[The jerk-test in external rotation in rupture of the anterior cruciate ligament. Description and significance].

The authors describe a dynamic test of anterior subluxation of the tibia in lateral rotation in ruptures of the anterior cruciate ligament. This jerk-test in lateral rotation indicates general anterior laxity, including the posteromedial and posterolateral capsular structures. It is only present in lesions of the anterior cruciate ligament, and is only positive in 60 per cent. Its presence is a contra-indication to an isolated lateral extra-articular ligamentoplasty and an indication for intra-articular ligamentoplasty of the anterior cruciate ligament. This test must be distinguished from the Jacob reverse pivot shift test, which indicates posterolateral laxity.