ACUTELY INJURED KNEE - EFFECT OF MR-IMAGING ON DIAGNOSTIC AND THERAPEUTIC DECISIONS

PURPOSE: To assess the effect of knee magnetic resonance (MR) imaging on the diagnosis and management of acute knee injury. MATERIALS AND ME THODS: Two orthopedic knee surgeons prospectively completed pre-and po st-MR imaging questionnaires on 84 of 91 consecutive patients with acu te knee injury. The pre- and post-MR imaging clinical diagnoses, certa inty regarding these diagnoses, other diagnostic tests, and subjective impression of the usefulness of MR imaging were determined. RESULTS: Seven hundred thirty-one of 840 pre-and post-MR imaging diagnoses agre ed. Agreement was lowest for medial meniscal injuries (54 of 84). Sign ificantly fewer meniscal injuries were suspected after MR imaging (P < .05). In 60 patients, the orthopedist changed at least one of the 10 potential diagnoses after MR imaging. Clinical diagnostic certainty in creased by a mean of 14% for all diagnoses. The increase in diagnostic certainty was greatest for medial meniscal injuries (30%), followed b y lateral meniscal injuries (21%). The proposed management changed in 41 patients, resulting in significantly fewer arthroscopic procedures (P < .01). The post-MR imaging management plans included 37% (27 of 73 ) fewer arthroscopic procedures. CONCLUSION: MR imaging affects the di agnosis and management of acute knee injury by decreasing the number o f arthroscopic procedures, improving clinician diagnostic certainty, a nd assisting in management decisions.