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.