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MRI KNEE
WHAT TO SEE
Dr. SHEKHAR SRIVASTAV
Sr.Consultant – KNEE & SHOULDER
ARTHROSCOPY
MRI KNEE - WHAT TO SEE
MRI is the most accurate and frequently used
diagnostic tool for evaluation of internal
derangement of knee.
MRI examination of knee consists of spin echo
sequences obtained in sagittal, coronal and usually
axial plane.
Sagittal cuts
most important
SAGITTAL CUTS
Cruciates
Meniscus
Cartilage
Extensor
mechanism
CORONAL CUTS
Collaterals
Meniscus
Cartilage
AXIAL CUTS
PATELLO-FEMORAL PROBLEMS
MRI Knee
Meniscus
ACL
PCL
Collateral
ligaments
Patello femoral
Chondral defects
Misc.
Meniscus
Normal anatomy
The normal meniscus shows uniform, low signal
intensity (Black)
Peripherally the meniscus have a bow- tie configuration
Centrally, the normal meniscus is composed of 2
separate triangular structures, the anterior horn and
the posterior horn. The apices (free edges or inner
margins) appear as sharp points of the triangle facing
each other.
MRI grading system for
Meniscal Degeneration
GRADE 1 & 2 , NOT
SIGNIFICANT
GRADE 3 , SIGNIFICANT
MENISCUS TEAR
Types of Meniscal Tear
Three basic meniscal tear
Longitudinal
Radial
Horizontal
Longitudinal Tears
Longitudinal tears separate the
meniscus into inner and outer
fragments and occur parallel to
the outer margin of the
meniscus are perpendicular to
the tibial plateau and
propagate parallel to the
circumferential axis of the
meniscus
Radial tears ( Transverse
Tears)
These are vertical tear
and propagate
perpendicular to the main
axis of the meniscus
Horizontal tear
These tears are also called
cleavage or fish- mouth tears
They divide the meniscal tear
into a top ( superior) portion and
a bottom ( inferior) portion
Most are degenerative,
occurring in older patients with
osteoarthritis.
Bucket- Handle Tears
These tears are displaced
vertical longitudinal tears and
usually involve the MM .
The separated central (
inner)
fragment,
when
viewed axially, resembles the
handle of a bucket The
remaining larger peripheral
portion of the meniscus
resembles the bucket.
Typical locations of the
displaced fragment include
the
intercondylar
notch
anterior and parallel to the
PCL ( double PCL sign)
MRI criteria for
meniscal tears
Two MRI criteria
established
for
meniscal tears.
have been
diagnosing
Criteria 1
Criteria 1 is increased internal
signal intensity in the meniscus
The abnormal signal intensity must
be in contact with one articular
surface, either the superior or
interior surface or at the tip ( free
edge) of the meniscus
Criteria 2
Criterion 2 is an abnormal meniscal
shape
ACL
The normal ACL appears on
sagittal images as a solid band
or as a striated band diverging
slightly, ruler straight although
mild sagging convex inferiorly
can be present, especially with
mild knee flexion.
The ACL shows low- to
intermediate signal intensity ,
higher than that of the PCL.
ACL Tear
– Primary Signs
– Secondary Signs
Primary signs of the ACL tear
Disruption, increased signal intensity in the substance of the
ACL on T2 weighted images, abrupt angulation or wavy
appearance and abnormal ACL axis.
Nonvisualization or near nonvisualization with replacement
be a cloud of focal edema and hemorrahage.
Secondary Signs of ACL Tear
Pivot - shift bone bruises and
osteochondral fracture
Anterior translocation of the tibia
Segond fracture
Anterior tibial spine fractures
Buckling of PCL
Secondary Signs of ACL Tear
Pivot- Shift Bone Bruises Anterior Translocation
of the Tibia
and Fractures
Secondary Signs of ACL Tear
Avulsion fracture
of the tibia at
ACL insertion
Buckling
PCL
Segond
Fracture
PCL
Major stabilizer of knee
Restrain against post.
displacement
Isolated –3%
Combined –97%
–
–
–
–
ACL injury - 65%
MCL – 50%
Medial Meniscus – 30%
Posterior capsule and fibular
collateral ligament
MRI Finding
Intrasubstantial
tear
Partial tear
Complete tear
Avulsions
Collateral Ligaments
Coronal images with anatomy defining and
fluid-sensitive sequences demonstrate the
medial and lateral supporting structures
optimally. Additional useful information can be
gleaned from sagittal and axial images of
these structures
Chondral Defects
Degenerative
cartilage defects
Osteochondritis
dissecans
Chondromalacia
patellae
Osteochondritis Dissecans
Chondromalacia Patellae
Miscellaneous
Meniscal cysts
Ganglion cyst
Discoid meniscus
Infections
PVNS
Extensor mechanism tear
– Quadriceps tendon tear
– Patellar tendon tear
– Tibial tuberosity avulsion
Meniscal Cysts
Ganglion Cysts
Discoid Meniscus
INFECTION
Tubercular
Hypointense Synovial
proliferation
Marrow Edema
Osteomyelitis
Abcess
Cortical erosion
Sinuses
PVNS
Low signal changes
Synovial proliferation
Hemosiderin
deposition
Extensor Mechanism Tear
Quadriceps
Tendon Tear
Patellar
Tendon Tear
Tibial
Tuberosity
Avulsion
MRI – Very useful tool in hands of
Radiologists & Orthopedicians
Orthopedicians probably in a
better position than Radiolologist
to read MRI
Visit
www.delhiarthroscopy.com
Thank You
MCL Tear
Grade I  Microscopic tear
Grade II  Partial tear
Grade III  Complete tear
LCL
LCL tear is seen as a
serpiginous or lax ligament
with discontinuous fibers (or
avulsed fibular head), often
without
significant
thickening of the ligament.
LCL tears rarely are
isolated, and an LCL tear
becomes more likely as
associated
PLC
and
cruciate ligament injuries
increase in severity
Studies reported
in diagnostic arthroscopy 
51% (With use of MRI)
MRI accuracy in Meniscus & ACL Pathology > 90%
Difference in radiologist & arthroscopist opinion in
meniscal injury because
Different radiologist are at different level of the
learning curve and different arthroscopist have
different level of experience
Partial ACL Tear
Partial tears of the ACL
are common, accounting
for 10-43% of all ACL
tears
Direct signs may include
focal angulation of the
ACL or partial – thickness
focal high signal intensity.
T2- weighted images
allow more confident
identification of abnormal
focal high signal intensity
in the ACL substance (
stoller, 1997).
MRI grading system for
Meniscal Degeneration
Grade I
Grade I is a nonarticular ,
focal or diffuse region of
increased signal intensity
within the substance of the
meniscus .
Grade 2
Grade 2 is a horizontal , linear
area of increased signal
intensity within the substance
of the meniscus that extends
to but does not involve the
articular surface.
.
Patients are usually asymptomatic
Meniscal Degeneration
Grade 3
Is a region of
abnormal signal
intensity within the
meniscus extending to
and communicating
with at least 1 articular
surface of the
meniscus
Clinically Significant