1️⃣Partial ACL tears
- The ACL consists of two primary bundles: the anteromedial bundle (AMB) and the posterolateral bundle (PLB). These bundles have different susceptibilities to injury based on the position and movement of the knee at the time of injury.
- Anteromedial Bundle (AMB) Injuries: The AMB is more prone to injury when the knee is flexed. Tears of the AMB are more common and can occur in isolation or alongside damage to the PLB.
- Posterolateral Bundle (PLB) Injuries: The PLB is at higher risk during knee hyperextension and internal rotation incidents. Injuries to the PLB can occur independently or with concomitant damage to the AMB.
2️⃣The patterns of Partial ACL tears
- Complete tear of the AMB with either a normal or a partially torn PLB. This is the most frequent injury pattern.
- Complete tear of the PLB with either a normal or a partially torn AMB.
- Both bundles' Partial tears indicate damage to both the AMB and PLB but without complete severance.
3️⃣ACL bell-hammer tear (preoperative cyclops syndrome)
- The ACL bell-hammer tear, or preoperative cyclops syndrome, is a rare ligament injury of the ACL's distal stump, where a retracted bell hammer may be trapped between the femur and tibia.
- MRI findings reveal the bell-hammer sign in 13.8% of partial tears (all in the AM bundle) and 1.6% of complete tears, indicating a significantly higher occurrence in partial ruptures
- This emphasizes the need for awareness of this condition, particularly in diagnosing partial ACL tears.
Knee Surg Sports Traumatol Arthrosc. 2014 May;22(5):1112-8
"Visualizing MSK Radiology: A Practical Guide to Radiology Mastery"
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#VisualizingMSK #ACLinjuries #KneeMRI #ACLtear #ACLpartialtear You may not distribute or commercially exploit the content. Nor may you transmit it or store it on any other website or other forms of the electronic retrieval system.
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Nor may you transmit it or store it on any other website or other forms of the electronic retrieval system.
© 2022 MSK MRI Jee Eun Lee All Rights Reserved.
#VisualizingMSK #ACLinjuries #KneeMRI #ACLtear #ACLpartialtear You may not distribute or commercially exploit the content. Nor may you transmit it or store it on any other website or other forms of the electronic retrieval system.
You may not distribute or commercially exploit the content.
Nor may you transmit it or store it on any other website or other forms of the electronic retrieval system.
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