Segond Fracture - more than a small bone fragment

HPI
A 43 y.o. male presents after a knee injury while playing basketball. Patient states he stopped suddenly and twisted his right knee as he fell to the ground. He complains of right knee pain and swelling. Denies any other injuries after this fall.

PHYSICAL EXAM
On exam, the patient has significant right knee swelling. His right knee is diffusely tender to palpation. ROM testing is limited by pain, especially during flexion. Anterior drawer test is positive for laxity without a firm end point. Lachmen test is also positive for anterior laxity without a firm end point.

RADIOGRAPH

DIAGNOSIS AND TREATMENT
Based on the physical exam and the above radiograph, the patient was diagnosed with an anterior cruciate ligament (ACL) tear and a Segond fracture.

Patient was treated with a knee immobilizer and crutches for the immediate post-injury period. He was given outpatient referral for possible later surgical intervention.

DISCUSSION
This fracture was first described by Dr. Paul Segond in 1879 after experiments on cadavers.

A Segond fracture is a small bone avulsion from the lateral aspect of the tibia. This fracture is significant because it has a strong association with ACL injuries. Approximately 75% of patients with this fracture pattern with have an ACL injury. The associated exists because the stresses needed to produce this fracture also frequently produce ACL injuries. The exact mechanism of this fracture is unclear. It has been thought to be the result of an avulsion of the middle third of the lateral capsular ligament, however other theories exist. The iliotibial band or anterior oblique band may instead be involved.
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A Segond fracture is a clue to the clinician to perform a thorough ligamentous exam of the knee to search for other injuries. A medial meniscus injury is also commonly seen.


A “reverse” Segond fracture also exists and is a small medial avulsion fracture of the tibia. This mirror fracture is rare, but is associated with injuries to the medial collateral ligament and the posterior cruciate ligament (PCL).

KEY POINTS
Segond fracture = small bone avulsion from lateral aspect of tibia.
ACL injury seen in 75% of these patients.
Perform a thorough ligamentous exam if this fracture pattern is seen.