ACL tear

70% of patients with acute traumatic hemarthrosis have ACL tear

Plain film findings:

• Segond fracture: bony fragments lateral to tibia on AP; avulsion of lateral capsular attachment
• Intraarticular bony fragments from avlusion of femoral or tibial ACL attachments on AP
• Deep sulcus (lateral condylar sulcus) sign greater than 1.5 cm on lateral

MRI findings

• “pseudomass” = high intensity of ACL on all sequences
• “uncovered lateral meniscus sign” = posteriorly displaced lateral meniscus
• “empty notch sign”
• “kissing contusions” = bony contusion of posterolateral tibia and anterolateral femur

MyPACS.net link