SLR - April 2021 - Usman Urooj

Intraoperative Three-Dimensional Imaging in Ankle Syndesmotic Reduction 

Reference: Markus Beck, Manuela Brunk, Alice Wichelhaus, Thomas Mittlmeier, and Robert Rotter. Intraoperative Three-Dimensional Imaging in Ankle Syndesmotic Reduction . BMC Musculoskeletal Disorders, 2021. 

Level of Evidence: IV

Scientific Literature Review

Reviewed By: Usman Urooj, DPM
Residency Program: Carl T Hayden VA Medical Center – Phoenix, AZ

Podiatric Relevance: When considering lower extremity injuries, the ankle joint has been shown to be the most common one to be injured. Treatment protocol is based on the severity and the type of injury. Treatments may be conservative or surgical but fractures accompanying unstable syndesmosis injuries are considered a good indication for surgical intervention. According to the literature, 16 percent of proximal ankle injuries include syndesmotic injury. Intra and post operative imaging provide a very low sensitivity and specificity in identifying any malreduction of the overall ankle complex; leading to future complications. The purpose of this study was to assess whether the position of the fibula in the tibial incisura can be determined by intraoperative 3D scanning and if this knowledge had any influence on the postoperative revision rate. 

Methods: This retrospective case series study was conducted from 2007 to 2015. 1127 patients with ankle region fractures were selected. Two hundred of these patients were noted to have instability of the distal tibio-fibular syndesmosis. The Vario 3D Image Intensifier from Ziehm was used to scan the ankles in these patients. All scans were performed after initial fixation of the ankle fracture but before final wound closure. One or two tricortical syndesmotic screw(s) were used to fixate the distal syndesmosis. Evaluation parameters for a correct joint position were defined as: Centered position of the fibular in the tibial incisura, Equal joint space width of fibular talar and tibiotalar in the joint area and congruence of the lateral malleolus joint surface to the lateral talar process. Any malreduction was corrected followed by a new 3D scan. A deviation of > 2 millimeters on CT scan performed post op, in comparison to the contralateral side, was defined as malposition and required revision. 

Results: Two hundred patients received 3D scan to identify unstable syndesmosis post ankle fracture. In this study, 64 percent were male and 36 percent were female patients. A total of 186 3D scans performed showed correct adjustment of the distal tibialfibular joint. Fibula position was corrected after intraoperative evaluation of the 3D scan in 14 cases. A follow up 3D scan confirmed correct position. In eight patients, long hardware was identified and was replaced with correct size hardware. Malposition of the medial malleolus was identified in six patients. In two patients, an intraarticular osteochondral fragment was detected by the 3D scan that was initially missed by conventional fluoroscopy. To summarize, 30/200 patients underwent a revision based on intraoperative findings of the 3D scan. Post operatively, CT of the contralateral side was compared to the operated side and no case of defective position of the fibula in the tibial incisura worth revision was identified. The postoperative revision rate was 0 percent. 

Conclusions: In conclusion, the authors agreed that their study confirmed that a 3D image intensifier allows for a reliable intraoperative assessment of the distal syndesmosis. Any malreductions were identified and corrected secondary to identification via 3D scan intra-operatively. If available, this technology can assist in avoiding a second trip to the operating room.

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