A test for the rotational knee instability a torn ACL leaves behind.
The pivot shift is a clinical test for anterolateral rotatory instability of the knee, most commonly used to confirm ACL deficiency. With the tibia held in internal rotation and a valgus load applied, moving the knee from extension towards flexion produces a visible or palpable subluxation of the lateral tibial plateau followed by a sudden reduction (clunk) as the iliotibial band shifts from an anterior extensor to a posterior flexor role around 20-40 degrees of flexion. It is graded from 0 (no shift) to III (gross, easily seen subluxation with a hard clunk).
A positive pivot shift is a stronger indicator of functional instability than laxity tests like Lachman alone, and it correlates better with a patient's giving-way symptoms and their ability to return to pivoting sport. Surgeons often use pivot shift grade to help decide on ACL reconstruction versus non-operative management, and to judge whether a reconstruction or added lateral extra-articular procedure has adequately controlled rotatory laxity.
The patient lies supine and relaxed; the examiner internally rotates the tibia and applies valgus stress at the knee while slowly flexing it from full extension. A positive test shows the tibia subluxing anteriorly near extension and then abruptly reducing with visible or palpable movement as flexion increases past roughly 20-30 degrees; grading (0-III) is based on the amount of subluxation and force of reduction, sometimes supplemented by quantitative or arthrometric methods in research settings.
The test is highly dependent on patient relaxation and examiner technique, so muscle guarding, hamstring spasm, or an apprehensive patient can mask a true positive, particularly in the acute post-injury setting. Grading is subjective and shows only moderate inter-examiner reliability, associated meniscal or other ligamentous injury can alter the quality of the shift, and the test should be interpreted alongside history, Lachman, and imaging rather than in isolation.
This guide was auto-drafted and is pending editorial review.