Forty-nine of the 300 patients went on to have arthroscopy, a minimally invasive surgical procedure in which a small incision is made in the joint and a fiber-optic cable with a video lens and light source on the end is inserted to examine possible tissue damage. In addition, 35 of the arthroscopy candidates were examined with magnetic resonance arthography, a procedure in which a series of X-rays is taken of a joint, followed by an MRI scan that images the contrast fluid that's injected to produce the X-rays.
According to Magee, the MRI scans generated no false positives and detected most of the wrist ligament and cartilage tears later found by surgeons during arthroscopy. MRI was a bit less sensitive than MR arthrography, but generated fewer false positives. The analysis found: -- The 49 patients who had arthroscopy had a total of 51 tears, including 22 triangular fibrocartilage complex (TFCC) tears, 18 tears in the scapholunate (a ligament), and 11 tears in the lunatotriquetral (another ligament).
-- MRI detected 19 of the TFCC tears, 16 of the scapholunate tears, and nine of the lunatotriquetral tears. -- Compared with arthroscopy, MRI sensitivity was 86 percent for triangular fibrocartilage complex tears, 89 percent for scapholunate tears, and 82 percent for lunatotriquetral tears. -- There were no false positives. - Compared with surgery, MR arthrography sensitivity for detection of ligament and triangular fibrocartilage complex tears was 100 percent. However, there were three false positives.