Pivot shift test
With the knee in full extension, a valgus and internal rotation force is applied. In an ACL deficient knee this will anterolaterally sublux the tibia away from the lateral femoral condyle (this is not usually visible). With flexion of the knee (past approximately 30 degrees), the iliotibial band goes from an extensor of the knee to a flexor and in the ACL deficient knee the tibial reduces (shifts) back into place.
This test can be done from initial flexion to full extension, where the lateral tibia is felt to sublux anteriorly in the last 30 degrees of extension (N.B. This is not the reverse pivot shift test).
A normal knee can be considered a "multi-axial one degree of freedom joint"1 and this change in the direction of motion is well described as a "pivot shift".
1J Feikes, DR Wilson, AB Zavatsky, and JJ O'Connor. The knee in passive flexion has one degree of unresisted freedom. J Biomechanics 31(S.1) 15, July 1998.
© Mr Gavin Holt :: CotswoldClinics.com :: Print this frame