Valgus Stress Test

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Top Contributors - Shejza Mino, Kim Jackson, Claire Knott and Matt Huey  

Purpose

The valgus stress test, also known as the medial stress test,  is used to assess the integrity of the medial collateral ligament (MCL) of the knee. MCL ruptures are common in the athletic population and can occur as either isolated injuries, or combined with other structural injuries .

Technique

Patient Position

• Begin with the patient in a supine position. Their leg should be relaxed as this test is performed. 

Performing the Test

• The examiner places one hand at the outside of the knee, acting as a pivot point, while the other hand is placed at the foot. The medial joint line is palpated while the examiner simultaneously applies an abducting force at the the foot, and a valgus force through the knee joint.
• This test is typically performed at both 30 and 0 degrees of knee flexion. When performed at 30 degrees, the MCL is more isolated from other medial joint structures, with a sensitivity of .86-.96 for MCL tears. This can be followed by performing the second version of the test, at 0 degrees of knee flexion, which allows for assessment of other medial joint structures.
• The two versions are summarized below: 
  • Knee valgus @ 0° - Along with the MCL, the medial joint capsule, anterior cruciate ligament (ACL), and the posterior cruciate ligament (PCL) are stressed.
  • Knee valgus @ 30° - The MCL is the prime stabilizer in this position and is therefore the primary structure assessed. The medial joint capsule is also stressed in this position. 

Interpretation

• Positive findings may include excessive gapping at the medial joint and/or pain, indicating MCL damage. This may also indicate capsular or cruciate ligament laxity, depending on what degree of knee flexion the test is performed at. 
• It should be noted that some joint gapping is considered normal at 30 degrees. No gapping should be present at 0 degrees.