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SplintER Series: A Case of Knee Pain

Posted by Alex Wertheimer, MD on

A 45-year-old male presents with right knee pain after he pivoted and felt a “pop” while making a move playing pickup basketball. You obtain knee x-rays and see a lateral irregularity in the AP view (photo courtesy of Dr. Gerry Gardner at Radiopaedia.org).

What is the most likely diagnosis, commonly associated injury, and appropriate management plan?

1. What is your diagnosis?

This is an avulsion fracture of the lateral tibial plateau, also known as a Segond Fracture.

2. What injuries are associated with this radiological finding?

This fracture is pathognomonic for an ACL injury (75-100% association). Contrary to popular belief, it is not an avulsion of the ACL insertion. There is additionally an association with a meniscal tear (66-75%).1

3. What fracture can this be confused with?

Radiographically, a Segond fracture can be confused with an avulsion fracture at the head of the fibula (arcuate sign). However, a fibular head fracture is typically oriented more horizontally.2

4. What is the mechanism of injury?

Segond fractures are often associated with internal rotation and varus stress. This is in opposition to a typical ACL injury caused by valgus stress.3

5. What causes this radiographic finding?

The exact cause of a Segond fracture is unknown. It is thought to occur from an avulsion of the lateral capsular ligaments, iliotibial (IT) band, or fibular collateral ligament.4

6. Which exams should you perform?

  • Assess the ACL, PCL, MCL, and LCL.
    • If more than 1 ligament is unstable, consider the possibility of knee dislocation-relocation.
  • Assess the meniscus
  • Read more on performing the knee physical exam.

7. What is your management in the ED?

Nonsteroidal anti-inflammatories (NSAIDs) for pain relief and crutches if non-ambulatory. Hinged knee brace (not a knee immobilizer) is preferred for stability and non-impact range of motion (ROM) exercises should be encouraged. If a hinged knee brace is not available and multi-ligamentous injury is very unlikely, crutches and a soft neoprene sleeve are recommended.

8. What is the disposition?

Weight bear as tolerated with crutches and follow up with an Orthopedics or Sports Medicine clinic in the next 1-2 weeks for imaging and definitive management after swelling improves. The patient will likely require surgery given the avulsion fracture indicates additional lateral instability beyond an ACL tear.

For more cases like these, you can subscribe to the Ortho EM Pearls email series hosted by Drs. Will Denq, Tabitha Ford, and Megan French, who have kindly shared some of their content with ALiEM.

References:

  1. Goldman AB, Pavlov H, Rubenstein D. The Segond fracture of the proximal tibia: a small avulsion that reflects major ligamentous damage. AJR Am J Roentgenol. 1988;151(6):1163-1167. PMID: 3263770
  2. Huang GS, Yu JS, Munshi M et-al. Avulsion fracture of the head of the fibula (the “arcuate” sign): MR imaging findings predictive of injuries to the posterolateral ligaments and posterior cruciate ligament. Am J Roentgenol. 2003;180(2):381-387. PMID: 12540438
  3. Gottsegen CJ, Eyer BA, White EA et al. Avulsion fractures of the knee: Imaging findings and clinical significance. Radiographics. 2008;28(6):1755-1770. PMID: 18936034
  4. Roberts CC, Towers JD, Spangehl MJ et-al. Advanced MR imaging of the cruciate ligaments. Radiol. Clin. North Am. 2007;45(6):1003-16, vi-vii. PMID: 17981180

Author information

Alex Wertheimer, MD

Department of Emergency Medicine
State University of New York at Buffalo

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