On MRI of the knee, a posterior cruciate ligament (PCL) appears as a continuous low-signal band on all sequences but shows a focal region of intrasubstance T2 heterogeneity with thickening. A plain radiograph shows a small avulsion fragment at the posterior tibial plateau. This constellation best represents:
- A ACL tear with posterior tibial translation
- B Posterior horn medial meniscus tear
- C PCL tibial footprint avulsion fracture with PCL sprain ✓
- D Segond fracture with ACL injury
Correct answer: C. PCL tibial footprint avulsion fracture with PCL sprain
Explanation
PCL avulsion fractures occur at the tibial footprint (posterior tibial plateau), where the PCL inserts. On MRI, the ligament maintains continuity but shows intrasubstance signal change at the injury site; the avulsion fragment is visible on lateral X-ray at the posterior tibial plateau. Segond fracture is a lateral tibial plateau avulsion associated with ACL injury. ACL tears produce anterior tibial translation, not posterior.
Reference: Grainger & Allison's Diagnostic Radiology, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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