(Fig 3-A.28) Anteromedial Rotatory Instability

https://youtu.be/P6KD4DuidKU

https://youtu.be/GSIg93UH3Oc

 

✅ Anatomy of the Posteromedial Corner

• Located between the superficial medial collateral ligament and posterior cruciate ligament
• Consists of 5 main structures: semimembranosus tendon, oblique popliteal ligament, posterior oblique ligament, posteromedial capsule, posterior horn of medial meniscus

✅ Biomechanical Importance

• Primary stabilizer against valgus laxity
• Secondary stabilizer against anterior tibial translation and external rotation
• Injuries can lead to anteromedial rotatory instability

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📌 The Posterior Oblique Ligament

• Most frequently injured structure of the PMC
• Unlike the MCL, it controls rotational instability and valgus forces in knee extension
• Unrepaired injuries can cause chronic instability, early arthritis, reconstruction failure

✅ Clinical Significance

• PMC injuries, especially of the POL, must be identified
• Failure to treat can compromise ACL/ligament reconstruction outcomes
• Unaddressed, can lead to persistent instability and prevent full recovery

 

Radiographics. 2015 Jul-Aug;35(4):1123-37

Skeletal Radiol. 2022 May;51(5):1063-1071

J Am Acad Orthop Surg. 2017 Nov;25(11):752-761

Semin Musculoskelet Radiol. 2016 Feb;20(1):12-25.

 

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