MRI SCANS IN ARTHRITIC KNEES – AN UNNECESSARY INVESTIGATION?

This study evaluates the relationship between radiographic knee osteoarthritis and the presence of a relevant meniscal tear detected with MRI in symptomatic patients over the age of 60. Seventy-seven patients over 60 investigated with a knee MRI in a 1 year period were identified. 60 patients had a full set of data available for analysis. The plain radiographs were graded for osteoarthritis using the Kellgren – Lawrence (K-L) scale in a blinded manner. The indication for the MRI was subdivided into: meniscal symptoms, general knee pain and other. These indications were correlated with the K-L grade and result of the MRI. Overall, 40% of patients with a K-L grade of 0 had a meniscal tear compared to 89% of patients with a K-L score of 3 and 88% with a K-L score of 4. The indication for a MRI was meniscal symptoms in 49, general pain in 6 and other in 5. In the group investigated for meniscal symptoms, the incidence of meniscal tears was 92% and 100% with a K-L grade of 3 and 4 respectively. In patients with meniscal symptoms and significant radiographic osteoarthritis the outcome of the MRI is so predictable that the scan is unnecessary.