MRI of the knee: its cost-effective use in a district general hospital.

In the first year of magnetic resonance imaging (MRI) scanning of the knee in the East Berkshire Health District, 175 patients were scanned and 79 of these subsequently had an arthroscopy performed. We found that MRI accurately demonstrated the pathology present in the knee, particularly for meniscal lesions, although it was less accurate for anterior cruciate and cartilage lesions. The relative costs of MRI scanning, arthroscopy and conservative treatment are compared. On the basis of this analysis we have worked out a protocol for the cost-effective use of MRI in imaging the knee. This protocol has reduced the number of arthroscopies performed, allowing us to expend resources on patients who would definitely benefit from arthroscopic surgery.