UMEM Educational Pearls

Title: Rotational Injury to the Knee

Category: Orthopedics

Posted: 2/28/2026 by Brian Corwell, MD
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Rotational Injury to the Knee

The plain film shows a small, crescent shaped bone fragment adjacent to the lateral tibial plateau.

This fracture is called a Segond fracture

It represents a bony avulsion of the anterolateral ligament (ALL) NOT the ACL

However, this fracture pattern is associated with a tear of the ACL tear 75-100% of the time.

Also associated with meniscal injuries (65-75%)

The ALL runs from the lateral femoral condyle and inserts on the anterolateral proximal tibia near the fibular head

The ALL helps to control tibia internal rotation

Works in concert with the ACL to prevent anterior rotational tibia subluxation

This injury pattern on plain film indicates a significant ligament injury and changes management because ACL reconstruction is often required.