Valgus stressing

Valgus stress test

Application of a valgus force to the knee in 20 degrees of flexion stresses several parts of the knee: -

Stretches the medial collateral ligament
Compresses the lateral compartment (lateral meniscus, lateral tibial plateau, lateral femoral condyle)

It is important to ask the location of any pain provoked by the maneuver, and to look for abnormal opening of the medial joint space. When there is injury to the MCL the grade is based on the amount of opening and feel of the end point1 :-

Normal laxity is 0
Grade 1: 0-0.5 cm of opening with an end point

(There may be no detectable opening in a Grade 1 injury)

Grade 2: 0.5-1.0 cm of opening with an end point
Grade 3: >1.0 cm of opening, usually there is no end point

This test is done in 20 degrees of flexion to isolate the MCL and avoid stressing the medial hamstrings or structures of the posterior capsule. In full extension a valgus stress may elicit pain from the medial hamstrings, their anserine bursa adjacent to the distal MCL or the structures of the posterior capsule

1 American Medical Association, Committee on the Medical Aspects of Sports. Standard nomenclature of athletic injuries. Chicago, IL: American Medical Association; 1966:99-100.