this study with aggressive pre-operative wound care and soft tissue monitoring. Dislocated ankles can predictably have less range of motion and pain in the long term when compared to the contralateral side. This should be discussed with the patient openly at the time of injury and during the post-operative course. 

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