'False positive' MRI of the knee: a literature review study

A retrospective literature review study was performed because our group has seen an increasing number of patients with a "positive MRI" for torn meniscus being referred for arthroscopic surgery yet their clinical signs and symptoms do not fit that of a "torn meniscus."

Fifteen literature articles from 1989 through 1999 were evaluated for MRI studies on asymptomatic volunteers.

Starting in the third decade, there is "age-dependent degeneration" of the meniscus with increasing MRI signals in the meniscus in asymptomatic patients. By the fourth and fifth decades, significant MRI changes are present, especially in the medial meniscus, yet these patients were asymptomatic. Studies in the literature urge that "clinicians match clinical signs and symptoms with magnetic resonance imaging before instituting surgical treatment."

The authors of this paper encourage the MRI report to use the term "signal change--1, 2, 3" rather than describing them as "tears." A "tear" is a clinical-pathological diagnosis.