0:00

This is a 20-year-old dancer,

0:03

female patient who has a hyperextension injury,

0:08

nine days prior to the MRI.

0:11

You can see the area of bone marrow contusion

0:15

involving the anterior aspect of

0:18

the lateral femoral condyle.

0:20

What matters most here is that the medial meniscus

0:25

has a discoid configuration.

0:27

You can see how the body segment of the meniscus

0:31

is projecting into the joint space,

0:33

interposed completely between the femoral condyle

0:37

and the medial tibial plateau.

0:40

The extension of this body segment is greater than 1.5 cm,

0:45

which is what defines discoid meniscus.

0:49

Now, in the setting of a discoid meniscus,

0:53

we want to see abnormal signal intensity that may

0:57

be just inside the substance of the discoid

1:02

meniscus and may not extend

1:03

to the articular surface.

1:05

And that would be enough to call it a tear.

1:08

So with discoid meniscus,

1:10

there is the exception to the rule,

1:13

that in order to call a meniscal tear,

1:16

we have to see extension to the articular surface.

1:19

In this patient, when we keep scrolling,

1:22

we can see that there is some violation of that

1:25

superior articular surface of this

1:28

discoid meniscus, posteriorly.

1:30

There is an extension to the

1:31

superior articular surface,

1:33

but the key message here is you

1:36

don't need to have that

1:38

if you only have linear signal intensity

1:42

within the substance of the meniscus,

1:44

like seen in this image,

1:46

you can go ahead and call it a meniscal tear.

Wk 1, Case 4 - Review

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0:00

This is a 20-year-old dancer,

0:03

female patient who has a hyperextension injury,

0:08

nine days prior to the MRI.

0:11

You can see the area of bone marrow contusion

0:15

involving the anterior aspect of

0:18

the lateral femoral condyle.

0:20

What matters most here is that the medial meniscus

0:25

has a discoid configuration.

0:27

You can see how the body segment of the meniscus

0:31

is projecting into the joint space,

0:33

interposed completely between the femoral condyle

0:37

and the medial tibial plateau.

0:40

The extension of this body segment is greater than 1.5 cm,

0:45

which is what defines discoid meniscus.

0:49

Now, in the setting of a discoid meniscus,

0:53

we want to see abnormal signal intensity that may

0:57

be just inside the substance of the discoid

1:02

meniscus and may not extend

1:03

to the articular surface.

1:05

And that would be enough to call it a tear.

1:08

So with discoid meniscus,

1:10

there is the exception to the rule,

1:13

that in order to call a meniscal tear,

1:16

we have to see extension to the articular surface.

1:19

In this patient, when we keep scrolling,

1:22

we can see that there is some violation of that

1:25

superior articular surface of this

1:28

discoid meniscus, posteriorly.

1:30

There is an extension to the

1:31

superior articular surface,

1:33

but the key message here is you

1:36

don't need to have that

1:38

if you only have linear signal intensity

1:42

within the substance of the meniscus,

1:44

like seen in this image,

1:46

you can go ahead and call it a meniscal tear.

Report

Patient History

Hyper-extension dance injury 9 days ago. Pain in the popliteal area. Severe pain with straightening.

Findings
Menisci:

Medial Meniscus: Discoid meniscus (Images A-C) with abnormal oblique high signal extending from the body into the posterior horn, extending to part of the superior articular surface (Images D and E). Appearances are consistent with an upper surface (but predominantly closed intrameniscal) flap tear of the discoid meniscus. The tear measures 2-3cm in length from anterior to posterior.

Lateral Meniscus: Intact.

Ligaments: Anterior Cruciate Ligament: Complete full-thickness ACL tear. No passive anterior tibial translation.

Posterior Cruciate Ligament: Intact

Medial Collateral Ligament: Diffuse periligamentous edema surrounding the tibial collateral ligament with swelling and increased intrasubstance signal in the proximal tibial collateral ligament, consistent with an intermediate grade/grade 2 injury. Extension anteriorly into a high-grade tear involving the proximal/central medial patellofemoral ligament as described below.

Lateral Collateral Ligament: Subtle periligamentous edema surrounding the fibular collateral ligament, consistent with low-grade/grade 1 sprain.

Posterolateral Corner Structures: Intact

Posteromedial Corner Structures: Swollen/edematous, but intact, popliteal oblique and oblique popliteal ligaments. Markedly edematous/swollen posterior mensicocapsular junction suggesting a RAMP 1 injury.

Extensor Mechanism:

Patellar Tendon: Intact

Distal Quadriceps Tendon: Intact

Medial Patellofemoral Ligament: High-grade full-thickness tear involving the proximal medial patellofemoral ligament attachment at the adductor tubercle, adjacent to the proximal MCL. The tear extends into the anterior tibial collateral ligament as an intermediate grade injury as described above.

Medial and Lateral Patellar Retinacula: Diffusely edematous lax medial patellar retinaculum. Slightly thickened, tight lateral retinaculum.

Hoffa’s Fat Pad: Mild focal superolateral Hoffa’s fat pad edema.

Articulations:

Patellofemoral compartment: No trochlear or patellar dysplasia.

Medial Compartment: Pivot-shift pattern of osseous injury as described below.

Lateral compartment: Pivot-shift pattern of osseous injury as described below.

General:

Bones: Subchondral microtrabecular fracture with minimally depressed sulcus terminalis and surrounding lateral femoral condyle high-grade osteoedema. Posterolateral tibial microtrabecular contusion. Posteromedial tibial microtrabecular injury/contusion.

Effusion: Moderate-sized hemoserous suprapatellar effusion with reactive synovitis.

Baker’s Cyst: Small partially decompressed Baker’s cyst measuring a 2.8 x 1.8 x 0.5 cm with evidence for partial dehiscence. Small amount of extravasated fluid seen tracking superiorly, anterior to the origin of the medial gastrocnemius, between myofascial planes.

Loose Bodies: None.

Soft Tissues: Unremarkable.

Conclusion
Evidence for recent pivot-shift mechanism injury with the following:

1.ACL transection.
2.Intermediate-grade/grade 2 tibial collateral ligament sprain.
3.Full-thickness high-grade tear involving the proximal attachment of the medial patellofemoral ligament at the adductor tubercle. Tear extends into the adjacent tibial collateral ligament as an intermediate grade injury.
4.Discoid medial meniscus with a predominantly intrameniscal flap tear extending from the body into the posterior horn, with upper articular surface communication.
5.Torn posterior medial meniscocapsular ligaments (RAMP 1 lesion) and swollen posteromedial corner.
6.Pivot-shift pattern of osseous injury with: Minimally depressed sulcus terminalis; microtrabecular injury/contusions of the posterolateral and posteromedial tibia.
7.Low-grade/grade 1 fibular collateral ligament injury.
8.Moderate sized hemarthrosis.

Case Discussion

Faculty

Omer Awan, MD, MPH, CIIP

Associate Professor of Radiology

University of Maryland School of Medicine

Stephen J Pomeranz, MD

Chief Medical Officer, ProScan Imaging. Founder, MRI Online

ProScan Imaging

Jenny T Bencardino, MD

Vice-Chair, Academic Affairs Department of Radiology

Montefiore Radiology

Edward Smitaman, MD

Clinical Associate Professor

University of California San Diego

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Wk 1, Case 4 - Review