Ask The Expert
November 14, 2004
The McMurray test (also called the McMurray sign) is part of the physical examination intended to identify torn cartilage in the knee. The test is usually performed in a person who has had an injury followed by knee pain, locking, or a feeling of instability.
When performing this test, the examiner bends the bothersome knee toward the buttock as far as it will comfortably flex and then straightens out the leg while rotating the ankle inward. The test is then repeated while rotating the ankle outward. If there a pop, clunk or thud that can be felt or heard by the examiner, the test is considered positive and suggests the presence of torn cartilage on one side of the knee. This test may be helpful to distinguish torn cartilage from other types of knee injuries or damage, such as ligament rupture, arthritis or problems with how the kneecap moves over the front of the knee.
The accuracy of the McMurray test has been assessed by comparing it with the results of magnetic resonance imaging (MRI) and arthroscopic surgery. In general, the McMurray test is not very sensitive (that is, many people who have torn cartilage in the knee will have a normal McMurray test), but it is quite specific (meaning that if your McMurray test is abnormal, it's likely you have torn cartilage in your knee). At the current time, most physicians probably rely more on your history especially if you have had a recent injury or that your knee locks or feels unstable and MRI results than on the results of the McMurray test. However, the McMurray test and other findings on examination that might suggest a ligament injury, joint inflammation or "wear-and-tear" arthritis can be very helpful in sorting out why a person has knee symptoms and who should have an MRI.