Wk 5, Case 4 - Review

Patient History
38-year-old man with left knee pain after an MVA in 2019. Suspect MCL tear and/or hemarthrosis.

Findings
Menisci:

Medial Meniscus: Intact.

Lateral Meniscus: Intact.

Ligaments:

Anterior Cruciate Ligament: Complete midsubstance anterior cruciate ligament tear/transection, with associated anterior tibial translation consistent with with ACL deficiency.

Posterior Cruciate Ligament: Increased intrasubstance signal with swelling of the distal PCL, consistent with a low-grade intrasubstance sprain.

Medial Collateral Ligament: Intact.

Lateral Collateral Ligament: Intact.

Posterolateral Corner Structures: Intact.

Posteromedial Corner Structures: Complete insertional semimembranosus tendon rupture, with approximately 4 cm of tendon retraction. Posterior oblique and oblique popliteal ligaments are torn. Posteromedial capsule torn. Marked posterior meniscocapsular swelling. A partially imaged, partial-thickness intrasubstance and deep surface tear is noted within the distal semitendinosis tendon.

Extensor Mechanism:

Patellar Tendon: Intact.

Distal Quadriceps Tendon: Intact.

Medial Patellofemoral Ligament: Intact.

Medial and Lateral Patellar Retinacula: Intact.

Hoffa’s Fat Pad: Infrapatellar plica swelling. Otherwise unremarkable.

Articulations:

Patellofemoral Compartment: Acute traumatic full-thickness medial femoral trochlear osteochondral fracture, extending to the cortical plate, measuring approximately 1.0 x 1.5 cm, with unstable full-thickness flap-type chondral delamination, and underlying microtrabecular fracture with osteoedema.

Medial Compartment: Unremarkable.

Lateral Compartment: Unremarkable.

General:

Bones: Posteromedial and posterolateral tibial condyle microtrabecular fractures with moderate grade anterior medial tibial condylar osseous contusion. Acute traumatic medial trochlear osteochondral fracture as described above.

Effusion: Large knee joint effusion/hemarthrosis with reactive synovitis within the suprapatellar recess.

Baker’s Cyst: Extensive fluid is seen tracking between myofascial planes of the medial gastrocnemius and distal semimembranosus muscles and superficial to the medial gastrocnemius muscle belly, consistent with gastrocnemius semimembranosus bursal dehiscence/rupture (Baker’s cyst rupture).

Loose Bodies: None
.
Soft tissue and neurovascular: Popliteal neurovascular structures unremarkable.

Conclusion
1. Complete midsubstance anterior cruciate ligament transection.
2. Low-grade distal posterior cruciate ligament sprain.
3. Posterior medial and posterior lateral tibial condylar microtrabecular fractures, with anterior medial tibial condylar rim bone contusions. Suspect hyperextension translation insult.
4. Acute, traumatic, full-thickness, medial femoral trochlear osteochondral fracture, extending to cortical plate, measuring approximately 1 x 1.5cm, with unstable full-thickness chondral delamination flap and underlying microtrabecular fracture. No intra-articular loose body.
5. High-grade posteromedial corner injury including: complete insertional semimembranosus tendon rupture, with approximately 4cm of tendon retraction, posterior oblique and oblique popliteal ligamentous tears, and meniscocapsular swelling.
6. Partially imaged, partial-thickness, deep surface semitendinosus tendon tear.
7. Dehisced gastrocnemius/semimembranosus bursal cyst.