The McMurray test is a well-known physical exam maneuver that doctors use to diagnose knee injuries, especially tears of the meniscus—a C-shaped piece of cartilage that cushions your knee joint. In recent years, there’s been some discussion around whether the McMurray test could also help identify injuries to the anterior cruciate ligament (ACL), one of the key ligaments that stabilizes the knee. In this article, we’ll take a closer look at how effective the McMurray test really is for detecting ACL tears. Drawing from current research and clinical experience, we’ll help clarify when this test is most useful, and when other methods may be more reliable.
Originally developed to detect meniscal tears without the need for expensive imaging, the McMurray test is straightforward. Your doctor will bend your knee, rotate your lower leg, and then straighten your knee while they check for any clicking, pain, or restricted movement. These signals can indicate a torn or damaged meniscus that’s catching between the knee bones.
While the McMurray test is designed to uncover meniscal injuries, some clinicians have wondered if it could also pick up on ACL tears, since symptoms like pain, swelling, or a sense of instability are common to both kinds of injuries.
Recent research has shown that certain types of ACL tears are more likely to be accompanied by meniscal injuries. For example, one study found that medial meniscus tears are most common in a particular variety of ACL tears (known as “type I” tears), even though this type makes up only a small fraction of total ACL injuries. This close association can sometimes make the exam findings more complex, as both injuries may present simultaneously.
The ACL is a tough band of tissue running through the center of your knee, keeping your shinbone from sliding forward and controlling rotation. ACL tears often happen during quick pivots, abrupt changes in direction, or hard landings. When it’s injured, the knee may feel unstable, swollen, and painful.
Diagnosing an ACL tear correctly is essential because treatment options range from physical therapy to surgery depending on the severity. To assess the ligament specifically, clinicians often use tests designed for the ACL, such as the Lachman test or the pivot-shift test, which directly evaluate ligament stability. Imaging, particularly an MRI, provides the most accurate glance at the soft tissue and helps confirm any diagnosis.
Because only about 8% of ACL tears are the “type I” variety most closely linked to medial meniscus tears, meniscal findings on physical exam don’t always point to an ACL injury. This nuance makes clear, targeted testing even more important.
Research consistently shows that the McMurray test is highly effective for diagnosing meniscal tears, but it’s not reliable for identifying ACL injuries. The test is specifically designed to stress the meniscus—not the ligaments. In contrast, the Lachman and pivot-shift tests are tailored to expose instability in the ACL by checking how much the shinbone moves relative to the thighbone.
Sometimes, the McMurray test may produce a false positive for an ACL tear, especially if there’s overlapping meniscal damage or acute inflammation, leading to pain during the maneuver. On the other hand, if the meniscus is intact, the McMurray test may entirely miss an ACL tear. This means that a positive McMurray result should never be used alone to diagnose ACL injuries.
Given these limitations, the McMurray test should be seen primarily as a tool for detecting meniscal tears. It is useful for identifying meniscal injuries—which can frequently occur alongside ACL tears and influence how the knee is treated—but when an ACL injury is suspected, doctors should turn to more specific tests like the Lachman or pivot-shift, with MRI used as confirmation.
Combining a thorough physical exam with imaging reliably paints the clearest picture of what’s going on inside the knee. For patients, this approach means a quicker and more accurate diagnosis, and a treatment plan tailored to the specific injuries involved.
The medical community continues to research and refine the best ways to diagnose knee injuries. Better diagnostic methods mean earlier, more precise detection and improved outcomes for patients.
In summary, the McMurray test remains a valuable and practical option for detecting meniscal injuries, but it isn’t sensitive or specific enough to diagnose ACL tears on its own. For ACL injuries, orthopedic providers depend on a combination of targeted physical tests and imaging studies. Staying up-to-date with current research helps clinicians choose the best diagnostic tools—and ensures that every patient receives the right care for their unique injury.
As our knowledge grows and techniques improve, both patients and providers can look forward to even greater accuracy in diagnosing and treating these common but complex knee injuries.
Tan, L., Liang, J., Feng, J., Cao, Y., Luo, J., Liao, Y., Cao, X., Wang, Z., He, J., & Wu, S. (2022). Medial meniscus tears are most prevalent in type I ACL tears, while type I ACL tears only account for 8% of all ACL tears. Knee Surgery, Sports Traumatology, Arthroscopy.
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