A passenger in a head-on road traffic accident sustains a dashboard injury with the knee flexed and a posteriorly directed force on the upper tibia. Which structure is most likely ruptured?

• A Anterior cruciate ligament
• B Posterolateral corner capsule
• C Lateral collateral ligament
• D Posterior cruciate ligament ✓

Explanation

With the knee flexed, the posterior cruciate ligament is the main check to posterior translation of the tibia on the femur, so a dashboard blow drives the tibia backwards and tears the PCL. The ACL is taut in extension and resists anterior tibial displacement, which kills that distractor. The classic sign is a positive posterior drawer test with loss of the normal step-off of the tibial plateau anterior to the femoral condyles.

Reference: Bailey and Love's Short Practice of Surgery, 28th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.