Below is a review for the positioning and procedure for performing a Pivot Shift test to look for an ACL tear. You can read more about ACL/ligamentous testing here.
Pivot Shift: The patient is positioned supine. The examiner applies a slight distraction to the leg just below the knee joint line, with a valgus and internal rotation force is applied to an extended knee. While maintaining these forces, the knee is flexed past 30 degrees. Sensitivity: 18-48% Specificity: 97-99%
Best + predictive value for ruling in a ruptured ACL is a positive pivot shift
Ostrowski JA. Accuracy of 3 diagnostic tests for anterior cruciate ligament tears. Journal of Athletic Training; 41:120-21.