Utilizando o "Notch Sign" para diagnóstico das lesões do ligamento cruzado anterior

Abstract

BACKGROUND: The evaluation of the knee joint, in relation to ligament injuries, can be divided into three parts: clinical history, physical examination and imaging tests. Magnetic resonance imaging, due to its high sensitivity and specificity in the diagnosis of intra-articular pathologies, has been the preferred imaging exam among surgeons, however its high cost and limited availability make it necessary to look for other resources in complementary exams. Therefore, the radiographic notch sign measured on simple lateral radiographs of the knee appears as a great tool in the diagnosis of anterior cruciate ligament (ACL) injuries due to its easy availability and low cost. OBJECTIVES: This study aimed to analyze the effectiveness of the notch sign as a predictor for ACL injuries. METHOD: A prospective, observational study - accuracy study, was carried out at the Knee Surgery Service of Fundação Hospital Adriano Jorge in patients who suffered some torsional trauma to the knee and were diagnosed with knee instability or meniscal injury. The lateral radiography of the patients' knees was evaluated, trying to find and measure the femoral notch sign. RESULTS: Of the total number of patients seen in the study, 30 had a notch sign test >1.5mm and were ACL deficient, which produced an accuracy of 34% and a specificity of 100%. Of these, 86.7% (26/30) are male and have an average age of 30.5, ranging from 19 to 52 years. The largest number of injuries occurred in the right knees (56.7% - 17/30) and the main accident mechanism was sports (86.7% - 26/30), the majority of which were football players (69.2% - 18/26). Regarding the diagnosis, the majority of patients had an association between the ACL injury and the medial meniscus and lateral meniscus (30.0% - 9/30), followed by those with an association only with the medial meniscus (26.7% - 8/30). CONCLUSION: The notch sign tool is useful and very specific for diagnosing anterior cruciate ligament injuries; its presence on lateral radiography is, although infrequent, pathognomonic.