THE ACCURACY OF THE CLINICAL EXAMINATION IN THE SETTING OF POSTERIOR CRUCIATE LIGAMENT INJURIES

Thirty-nine subjects volunteered for this blinded, randomized, and controlled study to assess the clinical examination skills of orthopaedic surgeons with fellowship training in sports medicine. Eighteen of the patients had 19 chronic isolated posterior cruciate ligament tears. The controls were 9 patients with 9 anterior cruciate ligament-deficient knees, 12 subjects with normal knees, and the contralateral normal knees of the ligament-deficient patients. To eliminate preexamination bias, all examiners were blinded from the examinee's history, identity, and diagnosis. The overall clinical examination accuracy for all orthopaedic surgeons was 96%. The accuracy for detecting a posterior cruciate ligament tear was 96%, with a 90% sensitivity and a 99% specificity. The examination accuracy was higher for grade II and III posterior laxity than for grade I laxity. Eighty-one percent of the time, the examiners agreed on the grade of the posterior cruciate ligament tear for any given patient. The posterior drawer test, which included palpation of the tibia-femur step-off, was the most sensitive and specific clinical test. A thorough and precise physical examination, coupled with a patient history, can be considered diagnostic in the majority of isolated posterior cruciate ligament injuries. With this accuracy level known, the natural history of isolated posterior cruciate ligament tears can be reliably documented and studied.