Tears of the meniscus as revealed by magnetic resonance imaging.

Forty-four patients who were examined by magnetic resonance imaging and arthroscopy to detect tears of the meniscus of the knee were studied. Twenty-eight patients (Group I) had had no previous operations on the knee. Sixteen patients (Group II) had had a previous operation on the knee that had been performed after a meniscal injury. In Group I, the percentage of correct diagnoses by magnetic resonance imaging was 45 per cent. If the false-negative results are excluded, the rate of accuracy was 65 per cent. Similarly poor results were found in Group II: a rate of accuracy of 49 per cent and, if we eliminate the false-negative results, the rate of accuracy was only 55 per cent.