A motorcyclist sustains a dashboard injury with a posteriorly directed force on the proximal tibia of a flexed knee. On examination the normal anterior prominence of the tibial tuberosity relative to the femoral condyles is lost, and with the hip flexed and unsupported the tibia visibly sags backwards (Godfrey test). The ligament most likely ruptured is:

• A Posterior cruciate ligament ✓
• B Anterior cruciate ligament
• C Popliteus tendon
• D Lateral collateral ligament

Explanation

The posterior cruciate ligament is the strongest knee ligament and is typically torn by a posteriorly directed force on the flexed knee, classically striking the dashboard. Loss of the normal anterior tibial step-off, posterior sag of the tibia (Godfrey test) and a positive posterior drawer are its hallmarks. An ACL tear produces anterior rather than posterior translation and follows a pivoting deceleration mechanism with rapid haemarthrosis, which does not fit this history.

Reference: Apley's System of Orthopaedics and Fractures, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.