Knee Valgus & Varus Stress Tests: Checking the MCL & LCL

The Valgus and Varus Stress Tests are the primary orthopedic maneuvers used to assess the stability of the knee's collateral ligaments (MCL and LCL). These ligaments prevent the knee from buckling sideways.

1. Purpose

The primary purpose is to test the integrity of the collateral ligaments of the knee.

• The Valgus Stress Test checks the Medial Collateral Ligament (MCL), which resists inward forces.
• The Varus Stress Test checks the Lateral Collateral Ligament (LCL), which resists outward forces.

2. How to Perform

The patient is positioned in supine (lying on their back).

Valgus Stress Test (MCL)

1. Stabilize the patient's ankle with one hand (lateral side).
2. Place the other hand on the lateral aspect of the knee.
3. Apply a valgus force (pushing the knee inward) while the knee is in 30 degrees of flexion. This isolates the MCL.
4. (Optional: Repeat at 0 degrees full extension to check for capsular damage).

Varus Stress Test (LCL)

1. Stabilize the patient's ankle (medial side).
2. Place the other hand on the medial aspect of the knee.
3. Apply a varus force (pushing the knee outward) at 30 degrees of flexion. This isolates the LCL.
4. (Optional: Repeat at 0 degrees full extension).

3. Positive & Negative Sign

Positive Sign (Test is POSITIVE):
A positive test (indicating a sprain or tear) is one of the following:

• Excessive gapping (opening up) of the joint line compared to the uninjured side.
• Reproduction of pain at the ligament site.
• A "soft" or empty end-feel (indicating a complete tear).

Negative Sign (Test is NEGATIVE):
A negative test is a firm end-feel with no increased laxity or pain.