Diagnosis of chronic injury of anterior cruciate ligament

Objective To estimate the value of anterior drawer test, Lachman test, pivot shift test and MRI in diagnosis of chronic anterior cruciate ligament injury. Methods One hundred and seven patients with the diagnosis of chronic injuries of the anterior cruciate ligament arthroscopically underwent the anterior drawer test, Lachman test, the pivot shift test and MR examination before operation. The sensitivity of each examination was calculated and the causes of false negative was analyzed postoperatively. Results 78.5%of the patients had positive anterior drawer test, 97.2% had positive Lachman test and 91.6% had positive pivot shift test. The sensitivity of MRI was 93.5%. In 10 cases (9.35%), arthroscopic examination showed reattachment of the proximally torn end of anterior cruciate ligament to the posterior cruciate ligament. Of those, 60% had positive anterior drawer test, 80% had positive Lachman test and 60% had positive pivot shift test. The sensitivity of MRI was 40%. Nine cases with a false negative pivot shift test, arthroscopy showed blockage of anterior subluxation of the lateral tibial condyle by a partially functioning portion of the anterior cruciate ligament, which was reattached to the posterior cruciate ligament in 4 cases. In 2 cases with a false negative Lachman test, there was firm reattachment of the torn end of anterior cruciate ligament to the proximal portion of the posterior cruciate ligament combined with a bucket handle tear of the medial meniscus. In 10 cases with reattachment, the obliquity of ligament on MRI was changed in 3 cases. Conclusion The Lachman test was most sensitive in diagnosing chronic injuries of the anterior cruciate ligament. The pivot shift and MRI were also sensitive but were influenced by many factors such as MR technique and concomitant injury.