Presentation
Fall with knee injury 4 days prior.
Patient Data
Large joint effusion. Extensive posterior knee soft tissue edema.
High signal of the body and posterior horn medial meniscus not reaching the articular surface; posteromedial meniscocapsular edema including medial posterior meniscotibial ligaments. Undisplaced vertical tear of the posterior horn lateral meniscus involving the insertion of the meniscofemoral ligament (Wrisberg rip).
Anterior cruciate ligament is completely ruptured. Posterior cruciate ligament is intact.
Medial collateral ligament is intact. Partial tear medial oblique ligament. High signal of the posterior oblique ligament. Lateral collateral ligament complex is intact. Partial tear of the popliteus tendon insertion. Remainder of the posterolateral corner appears uninjured.
Osteochondral impaction fractures at the sulcus terminalis and peripheral weight-bearing medial femoral condyle.
Case Discussion
Typical findings of an anterior cruciate ligament rupture. Vertical tear of the posterior horn lateral meniscus in a Wrisberg rip morphology, which is highly associated with anterior cruciate ligament ruptures. These can sometimes appear as a "Wrisberg pseudotear" where a cleft is seen where the meniscofemoral ligament of Wrisberg inserts onto the posterior horn lateral meniscus, these tend to be more medial and as a rule thumb do not extend to the level of the fibular head. In the setting of the anterior cruciate ligament rupture, the posteromedial meniscocapsular edema is suspicious for an occult meniscal tear and/or ramp lesion.