What degree of flexion is the knee in for a positive outcome in the Knee Valgus Stress Test?

In the context of the Knee Valgus Stress Test, the knee should be positioned around 25 degrees of flexion to effectively assess for potential instability in the medial structures of the knee. When the knee is flexed to this degree, it allows for a better evaluation of the medial collateral ligament (MCL) by placing it under tension, as well as other supporting soft tissue structures. This angle is optimal because it minimizes the influence of other knee stabilizers, such as the surrounding muscles and other ligaments, allowing for a clearer interpretation of the test results.

At 25 degrees of flexion, the lateral structures are relaxed enough to avoid confounding the test, and any excessive movement or gapping on the medial side can be indicative of injury or laxity. Testing at this specific angle ensures that clinicians can accurately assess the integrity of the MCL and determine any necessary interventions. The other angles of flexion—full extension, 20 degrees, and 15 degrees—do not provide the same level of specificity for isolating the MCL assessment required in this test.