The utilization of intraoperative contralateral ankle images for syndesmotic reduction.

PURPOSE: To evaluate the variability in ankle syndesmotic morphology on contralateral ankle fluoroscopic images and the reductions obtained utilizing these images. METHODS: A retrospective cohort study was performed at a level one trauma center including 46 adult patients undergoing operative fixation of malleolar ankle fractures that also had anteroposterior (AP) and lateral fluoroscopic images of the uninjured contralateral ankle intraoperatively. Contralateral and post-fixation fluoroscopic images were used to measure the tibiofibular clear space (TFCS) as a proportion of the superior clear space (SCS) on mortise images and the posterior tibiofibular distance (PTFD) as a proportion of the lateral superior clear space (LSCS) on lateral images. Differences between contralateral and post-fixation ankle measurements were compared between those patients with syndesmotic injuries and those without (control group). RESULTS: The mean TFCS/SCS and PTFD/LSCS ratios measured on contralateral ankle images were 1.2 (95% confidence interval (CI) 1.1 to 1.3; range 0.7 to 1.8) and 1.8 (95% CI 1.5 to 2; range 0.5 to 3.4). The mean difference between the contralateral and post-fixation TFCS/SCS and PTFD/LSCS in patients with and without syndesmotic fixation was 0.07 vs. 0.13 (F-ratio 0.3, p = 0.5) and -0.2 vs 0.5 (F ratio 5.2, p= 0.02). CONCLUSIONS: Contralateral syndesmotic measurements varied widely and the utilization of these images allowed for syndesmotic reductions with similar measurements. Intraoperative contralateral ankle images should be considered to assess syndesmotic reduction.

Need for syndesmotic fixation and assessment of reduction during ankle fracture fixation, with and without contralateral fluoroscopic images, has poor interobserver reliability.

PURPOSE: To determine the interobserver reliability of syndesmosis assessment using intraoperative ankle mortise fluoroscopic images, with and without contralateral images. METHODS: A survey of 19 operative ankle fracture cases was administered to 17 orthopedic surgeons. Respondents were presented with fluoroscopic mortise and stress images of the ankle after fracture fixation and asked if they would fix the syndesmosis. Final fluoroscopic mortise images were then shown, and respondents were asked to assess the reduction of the syndesmosis. Six weeks later, the survey was administered again with the addition of contralateral fluoroscopic ankle mortise images. Responses were compared to a standard response agreed upon by fellowship-trained orthopedic trauma surgeons. RESULTS: Interobserver reliability for syndesmosis fixation and reduction, with and without contralateral images, was considered weak (kappa 0.48 and 0.43; mean difference 0.05, 95% confidence interval (CI) 0.01 to 0.1) and minimal (kappa 0.25 and 0.22; mean difference 0.02, CI - 0.02 to 0.08). With the addition of contralateral mortise images, the number of surgeons who changed their response for syndesmosis fixation and reduction quality ranged from 0% to 41% and 0% to 88%; with the number of responses matching the standard increasing for both fixation (proportional difference (PD) 7%, CI 1% to 14%) and reduction (PD 14%, CI 7% to 21%); CONCLUSIONS: Interobserver reliability of syndesmosis fixation and reduction remained weak to minimal between surgeons, with and without contralateral images. Future studies are necessary to understand the variability in surgeon responses in order to improve the intraoperative assessment and fixation of syndesmotic injuries.