Nonanatomic All-Inside Arthroscopic Anterior Talofibular Ligament Repair With a High-Position Anchor versus Anatomic Repair: An Analysis Based on 3D CT

Background: In patients with chronic ankle instability, it is important to repair the anterior talofibular ligament (ATFL) at the anatomic origin site. However, there are limited reports on the clinical outcomes according to anatomic ATFL repair. Purpose: To compare the clinical outcomes after arthroscopic ATFL repair according to whether the anchor is fixed at an anatomic position. Study Design: Cohort study; Level of evidence, 3. Methods: We performed a retrospective review of consecutive patients who underwent arthroscopic ATFL repair for chronic ankle instability and were available for a minimum 2-year follow-up. The patients were divided into 3 groups according to the anchor position at the distal fibula on 3-dimensional computed tomography: anatomic arthroscopic ATFL repair (anatomic group), subanatomic arthroscopic ATFL repair (subanatomic group), and nonanatomic arthroscopic ATFL repair (nonanatomic group). The visual analog scale for pain, Foot and Ankle Outcome Score (FAOS), and Karlsson ankle functional score were measured as subjective outcomes. Posturographic analysis and radiologic evaluation using stress radiographs and axial view magnetic resonance imaging were performed as objective outcomes. Results: Of 96 patients, 16 were excluded per the exclusion criteria, and 80 were evaluated (anatomic group, n = 24; subanatomic group, n = 42; nonanatomic group, n = 14). The mean age of the patients was 34.5 years, and the mean follow-up period was 27.4 months. A between-group comparison revealed significant differences in FAOS, Karlsson score, and fall risk evaluated by posturography at the final follow-up. Post hoc analysis revealed that the anatomic group had better clinical scores on the FAOS than did the nonanatomic group in all 5 domains (all P < .017). Patients in the anatomic and subanatomic groups had better Karlsson scores and fall risk than those in the nonanatomic group (P = .004 and P = .013, respectively). In terms of objective outcomes, patients in the anatomic and subanatomic groups had better outcomes in fall risk than did those in the nonanatomic group (both P = .001). There were no differences in clinical scores and objective outcomes between the anatomic and subanatomic groups. Conclusion: Nonanatomic ATFL repair showed inferior outcomes when compared with anatomic ATFL repair. When arthroscopic ATFL repair is performed, the anchor should be fixed in the anatomic position to improve prognosis.