Knee Ligament Tests

Determining if knee pain is due to ACL, LCL, PCL, or MCL injury

  • Varus: Assuming you mean LCL here, so I changed in Flow: ""


Knee ligament tests involve a healthcare provider manually putting pressure on the four major ligaments of the knee to help determine if knee pain could be due to sprain or tear. Such tests include the anterior drawer test, the posterior drawer test, the valgus stress test, and the varus stress test.

The anterior cruciate ligament (ACL), posterior cruciate ligament (PCL), medial collateral ligament (MCL), and lateral collateral ligament (LCL) all stabilize the knee in a different direction. A knee ligament test that reveals compromised stability in a specific direction can, therefore, help identify which ligament is affected (if any).

Knee ligament tests can be performed in a medical office without any special equipment. Based on their outcome and a review of your medical history, your healthcare provider may order imaging tests to support the findings and determine how serious the injury is.

This article walks you through how each knee ligament test is done and what it can reveal.

Anterior Drawer Test

The Anterior Test

Brett Sears, PT

Purpose: The anterior drawer test is used to assess whether the movement between the femur (thigh bone) and tibia (the larger of the two bones of your lower leg) is within the normal range or not.

This gauges the integrity of your anterior cruciate ligament (ACL), which prevents the forward slippage of your shin bone underneath your thigh bone.

How It's Done: The test is performed while you are lying on your back with your knee bent at a 90-degree angle and your foot placed flatly on the table.

The healthcare provider takes hold of your lower leg just behind the knee and gently tugs your leg forward.

What Results Suggest: Excessive motion of your tibia beneath the femur suggests that your ACL may be torn.

Posterior Drawer Test

Purpose: The posterior drawer test evaluates the stability of the posterior cruciate ligament (PCL). This ligament prevents your shin bone from slipping backward underneath your thigh bone.

As with the anterior drawer test, this is done to assess whether the movement of the tibia in relation to the femur is normal or not.

How It's Done: The test is performed while you are lying with your back with your knee bent at a 90-degree angle and tilted outward at a 45-degree angle. Your foot is placed flat on the table.

The healthcare provider takes hold of the front of the lower leg just below the knee and exerts steady pressure against it.

What Results Suggest: If the tibia moves backward beyond what is normal, it suggests a PCL tear or injury.

Valgus Stress Test

Purpose: The valgus stress test, also known as the abduction stress test, is done to determine if the medial collateral ligament (MCL) is fully intact. It involves checking for any gaps between the tibia and femur on the inner side of your knee joint.

The MCL stabilizes the inner knee and prevents it from splaying too far inward. It also guards it against impact from the outside of the knee.

How It's Done: The test is performed while you are on your back with your knee bent at a 30-degree angle. A bolster may be placed under your knee to place it in an optimal position.

Some healthcare providers perform the valgus stress test with the knee straight and your leg placed flat on the table.

The healthcare provider grasps your ankle with one hand and your outer thigh with the other. They then exert gentle but forceful pressure, tugging the ankle outward.

What Results Suggest: An MCL tear is suggested if the knee gaps on the inner portion of the joint more than what is normal (compared to the other knee). In some cases, an audible "clunk" may be heard.

Varus Stress Test

Purpose: The varus stress test, also known as the adduction stress test, evaluates the stability of the lateral collateral ligament (LCL).

This ligament stabilizes the outer knee and prevents it from splaying too far outward. It also protects it against impact from the inside of your knee.

The purpose of the test is to assess whether the LCL is fully intact by checking for any gaps between the tibia and femur on the outer side of the knee joint.

How It's Done: Like the valgus stress test, this test is performed while you are on your back with your knee bent at a 30-degree angle. A bolster may be placed under your knee for support.

The valgus stress test can also be performed with your knee straight and your leg placed flat on the table.

The healthcare provider grasps your ankle with one hand and places the other on the inner side of your knee. They then exert forceful but gentle pressure, tugging the ankle inward.

What Results Suggest: If the knee gaps on the outer portion of the knee joint more than what is normal, this would suggest an LCL tear. An audible "clunk" may also be heard.

4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Kilinc BE, Kara A, Celik H, Oc Y, Camur S. Evaluation of the accuracy of Lachman and Anterior Drawer Tests with KT1000 ın the follow-up of anterior cruciate ligament surgery. J Exerc Rehabil. 2016;12(4):363-7.

  2. Badri A, Gonzalez-lomas G, Jazrawi L. Clinical and radiologic evaluation of the posterior cruciate ligament-injured knee. Curr Rev Musculoskelet Med. 2018;11(3):515-520. doi:10.1007/s12178-018-9505-0

  3. Rossi R, Dettoni F, Bruzzone M, Cottino U, D'elicio DG, Bonasia DE. Clinical examination of the knee: know your tools for diagnosis of knee injuries. Sports Med Arthrosc Rehabil Ther Technol. 2011;3:25. doi:10.1186/1758-2555-3-25

  4. Grawe B, Schroeder AJ, Kakazu R, Messer MS. Lateral Collateral Ligament Injury About the Knee: Anatomy, Evaluation, and Management. J Am Acad Orthop Surg. 2018;26(6):e120-e127. doi:10.5435/JAAOS-D-16-00028

Additional Reading
  • Failla, MJ, et al. Does Extended Preoperative Rehabilitation Influence Outcomes 2 Years After ACL Reconstruction? A Comparative Effectiveness Study Between the MOON and Delaware-Oslo ACL Cohorts. Am J Sports Med. 2016 Oct; 44(10): 2608-2614.
  • Shaarani, SR, etal. Effect of prehabilitation on the outcome of anterior cruciate ligament reconstruction. AM J Sports Med. 2013 Sep; 41(9):2117-27.

By Laura Inverarity, DO
 Laura Inverarity, PT, DO, is a current board-certified anesthesiologist and former physical therapist.