Segond fracture is an avulsion fracture of the knee which involves the lateral aspect of the tibial plateau, and is very frequently associated with disruption of the anterior cruciate ligament.
Clinical presentation: Segond fracture typically occurs as a result of internal rotation and varus stress. Typically these injuries are seen in two settings: falls and sports: especially skiing, basketball and baseball.
Pathology: Originally thought to be a result of avulsion of the medial third of the lateral collateral ligament, the Segond fracture has been shown by more recent research to relate also to the insertion of the iliotibial tract (ITT) and the anterior oblique band (AOB), a ligamentous attachment of the fibular collateral ligament (FCL), to the midportion of the lateral tibia.
Plain film: 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 which is best seen on the straight anteroposterior view of the knee.
MRI: 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 include:
- ACL tear
- medial or lateral meniscal tear
- avulsion of ACL from tibial attachment: rare
- avulsion of fibular attachment of long head of biceps femoris
- avulsion of the fibular collateral ligament