Posterior Cruciate Ligament Pathology Workup

Updated: May 11, 2018
  • Author: Matthew Lawless, MD; Chief Editor: Thomas M DeBerardino, MD  more...
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Workup

Imaging Studies

Radiography

Initial radiographs should include weightbearing 45° posteroanterior (PA), lateral, and Merchant views. (See the images below.)

Lateral radiograph of a normal knee. In a normal k Lateral radiograph of a normal knee. In a normal knee, a line drawn along the posterior femoral condyle does not intersect the posterior tibial condyle. Image courtesy of Janos P. Ertl, MD.
Lateral radiograph of a knee with a posterior cruc Lateral radiograph of a knee with a posterior cruciate ligament injury. Note that the same line as in the image above bisects the posterior tibial condyle due to a posterior sag and an incompetent PCL. Image courtesy of Janos P. Ertl, MD.

An avulsion fracture from the origin of the posterior cruciate ligament (PCL) may be seen with hyperextension injuries. Avulsion fractures from the insertion of the PCL are associated with flexion injuries. [2]  (See the images below.)

Radiograph depicting a chronic avulsed posterior c Radiograph depicting a chronic avulsed posterior cruciate ligament (PCL). Image courtesy of Mervyn J. Cross, MBBS, FRACS.
Sagittal view radiograph showing a posterior cruci Sagittal view radiograph showing a posterior cruciate ligament (PCL) rupture. Note the posterior positioning of the tibia in relation to the femur. Image courtesy of Mervyn J. Cross, MBBS, FRACS.

Stress views are more sensitive than physical examination for diagnosing PCL tears. Posterior tibia translation of more than 8 mm on stress radiographs is consistent with a complete PCL tear, and translation of less than 8 mm suggests a partial tear. [42]

Magnetic resonance imaging

Magnetic resonance imaging (MRI) is 97-100% sensitive for PCL injuries. [43, 44, 45, 46, 47, 48, 49, 50, 51]  (See the image below.) However, MRI is only 67% sensitive in distinguishing between partial and complete PCL tears. [52, 53]

An MRI showing a torn posterior cruciate ligament An MRI showing a torn posterior cruciate ligament (PCL). Image courtesy of Mervyn J. Cross, MBBS, FRACS.

Bone scanning

A bone scan can be used to evaluate patients with chronic PCL insufficiency for early chondrosis. Increased signal at the medial femoral condyle and the patellofemoral compartment suggests degenerative changes secondary to PCL insufficiency. [2, 54]