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Laying a Finger on Accurate Tests for Meniscal Tears

Even with all of today's technology, doctors still rely on their feelings -- literally -- to diagnose some problems. For example, there are 20 special tests to diagnose tears of the meniscus in the knee. But one of the oldest and best known tests is just to feel the joint for tenderness. The doctor feels along the joint line on the inside or outside of the knee. Tenderness along the inside points to a tear of the medial meniscus. Pain along the outside is more likely to be a tear of the lateral meniscus.

One doctor in Turkey compared the joint-line test to results of arthroscopic exams. Arthroscopy allows the doctor to look inside the knee with a special tool. The condition of the meniscus is clearly visible with this test. More than 100 young men, ages 18 to 20, were tested. All were injured as members of the Turkish army.

The doctor found that tenderness along the joint line gave the correct diagnosis in about two-thirds of the cases. This is called a true positive result, meaning that the joint line was tender and a tear was confirmed with the arthroscope. A false negative result is when there's no joint tenderness, but a tear is found in the meniscus. Another possible result is a true negative result, in which there is no tenderness and no tear.

The author reports that joint-line tenderness is more accurate for lateral meniscal tears. He was more likely to have false negative results with medial meniscal tears. In this study, there was a high false positive rate. A false positive means there is joint-line tenderness, but the arthroscope shows nothing wrong with the meniscus. The author thinks this may have been caused by recruits who had nothing wrong with them but who wanted sick leave.

References: Osman Tugrul Eren, MD. The Accuracy of Joint Line Tenderness by Physical Examination in the Diagnosis of Meniscal Tears. In Arthroscopy. October 2003. Vol. 19. No. 8. Pp. 850-854.

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