During varus/valgus testing, which position combination best evaluates the collateral ligaments?

• A. Full extension only
• B. 90 degrees flexion only
• C. Full extension and 30 degrees flexion
• D. 60 degrees flexion only

Answer: (C)

The collateral ligaments are best evaluated by testing the knee in two angles because their restraint changes with knee position. At full extension, the MCL and LCL are taut along with the joint capsule, so you can detect generalized laxity and injuries affecting multiple structures. About 30 degrees of flexion reduces the influence of the cruciate ligaments and places the collateral ligaments as the primary restraints to varus/valgus stress, making it easier to isolate tears of the MCL or LCL. Testing in both positions—full extension and around 30 degrees of flexion—provides the most accurate assessment of collateral ligament integrity. Relying on a single angle may miss injuries or overestimate instability because different structures contribute to stability at different angles.