Which description best matches the valgus stress test protocol?

Which description best matches the valgus stress test protocol?

• A. Lateral force is applied at knee in slight flexion to isolate LCL.
• B. Medial force is applied at knee in full extension to assess capsule involvement.
• C. Medial force is applied at knee in slight flexion to isolate MCL and in full extension to assess capsule involvement.
• D. Medial force is applied at the knee in deep flexion to assess meniscal structures.

Answer: (C)

The test checks medial knee stability by applying valgus stress and adjusting knee bend to see which tissues resist the force. When the knee is in slight flexion, a medial push stresses the medial collateral ligament (MCL) more than the capsule, effectively isolating the MCL. With the knee in full extension, the medial capsule and other stabilizers contribute more to stability, so applying a medial force then assesses capsule involvement as well. This combination precisely matches the protocol of using a medial force with slight flexion to isolate the MCL and in full extension to evaluate capsule involvement. Lateral force would stress the lateral collateral ligament, not what this test aims to evaluate. Medial force in full extension alone doesn’t isolate the MCL, and deep flexion shifts the focus toward meniscal structures rather than the MCL and capsule.

The test checks medial knee stability by applying valgus stress and adjusting knee bend to see which tissues resist the force. When the knee is in slight flexion, a medial push stresses the medial collateral ligament (MCL) more than the capsule, effectively isolating the MCL. With the knee in full extension, the medial capsule and other stabilizers contribute more to stability, so applying a medial force then assesses capsule involvement as well. This combination precisely matches the protocol of using a medial force with slight flexion to isolate the MCL and in full extension to evaluate capsule involvement.

Lateral force would stress the lateral collateral ligament, not what this test aims to evaluate. Medial force in full extension alone doesn’t isolate the MCL, and deep flexion shifts the focus toward meniscal structures rather than the MCL and capsule.