SLR - November 2017 - Calvin J. Rushing

Medial Clamp Tine Positioning Affects Ankle Syndesmosis Malreduction

Reference: Cosgrove CT, Putnam SM, Cherney SM, Ricci WM, Spraggs-Hughes A, McAndrew CM, Gardner MJ. Medial Clamp Tine Positioning Affects Ankle Syndesmosis Malreduction. J Orthop Trauma. 2017 Aug;31(8):440–446.

Reviewed By: Calvin J. Rushing, DPM
Residency Program: Westside Regional Medical Center, Plantation, FL
 
Podiatric Relevance: Syndesmotic malreduction following operative fixation of ankle fractures is becoming increasingly recognized owing to postoperative computerized topography (CT). Several investigations have demonstrated malreduction rates ranging from 16 to 52 percent, despite intraoperative fluoroscopy and direct visualization. Significantly poorer functional outcomes and early onset ankle arthrosis have been correlated with syndesmotic malreduction, which may occur from off axis clamping, screw trajectory or difficulty in accessing the reduction under fluoroscopy. While proper clamp placement laterally on the fibula has been emphasized, little attention has been given to clamp placement medially on the tibia, which may predispose patients to iatrogenic malreduction.

Methods: A level IV prospective cohort study was performed on 54 patients who underwent operative intervention for ankle fractures requiring syndesmotic reduction (OTA/AO 44-B2/B3, 44-C1) by one of three orthopaedic traumatologists at a level 1 trauma center from 2013 to 2015. Intraoperatively following operative fixation of the ankle fracture, the medial tine’s placement during syndesmotic reduction was recorded on talar dome lateral fluoroscopic images. The anterior-posterior width of the tibia was divided into three sections (Anterior 1/3, Central 1/3 and Posterior 1/3) on this image, and the incidence of syndesmotic malreduction (>2 mm) as described by Nault et al. on bilateral postoperative CT was correlated with the position of the medial tine intraoperatively.

Results: Between the three orthopaedic traumatologists, sagittal plane malreduction occurred in 33 percent, 37 percent and 33 percent of their respective cases. There was no statistical difference among the surgeons regarding their placement of the medial tine intraoperatively or the type of ankle fracture and the incidence of syndesmotic malreduction. However, a statistically significant association was found between the placement of the medial tine intraoperatively and the incidence of sagittal plane syndesmotic malreduction. On a talar dome lateral image, tine placement in the anterior 1/3 of the tibia resulted in no anterior malreductions and an 11.1 percent incidence of posterior syndesmotic malreduction. Conversely, placement in the central 1/3, or posterior 1/3 of the tibia resulted in higher sagittal plane syndesmotic malreduction rates, both anteriorly (19.4 percent, 60 percent) and posteriorly (16.4 percent, 60 percent). No significant association was found between medial tine placement and coronal plane malreduction.     

Conclusions: Sagittal plane syndesmotic malreduction is highly sensitive to clamp obliquity. Although medial tine placement is variable between surgeons, off axis clamping resulting from medial tine placement contributes to iatrogenic sagittal plane syndesmotic malreduction. Based on this study, foot and ankle surgeons should use talar dome lateral fluoroscopic images and should ensure the medial tine is placed in the anterior 1/3 of the tibia to reduce the incidence of iatrogenic sagittal plane syndesmotic malreduction.  

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