Anatomic Anterior Talofibular Ligament Repair: Response

Dear Editor: We read with great interest the article titled ‘‘Nonanatomic All-Inside Arthroscopic Anterior Talofibular Ligament Repair With a High-Position Anchor Versus Anatomic Repair: An Analysis Based on 3D CT’’ by Lee et al. Previous biomechanical and clinical studies suggested that anatomic repair of anterior talofibular ligament (ATFL) was extremely important to restore ankle stability and obtain a good prognosis, especially under arthroscopy. This study provides a clinical evidence of the necessity of anatomic repair by comparing the clinical outcomes of anatomic and nonanatomic repair of ATFL arthroscopically in patients with chronic ankle instability (CAI). After investigating 80 patients with CAI in this cohort study, Lee et al concluded that nonanatomic ATFL repair showed inferior clinical outcomes compared with anatomic repair. We appreciated the efforts of Lee et al, but we would like to address some concerns regarding the methods and results of the study. First, as shown in Table 1, there were a total of 16 patients (20.0%) with os subfibulare in this study. Ahn and Lee measured 42 patients with CAI with os subfibulare using radiographs and concluded that the mean diameter of the ossicle was 8.8 mm. These ossicles may originate from chronic avulsion fractures of the ATFL from the fibular attachment. In the study of Lee et al, the center of ATFL origin was located 3.7 mm (range, 0-6.7 mm) proximal to the fibular obscure tubercle (FOT), which was shorter than the ossicle size reported by Ahn and Lee. FOT morphology could be damaged and hard to identify arthroscopically or on 3dimensional computed tomography (3D-CT) due to the avulsion fracture. Given these, and also with our clinical experience, we believe that not all FOTs can be distinguished accurately, just like Figure 4B in this article, in which the FOT was not clear. The presence of an os subfibulare in 16 patients might interfere with the anchor position arthroscopically and the measured results on 3D-CT. Therefore, we wanted to know if the 4-quarters measurement holds in all 80 patients? Second, Lee et al defined the retear as when a discontinuity or a focal high signal intensity change of the ATFL occurred on 3 or 4 slices on magnetic resonance imaging (MRI). We all know that a certain percentage of patients with chronic lateral ankle ligament injuries will have ankle resprain after surgery, which is a major concern for clinicians. However, in this study, MRI at final follow-up may underestimate the resprain rate because the injured ligaments in patients with mild resprain may be not obvious or may have been healed by the time of final follow-up MRI. We really want to know if there were different resprain rates during the follow-up period between groups. Third, as presented in the limitations, some of the patients in this study might have had a ruptured calcaneofibular ligament (CFL). Some studies have shown that repairing the ATFL alone has good clinical outcomes. Nonetheless, clinicians are practically concerned about the combined CFL injury, which may be the reason for inferior clinical outcomes in the nonanatomic group. The number of injured CFL between groups and P value should have been presented in Table 1, as should the number of os subfibulare and osteochondral lesion of talus.