Select a Community
Are you sure you want to trigger topic in your Anconeus AI algorithm?
You are done for today with this topic.
Would you like to start learning session with this topic items scheduled for future?
Anterior cruciate ligament (ACL)
2%
84/4947
Lateral collateral ligament (LCL)
10%
478/4947
Anterior cruciate ligament (ACL) and lateral collateral ligament (LCL)
9%
446/4947
Lateral collateral ligament (LCL) and posterolateral corner (PLC)
77%
3800/4947
Posterior cruciate ligament (PCL) and posterolateral corner (PLC)
106/4947
Select Answer to see Preferred Response
The individual in the above scenario likely has torn his lateral collateral ligament (LCL) and posterolateral corner (PLC). The LCL is part of the posterolateral corner, but can be injured in isolation or along with the rest of the posterolateral corner. An isolated LCL tear would be tested by flexing the knee at 30 degrees and applying varus stress. The posterolateral corner can be tested by the dial test, which is done by externally rotating the affected tibia. A PLC injury shows increased external rotation at 30 degrees, while a combined PLC/PCL injury would show increased external rotation at 30 and 90 degrees. Lubowitz et al review the history and physical examination used in determining ligamentous instability of the knee joint. Ultimately, information must be obtained from multiple tests and imaging to reach the final diagnosis. Chen et al review isolated posterolateral rotatory instability (PLRI)of the knee. Although these injuries are rare, they do result in significant instability in the knee. In the article, they discuss physical exam maneuvers to distinguish PLC vs PCL injuries. They describe that posterolateral subluxation of the lateral tibial plateau only at 30 degrees is indicative of isolated PLC injury vs subluxation at both 30 and 90 degrees is indicative of combined PLRI and PCL injury. Attached is a video showing physical exam maneuvers including the dial test which test the posterolateral corner. Incorrect resonses: 1: Isolated ACL injury would have a positive Lachman's test with increased anterior knee translation at 30 degrees of knee flexion. In the given scenario, Grade 1A indicates less than 5mm of translation and a firm endpoint indicating that the ACL is intact. 2: Isolated LCL injury would have increased laxity to varus force at 30 degrees of knee flexion, but would not have a positive dial test. 3: Would have both ACL and LCL findings as above. 5: Would have increased external rotation of tibia at both 30 and 90 degrees of knee flexion.
3.6
(31)
Please Login to add comment