What is McMurray Test?
The McMurray Test is used by doctors and physiotherapists to find if there is a tear in the meniscus
Three bones meet each other to form your knee: your femur (the thigh bone), the tibia (the leg bone), and the patella.
Two pieces of wedge-shaped fibrous cartilage act as “shock absorbers” between the femur and the tibia. They are called menisci consisting of the medial or internal meniscus and lateral or external meniscus. They resemble conventional gaskets like those of a tap and are made in the shape of a “C,” are hard and rubbery and help to cushion the knee loads and keep it stable.
One of the most used ways of detecting meniscal tears is the McMurray test. The orthopedist will bend your knee and then straighten and rotate it. This movement puts a broken meniscus in tension. If you have a meniscal injury, this movement causes a painful jerk. The knee will snap and hurt every time the doctor takes the test.
Diagnosing Knee Injury With a McMurray Test
The knee is the largest joint in your body and also one of the most complex. Because it is used so much, it is also more vulnerable to damage. It is made up of many parts, so many different things can go wrong. Meniscal injuries are probably the most typical knee injuries. Athletes, especially those who practice sports such as football, are more at risk of meniscal injuries. However, anyone can damage their meniscus in day to day life.
There are several tests for the knee, and their importance is not to be underestimated as the diagnosis of knee pathologies are certainly more complex than those of foot pathologies; in fact, the knee is a complex structure in which the different subunits cooperate very closely to achieve the movement.
In male subjects, knee related diseases are usually linked to traumatic or degenerative problems due to usually heavier physical activities, while in female subjects the problem is more frequently associated with weakness or muscle imbalance; in women, the risk of degenerative problems linked to arthrosis phenomena increases markedly in the post-menopausal period.
As mentioned, the parts usually affected by traumatic events are the cruciate ligaments and the menisci
The cruciate – There are two, one anterior (which prevents the tibia from moving too far ahead of the femur) and one posterior (which performs the opposite function). It is usually the front end that suffers the most damage from trauma since, in general, it is the forward movements that stress the knee more, charging it more.
The menisci – They are two, lateral and medial, and function as shock absorbers protecting the bones that join the knee joint. The medial ligament is generally more stressed because it is less mobile than the lateral one. Meniscal injuries often result from movements that are too abrupt and do not give the meniscus time to follow the movement.
McMurray test is a well-known knee test. With the patient supine, the examiner lifts the heel with one hand and with the other supports the lower part of the knee, trying to make the knee fully extend while rotating the tibia first inward then outward.
The appearance of pain in forced flexion suggests the presence of a lesion affecting the posterior meniscal horns (these meniscal portions slide backward when the knee is flexed). The appearance of forced extension pain makes one suspect an injury of the anterior meniscal horns (in the extension, the menisci have a tendency to slide forward, and the anterior meniscal horns are compressed between the tibial and femoral bones). Any pain caused by 90 degrees of flexion is indicative of a lesion of the meniscal body.
How the McMurray Test Is Performed
The meniscus test for McMurray is a sensitive test for a meniscus injury. The implementation at McMurray is similar to the analysis of Steinmann. The patient lies on his back. The examiner raises the affected leg and bends it in the knee joint, while the thumb and forefinger of one hand palpates the joint space of the knee. In this meniscus test, the knee is externally rotated to test the inner meniscus and internally rotated to examine the exterior meniscus.
Then, with a constant touch of the joint space, the leg is stretched slowly till it becomes straight. If there is a pain due to this, the McMurray test is probably positive, and a meniscal lesion is likely.
Also, during a McMurray test, if a noticeable click is heard, it is also further evidence of damage.
Advantages and Disadvantages of a McMurray Test
The McMurray Test was used by orthopedists before the era of MRI. It is useful for detecting posterior meniscal damage. Tears to the meniscal body in front of the knee may require an MRI. The test has an accuracy of 56% or about 6 out of 10.
A McMurray meniscus test, in many cases, provides clues as to whether a meniscus is damaged or not. Most of the tests are positive for a lesion, but this does not necessarily prove meniscal damage. At the same time, ligaments and other structures are tested that can also hurt. At the same time, a negative meniscus test does not preclude existing damage, so that the result in the meniscus test must always be seen in the overall context. Nonetheless, positive results provide enough reason for further research in this direction, for example, in the form of an MRI scan or arthroscopy.
The advantage is that it can be performed quickly and in a few minutes. The disadvantage is that it cannot detect about 4 out of 10 cases. It used to be the gold standard of meniscal tests, but in the era of advanced imaging, it is used to confirm the findings rather than make a positive diagnosis.
Physical Examination of the Knee
The main symptom of a damaged meniscus is pain. These often occur in a characteristic way and thus form the background of the meniscus test. Depending on the affected meniscus, the pain is noticeable above all on the inside or outside of the knee and is dependent on the movement, i.e., the pain worsens when the knee revolves or flexes. Some of them radiate further from the knee into the upper or lower leg. Besides, there is usually a restriction of movement caused by the pain.