Performing the Test: Have the patient's tested leg bent to about 90 degrees of flexion. The examiner should sit on the foot of the patient's leg. Place a hand along each side of the patient's knee, while palpating the joint line. Apply a posterior-to-anteriorly directed force through the superior tibia. Compare the involved side to the non-involved side. A positive test includes the lack of an end-feel or excessive translation.
Diagnostic Accuracy: Acute: Sensitivity: .49, Specificity: .58, +LR: 1.4, -LR: .7; Chronic: Sensitivity: .92, Specificity: .91, +LR: 8.9, -LR: .1 ("Clinical diagnosis of an anterior cruciate ligament rupture: a meta-analysis").
Importance of Test:Importance of Test: The anterior cruciate ligament stabilizes against anterior translation of the tibia on the femur, due to the attachment at the anterior tibial plateau and posteriorly on the medial side of the lateral femoral condyle (Neumann 534). The force applied by the examiner stresses the ligament. In the acute stage, this test does not adequately assess the integrity of the ligament due to 3 hypotheses: a) swelling following ACL rupture prohibits the test position of 90 degrees of knee flexion b) hamstring protective spasms following injury restricts anterior translation of the tibia c) the posterior horn of the medial meniscus may become blocked by the medial femoral condyle, again blocking anterior translation of the tibia ("Clinical diagnosis of an anterior cruciate ligament rupture: a meta-analysis"). Often with ACL injuries, other tissues and structures can be injured as well. One of the more significant findings recently has been bone contusions with ACL injuries. Look for research on the topic coming out soon!
Note: these tests should only be used by properly trained health care practitioners
References: Benjaminse A, Gokeler A, van der Schans CP. "Clinical diagnosis of an anterior cruciate ligament rupture: a meta-analysis." The Journal of orthopaedic and sports physical therapy. May 2006; 36(5):267-288.
Neumann, Donald. Kinesiology of the Musculoskeletal System: Foundations for Rehabilitation. 2nd edition. St. Louis, MO: Mosby Elsevier, 2010. 334. Print.