Which test is used to identify posterior cruciate ligament deficiency by observing tibial sag?

• A. Sag sign (Godfrey’s test)
• B. Anterior Drawer
• C. Lachman’s test
• D. McMurray’s test

Answer: (A)

Observing tibial sag under gravity is a direct way to reveal PCL deficiency. The Sag sign, known as Godfrey’s test, uses the knee flexed to about 90 degrees with the patient lying on their back; gravity pulls the tibia posteriorly if the PCL is torn, so the affected leg sags relative to the other. This makes the test specifically suited to detecting posterior cruciate ligament laxity.

The other tests target different structures. Anterior Drawer and Lachman’s test stress the knee to reveal ACL laxity by causing forward translation of the tibia, not backward sag. McMurray’s test assesses meniscal pathology through flexion and rotation with a click or pain, not PCL integrity.