externally rotated. The practitioner applies a valgus force while slowly extending the knee. A clunk will be felt around 30° of knee flexion if the subluxed or dislocated joint has reduced. This occurs as the iliotibial band changes from a knee flexor to extensor around 30°. Again, the affected knee should be compared the normal side to rule out a false positive test. Lachman & Posterior drawer tests - Increased anterior translation on the Lachman test is found when the patient has had a combined ACL and PLC injury. Increased posterior translation on the posterior drawer test indicates a combined posterior cruciate ligament tear with the PCL injury. Figure 4 Test - The patient lies supine and flexes their affected knee to approximately 90° then crosses it over the normal side with the foot across the knee and the hip externally rotated. The practitioner applies a varus stress on the joint by pushing the affected knee towards the exam table. This places tension on the posterolateral structures of the knee, especially the popliteus complex and popliteomeniscal fascicles. If these structures have been disrupted by injury, there is no tension to stabilize the lateral meniscus and the lateral meniscus can displace medially into the joint causing the patient pain and reproducing their symptoms at the lateral joint line. As always, the injured knee should be compared to the contralateral normal side. Gait analysis Patients with knee injuries suspected to involve the posterolateral corner should have their gait observed to look for a varus thrust gait, which is indicative of these types of injuries. As the foot makes contact with the ground, the compartments of the knee should remain tight and stabilize the joint through the impact and movements of walking. In posterolateral corner injuries, the lateral compartment has lost all or part of its stability and cannot maintain normal anatomic positioning when stressed. A varus thrust gait occurs as the foot strikes and the lateral compartment opens due to the forces applied on the joint. This forces the joint to sublux into a varus position to compensate. In chronic injuries, patients sometimes learn to walk with a partially flexed knee to alleviate the instability caused by their injury. Patients with medial compartment arthritis can also demonstrate a varus thrust gait, so it is important to differentiate between the two causes using plain radiographs. Patients with PLC injuries will have increased lateral