UCLA

The authors reviewed 610 consecutive magnetic resonance (MR) examinations of patients with suspected internal derangements of the knee, paying special attention to the posterior cruciate ligament (PCL). The normal PCL shows a low MR signal intensity and an arcuate shape. An accessory anterior or posterior meniscofemoral ligament was identified in 58.5% of examinations. Among 202 patients who underwent arthroscopy or arthrotomy, MR imaging depicted 11 PCL injuries: eight complete or incomplete ligament disruptions and three avulsions. All were confirmed by means of arthroscopy or arthrotomy. MR findings of PCL injury were anatomic disruption, increased signal intensity in the ligament, and redundancy of an avulsed ligament. Of the 11 PCL injuries, four were not detected at initial clinical examination. In none of the 202 patients in whom arthroscopy or surgery was performed was an abnormal PCL identified in the presence of a normal MR examination. MR imaging is a reliable method for the detection of PCL injuries.