Final answer:
The most useful physical exam tests for diagnosing an ACL tear are the Lachman test, Pivot-Shift test, and Drawer test.
Step-by-step explanation:
The most useful physical exam test for diagnosing an ACL tear is the Lachman test. In this test, the patient lies down with the knee bent at a 30-degree angle. The examiner stabilizes the thigh with one hand and uses the other hand to pull the tibia forward. If the tibia moves too far forward compared to the femur, it indicates a possible ACL tear.
Another physical exam test for diagnosing an ACL tear is the Pivot-Shift test. In this test, the patient lies down with the knee bent at a 30-degree angle. The examiner holds the heel with one hand and applies a valgus stress to the knee while internally rotating the tibia with the other hand. If there is a palpable clunk or a sudden shift in the knee joint, it indicates a possible ACL tear.
Finally, the Drawer test can also be used to diagnose an ACL tear. In this test, the patient lies down with the knee bent at a 90-degree angle. The examiner stabilizes the thigh with one hand and uses the other hand to push or pull the tibia forward and backward. If there is excessive forward or backward movement of the tibia compared to the femur, it suggests a possible ACL tear.