Posterior cruciate Iigament instabilities

Abstract

Posterior cruciate Iigament (PCL) injuries represent 3% to 20% of all knee Iigamentous injuries, but the diagnosis often is missed at initial evaluation. Diagnostic ability is increased by knowledge of knee biomechanics and selective Iigament cutting studies. The examiner must differentiate the isolated PCL injury from combined Iigamentous injury to determine appropriate treatment. Isolated acute PCL tears with Iess than 1O mm of posterior Iaxity at 90 degrees of flexion should be treated with an aggressive rehabilitation program. This amount of Iaxity is found in the majority of isolated acute PCL tears. Isolated acute PCL tears with more than 10 to 15 mm of posterior Iaxity and PCL tears with combined Iigamentous injuries should be reconstructed. Large PCL bony avulsions should be fixed internally. Small PCL bony avulsions with more than 10 mm of posterior Iaxity should be reconstructed. Chronic PCL injuries initially should be treated with an aggressive rehabilitation program. If such a program is not successful in a patient with inore than 10 to 15 mm of posterior Iaxity and no significant radiographic evidence of degenerative changes, the PCL should be reconstructed.