Reevaluating the McMurray Test in Diagnosing ACL Tears: A Biomechanical and Clinical Perspective

Introduction

ACL tears are among the most common and serious knee injuries, especially for athletes and active individuals. Quick and accurate diagnosis is critical for effective treatment and recovery. For decades, the McMurray test has been a go-to physical exam for assessing knee problems, mainly for detecting meniscus tears—the cartilage that acts as the knee’s cushion. However, some doctors have also used it in evaluating anterior cruciate ligament (ACL) injuries. With the evolution of medical knowledge and advanced imaging, it’s time to reconsider just how reliable the McMurray test is for diagnosing ACL tears specifically.

In this article, we’ll explore the test from both biomechanical (how the knee moves and functions) and clinical (how doctors use it) perspectives. We’ll break down its strengths and limitations, compare it with newer diagnostic tools, and discuss what this means for healthcare providers treating knee injuries.

Understanding the Knee and the McMurray Test

The knee is a complex joint made up of bones, ligaments, tendons, and cartilage—each working together for stability and smooth movement. The ACL, one of the knee’s crucial ligaments, acts like a strong rope keeping the shinbone (tibia) from sliding too far forward and controlling twisting motions. ACL tears often occur during sudden stops, quick pivots, or impacts—movements common in sports like soccer or basketball—and can lead to pain and instability.

The McMurray test was developed to help doctors detect meniscus tears. During the exam, the doctor bends and rotates the knee while feeling along the joint for clicking or pain. If a distinctive “click” is felt or heard, a meniscus tear is suspected. Over time, this test has sometimes been used to check for ACL tears as well. However, how well it really works for that purpose has been debated.

Research shows that McMurray test findings don’t always match classic injury patterns. For example, some patients report pain or clicking in areas of the knee that don’t follow the usual expectations, making it more difficult to interpret results. Studies indicate the test isn’t perfectly reliable: one large review found that the McMurray test had a sensitivity of 58.5% and a specificity of 93.4% for meniscus tears, meaning that while it can be highly accurate when positive, it often misses real injuries when negative.

Other studies have shown that only specific findings during the test, such as a palpable “thud” on the medial side of the knee, are strongly associated with actual meniscus injuries. Even then, the consistency between different examiners is only fair, and the test doesn’t catch all cases. This variability complicates its use, especially when trying to diagnose ligament injuries like ACL tears.

How Well Does the McMurray Test Detect ACL Tears?

It’s important to remember that the McMurray test was designed to spot meniscus tears, not injuries to the ACL. A positive result—typically a click or pain—suggests meniscus involvement, but not necessarily an ACL problem. While meniscus and ACL injuries often occur together, using the McMurray test alone to diagnose an ACL tear is unreliable.

Research comparing diagnostic techniques consistently shows that the McMurray test is less effective for ACL injuries than other tools. Advanced imaging like MRI provides detailed views of the knee’s soft tissues and is highly accurate in identifying ACL tears. Among physical exams, the Lachman test is more specific for evaluating the ACL’s stability. Furthermore, natural differences in knee anatomy and movement can affect McMurray test results, sometimes leading to false positives (signals injury when there isn’t one) or false negatives (misses a real injury).

Clinical studies have stressed these limitations, noting that the test can yield unexpected findings depending on the exact motion and location of knee pain or clicking. Ultimately, relying solely on the McMurray test risks missing ACL injuries or generating confusion when interpreting results. Instead, a combination of physical exams and imaging should be used to get the most accurate diagnosis.

What This Means for Doctors and Future Research

Based on current evidence, doctors should prioritize other diagnostic methods—such as the Lachman test and MRI—when evaluating possible ACL injuries. Ongoing education about knee biomechanics can also help clinicians refine their exam skills and interpret results with greater accuracy.

Looking ahead, continued research should aim to improve physical exam techniques and develop clear, evidence-based guidelines that account for individual differences in knee anatomy and injury patterns. This will help doctors diagnose ACL injuries sooner and more reliably, which is vital for patient outcomes.

Conclusion

A fresh look at the McMurray test reveals that while it remains a valuable tool for detecting meniscus tears, it isn’t reliable enough on its own for diagnosing ACL injuries. The best results come from using a combination of physical exams and imaging to fully assess knee injuries.

By integrating traditional techniques with modern advances, healthcare professionals can raise the standard of ACL injury diagnosis and care. With ongoing research and careful clinical practice, patients with knee injuries can look forward to better, swifter recoveries.