Epidemiology of posterior cruciate ligament injuries.

BACKGROUND:
The epidemiology of posterior cruciate ligament (PCL) injuries has not been well clarified. Isolated and combined PCL injuries are a frequently missed diagnosis. A better understanding of typical injury mechanisms may help in more accurate diagnosis of these injuries.

METHODS:
In this study the epidemiology of PCL insufficiency in 494 patients was retrospectively analysed. Stress-radiography was used to quantify posterior tibial displacement.

RESULTS:
The mean age at the time of injury was 27.5+/-9.9 years. Traffic accidents (45%) and athletic injuries (40%) were the most common injury causes. Motorcycle accidents (28%) and soccer-related injuries (25%) accounted for the main specific injury causes. The most common injury mechanisms were dashboard injuries (35%) and falls on the flexed knee with the foot in plantar flexion (24%). The mean side-to-side difference of posterior tibial displacement on posterior stress-radiographs in 90 degrees of flexion was 13.4+/-4.7 mm. According to the posterior displacement values, 232 (47%) patients had isolated PCL ruptures, while 262 (53%) patients with a posterior displacement of >12 mm were classified as having a combined posterior instability. There were significantly more combined PCL lesions due to vehicular trauma as compared with athletic trauma ( p< 0.0001).

CONCLUSIONS:
In many PCL lesions, initiation of an adequate treatment regimen is delayed despite typical injury mechanisms and symptoms. In the future, a better understanding of the epidemiology of PCL injuries should enable us to diagnose the injury more reliably through a detailed history and a thorough physical and radiographic examination in the acute setting.