Pivot-Shift-Test

The pivot-shift test, and rotational -slip test or Subluxationstest is one of the clinical studies carried out on suspicion of a violation of the anterior cruciate ligament (ACL ) in the knee joint. Not to be confused with the so-called reversed pivot- shift test, which is used for the clinical diagnosis of injury to the posterior cruciate ligament (PCL ).

Basis

The task of the ACL is to prevent in the first place, that the head of the tibia against the femoral condyle pushes ( dislocation ). Moreover, it works against hyperextension of the knee and stabilizes the rotational motion (rotation) of the lower leg in flexion (flexion ).

Another cause of a positive pivot-shift test, a rupture of the anterolateral ligament is discussed (proportion of the outer band ).

Implementation

The test consists of a provoked subluxation of the tibia inwards, ie the examiner pushes the lower leg with one hand while the patient lying down towards your knees and simultaneously performs an internal rotation of. With the other hand he bends the knee and put it under valgus stress, that is, he brings it to an X - leg position.

In the initial position of the pivot-shift test, the knee is subluxed. The anterior cruciate ligament is in fact no longer able to prevent movement of the tibial plateau against the condyles. You bend the knee now under valgus, internal rotation and axial compression, the joint snaps at a flexion of 20-30 ° to each other back in the normal position of the two joint surfaces. This is the train of the iliotibial band, which pulls the tibia in flexion 20-30 ° posteriorly. This snap is felt, and in some situations also audible. The pivot-shift test is therefore positive and it is assumed that damage to the anterior cruciate ligament. Should also be noted that the test in the acute stage usually felt ( directly after the injury ) as painful and is therefore rarely performed by many doctors. It has the advantage over the less painful Lachman test that he used to assess the joint stability of the posterolateral joint structures and thus to further surgical planning.