During a valgus stress test of the knee performed with the patient supine, laxity or pain indicates injury to which structure?

During a valgus stress test of the knee performed with the patient supine, laxity or pain indicates injury to which structure?

• A. MCL tear
• B. LCL tear
• C. ACL tear
• D. Medial meniscus tear

Answer: (A)

A valgus stress test targets the medial side of the knee because the medial collateral ligament is the main restraint against valgus (inward) opening of the knee. If there is laxity or pain when you apply the force with the knee slightly flexed and the patient supine, that points to an injury of the MCL. The LCL is tested with a varus stress test, not valgus. An ACL tear shows instability in the anterior direction and is evaluated with tests like the Lachman or pivot shift, not primarily a valgus test. A medial meniscus tear can cause joint line pain or mechanical signs, but it does not typically produce valgus laxity.

A valgus stress test targets the medial side of the knee because the medial collateral ligament is the main restraint against valgus (inward) opening of the knee. If there is laxity or pain when you apply the force with the knee slightly flexed and the patient supine, that points to an injury of the MCL. The LCL is tested with a varus stress test, not valgus. An ACL tear shows instability in the anterior direction and is evaluated with tests like the Lachman or pivot shift, not primarily a valgus test. A medial meniscus tear can cause joint line pain or mechanical signs, but it does not typically produce valgus laxity.