Introduction:
The most frequent knee injury is meniscus tears. In general, medial meniscus tears occur more commonly than lateral meniscus tears, with a ratio of about 2:1. Meniscal tears can happen in young patients with acute knee injuries or elderly people with degenerative conditions.
A twisting action on the slightly flexed, weight-bearing knee typically occurs after sports injuries, usually leading to acute tears. There has been extensive testing of McMurray's test and joint line discomfort for meniscus tear diagnosis, although the results from different authors differ.
The wide variances documented influence clinical decisions about further diagnostic testing like Magnetic Resonance Imaging (MRI) before undergoing diagnostic arthroscopy, which is regarded as the most reliable and most popular knee joint surgery.
How Does the McMurray Test Work?
The McMurray test is a sequence of knee and leg movements used by medical professionals to identify a torn meniscus. The doctor can carry it out without specific tools or a separate visit since it is an in-office physical examination. The healthcare professional will move the knee and leg to check for discomfort or other symptoms. The McMurray test is frequently included in a preliminary examination for knee pain or following an accident.
The following actions could be part of the McMurray test:
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A doctor will instruct a patient to recline on their back and bend one knee.
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The doctor will stretch the knee while providing pressure and internally rotating the leg.
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The next step is for a doctor to apply pressure, externally rotate the leg, and extend the knee.
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The leg will subsequently be straightened.
The meniscus is subjected to light strain throughout the evaluation to simulate the strain placed on the knee during daily activities. The patient will be asked if they are in pain during the examination, and the doctor will feel and listen for knee popping.
What Does a McMurray Test Result Indicate?
It can be challenging to correctly diagnose meniscal pathology based on the results of the examinations. Joint line soreness has been identified as the only valid clinical sign of meniscal pathology in the most recent evidence-based strategy for treating acute soft tissue injuries to the knee. A positive McMurray test occurs when the physical examination results in the presence of pain and the joint making a sound that:
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Pops.
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Clicks.
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Snaps.
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Clunks.
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Thuds.
A lateral meniscus tear, which resides outside the knee, is indicated by a painful click as the knee is rotated inward. A medial meniscus tear, located on the inside of the knee, is indicated by a painful click as the knee is rotated outward.
What Is the Accuracy of the McMurray Test?
Specificity and sensitivity evaluate the precision with which a test can identify the existence or absence of a health issue. The test's sensitivity is its capacity to identify positive cases accurately, while its specificity is its capacity to identify negative cases accurately.
According to reports, the McMurray test has 84% specificity and 61% sensitivity ratings. However, certain research shows sensitivity can range from 16 to 70%, while specificity can be between 59 and 97%.
Because there are various alternative ways to administer the test, its accuracy may vary greatly. MRIs, however, had sensitivity and specificity of 93 % and 88 %, respectively, for medial meniscus tears and 79% and 96% for lateral meniscus tears. A meniscus tear cannot be accurately diagnosed with the McMurray test. However, it might simply be the first step a medical expert takes to identify a knee injury.
What Are the Risks Involved?
The McMurray test performed by the doctor poses no hazards to the knee. During the exam, there can be some minor pain or discomfort. According to several studies, the McMurray test may not be reliable for determining whether or not the meniscus is torn. The diagnosis of the injury is typically only the first step, though. Individuals will likely require at least one imaging test after the McMurray test because they will provide a more definite answer.
What Are Some of McMurray’s Modified Versions?
Several studies have evaluated the diagnostic usefulness of McMurray's test to that of modified tests. According to this study, axial loading and varus or valgus stress can improve the diagnostic usefulness of the original McMurray test. By Anderson and Lipscomb, the Medial-Lateral Grind test—which included a varus or valgus component missing from the original McMurray's test—was contrasted with McMurray's.
Kurosaka et al. enhanced the modification of the Medial-Lateral Grind test by contrasting McMurray's test to a pivot shift test that featured both the component of varus or valgus stress and an axial loading component. These authors say McMurray's test was less accurate than the axially loaded pivot shift test overall. Due to the inability to calculate confidence intervals utilizing the data the researchers provided, it is difficult to assess the accuracy of the results.
The final investigation by Sae-Jung et al. compared a modified variation to Kurosaka et al.'s enhanced axial compression but excluded added valgus or varus stress. Additionally, these researchers revealed that their modified test (the KKU test), which they changed, was highly specific for lateral meniscal tears. This suggests that the test can be utilized to figure out a condition when it is negative.
Even though it is difficult to compare results between studies due to the differences in the tests used, the results of this review indicate that the modified tests have superior diagnostic value than the McMurray test.
Conclusion:
According to the research findings included in this review, McMurray's test appears to have low intertester reliability. This is understandable, considering the technique's complexity and challenges in managing the quantity and the direction of forces among testers. This is crucial to remember while examining test results from research involving multiple examiners. The only available statistical evidence in this area reveals no difference between an expert and a novice tester, despite some research claiming that more clinical experience helps with accurate diagnosis.
