A Segond fracture is an avulsion fracture of the knee which involves the lateral aspect of the tibial plateau, and is very frequently (~75% of cases) associated with disruption of the anterior cruciate ligament (see ACL tear).
Contrary to the more common causes of an ACL tear, which typically involve a valgus stress 3, a Segond fracture typically occurs as a result of internal rotation and varus stress 1,4. Typically these injuries are seen in two settings:
- sports : especially skiing, basketball and baseball 4
Somewhat surprisingly, the exact cause of a Segond fracture continues to be contentious. The conventional teaching has been that it is the result of avulsion of the middle third of the lateral capsular ligaments. Other candidate structures include the iliotibial band and anterior oblique band of the fibular collateral ligament 3.
The classical appearance of a Segond fracture is that of a curvilinear or elliptic bone fragment projected parallel to the lateral aspect of the tibial plateau. This has been referred to as the lateral capsular sign 1 which is best seen on the straight anteroposterior view of the knee.
MRI is essential in all cases of Segond fractures to identify internal derangement. Disruption of the ACL is most common, however there are additional frequently encountered injuries. Associated injuries include1,3:
- ACL tear
- most common associated injury
- 75-100% of cases 6
- medial or lateral meniscal tear
- 66-75% of cases 6
- posterior horn most common
- avulsion of ACL from tibial attachment : rare
- avulsion of fibular attachment of long head of biceps femoris
- avulsion of the fibular collateral ligament
Treatment and prognosis
Although the fracture itself is small, the extensive ligamentous injury associated with it usually requires surgical intervention, to correct anterior rotational instability 4. Healing of the Segond fracture is associated with a characteristic bone excrescence arising below the lateral tibial plateau.
First described by Paul Ferdinand Segond : French surgeon (1851 - 1912) based on cadaveric experiments 1-2,4.
Imaging differential considerations include
- arcuate sign : avulsion fracture of the head of the fibula 5 : fragment oriented more horizontally
- 1. Gottsegen CJ, Eyer BA, White EA et-al. Avulsion fractures of the knee: imaging findings and clinical significance. Radiographics. 2008;28 (6): 1755-70. doi:10.1148/rg.286085503 - Pubmed citation
- 2. Paul Ferdinand Segond from whonamedit.com, the dictionary of medical eponyms. Paul Ferdinand Segond
- 3. 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. doi:10.1016/j.rcl.2007.08.007 - Pubmed citation
- 4. 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): 1163-7. AJR Am J Roentgenol (abstract) - Pubmed citation
- 5. 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. AJR Am J Roentgenol. 2003;180 (2): 381-7. AJR Am J Roentgenol (full text) - Pubmed citation
- 6. Campos JC, Chung CB, Lektrakul N et-al. Pathogenesis of the Segond fracture: anatomic and MR imaging evidence of an iliotibial tract or anterior oblique band avulsion. Radiology. 2001;219 (2): 381-6. Radiology (full text) - Pubmed citation
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