Evaluation of the Anterior Talofibular Ligament Using MRI after Arthroscopic Lateral Ankle Ligament Repair

CATEGORY: Ankle, Arthroscopy INTRODUCTION/PURPOSE: Ankle sprain commonly occurs in sports activities and most patients are successfully managed with conservative treatment. An incidence of 10–30% of patients will fail conservative treatment and result in chronic lateral ankle instability (CLAI) that may require surgical treatment. Recently, several systematic reviews reported that arthroscopic lateral ankle ligament repair for CLAI are provided good clinical results. However, the pathologic condition of the lateral ankle ligament after anatomical repair has not been clarified. Previous investigations have reported that ligament signal intensity using MRI has a strong negative linear relationship with material biomechanical strength properties. The purpose of this study was to report the clinical outcome and evaluation of the anterior talofibular ligament (ATFL) using MRI after arthroscopic lateral ankle ligament repair. METHODS: We retrospectively reviewed 40 patients (40 ankles) who underwent arthroscopic lateral ankle ligament repair for CLAI. The average age at the time of surgery was 28 years (range 12–66 years). The average follow-up was 13 months (range 12– 18 months). Clinical outcomes were assessed preoperatively and 12 months postoperatively using Japanese Society for Surgery of the Foot (JSSF) ankle-hindfoot scale and Self-Administered Foot Evaluation Questionnaire (SAFE-Q). The ATFL was evaluated using 3.0-T MRI at the preoperatively, six months postoperatively and 12 months postoperatively. The ATFL characteristics classified into the following categories: nonvisualization of the ligament, discontinuity, a wavy or curved contour, or high signal intensity within the ligament. RESULTS: The mean JSSF score increased from 72 preoperatively to 95 at 12 months postoperatively. The preoperative MRI findings of the ATFL were categorized as discontinuity (11 ankles), a wavy or curved contour (14 ankles), or high signal intensity within the ligament (22 ankles). The all ATFL findings at the six months postoperatively had straight band extending from the talus to the fibular malleolus, and nine of 40 ankles had high signal intensity within the ligament. The ATFL findings at the 12 months postoperatively revealed residual high signal intensity within the ligament in six of nine ankles. A comparison of the postoperative ATFL with high signal intensity and with low signal intensity group, there were no significant difference in postoperative clinical outcomes between the groups. CONCLUSION: This study demonstrated that arthroscopic lateral ankle ligament repair was an effective procedure for the treatment of CLAI and restored the condition of ATFL.