AJR 2002; 178:979-983
© American Roentgen Ray Society
The "Reverse Segond" Fracture
Association with a Tear of the Posterior Cruciate Ligament and Medial Meniscus
Eva M. Escobedo1,
William J. Mills2 and
John C. Hunter1
1
Department of Radiology, University of Washington Harborview Medical Center,
325 Ninth Ave., Seattle, WA 98104-2499.
2
Department of Orthopaedics, University of Washington Harborview Medical
Center, Seattle, WA 98104-2499.
Received July 10, 2001;
accepted after revision October 1, 2001.
Address correspondence to E. M. Escobedo.
Abstract
OBJECTIVE. We describe three patients who presented with
radiographic findings of a fragment on the medial side of the tibial plateau
of the knee that represented an avulsion of the deep portion of the medial
collateral ligament. These findings were all associated with disruption of the
posterior cruciate ligament and a peripheral medial meniscal tear—the
so-called reverse Segond fracture.
CONCLUSION. Avulsion fracture at the tibial insertion of the deep
component of the medial collateral ligament is a rare finding. When this type
of injury is diagnosed, the radiologist should consider posterior cruciate
ligament injury and peripheral medial meniscal tears as possible associated
findings.
Introduction
The Segond fracture is an avulsion of the lateral capsular ligament, which
manifests as an elliptic bony fragment off the lateral proximal tibia, that
has a high association with tear of the anterior cruciate ligament
[1,2,3].
We describe three cases of a similar fragment on the opposite medial aspect of
the proximal tibia representing an avulsion of the deep capsular component of
the medial collateral ligament. All three patients sustained injury (two
avulsions and one tear) to the posterior cruciate ligament and a peripheral
tear of the medial meniscus. To our knowledge, there has been only one report
in the literature of a cortical avulsion adjacent to the medial tibial
plateau. This injury, termed the "medial" or "reverse
Segond" fracture, was reported to be associated with disruption of the
posterior cruciate ligament and with medial meniscal tear
[4].
Materials and Methods
We retrospectively reviewed the medical records and imaging studies of
three patients in whom a bony avulsion at the medial articular margin of the
tibial plateau on radiographs of the knee was found. Two of these patients
presented to the emergency department within 1 day of each other after
pedestrian-versus-automobile collisions. The third was referred to our
institution's orthopedic surgery clinic from an outside institution 6 months
after being involved in a motor vehicle collision. Two patients were women and
one was a man. The average age of the three patients was 39 years (age range,
29-52 years). All patients underwent radiography, two underwent MR imaging,
and one underwent CT of the knee within 3 days of injury. All underwent
surgery of the knee: two, within 3 days of injury; and one, 6 months after
injury.
Results
A 29-year-old man, a 36-year-old woman, and a 52-year-old woman all
sustained high-energy trauma to the knee. The man was struck by a van while he
was crossing the street. The younger woman was struck by a vehicle while she
was jogging. By report, she sustained a knee dislocation, which spontaneously
reduced before she arrived in the emergency department. The older woman was
ejected from an automobile after a motor vehicle collision, sustaining a knee
dislocation and lateral dislocation of the patella.
Physical examination of both the man and the younger woman revealed
ligamentous laxity, but both examinations were difficult to perform because
both patients were in pain, had swelling, and had other injuries. Examinations
performed with the patient under anesthesia revealed gross medial collateral
and posterior cruciate ligament laxity in both of these patients. The woman
also had anterior cruciate ligament laxity. The 52-year-old woman presented to
the emergency department with a dislocated knee. Her knee dislocation was
reduced at arrival to the emergency department, and external fixation of the
knee was performed to maintain reduction. She presented 6 months after injury
to our institution's orthopedic surgery clinic.
In all three patients, anteroposterior radiographs of the knee showed a
bone fragment at the medial aspect of the tibial plateau just distal to the
articular surface (Figs. 1A,
1B,
2A,
2B, and
3A). A bony fragment adjacent
to the tibial eminence in the knee of the 29-year-old
(Fig. 1A) was also present. For
the 52-year-old woman, who had returned to the clinic 6 months after injury, a
follow-up radiograph of the knee was obtained and showed the medial tibial
avulsion fragment, which appeared well corticated
(Fig. 3C).
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Fig. 1A. —29-year-old man involved in pedestrian-versus-automobile
collision. Anteroposterior (A) and close-up anteroposterior (B)
radiographs of knee show small avulsion fragment (white arrow) off
medial aspect of tibial plateau. Bone fragment adjacent to tibial eminence
represents posterior cruciate ligament avulsion (black arrow).
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Fig. 1B. —29-year-old man involved in pedestrian-versus-automobile
collision. Anteroposterior (A) and close-up anteroposterior (B)
radiographs of knee show small avulsion fragment (white arrow) off
medial aspect of tibial plateau. Bone fragment adjacent to tibial eminence
represents posterior cruciate ligament avulsion (black arrow).
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Fig. 2A. —36-year-old woman involved in pedestrian-versus-automobile
collision. Anteroposterior (A) and close-up of anteroposterior
(B) radiographs of knee shows small avulsion fragment (arrow)
off medial aspect of tibial plateau.
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Fig. 2B. —36-year-old woman involved in pedestrian-versus-automobile
collision. Anteroposterior (A) and close-up of anteroposterior
(B) radiographs of knee shows small avulsion fragment (arrow)
off medial aspect of tibial plateau.
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Fig. 3A. —52-year-old woman involved in high-energy motor vehicle
collision. Anteroposterior intraoperative fluoroscopic spot film of knee shows
small avulsion fragment (arrow) adjacent to medial joint line and
evidence of cortical disruption (arrowhead) of medial tibia.
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Fig. 3C. —52-year-old woman involved in high-energy motor vehicle
collision. Anteroposterior radiograph of knee 6 months after trauma shows
avulsion fragment (white arrow), now well corticated. Black arrow
shows medial tibial bony defect.
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A CT scan was obtained in the 29-year-old patient. This scan showed an
avulsion fragment off the medial rim of the tibial plateau
(Fig. 1C) and bony fragments
off the site of the femoral attachment of the posterior cruciate ligament
(Fig. 1D), one of which
corresponded to the fragment seen adjacent to the tibial eminence on
radiograph of the knee (Fig.
1A). A minimally depressed fracture of the lateral tibial plateau
(not shown) was also found in this patient.
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Fig. 1C. —29-year-old man involved in pedestrian-versus-automobile
collision. Coronal reformation of CT scan shows deep medial collateral
ligament avulsion fragment (white arrow) and resultant cortical
defect (black arrow).
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Fig. 1D. —29-year-old man involved in pedestrian-versus-automobile
collision. Sagittal reformation of CT scan shows avulsion fracture fragments
(black arrows) of proximal attachment of posterior cruciate ligament.
More superior fragment remains attached to posterior cruciate ligament
(white arrows).
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MR imaging of the knee was performed in the other two patients. In the
36-year-old woman, MR images showed severe disruption of the medial collateral
ligament (Fig. 2C). The medial
tibial fragment seen on radiographs was noted retrospectively, as were both a
small adjacent cortical defect and a peripheral tear of the medial meniscus
(Fig. 2C). Avulsion of the
posterior cruciate ligament at the femoral insertion
(Fig. 2D) and avulsion of the
anterior cruciate ligament at the tibial insertion (not shown) were also
noted. Imaging (not shown) also revealed a small focal fracture of the rim of
the lateral tibial plateau. In the 52-year-old woman, MR imaging showed
complete disruption of the superficial and deep medial collateral ligament and
a tear of the posterior cruciate ligament
(Fig. 3B). Evaluation was
otherwise limited because of severe subluxation and rotation of the unstable
knee.
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Fig. 2C. —36-year-old woman involved in pedestrian-versus-automobile
collision. Proton density—weighted fast spin-echo coronal MR image of
knee shows bony avulsion (arrowhead) of deep medial collateral
ligament with cortical defect (small arrow). Large arrow shows
peripheral tear of medial meniscus.
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Fig. 2D. —36-year-old woman involved in pedestrian-versus-automobile
collision. T2-weighted fat-suppressed fast spin-echo sagittal MR image of knee
shows avulsion (arrow) of proximal posterior cruciate ligament.
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Fig. 3B. —52-year-old woman involved in high-energy motor vehicle
collision. Proton density—weighted fast spin-echo sagittal MR image
shows disruption of posterior cruciate ligament. Note coronal position of
tibia that results from significant ligamentous instability. Distal end of
posterior cruciate ligament (long white arrow) is intact, but entire
proximal portion (short white arrows) is disrupted. Disruption
(black arrows) of superficial medial collateral ligament is shown.
Deep medial collateral ligament (arrowhead) is also torn.
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In all three patients, surgery revealed avulsion of the deep medial
collateral ligament from the tibia and either a tear or an avulsion of the
superficial medial collateral ligament; moreover, a peripheral medial meniscal
avulsion from the deep medial collateral ligament was also detected. Healing
of this injury was seen in the patient who had surgery 6 months after injury.
Two patients had an avulsion of the posterior cruciate ligament from its
femoral origin. One had a tear of the midsubstance of the posterior cruciate
ligament. The lateral ligaments were intact in all patients. In addition to
these injuries, the 36-year-old woman had an avulsion of the anterior cruciate
ligament from its tibial insertion.
The 36-year-old woman sustained a concomitant injury to the opposite knee;
at surgery, tears of the anterior cruciate ligament, lateral capsule, lateral
collateral ligament, biceps tendon, and popliteal fibular ligament were found.
These injuries were consistent with a varus and internal rotation
mechanism—presumably opposite that of the right knee.
Discussion
In all three patients, the medial avulsion seen on radiographs corresponded
to an avulsion of the tibial attachment of the deep medial collateral capsular
ligament. Other than in one previous case report by Hall and Hochman
[4], we are not aware of other
reports in the literature describing this finding. Our three patients and the
patient previously reported all had disruption of the posterior cruciate
ligament: two midsubstance tears and two femoral avulsions.
Because of the disruption of the medial collateral ligament, the presumed
mechanism of injury for all three patients is valgus stress, with probable
external rotation. Two of our patients had minimally depressed lateral tibial
plateau fractures. In addition, neither lateral instability on examination nor
lateral capsular injury at surgery was noted in either patient. These findings
further support a valgus mechanism of injury. Although we found no lateral
ligamentous injuries, other concomitant injuries such as the anterior cruciate
ligament tear in one patient are not surprising considering the often
complicated nature of these high-energy injuries.
Two patients (the previously reported case
[4] and one of our cases)
presumably underwent valgus stress in one knee with varus stress in the
opposite knee. This mechanism, producing a tear of the medial capsule (deep
medial collateral ligament) and disruption of the posterior cruciate ligament,
appears to be the opposite mechanism of the Segond fracture—that is,
valgus and external rotation versus varus and internal rotation. In fact, in
these two patients, a Segond fracture of the opposite knee was noted in the
former, and a Segondlike injury of the opposite knee with a tear of the
lateral capsule and anterior cruciate ligament (among other injuries) was seen
in the latter.
Because little about avulsion fractures off the medial tibia has been
mentioned in the literature, we are presuming that this finding is rare. Two
of our cases and the previously reported case
[4] were all a result of motor
vehicle—versus-pedestrian collisions. Two of our patients sustained knee
dislocations. Perhaps this high-speed direct blow involves a unique mechanism
not seen with the more common sports injuries. Even in the absence of the
finding of an associated disruption of the posterior cruciate ligament, this
avulsion injury is an important radiographic finding because it indicates
severe injury to both superficial and deep portions of the medial collateral
ligament.
The three patients we have described were all involved in high-energy
trauma. One presented with a dislocation; one had a reported dislocation; and
one had a grossly unstable knee with multiligamentous instability, or a
"dislocatable" knee. The concept that the dislocatable knee has a
similar clinical significance and complications (i.e., vascular and nerve
injury) as a recognized dislocation was emphasized by Twaddle et al.
[5]. Although we are uncertain
whether the reverse Segond fracture is always associated with a dislocated or
dislocatable knee, we can say that—at least in our limited number of
cases—there was a high association with multiligamentous instability
that may imply dislocation. Therefore, just as the presence of a Segond
fracture on radiography is an indication of significant internal derangement,
the presence of the reverse Segond fracture could be the only indication of an
unrecognized dislocation. Such suspicion should alert both the radiologist and
clinician to a potential dislocation so that appropriate physical examination
and, if needed, vascular imaging can be performed in a timely manner.
The cases presented here as well as the case described by Hall and Hochman
[4] show that a consistent
triad of posterior cruciate ligament, medial collateral ligament, and medial
meniscal injuries is suggested by the radiographic finding of the reverse
Segond fracture. We believe this finding has not only diagnostic significance
but also clinical significance. Physical examination of our patients revealed
gross valgus knee laxity without an appreciable end point, which is consistent
with a grade IV medial collateral ligament tear. At surgery, these findings
were confirmed by the fact that both the deep and superficial layers of the
medial collateral ligament were completely disrupted. Of equal importance was
the essentially complete separation of the medial meniscus from its deep
medial collateral ligament capsular margin. This injury was present in all
three of our patients. Hall and Hochman reported that a medial meniscus tear
was present in their patient, but the exact type of tear was not
mentioned.
Although we routinely address high-energy medial collateral ligament
injuries with grade IV laxity surgically, this treatment is not necessarily a
common practice. Recently other researchers have recommended surgical repair
of the medial collateral ligament injury when it occurs in conjunction with an
anterior cruciate ligament tear
[6]; this recommendation
deviates from the previously accepted treatment of patients with closed
management of the medial collateral ligament and surgical treatment of the
anterior cruciate ligament injury
[7]. Although few reports in
the literature detail the treatment of combined posterior cruciate and medial
collateral ligament injury, many clinicians would likely manage both tears
closed. However, the high-grade nature of the medial collateral ligament
injury and the complete separation of the medial meniscus from the capsule
represented by the reverse Segond fracture suggest that surgical intervention
would be necessary to restore the anatomy of these medial structures. In the
future, we will anticipate this injury triad when a patient with a
valgus-loading injury presents with this unusual radiographic finding.
In conclusion, the radiographic finding of a small bone fragment adjacent
to the medial tibial plateau represents an avulsion of the deep medial
collateral ligament. It is associated with significant injury to the medial
collateral ligament and may be associated with significant internal
derangement, including disruption of the posterior cruciate ligament and a
peripheral medial meniscal tear.
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Abstract
Introduction
