Purpose: The Valgus Stress Test is used to assess the integrity of the MCL or medial collateral ligament of the knee.
How to Perform Valgus Stress Test
Position of Patient: The patient should be relaxed in the supine position.
Performance: The examiner will support the knee and lower leg at the ankle, applying a valgus stress at the knee in full extension. The test should also be performed with the knee positioned into 30 degrees of flexion, applying the same valgus force at the knee.
How to Interpret Valgus Stress Test
Positive Finding: A positive test occurs when gapping or pain is noted with this test in full knee extension; this may suggest both an MCL and cruciate injury. With the knee at 30 degrees of flexion, a positive test occurs when pain is noted along the medial knee or significant gapping is present.
Test Accuracy / Reliability / Evidence:
Knee in 0 degrees of flexion, weighted Kappa value for judgments of motion was .06 (.40 for pain and 0.00 for end feel.)
Knee in 30-degree test position, weighted Kappa value for judgments of the amount of motion was .16, (0.33 for pain and 0.38 for end-feel)
Research Source: McClure, P., Rothstein, J., & Riddle, D. (1989). Intertester Reliability of Clinical Judgments of Medial Knee Ligament Integrity. Physical Therapy, 69(4), 268-275. doi: 10.1093/ptj/69.4.268