The McMurray test is a procedure done during a physical examination of the knee joint. Two pieces of cartilage protect the knee joint; one or both of these can become torn after a knee injury. Rotation of the knee during a McMurray test can help diagnose a tear in the cartilage.
Two bones of the leg, the femur and the tibia, come together at the knee joint. Each side of the knee joint has a c-shaped piece of cartilage called a meniscus that cushions and supports the knee. Heavy sports activity or a sudden twisting of the knee can lead to a tear in any of the menisci.
If one of the menisci tear, the patient may experience pain and the feeling that the knee is going to give way. Upon physical exam, the physician will perform various tests, including the McMurray test, to determine if there is damage. Named after British orthopedic surgeon Thomas Porter McMurray, the McMurray test has been in use since the mid-1900s.
To diagnose a tear in the inner or medial meniscus, the medical professional will have the patient lie on his or her back with the knees bent. The medical professional will place one hand on the bottom of the foot of the affected leg, and the other hand on the inner side of the knee. While extending the leg, the knee joint will be rotated outward, away from the patient. If there is a tear, there will be a click or a popping sensation in the joint that can be felt and maybe heard.
Evaluation of the outer or lateral meniscus is done in a similar way, but with the physician placing one hand on the foot and the other hand on the outside of the knee joint. Rotation of the joint would be done inward toward the patient while the leg is extended. A distinctive pop at the joint would indicate a positive McMurray test.
Patients who have a positive result during the McMurray test may have pain and swelling in the knee joint. For minor tears, the symptoms may disappear in a few weeks with rest and ice packs to control the swelling. Patients with a major tear may have more severe symptoms that will not subside. These patients may need further testing and possibly surgery to repair the cartilage.