In the management of isolated posterior cruciate ligament (PCL) injuries, the clinical test that most reliably demonstrates posterior tibial sag in a PCL-deficient knee is:
- A Pivot shift test
- B Posterior sag sign (Godfrey's gravity test) at 90° hip and knee flexion ✓
- C Posterior drawer test at 90° flexion
- D Reverse Lachman test
Correct answer: B. Posterior sag sign (Godfrey's gravity test) at 90° hip and knee flexion
Explanation
The posterior sag sign (Godfrey's test) is performed with the patient supine, hip and knee flexed to 90°. The tibia sags posteriorly due to gravity in PCL rupture, creating a visible posterior step-off at the knee compared to the contralateral side. It is the most specific test for PCL injury. The posterior drawer test is sensitive but the examiner may not appreciate the starting position of posterior subluxation (leading to a false Lachman/anterior drawer). The pivot shift is for ACL injuries. Reverse Lachman tests are less standardized.
Reference: Maheshwari Essential Orthopaedics, 6th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.