DOI:10.2214/AJR.07.3811
AJR 2008; 191:1002-1009
© American Roentgen Ray Society
MRI of Acute Meniscal Injury Associated with Tibial Plateau Fractures: Prevalence, Type, and Location
Antti O. T. Mustonen1,
Mika P. Koivikko1,
Jan Lindahl2 and
Seppo K. Koskinen1
1 Department of Radiology, Helsinki Medical Imaging Center, Helsinki University
Central Hospital, Toolo Trauma Center, Topeliuksenkatu 5, FIN–00029,
Helsinki, Finland.
2 Department of Orthopedics and Traumatology, Helsinki University Central
Hospital, Toolo Trauma Center, Helsinki, Finland.
Received February 10, 2008;
accepted after revision April 11, 2008.
Address correspondence to A. O. T. Mustonen
(antti.mustonen{at}helsinki.fi).
Abstract
OBJECTIVE. The purpose of this study was to evaluate the prevalence,
type, and location of meniscal injuries, particularly to assess the prevalence
of unstable meniscal tears in acute knee trauma with tibial plateau
fractures.
MATERIALS AND METHODS. A total of 78 menisci were evaluated in 39
patients who had undergone knee MDCT and MRI. Meniscal tears were classified
as horizontal, vertical (subdivided into longitudinal and radial), flap,
bucket-handle, or complex. The presence of meniscal contusion was documented.
The anterior horn, body, and posterior horn were assessed separately for both
menisci. Knee arthroscopy was performed on 28 patients.
RESULTS. Of the 39 patients in the study, 24 had detectable abnormal
menisci, for a total of 33 abnormal menisci (42%). Among the 33 meniscal
abnormalities were 11 longitudinal tears (33%), 17 contusions (52%), four flap
tears (12%), six horizontal tears (18%), and six radial tears (18%). Among the
16 patients with meniscal tears (41% of the 39), 14 patients had an unstable
tear. No significant correlation was found between degree of articular
depression and site or morphologic features of the meniscal injury.
Correspondingly, no statistical correlation was evident between normal menisci
and degree of articular depression, nor was a significant correlation found
between differing fracture groups and meniscal findings.
CONCLUSION. A high percentage of patients (36%) with a tibial
plateau fracture had an unstable meniscal tear. If a meniscal tear is detected
preoperatively, meniscal surgery can be combined with fracture fixation, and
reoperation can be avoided. A large number of meniscal contusions were found.
Awareness of this abnormality can help radiologists increase specificity by
avoiding false-positive findings of meniscal tear.
Keywords: arthroscopy • knee • MDCT • meniscal tear • MRI • tibial plateau fracture
Introduction
Tibial plateau fractures are a complex group of injuries that often
manifest with severe ligamentous or meniscal injury challenging to the
orthopedic surgeon [1,
2]. Previous studies
[1–6]
have shown a high number of meniscal tears in cases of tibial plateau
fractures. Because meniscal injuries can lead to posttraumatic arthrosis and
decreased knee function [7,
8], it is important that
meniscal tears be accurately repaired or débrided to maintain knee
joint stability and congruency and to minimize articular contact pressure
[7–9].
Meniscal stability is an important concept in the differentiation of
symptomatic and asymptomatic meniscal tears. Unstable tears are associated
with pain, which is an important criterion for many orthopedic surgeons
considering meniscal treatment
[10].
In addition to radiography and CT, MRI has become an increasingly popular
imaging technique for surgical planning
[2,
6,
8,
11]. To our knowledge,
however, detailed MRI analysis of meniscal injury, such as prevalence of
unstable meniscal tears and exact location of a tear, in acute knee trauma
with tibial plateau fractures is lacking. The purpose of this retrospective
study was to evaluate the prevalence, type, and location of meniscal injury,
particularly to assess the prevalence of unstable meniscal tears that would
justify routine use of MRI in the evaluation of acute knee trauma involving
tibial plateau fractures.
Materials and Methods
This retrospective study was conducted at a hospital that serves almost 1.5
million people and is the leading level 1 trauma center in its country. The
study was approved by the hospital ethics committee.
Patient Selection
Using the hospital PACS, we retrieved all emergency department MDCT
requests regarding knee trauma from January 2001 to the end of August 2007
(718 patients). Indications for MDCT were ruling out a fracture or assessing
the morphologic features of a fracture. MDCT in the acute phase (within 1 week
of injury; mean, within 24 hours) showed 554 patients had acute knee injury
and tibial plateau fracture. When clinically indicated, preoperative MRI was
performed on all patients with suspected soft-tissue injuries. A total of 46
patients underwent MRI within 3 weeks (mean, 3 days) of injury. Patient charts
allowed verification of clinical history, and patients who had previously
undergone knee surgery were excluded (three patients). To reduce the number of
menisci with possible degenerative changes, patients with any sign of
osteoarthritis also were excluded (four patients). This exclusion would help
to differentiate meniscal findings due to contusion from those due to
degeneration. Absence of osteoarthritis was determined from MDCT and MR
images.
The final study group comprised 39 patients (21 men, 18 women; mean age, 37
years; range, 17–76 years) and 78 menisci. Only the injured knee was
studied. The injury mechanisms were traffic accident in 19 cases, simple fall
in nine cases, sports injury in six cases, and twisting injury in five cases.
Arthroscopy was considered the reference standard in the cases of 28 patients.
Eight of the 28 had normal MRI findings, and arthroscopy was performed with
clinical indications. MRI was considered the reference standard in the cases
of 11 patients. These patients had neither MRI findings of abnormal menisci
nor clinical symptoms of meniscal tear, so arthroscopy was deemed ethically
unacceptable.
Image Analysis
The images were evaluated on clinical PACS workstations (Impax DS3000,
version 4.5, Agfa-Gevaert) by two radiologists with 2 and 8 years of
subspecialty experience in musculoskeletal radiology. Aware of the
preoperative clinical history, they reviewed MDCT and MR images and reached a
consensus while blinded to initial interpretations and surgical findings.
MDCT Protocol
All patients underwent knee MDCT with a 4-MDCT scanner (LightSpeed QX/i, GE
Health-care). The routine protocol was collimation, 4 x 1.25 mm;
interval, 0.62 mm; gantry rotation time, 1.0 second; pitch 3; table feed, 3.75
mm; 120 kV; 150 mA; approximate total exposure time, 10–15 seconds. MDCT
acquisition ranged from the upper pole of the patella to caudal to the fibular
head. Routine multiplanar reconstructions were made in standard sagittal and
coronal planes with a slice thickness of 2.0 mm and reconstruction increment
of 2.0 mm.
MRI Protocol
The MR images were obtained with a 1.5-T unit (Signa MRI Echospeed, GE
Healthcare) with a dedicated transmit–receive quadrature lower extremity
coil. The standard clinical sequences were coronal T2-weighted fast spin-echo
with fat saturation, sagittal proton-density spin-echo, sagittal T2-weighted
fast spin echo, and axial proton-density fast spin-echo with fat saturation
(Table 1).
Arthroscopy Protocol
Arthroscopy was performed in the acute phase of injury by three orthopedic
surgeons specialized in trauma surgery and knee arthroscopy with more than 10
years of experience each. All but one patient with MRI findings of tear
underwent arthroscopy. The exception was patient 24
(Table 2), who had a radial
tear in the posterior horn of the medial meniscus
(Fig. 1). The knee was stable,
and the nondisplaced B2 fracture was managed conservatively. In this case,
repairing the menisci and arthroscopy were deemed unnecessary.
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Fig. 1 —76-year-old man with MDCT findings of B2 tibial plateau
fracture after simple fall. Coronal T2-weighted fat-suppressed MR image
(TR/TE, 4,740/40) shows radial tear (arrow) in posterior horn of
medial meniscus. Findings were not verified with arthroscopy.
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Classification of Tibial Plateau Fractures
Tibial plateau fractures were assessed according to the Arbeitsgemeinschaft
für Osteosynthesefragen (AO)-Orthopaedic Trauma Association
classification [12]. All
fractures were classified type B or C and group 1, 2, or 3 (Fig.
2A,
2B,
2C,
2D,
2E,
2F,
2G). The fractures were not
further divided into subgroups because that practice is not routinely used at
our institution. Avulsion fractures of the anterior or posterior cruciate
ligament (A1.3) (Fig. 2A,
2B,
2C,
2D,
2E,
2F,
2G) from its tibial insertion
were included when the tibial plateau also was fractured (e.g., B2 + A1.3
fractures) (Fig. 3A,
3B). The maximal depression of
the tibial articular surface was measured.
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Fig. 2A —Arbeitsgemeinschaft für
Osteosynthesefragen–Orthopaedic Trauma Association classification of
tibial plateau fractures. A1.3 fractures were included in study if they
existed with type B or C fractures. Drawing shows avulsion fracture (A1.3) of
anterior or posterior eminence.
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Fig. 2B —Arbeitsgemeinschaft für
Osteosynthesefragen–Orthopaedic Trauma Association classification of
tibial plateau fractures. A1.3 fractures were included in study if they
existed with type B or C fractures. Drawings show type B fractures (not
specific to medial or lateral plateau) involve one condyle. Type B1 (B)
is pure slit fracture, B2 (C) is pure depression fracture, and B3
(D) is split–depression fracture.
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Fig. 2C —Arbeitsgemeinschaft für
Osteosynthesefragen–Orthopaedic Trauma Association classification of
tibial plateau fractures. A1.3 fractures were included in study if they
existed with type B or C fractures. Drawings show type B fractures (not
specific to medial or lateral plateau) involve one condyle. Type B1 (B)
is pure slit fracture, B2 (C) is pure depression fracture, and B3
(D) is split–depression fracture.
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Fig. 2D —Arbeitsgemeinschaft für
Osteosynthesefragen–Orthopaedic Trauma Association classification of
tibial plateau fractures. A1.3 fractures were included in study if they
existed with type B or C fractures. Drawings show type B fractures (not
specific to medial or lateral plateau) involve one condyle. Type B1 (B)
is pure slit fracture, B2 (C) is pure depression fracture, and B3
(D) is split–depression fracture.
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Fig. 2E —Arbeitsgemeinschaft für
Osteosynthesefragen–Orthopaedic Trauma Association classification of
tibial plateau fractures. A1.3 fractures were included in study if they
existed with type B or C fractures. Drawings show type C fractures involve
both condyles. Type C1 (E) is metaphyseal simple fracture, C2
(F) is metaphyseal multifragment fracture, and C3 (G) is
multifragment fracture.
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Fig. 2F —Arbeitsgemeinschaft für
Osteosynthesefragen–Orthopaedic Trauma Association classification of
tibial plateau fractures. A1.3 fractures were included in study if they
existed with type B or C fractures. Drawings show type C fractures involve
both condyles. Type C1 (E) is metaphyseal simple fracture, C2
(F) is metaphyseal multifragment fracture, and C3 (G) is
multifragment fracture.
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Fig. 2G —Arbeitsgemeinschaft für
Osteosynthesefragen–Orthopaedic Trauma Association classification of
tibial plateau fractures. A1.3 fractures were included in study if they
existed with type B or C fractures. Drawings show type C fractures involve
both condyles. Type C1 (E) is metaphyseal simple fracture, C2
(F) is metaphyseal multifragment fracture, and C3 (G) is
multifragment fracture.
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Fig. 3A —28-year-old man with MDCT findings of B2 and A1.3 tibial
plateau fractures after traffic accident. Findings were verified with
arthroscopy. Coronal T2-weighted fat-suppressed MR image (TR/TE, 3,800/40)
shows fracture line (arrows).
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Fig. 3B —28-year-old man with MDCT findings of B2 and A1.3 tibial
plateau fractures after traffic accident. Findings were verified with
arthroscopy. Sagittal proton density MR image (1,700/20) shows longitudinal
tear (arrow) in posterior horn of medial meniscus.
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Classification of Meniscal Injury at MRI
The menisci were assessed as normal or torn. Tears were classified as
horizontal (Fig. 4A,
4B), vertical (subdivided into
longitudinal [Fig. 3A,
3B] and radial), flap (Fig.
5A,
5B,
5C), bucket-handle (Fig.
6A,
6B,
6C), or complex
[7]. A complex tear consisted
of two or more tear configurations (Fig.
5A,
5B,
5C). The presence of any
meniscal contusion [13] was
documented. The anterior horn, body, and posterior horn were assessed
separately for both menisci. Possible meniscocapsular separation was
documented.
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Fig. 4A —33-year-old man with MDCT findings of B2 tibial plateau
fracture after traffic accident. Findings were verified with arthroscopy.
Coronal T2-weighted fat-suppressed (TR/TE, 4,740/40) (A) and sagittal
proton-density (1,800/20) (B) MR images show horizontal tear
(arrow) in posterior horn of medial meniscus. Bone marrow edema is
present in proximal tibia (arrowheads, A).
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Fig. 4B —33-year-old man with MDCT findings of B2 tibial plateau
fracture after traffic accident. Findings were verified with arthroscopy.
Coronal T2-weighted fat-suppressed (TR/TE, 4,740/40) (A) and sagittal
proton-density (1,800/20) (B) MR images show horizontal tear
(arrow) in posterior horn of medial meniscus. Bone marrow edema is
present in proximal tibia (arrowheads, A).
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Fig. 5A —40-year-old woman after simple fall. Findings were verified
with arthroscopy. Coronal MDCT image shows B2 tibial plateau fracture of
lateral condyle with 3-mm articular depression (arrows).
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Fig. 5B —40-year-old woman after simple fall. Findings were verified
with arthroscopy. Coronal T2-weighted fat-suppressed MR image (TR/TE,
3,800/40) shows complex (longitudinal and flap) tear (arrows) in
posterior horn of lateral meniscus. No isolated flap tear is visible. Bone
marrow edema is present in proximal tibia (arrowheads).
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Fig. 5C —40-year-old woman after simple fall. Findings were verified
with arthroscopy. Sagittal proton-density MR image (1,800/20) shows part of
meniscus (white arrow) is flipped behind and below posterior horn.
Articular depression (black arrow) is visible.
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Fig. 6B —32-year-old man after traffic accident. Findings were
verified with arthroscopy. Coronal T2-weighted fat-suppressed (TR/TE,
4,200/40) (B) and T1-weighted (500/22) (C) MR images show
bucket-handle tear. Part of torn meniscus body is flipped medially
(arrow). Rest of body is in normal position (arrowhead).
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Fig. 6C —32-year-old man after traffic accident. Findings were
verified with arthroscopy. Coronal T2-weighted fat-suppressed (TR/TE,
4,200/40) (B) and T1-weighted (500/22) (C) MR images show
bucket-handle tear. Part of torn meniscus body is flipped medially
(arrow). Rest of body is in normal position (arrowhead).
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MRI Criteria
A meniscus was considered torn when an area of increased internal signal
intensity was in unequivocal contact with a meniscal articular surface on one
or more images. Meniscal contusion (Fig.
7A,
7B) was defined as an area of
increased internal signal intensity in the meniscus in contact with the
articular surface but less discrete and less well defined than the signal
intensity associated with a tear or with intrasubstance degeneration
[13]. Except for discoid and
buckled (flounce) menisci, menisci with abnormal morphologic features (e.g.,
radial tears) were considered torn
[7]. Horizontal tears were
considered stable, and longitudinal, radial, flap, and complex tears unstable
[10].
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Fig. 7B —17-year-old woman after simple fall. Findings were verified
with arthroscopy. Sagittal proton-density MR image (TR/TE, 1,800/20) shows
contusion (arrow) in posterior horn of lateral meniscus as area of
increased signal intensity. Asterisk indicates proximal fibula.
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Ligamentous Injuries
Anterior cruciate ligament, posterior cruciate ligament, medial collateral
ligament, and lateral collateral ligament injuries were documented at MRI.
Management of ligamentous injuries was verified from patient charts.
Classification of Meniscal Injury at Arthroscopy
The surgeons at our institution divide menisci into three parts (anterior
horn, body, and posterior horn) and classify meniscal tears as longitudinal,
flap, radial, horizontal, root, or bucket handle.
Data Analysis
In cases with arthroscopic verification, values determined were
sensitivity, specificity, accuracy, positive predictive value, and negative
predictive value of MRI in the detection of meniscal tear.
Statistical Analysis
The appropriate procedures in the SPSS program (version 15.0, SPSS) were
used for the statistical computation. Correlation of articular depression and
meniscal findings between different groups (normal menisci, meniscal
contusions, and torn menisci) was analyzed with one-way analysis of variance
(Tukey test). Correlation of articular depression and meniscal findings
between normal menisci and abnormal menisci (tear or contusion) was analyzed
with the Mann-Whitney U test (nonparametric data). The statistical
significance level was set at p < 0.05.
Results
MDCT Findings
The distribution of tibial plateau fractures on MDCT according to the
AO–Orthopaedic Trauma Association classification is shown in
Table 3. All types of tibial
plateau fractures except C1 were visible. The average articular depression of
the tibial plateau was 3.2 mm (range, 0–25 mm).
MRI Findings
Of the 78 menisci studied, 33 abnormal menisci (42%) (17 medial, 16
lateral) were detected in 24 patients
(Table 2). Sixteen the 39
patients (41%) had a meniscal tear, 14 of them having an unstable tear. An
unstable tear was evident in 10 medial (25%) and seven lateral (18%) menisci.
A stable tear was found in seven medial (18%) and 10 lateral (25%) menisci.
Complex tears occurred in nine menisci (12%) and bucket-handle tears in two
(3%), but neither isolated flap tears nor meniscal root injuries were found.
The distribution of tears and contusions in different meniscal parts is shown
in Table 4.
Arthroscopic Findings
Arthroscopy was performed on the knees of 28 patients (72%), and 56 menisci
were assessed. That group comprised 20 patients with a tear detected on MRI;
eight patients with normal MRI findings had symptoms. In the B1, B2, and B3
fracture groups, a total of 12 meniscal tears with arthroscopic verification
were detectable. Six of those 12 tears were at the site of the fracture, four
were ipsilateral, and in two cases both menisci were torn. Two meniscocapsular
separations, also evident on MRI, were sutured.
MRI Correlation with Arthroscopy
A total of two false-negative findings (a small radial tear and a small
isolated flap tear in the posterior horn of the medial meniscus, which were
slightly trimmed at arthroscopy) and four false-positive interpretations
(three posterior horn of the medial meniscus and one posterior horn of the
lateral meniscus) were made. In these cases, the menisci were intact, and no
degenerative changes were evident at arthroscopy. For meniscal tear, the
diagnostic values of MRI were sensitivity, 88%; specificity, 90%; accuracy,
89%; positive predictive value, 78%; and negative predictive value, 95%.
Ligamentous Injuries
A total of 19 anterior cruciate ligament, 12 posterior cruciate ligament,
13 medial collateral ligament, and eight lateral collateral ligament injuries
were detected. Of those injuries, 15 anterior cruciate ligament, nine
posterior cruciate ligament, two medial collateral ligament, and three lateral
collateral ligament were managed surgically.
Statistical Findings
No significant correlation emerged between site and morphologic features of
meniscal injury and degree of articular depression. Correspondingly, no
significant correlation was apparent between normal meniscus and degree of
articular depression, nor was there a significant association between fracture
group and meniscal findings.
Discussion
Acute knee injury with tibial plateau fracture is commonly encountered in
emergency departments. Radiography and MDCT have been widely used for
preoperative evaluation of these injuries
[14,
15], but high-energy tibial
plateau fractures are often associated with severe soft-tissue injury and
meniscal tears [2,
3,
5,
6,
8,
11]. Adequate physical
examination of the knee in the acute phase of injury is demanding, and
clinical detection of meniscal injury is particularly challenging or even
impossible because of pain and swelling
[6,
9]. MRI is painless, and the
presence of possible joint effusion does not interfere with its accuracy in
the detection of meniscal injury
[16,
17]. MRI has therefore become
an increasingly popular imaging technique before surgery
[2,
3,
5,
6,
8,
11]. The association between
meniscal tears and tibial plateau fractures has been well documented
[1–6,
9,
11]. In an arthroscopic study,
Vangsness et al. [4] found
meniscal injury necessitating surgery in 47% of knees with tibial plateau
fractures. To our knowledge, however, no MRI studies with a more detailed
analysis of meniscal injury (such as prevalence of unstable meniscal tears and
exact location of tears) in the setting of acute knee trauma with tibial
plateau fracture have been conducted.
In clinical practice, debate has arisen regarding symptomatic and
asymptomatic meniscal tears, pain being thought to relate to meniscal
stability [10]. Pain has been
an important criterion for many orthopedic surgeons considering meniscal
treatment [10]. At palpation
with a probe at arthroscopy, meniscal tears can been classified as stable or
unstable [18,
19]. A functional study
[10] showed that longitudinal,
radial, and complex meniscal tears are usually unstable but that horizontal
tears are stable. Unstable tears are associated with a considerable amount of
pain. We found a large percentage of unstable tears in both menisci: 25% of
medial menisci and 18% of lateral menisci.
The term meniscal contusion was adopted in 2001 by Cothran et al.
[13]. In our study, we found a
large number of meniscal contusions (22 menisci, 28%). However, our study
differed markedly from that of Cothran et al. Our patient population had
tibial plateau fractures with a notable average articular depression of more
than 3 mm. These lesions can be considered high-energy fractures, whereas the
knees evaluated by Cothran et al. had bone contusions only, no tibial plateau
fractures. We can hypothesize that the trauma energy in our cases was greater,
which may explain the large number of contusions. Shearing and compressive
forces by the femoral condyles against the tibial plateau are involved in
tibial plateau fractures [5],
so the menisci may undergo concurrent compressive injury, eventually leading
not to frank tear but to meniscal contusion.
Barrow et al. [11] found a
number of menisci with increased intrameniscal signal intensity thought to
represent intrameniscal injury. As was ours, that study was conducted with
patients with tibial plateau fractures. The definitive cause of the abnormal
intrameniscal signal intensity remains unknown. Results of animal experiments
have suggested fibrovascular scarring, but to our knowledge, this finding has
not been made in humans [13].
In the study by Cothran et al.
[13], follow-up imaging showed
the abnormal signal intensity had disappeared in two patients, no change was
visible in one patient, and the abnormal signal intensity had decreased
slightly in one patient. The authors' view was that it seemed that a transient
injury had occurred that did not have long-term effects on the meniscus.
Vangsness et al. [4], in an
arthroscopic study, found no correlation between fracture pattern and meniscal
injury. We also found no significant difference between degree of articular
depression and meniscal findings. Although the small number of patients in our
study might have influenced this finding, it can be hypothesized that even
nondisplaced tibial plateau fractures can be associated with severe meniscal
injuries and that clearly displaced tibial plateau fractures can have normal
menisci. Meniscal tears were most often seen in our patients with split-type
fractures (B1), indicating the harmful effect of axial load with shearing
force combined, eventually leading to meniscal tear. In contrast, most
contusions in our study occurred in patients with type B2 fractures
(Table 1), in which the
articular depression (axial compressive force) is the characteristic finding.
Despite the high-energy fractures, somewhat surprisingly, neither MRI nor
arthroscopy depicted meniscal root injuries. When designing the study, we had
assumed that we would detect such injuries. A large number of ligamentous
injuries, most of which necessitated surgery, were evident in our study. This
finding is also in agreement with previous findings
[3,
5,
6,
11].
The lack of arthroscopic or surgical verification of meniscal tears in 11
patients with normal MRI findings might have been a limitation of this study,
but a fact well documented [7,
16,
17,
20,
21] is that MRI can depict
meniscal tears with excellent sensitivity, specificity, and accuracy. The
results of our study also confirmed this finding. Reicher et al.
[17] found that the presence
of joint effusion, commonly associated with tibial plateau fractures, does not
affect accurate MRI detection of meniscal lesions. Thus the high negative
predictive value in our study strongly suggests that the 11 patients had
true-negative findings, and those patients were included in the study.
Clinical tests revealed no signs of meniscal tear. Arthroscopy after normal
findings at MRI and without symptoms would be ethically unacceptable.
In nine menisci, contusion was an isolated finding, and at arthroscopy, the
menisci were intact. We can thus hypothesize that if it is an isolated
finding, contusion should be managed conservatively. However, lack of
follow-up MRI represents a limitation of this hypothesis, and the natural
behavior of this increased contusion signal intensity in the menisci over a
long period remains unknown. Further studies with follow-up MRI are
necessary.
The two false-negative interpretations (a small radial tear and a small
flap tear in the posterior horn of the medial meniscus at arthroscopy) were
invisible even at repeated retrospective evaluation. In four false-positive
findings (three posterior horns of the medial meniscus and one posterior horn
of the lateral meniscus), the menisci also had abnormal signal intensity at
repeated retrospective evaluation, and meniscal contusion may explain the
findings. At arthroscopy, menisci were intact with no degenerative changes
evident.
Degenerative changes in the menisci (tear or intrasubstance degeneration)
are known to be strongly associated with osteoarthritis
[22]. The results of our
study, in which the patients had a mean age of 37 years and no signs of
osteoarthritis at MDCT or MRI, strongly suggest that increased signal
intensity in the menisci would be due to contusion. Thus in our study group,
degenerative changes in the menisci instead of contusion would be unlikely.
The arthroscopic findings supported this hypothesis.
A high percentage of patients (33%) with tibial plateau fractures had an
unstable meniscal tear. Pain and poor outcome have been related to unstable
tears, usually necessitating surgical intervention. If a meniscal tear is
detected preoperatively, meniscal surgery (arthroscopic or open) can be
combined with fracture fixation, avoiding another operation. Moreover, because
a large number of meniscal contusions were found, awareness of this
abnormality may help radiologists increase specificity by avoiding the
false-positive finding of meniscal tear. We therefore suggest that knee MRI be
considered a complementary study after MDCT in the care of patients who have
sustained high-energy tibial plateau fractures.
References
- Gardner MJ, Yacoubian S, Geller D, et al. The incidence of soft
tissue injury in operative tibial plateau fractures: a magnetic resonance
imaging analysis of 103 patients. J Orthop Trauma2005; 19:79
–84[CrossRef][Medline]
- Yacoubian SV, Nevins RT, Sallis JG, Potter HG, Lorich DG. Impact of
MRI on treatment plan and fracture classification of tibial plateau fractures.
J Orthop Trauma 2002;16
: 632–637[CrossRef][Medline]
- Brophy DP, O'Malley M, Lui D, Denison B, Eustace S. MR imaging of
tibial plateau fractures. Clin Radiol1996; 51:873
–878[CrossRef][Medline]
- Vangsness CT Jr, Ghaderi B, Hohl M, Moore TM. Arthroscopy of
meniscal injuries with tibial plateau fractures. J Bone Joint Surg
Br 1994; 76:488
–490[Medline]
- Colletti P, Greenberg H, Terk MR. MR findings in patients with
acute tibial plateau fractures. Comput Med Imaging
Graph 1996; 20:389
–394[CrossRef][Medline]
- Kode L, Lieberman JM, Motta AO, Wilber JH, Vasen A, Yagan R.
Evaluation of tibial plateau fractures: efficacy of MR imaging compared with
CT. AJR 1994; 163:141
–147[Abstract/Free Full Text]
- Fox MG. MR imaging of the meniscus: review, current trends, and
clinical implications. Magn Reson Imaging Clin N Am2007; 15:103
–123[CrossRef][Medline]
- Weigel DP, Marsh JL. High-energy fractures of the tibial plateau:
knee function after longer follow-up. J Bone Joint Surg
Am 2002; 84A:1541
–1551[Abstract/Free Full Text]
- Shepherd L, Abdollahi K, Lee J, Vangsness CT Jr. The prevalence of
soft tissue injuries in nonoperative tibial plateau fractures as determined by
magnetic resonance imaging. J Orthop Trauma2002; 16:628
–631[CrossRef][Medline]
- Boxheimer L, Lutz AM, Zanetti M, et al. Characteristics of
displaceable and nondisplaceable meniscal tears at kinematic MR imaging of the
knee. Radiology 2006;238
: 221–231[Abstract/Free Full Text]
- Barrow BA, Fajman WA, Parker LM, Albert MJ, Drvaric DM, Hudson TM.
Tibial plateau fractures: evaluation with MR imaging.
RadioGraphics 1994;14
: 553–559[Abstract]
- Muller ME, Nazarian S, Koch P, Schatzker J. The
comprehensive classification of fractures of long bones. New
York: Springer, 1990
- Cothran RL Jr, Major NM, Helms CA, Higgins LD. MR imaging of
meniscal contusion in the knee. AJR 2001;177
:1189
–1192[Abstract/Free Full Text]
- Mustonen AO, Koivikko MP, Haapamaki VV, Kiuru MJ, Lamminen AE,
Koskinen SK. Multi-detector computed tomography in acute knee injuries:
assessment of cruciate ligaments with magnetic resonance imaging correlation.
Acta Radiol 2007;48
: 104–111[CrossRef][Medline]
- Mustonen AO, Koskinen SK, Kiuru MJ. Acute knee trauma: analysis of
multidetector computed tomography findings and comparison with conventional
radiography. Acta Radiol 2005;46
: 866–874[CrossRef][Medline]
- Crues JV 3rd, Mink J, Levy TL, Lotysch M, Stoller DW. Meniscal
tears of the knee: accuracy of MR imaging. Radiology1987; 164:445
–448[Abstract/Free Full Text]
- Reicher MA, Hartzman S, Duckwiler GR, Bassett LW, Anderson LJ, Gold
RH. Meniscal injuries: detection using MR imaging.
Radiology 1986;159
: 753–757[Abstract/Free Full Text]
- Dandy DJ. The arthroscopic anatomy of symptomatic meniscal lesions.
J Bone Joint Surg Br 1990;72
: 628–633[Medline]
- Newman AP, Daniels AU, Burks RT. Principles and decision making in
meniscal surgery. Arthros-copy 1993;9
: 33–51[Medline]
- Schafer FK, Schafer PJ, Brossmann J, et al. Value of fat-suppressed
proton-density-weighted turbo spin-echo sequences in detecting meniscal
lesions: comparison with arthroscopy. Acta Radiol2006; 47:385
–390[CrossRef][Medline]
- Zanetti M, Pfirrmann CW, Schmid MR, Romero J, Seifert B, Hodler J.
Patients with suspected meniscal tears: prevalence of abnormalities seen on
MRI of 100 symptomatic and 100 contralateral asymptomatic knees.
AJR 2003; 181:635
–641[Abstract/Free Full Text]
- Link TM, Steinbach LS, Ghosh S, et al. Osteoarthritis: MR imaging
findings in different stages of disease and correlation with clinical
findings. Radiology 2003;226
: 373–381[Abstract/Free Full Text]
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Abstract
Introduction
