Finally a Way to Tell if that Meniscus Tear on MRI is Really causing Pain
For the past 30 years, we doctors have had the knee jerk reaction that a meniscus tear on MRI must be causing the patient’s knee pain. This assumption has lead to millions of unnecessary surgeries based on a recent study showing that in middle aged or elderly people, asymptomatic meniscus tears are common. This study unveiled that in many patients, meniscus tears are part of normal aging. This new theory of meniscus pathology has lead to two distinctly different meniscus tear types: the normal degenerative tear and traumatic tear that’s really causing pain. How does the doctor tell the difference? Our recommendation has been reinstating that tried and true method of physical examination (actually laying hands on the patient). However, a new test may allow doctors to make this diagnosis simply by looking for a biomarker in the patient’s knee. The researchers looked at a specific chemical in the synovial fluid (the normal fluid in the knee) and found this marker was present in painful meniscus tears caused by trauma but absent in meniscus tears that were degenerative in nature. (see also this PubMed link). This test will now allow your doctor to test for “enzymes” just he or she does when a patient presents with chest pain. In that situation the doctor can check for certain markers in the blood that are only present during a heart attack. The same research team has also found other biomarkers associated with a chronically loose ACL causing symptoms, so it looks like multiple tests may soon be available. The upshot? Beware of relying solely on an MRI to make a diagnosis without a thorough exam to confirm that finding, or a neat biomarker test!