Accuracy of Wrist MRI in Detecting Synovitis and Correlation with Arthroscopy.

Wrist magnetic resonance imaging (MRI) has shown excellent diagnostic accuracy in evaluating soft-tissue pathology of the wrist including ganglion cysts, ligament tears, and triangular fibrocartilage complex (TFCC) pathology. However, it is unclear how often MRI detects synovitis that is subsequently encountered during wrist arthroscopy and may be a source of pain for patients with symptoms unresponsive to conservative treatment. The aim of this study is to assess the diagnostic accuracy of conventional MRI in the detection of wrist synovitis observed intraoperatively with wrist arthroscopy.  A retrospective chart review was performed on 51 patients who underwent arthroscopy for chronic wrist pain and MRI confirmed wrist pathology that did not resolve with nonoperative treatment. Wrist arthroscopy was performed by three fellowship-trained hand surgeons. While the primary pathology like TFCC or scapholunate ligament tear was identified and treated arthroscopically, it was noted that many of the patients had concomitant synovitis observed arthroscopically that was not identified preoperatively on MRI. Therefore, the diagnosis of wrist synovitis on MRI scan was compared with the observed presence of synovitis at the time of wrist arthroscopy. Results of preoperative MRI without contrast were categorized as true positive, false positive, true negative, and false negative, based upon intraoperative arthroscopic findings.  In total, 45/51 patients were confirmed to have dorsal and ulnar synovitis on wrist arthroscopy. MRI identified 16/51 patients as having synovitis. Of those 16 patients, 2 were false positives.  The results demonstrate that conventional MRI without contrast has poor diagnostic accuracy in detecting wrist synovitis. Patients with ligament or chondral pathology or no clearly identifiable pathology on MRI whose clinical symptoms persist despite conservative treatment may have underlying dorsal and ulnar wrist synovitis that is not detected on MRI. Wrist arthroscopy facilitates the identification and treatment of synovitis in patients with concomitant wrist pathology and pain refractory to nonoperative treatment. This study suggests that MRI may have a low sensitivity for identifying wrist synovitis when compared with wrist arthroscopy during the evaluation of patients presenting with wrist pain.