Sonographically Guided Anchor Placement in Anterior Talofibular Ligament Repair Is Anatomic and Accurate

BACKGROUND: Arthroscopic repair is a widely accepted surgical treatment for chronic ankle instability; however, recent studies have shown that arthroscopic repair is nonanatomic in its anchor placement and resultant biomechanics. Ultrasound may improve the accuracy of the anchor placement. HYPOTHESIS: Our hypothesis was that the accuracy of anchor placement in sonographically guided anterior talofibular ligament (ATFL) repair will be comparable with that in open ATFL repair. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: The study included 26 patients who received surgical treatment between April 2012 and October 2019 for chronic ankle instability. Fifteen patients underwent open modified Broström repair and 11 underwent sonographically guided ATFL repair. The distance between the anchor hole and the fibular obscure tubercle was measured using 3-dimensional computed tomography and was compared between the operative procedures. For comparison, a noninferiority trial was employed, with open modified Broström repair as the reference surgery. The noninferiority margin was defined as 5 mm. RESULTS: The mean ± SD distance between the anchor and fibular obscure tubercle was 6.0 ± 2.7 mm in open repair and 5.6 ± 3.3 mm in sonographically guided repair. The mean difference in distance between the techniques (open repair – sonographically guided repair) was 0.37 mm (95% CI, –2.1 to 2.9 mm). The lower margin of the confidence interval was within the noninferiority margin (–5 to 5 mm). CONCLUSION: Anchor placement under sonographically guided ATFL repair was equivalent to that of open ATFL repair and can be considered anatomic and accurate.