Does Sectioning and Then Repairing of the Calcaneofibular Ligament at Subtalar Approach Lead to Residual Lateral Ankle Instability?

Background: The calcaneofibular ligament is cut to increase vision in surgical field in minimally invasive surgery of displaced intraarticular calcaneus fractures with subtalar incision. We aimed to investigate whether this causes talar tilt instability in ankle stress radiographs due to the calcaneofibular ligament deficiency in postoperative period. Methods: The files of 38 patients who were operated with the diagnosis of displaced calcaneus fracture between 2013 and 2018 were examined retrospectively. All the cases underwent with subtalar approach and the calcaneofibular ligament was repaired after the operation. The age, sex, injury mechanism, follow-up length, type of fracture by the Sanders classification, preoperative and postoperative Bohler's and Gissane's angle measurements, talar tilt measurements of intact and fractured side, postoperative calcaneal length, calcaneal height and calcaneal width of the cases were recorded. The obtained data were evaluated statistically. Results: 31 (81.6%) of the cases were men, seven (18.4%) were women. The average age was 31.92 +/- 7.95 years. The average follow-up time was 15.82 +/- 3.33 months. The preoperative Bohler's angle was 14.16 +/- 3.67 degree, while the postoperative Bohler's angle was 31.53 +/- 4.60 degree (P<0.05). The average talar tilt was 0.96 +/- 0.87 degrees on the intact side and 1.19 +/- 1.12 degrees on the fractured side (P:0.001). Although the talar tilt values were statistically higher on the fractured side than the intact side, no radiological instability finding was found in any case. The average postoperative Gissane's angles were 126.45 +/- 6.69 degrees. The calcaneal length (P:0.665), calcaneal width (P:0.212) and calcaneal height (P:0.341) were statistically similar between the postoperative fractured foot and intact foot. Conclusion: Sectioning of the calcaneofibular ligament in the surgical treatment with subtalar approach does not cause lateral ankle instability in stress radiographs but may cause laxity. Possible postoperative lateral ankle injuries can be prevented by ankle proprioception exercises.