In a prospective study of 100 patients with internal derangement of the
knee, clinical diagnosis, arthrography, arthroscopy, and arthrotomy
findings were compared. The clinical diagnosis was correct in seventy-two
patients, correct but incomplete in ten, and incorrect in eighteen.
Arthroscopy was accurate in ninety-four, influenced surgical therapy in
fifty-five, and revealed unexpected disease in twenty-five patients. It was
found to be critical for diagnosis in sixteen patients. Twenty-three
additional patients were analyzed who underwent arthroscopy but not
arthrotomy. Unnecessary operations were avoided in twenty-one of these
twenty-three patients.