Transcript Musculoskeletal Case of the Day

Case of the Day – Thursday
MUSCULOSKELETAL
Davis,
1
KW
and Smith,
2
SE
1. University of Wisconsin Medical School, Madison, Wisconsin
2. Dept. of Diagnostic Imaging, University of Maryland School of Medicine, Baltimore, MD
History: History: 24 y.o. female riding her moped was struck by a
car on her left side.
Figure 1A: AP Left Knee Radiograph
Figure 1B: Close-up AP of Left Knee
Findings: Initial survey of the left knee is unremarkable.
Close-up of the
left knee reveals a thin fracture fragment at the medial margin of the tibial
plateau (Figure 1B, arrow). What is the significance of this?
Diagnosis: Posterior Cruciate Ligament Tear
with “Reverse Segond” Fracture
Discussion: The standard Segond fracture is a thin vertical avulsion fracture from
the peripheral surface of the lateral tibial plateau. It occurs at the insertion of the lateral
capsular ligament, a thickening of the lateral capsule, and its high association with tears of
the anterior cruciate ligament is well known. Lateral meniscal tears are a frequent but
inconstant accompanying injury.
Recent reports have described a similar injury on the other (medial) side of the knee, termed
the “reverse Segond” fracture. As in the current case, impact is typically from the lateral
direction, forcing the knee into valgus and external rotation. Like the four reported cases in
the literature, this patient has a complete rupture of the posterior cruciate ligament (PCL)
(Figure 2 below). This patient has no medial meniscus tear, unlike the reported cases.
While these injuries appear to be uncommon, they should alert physicians to the likelihood
of PCL tears and instability. This injury pattern has been reported with knee dislocations,
so attention to vascular and neurologic status is important.
Figure 2A and B: Sagittal proton density-weighted and spin-echo T2-weighted MR images
demonstrate the PCL tear 13 days after injury.
Figure 2C: Coronal T1-weighted MR image demonstrates rupture of the tibial portion of the
deep MCL with underlying marrow edema. Tiny fracture fragment not clearly
demonstrated.
A
B
C
References:
1. Cohen AP, King D, Gibbon AJ. Impingement Fracture of the Anteromedial Tibial Margin: a Radiographic Sign of
Combined Posterolateral Complex and Posterior Cruciate Ligament Disruption. Skeletal Radiology 2001; 30:114-116.
2. Escobedo EM, Mills WJ, Hunter JC. The “Reverse Segond” Fracture: Association with a Tear of the Posterior Cruciate
Ligament and Medial Meniscus. AJR 2002; 178:979-983.
3. Hall FM, Hochman MG. Medial Segond-Type Fracture: Cortical Avulsion off the Medial Tibial Plateau Associated with
Tears of the Posterior Cruciate Ligament and Medial Meniscus. Skeletal Radiology 1997; 26:553-555