Which best describes a Grade 3 medial knee injury?

Which best describes a Grade 3 medial knee injury?

• A. Tenderness, no instability
• B. Broad tenderness, partially torn medial knee structures
• C. Complete medial knee disruption, no end point to valgus stress at 20 degrees knee flexion
• D. Isolated MCL sprain with end point

Answer: (C)

Grading a medial knee injury hinges on how much ligament is torn and how the joint responds to valgus stress, especially around 20 degrees of knee flexion. A Grade 3 injury means a complete disruption of the medial stabilizers, so the knee becomes grossly unstable when you apply valgus stress. On the test, that shows up as a valgus stress with no end point—there’s no firm stopping point as the joint opens further, indicating the ligament is fully torn. So this description fits Grade 3 because it reflects full rupture with marked laxity under stress. By contrast, mild tenderness with no instability points to a Grade 1 sprain, partial tearing with increased laxity but a residual endpoint points to a Grade 2, and an isolated sprain with a definite end point wouldn’t match complete disruption.

Grading a medial knee injury hinges on how much ligament is torn and how the joint responds to valgus stress, especially around 20 degrees of knee flexion. A Grade 3 injury means a complete disruption of the medial stabilizers, so the knee becomes grossly unstable when you apply valgus stress. On the test, that shows up as a valgus stress with no end point—there’s no firm stopping point as the joint opens further, indicating the ligament is fully torn.

So this description fits Grade 3 because it reflects full rupture with marked laxity under stress. By contrast, mild tenderness with no instability points to a Grade 1 sprain, partial tearing with increased laxity but a residual endpoint points to a Grade 2, and an isolated sprain with a definite end point wouldn’t match complete disruption.