All-inside Arthroscopic Repair of ATFL and CFL Separately for Chronic Lateral Ankle Instability in Conjunction with Subtalar Instability

Background Chronic lateral ankle instability (CLAI) is a common condition often associated with damage to the anterior talofibular ligament (ATFL). In cases where CLAI is accompanied by subtalar instability (STI) due to calcaneofibular ligament (CFL) injury, the optimal surgical approach remains controversial. While isolated ATFL repair has been shown to effectively restore ankle joint stability, it may be insufficient to address the subtalar joint instability caused by CFL damage. This study aimed to evaluate the clinical importance of CFL repair by comparing the outcomes of isolated ATFL repair versus combined ATFL and CFL repair. Methods A retrospective cohort study was conducted involving patients diagnosed with CLAI in conjunction with STI from January 2018 to January 2022. Participants were divided into two groups: one underwent isolated ATFL repair (ATFL group), and the other underwent combined ATFL and CFL repair (ATFL + CFL group). Clinical outcomes were assessed using the American Orthopaedic Foot & Ankle Society Ankle-Hindfoot Scale (AOFAS-AH), Karlsson Ankle Functional Score (KAFS) and Visual Analog Scale (VAS) scores, while radiological outcomes were evaluated by MRI and stress radiographs. Results All the functional scores significantly improved in both groups post-surgery. However, the ATFL + CFL group demonstrated superior functional recovery, with higher AOFAS scores and greater reductions in VAS pain scores compared to the ATFL group. Radiological evaluation indicated better restoration of subtalar joint stability in the ATFL + CFL group. At the final follow-up, 3 cases of recurrent instability were observed in the isolated ATFL repair group. No significant difference in other complication rates was observed between the two groups. Conclusion The study demonstrated the importance of CFL repair in patients with CLAI in conjunction with STI. While isolated ATFL repair is effective for ankle joint stability, combined ATFL and CFL repair offers superior outcomes by addressing both ankle and subtalar joint instability. These findings suggest that CFL repair should be considered in surgical planning for patients with STI to optimize functional recovery and long-term stability. Level of Evidence Level III.