The anterior cruciate ligament attaches on or adjacent to the medial tibial spine of the intercondylar eminence while the posterior cruciate ligament attaches to the posterior surface of the tibia. Fractures of the medial tubercle (spine) therefore indicate that the ACL has been likely be torn from the tibia.

A	Sagittal MRI. This gradient echo sequence image shows avulsion of a portion of the posterior tibia by the PCL.
B	Lateral radiograph of the knee. This shows the radiographic appearance of the MRI findings.

Links to online textbooks:

• Wheeless' Orthopedics: discussion of tibial plateau fractures

Links to online cases:

• The Physician and Sports Medicine

References:

• Sonin AH, Fitzgerald SW, Friedman H, Hoff FL, Hendrix RW, Rogers LF: Posterior cruciate ligament injury: MR imaging diagnosis and patterns of injury Radiology. 1994 Feb;190(2):455-8.           [See related articles]
• Moyer RA, Marchetto PA: Injuries of the posterior cruciate ligament Clin Sports Med. 1993 Apr;12(2):307-15.           [See related articles]