Dr. Ebraheim’s educational animated video describes test for evaluation of knee injuries and all the maneuvers you need to know to preform an excellent knee examination.
McMurray’s test is a knee examination test that elicits pain or a painful click as the knee is brought from flexion to extension with either internal or external rotation. The McMurray’s test uses the tibia to trap the meniscus between the femoral condyle and the tibia.
When performing the McMurray’s test, the patient should be lying supine with the knee flexed. The examiner grasps the patient’s heel with one hand and places the other hand over the knee joint. To test the medial meniscus, the knee is fully flexed and the examiner then passively externally rotates the tibia and places a valgus force. The knee is then extended in order to test the medial meniscus. to tests the lateral meniscus, the examiner passively internally rotates the tibia and places a varus force. The knee is then extended in order to test the lateral meniscus. A positive test is indicated by pain, clicking or popping within the joint and may signal a tear of either the medial or lateral meniscus when the knee is brought from flexion to extension.
Lachman’s test is the most sensitive and best test for examining an ACL injury. The patient should be lying supine and completely relaxed. Make sure that the patient’s hip, quadriceps and hamstring muscles are all relaxed. Bend the knee to about 20-30°. Stabilize the femur with one hand and with the other hand, pull the tibia anteriorly and posteriorly against the femur. With an intact ACL as the tibia is pulled forward the examiner should feel an endpoint. If the ACL is ruptured, the ACL will be lax and the examination will feel softer with no endpoint. The tibia can be pulled forward more than normal (anterior translation).
Both the Lachman’s test and the Pivot shift test are associated with 20-30°s of knee flexion. The Lachman’s test starts at 20-30 ° of flexion. With the Pivot shift test you feel the clunk at 20-30°s of flexion. 20-30°s of flexion is important for examination of the ACL (remember that). The patient should be lying supine. Make sure the patient is totally relaxed. With pivot shift, the knee is in the subluxed position and the knee is in full extension. The pivot shift starts with extension of the knee and you can feel the clunk at 20-30° of flexion. Hold the knee in full extension then add valgus force plus internal rotation of the tibia to increase the rotational instability of the knee. Then take the knee into flexion. A palpable clunk is very specific of an ACL tear. the iliotibial band will reduce the tibia and create the clunk on the outside of the knee. Always compare with the other side.
The reverse pivot shift test helps to diagnose acute or chronic posterolateral instability of the knee. A significantly positive reverse pivot shift test suggests that the PCL, the LCL, the arcuate complex and the popliteofibular ligament are all torn.
The reverse pivot shift test begins with the patient supine with the knee in 90° flexion. Valgus stress is then applied to the knee with an external rotation force. Bring the knee from 90°s of flexion to full extension. The tibia reduces from a posterior subluxed position at about 20°s of flexion. A shift and reduction of the lateral tibial plateau can be felt as it moves anteriorly from a posteriorly subluxed position. A clunk occurs as the knee is extended. This is called reverse pivot shift because shift of the lateral tibial plateau occurs in the opposite direction of the true pivot shift (Seen in ACL tears). If the tibia is posterolaterally subluxed, the iliotibial band will reduce the knee as the IT band transitions form a flexor to extensor of the knee. It is very important to compare this tests to the contralateral knee. Pivot shift = ACL tear
The test is done with the patient in supine position and the knee is flexed to 90°. The examiner stabilizes the foot. Next the examiner pushes backward on the tibia, looking for the tibia to sag posteriorly. Observer the sag that develops due to tear of the posterior cruciate ligament (PCL). The amount of translation in relationship to the femur is observed. The test is considered positive if excessive posterior translation of the tibia is demonstrated.
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Background music provided as a free download from KZfaq Audio Library.
Song Title: Every Step