MRI Evaluation of Anterior Cruciate Ligament Tears with Arthroscopic Correlation.

Abstract

Anterior Cruciate Ligament Injury Is The Most Commonly Injured Of The Major Knee Ligaments. Injuries Occur Frequently In Both Athletes And Nonathletes. In United States The Prevalence Of ACL Injury Is About 1 In 3000, And Approximately 2,50,000 Injuries Occur Every Year. Prompt Assessment Of Full Extent Of Ligamentous Damage Is Essential For Appropriate Management. Because Of Its Intraarticular Location, The ACL Has Poor Healing Potential. The Ruptured ACL Does Not Form A Bridging Scar After Complete Disruption. The Prognosis For A Partially Torn ACL May Be Favorable, If The Synovial Envelope Remains Intact. Without Treatment Complete ACL Injury Can Result In Progressively Increasing Symptomatic Knee Instability And Osteoarthritis. Meniscus Injury Occurs In Association With 50% Of Acute ACL Tears, And It Increases To 90% In Chronic ACL Deficient Knees. The Incidence Of Articular Cartilage Lesions Increases From 30% In Acute ACL Injuries To Approximately 70% Of Knees With Chronic ACL Instability. The Fundamental Rationale For Diagnosing And Treating ACL Injury Is To Prevent Future Meniscal Tears And Associated Joint Damage. For Treating ACL Injury The Orthopaedician Or Arthroscopist Needs The Answer To Following Questions: 1. Whether ACL Is Normal Or Abnormal? If ACL Is Normal, Invasive Arthroscopy Can Be Avoided In Patients With Suspected ACL Injury. 2. If Abnormal, Whether The Tear Is Complete Or Partial? If Partial Conservative Management Or Repair Can Be Done. However In Complete Tears Reconstruction Needs To Be Done In Most Of Cases. 3. What Is The Status Of Associated Structures Such As PCL, Menisci, MCL, LCL, Posterolateral, Posteromedial Plateau In ACL Injured Patients? Because An Injury To Above Structures Along With Complete Tear Of ACL Needs Early Reconstruction Of ACL. ACL Injury Can Be Diagnosed In Majority Of Patients By History And Clinical Examination. The Clinical Diagnosis Is Fraught With Difficulty In Acute Cases And In Large Patients. Also Partial Tears Are Difficult To Diagnose And The Associated Injuries Could Not Be Completely Evaluated By Clinical Examination. Arthroscopy And Arthrotomy Are The Criterion Standards For Definitive Diagnosis But Are Invasive And Costly. It Can Get Unnecessary If ACL Turns Out To Be Normal. Spiral CT Arthrography Is More Invasive Than Conventional MR Imaging. It Uses Ionizing Radiation And Is Subject To The Potential Complications Inherent In Intraarticular Injection Of Iodinated Contrast Material. The Continuing Need For A Better Non Invasive Imaging Modality For ACL Injury Led To The Use Of MRI As A Diagnostic And Pre- Operative Evaluation Modality. MRI Is A Recently Devised Modality For Evaluation Of ACL And Knee Joint. Imaging Is Done In Sagittal, Axial And Coronal Planes Using T1, T2 And STIR Sequences Using Quadrature Knee Coil. The Following Study Involves Detailed Evaluation ACL Injury And Its Associated Injuries Using MRI And Comparing With Arthroscopic Results. MR Primary And Secondary Signs Of ACL Tear Are Also Analysed And Their Usefulness Assessed In Comparison With Arthroscopic Findings.