A lower talar tunnel placement is associated with postoperative recurrent sprain in CLAI patients following anatomic reconstruction

Abstract Purpose To investigate whether bone tunnel position is associated with postoperative recurrent sprain in chronic lateral ankle instability (CLAI) patients following anatomic lateral ligament reconstruction with autograft and to propose potential safe zones for bone tunnel placement. Methods Four hundred fifty‐seven CLAI patients following anatomic reconstruction at our institution from June 2015 to September 2023 were retrospectively reviewed. Among them, 30 patients sustaining recurrent sprain within 48 months after surgery were included in the recurrent sprain group. Then, 206 consecutive patients who showed no recurrent sprain with minimum 48‐month follow‐up were selected as potential controls. Patients were further divided into two groups based on whether the calcaneofibular ligament was reconstructed, and 1:1 propensity score matching was performed separately in the two groups. The positions of the fibular, talar and calcaneal tunnel were measured on three‐dimensional computed tomography (3D‐CT) scans acquired at postoperative Day 1 and were compared. Potential safe zones for tunnel placement were identified through receiver operating characteristic analysis. Results There was no difference in fibular and calcaneal tunnel position along the reference line between groups. Patients with postoperative recurrent sprain demonstrated a significantly lower talar tunnel position on the reference line from the apex of the lateral talar process (ALTP) to the anterolateral corner of the trochlea (ACT) on the talus compared to those without postoperative recurrent sprain (58.1 ± 6.3% vs. 63.9 ± 6.0%, p = 0.001). The area under the curve value of the talar tunnel position was 0.744 ( p = 0.001), and the determined cutoff value was 58.9% with a sensitivity of 90.0% and a specificity of 53.3%. Conclusion A lower talar tunnel placement is associated with postoperative recurrent sprain in CLAI patients following anatomic reconstruction, with 58.9% above the ALTP‐ACT reference line can be a potential safe zone. The talar tunnel placement needs to be carefully considered to reduce postoperative recurrent sprain. Level of Evidence Level III, retrospective study.