The Value Of Preoperative MRI In The Selection Of Surgical Methods For Chronic Ankle Instability

Background:Ankle sprain is one of the most common lower limb sports injuries.In most cases,early conservative treatment for ankle sprain is effective,but about 20% ~ 40% of patients will progress to chronic ankle instability after conservative treatment.The stability of the ankle joint is mainly maintained by the complex of the medial and lateral collateral ligaments of the ankle joint.The medial collateral ligaments are stronger,wider and less prone to injury than the lateral collateral ligaments.The lateral collateral ligament is often injured due to excessive stretching when the plantar flexion and inversion of the ankle joint occurs.The lateral collateral ligament of the ankle joint is composed of the anterior talofibular ligament,the calefibular ligament and the posterior talofibular ligament,among which the anterior talofibular ligament injury is the most common.For patients with lateral ankle instability who failed to respond to conservative treatment for 3 to 6 months,surgical intervention should be adopted.Currently,surgical methods for chronic lateral ankle instability mainly include anatomical repair,anatomical reconstruction and non-anatomical reconstruction.Represented by brostrom-Gould modified repair,anatomic repair was performed on the ligament stump directly and the broken end was shortened and sutured,so as to achieve the purpose of in-situ repair of the lateral ligament complex.This operation was simple,with relatively few postoperative complications,and was suitable for patients with good ligament quality.Patients with poor quality of ligament stump,systemic ligament laxity and failure of initial operation have poor efficacy.Ligament reconstruction is divided into anatomic ligament reconstruction and non anatomic ligament reconstruction.Anatomic ligament reconstruction is applicable to the lateral collateral ligament rupture and be absorbed,or poor quality ligaments do not apply to the original repair methods of the patients,by grafting fixation in original to get close to normal anatomic ligament attachment points of the ankle and subtalar joint stability.Non-anatomical ligament reconstruction may accelerate the degeneration and osteophyte formation of the ankle joint because it changes the biomechanical mechanism of the ankle joint,leading to osteoarthritis and secondary instability of the ankle joint,affecting the long-term efficacy,and therefore should be avoided as a first-line treatment.At present,the selection of surgical methods mainly depends on the experience of surgeons,and there is still no clear selection criteria,especially imaging criteria,for the selection of surgical methods before surgery.Objective: The results of intraoperative and preoperative MRI evaluation of anterior talofibular ligament quality were compared.We analyzed the efficacy of MRI in the diagnosis of chronic ankle instability and discussed the significance of MRI diagnostic results for ATFL surgical selection.Methods:A total of 43 patients who were treated with CAI in our hospital from September 2018 to November 2020 were included in this study.Before surgery,thickness measurement,morphological continuity and signal strength analysis of ATFL were performed on cross-sectional images by 2 specialists twice a week at an interval.The characteristic changes of ATFL injuries were classified as(1)ligament separation,deformation but normal thickness or thickening,and(2)ligament loss or thinning,using intraoperative arthroscopic and open ligament quality assessment as reference criteria(performed by a senior sports medicine physician).Kappa test was used to evaluate inter-observer and intra-observer consistency,and the sensitivity,specificity,accuracy,positive prediction rate and negative prediction rate of MRI diagnosis of CAI were analyzed.Results:Forty-three patients were included,including 39 males and 4 females,with an average age of 30.3±5.6 years.Finally,38 patients underwent anatomy and repair of lateral ligament complex(LLC),and 5 patients underwent anatomy and reconstruction with LLC.The 2 observers had high intragroup consistency(Kappa values were 0.765 and 0.662,respectively)and high inter-group consistency(Kappa values were 0.859,0.771,0.651 and 0.772,respectively)after two times of tablet reading.MRI and intraoperative diagnostic results were also highly consistent(Kappa values were 0.807,0.688 and 0.774,respectively).Compared with intraoperative MRI,the average accuracy of ATFL injury diagnosis was 94.33%,the average sensitivity 94.73%,the average specificity 99.13%,the average positive prediction rate 99.13%,and the average negative prediction rate 71.3%.Conclusion:MRI is accurate and reliable in the preoperative diagnosis of ATFL and can be used as an important basis for the selection of surgical methods for CAI patients.