Corpus3D

Knee

Posterior sag sign

Godfrey-test

What you examine
Posterior cruciate injury, visible without applying force.
Procedure
Supine, both hips and knees flexed to 90 degrees with the lower legs supported. Look from the side at the contour of the tibial tuberosity, comparing left and right.
Positive when
On the affected side the tibia visibly drops posteriorly relative to the femoral condyles.
What the test is worth
High specificity, lower sensitivity: a visible sag confirms the injury, but its absence does not rule it out.
Caution
Always do this test before the drawer tests. It costs nothing and it prevents you from misjudging the neutral position.
Joint
Knee joint
Body region
Knee

Structures involved