Structural integrity of collateral ligaments are tested by :

C i.e. Varus / valgus stress test in 30deg of flexion Lachmans test , most sensitive for ACL injury is done in 20deg of knee flexion. Tension in ACL is least at 30 - 40deg of knee flexion Main test for MCL (medial collateral ligament) is valgus (abduction) stress in 30deg of knee flexionQ. Because in full extension it is indicative of combined MCL, posterior oblique ligament injury & possible cruciate ligament injury. Varus (Adduction) stress test in 30deg flexion removes the lateral stabilizing effect of illotibial band so that the lateral collateral ligament can exclusively be examined. Mechanism of Injury Valgus force MCL Varus force LCL Backward force PCL Twisting Injury - ACL - Menscus (medial & lateral) - MCL Examination Direction of Force Position of knee Ligament Tested Varus /Valgus Full extension PCL, Posterior capsule LCL MCL Varus Valgus 30deg flexionQ 30deg flexionQ Posterior 90deg flexion PCL Anterior - 30deg flexionQ (lachman's test) - 90deg flexion (anterior drawer) ACL