Wk 5, Case 2 - Review

Patient History
16-year -old with medial knee pain and instability following a football injury. Query ACL injury.

Findings
Menisci:

Medial Meniscus: Thin vertical longitudinal tear at the meniscocapsular junction, consistent with a ramp lesion (ramp 1). Slightly prolapsed posterior meniscal root indicative of a “break stop mechanism” injury.

Lateral Meniscus: Delicate undersurface Wrisberg rip tear on several sequential images, from the Wrisberg meniscofemoral attachment extending into the posterior horn. Tear measures approximately 1 cm in length. No displacement.

Ligaments:

Anterior Cruciate Ligament: Complete ACL transection with interposed hemorrhage and debris between the torn fiber fragments.

Posterior Cruciate Ligament: Intact.

Medial Collateral Ligament: Diffuse periligamentous edema along the tibial collateral ligament with partial-thickness tear anteriorly, consistent with intermediate grade injury (grade 2).

Disruption of the anterior aspect of the meniscofemoral ligament.

Lateral Collateral Ligament: Intact.

Posterolateral Corner Structures: Mildly swollen popliteofibular ligament.

Posteromedial Corner Structures: Ramp 1 lesion. Mildly swollen but intact posterior oblique ligament.

Extensor Mechanism:

Patellar Tendon: Intact.

Distal Quadriceps Tendon: Intact.
Medial Patellofemoral Ligament: Intermediate to high-grade tear of the femoral origin of the medial patellofemoral ligament.

Medial and Lateral Patellar Retinacula: Swollen but intact medial patellar retinaculum.

Unremarkable lateral patellar retinaculum.

Hoffa’s Fat Pad: Swollen edematous infrapatellar plica.
Articulations:

Patellofemoral Compartment: No patella alta, Baja, trochlear dysplasia or patellar dysplasia. No patella lateralization/subluxation. No intermediate or high-grade chondromalacia. No traumatic osteochondral injury.

Medial Compartment: Subcortical osteoedema of the medial femoral condyle, likely representing stress related osteoedema associated with the MCL and MPFL injuries.

Lateral Compartment: Pivot-shift pattern of osseous injury with minimally depressed sulcus terminalis and subchondral fracture with osteoedema of the lateral femoral condyle and a posterolateral tibial plateau microtrabecular fracture with osteoedema.
General:

Bones: Pivot-shift pattern of osseous injury as described above. Open growth plates. Incidental wide dysplastic intercondylar notch.

Effusion: Moderate-sized suprapatellar effusion/hemarthrosis.

Baker’s Cyst: None.

Loose Bodies: None.

Soft tissue: Unremarkable. Preserved neurovascular bundle.
Conclusion
Pivot-shift mechanism injury with the following:

1.Complete ACL transection.
2.Ramp lesion posterior horn medial meniscus (ramp 1). Slightly prolapsed posterior horn indicative of a “break stop mechanism” injury.
3.Delicate Wrisberg rip tear, measuring approximately 1 cm in length.
4.Intermediate-grade MCL sprain with partial tear of the anterior fibers. Tear extends to involve the femoral origin of the MPFL. Medial meniscofemoral ligament disruption anteriorly.
5.Pivot-shift pattern of osseous injury with minimally depressed sulcus terminalis and microtrabecular posterolateral tibial plateau fracture. Stress related osteoedema medial femoral condyle, in keeping with valgus moment MCL/MPFL injury.
6.Low-grade sprain posterolateral corner without frank disruption. No evidence for posterolateral corner instability.