Adam C. Zoga MD, Presenter: Nothing to Disclose

William Brian Morrison MD, Abstract Co-Author: Nothing to Disclose

Joshua D. Mamelak MD, Abstract Co-Author: Nothing to Disclose

Randall W. Culp MD, Abstract Co-Author: Nothing to Disclose

Ulnar sided wrist pain is a common indication for MRI, with many potential etiologies. Triangular fibrocartilage complex(TFCC) tears can be difficult to diagnose by MRI. Anecdotally, we have noted subcortical hyperintensity at the dorsum of the distal ulna, subjacent to the extensor carpi ulnaris(ECU) tendon on fluid sensitive sequences with some frequency. Though described in the ankle, to the best of our knowledge, subtendinous bone marrow edema(BME) has not been reported in the wrist. We sought to describe this pattern of ECU subtendinous BME and correlate its presence on MRI with findings at arthroscopy.

37 patients had MRI for dorsal or ulnar sided wrist pain and had subsequent arthroscopy within 6 months. Retrospectively, preoperative MRI exams were reviewed by two MSK radiologists and the presence of subtendinous BME at the ECU was recorded, as was abnormal ECU signal, ECU tenosynovitis, distal radial-ulnar joint effusion and visible TFCC defects. Arthroscopy reports were then reviewed and compared with MRI findings to assess the significance of ECU subtendinous BME.

23 of 37 patients had subtendinous BME. All 9 patients with peripheral TFCC tears at arthroscopy had subtendindinous BME on MRI. 12/15 patients with central TFCC tears had subtendinous BME. All 6 with ulnar extrinsic ligament tears as well as the 1 patient with a reported ECU tear at arthroscopy had subtendinous BME. Of the patients with the subtendinous BME, 22/23 had either a TFCC tear, ulnar extrinsic ligament tear or ECU tear at arthroscopy. Of the 14 patients with no subtendinous BME, 11 had no TFCC tear and 3 had a central TFCC tear. In this group there were no peripheral TFCC tears or ulnar extrinsic ligament tears at arthroscopy.

Bone marrow edema subjacent to the ECU at the distal ulna is a harbinger of TFCC, ulnar extrinsic ligament or ECU injury with surprising specificity, especially in the setting of peripheral TFCC tears. Potential pitfalls include artifacts related to ulnar proximity to the receiver coil and marrow edema from direct trauma. Nevertheless, ECU subtendinous bone marrow edema should be observed and should raise suspicion for associated soft tissue injury.

Zoga, A, Morrison, W, Mamelak, J, Culp, R, Subtendinous Bone Marrow at the Extensor Carpi Ulnaris as a Harbinger of Triangular Fibrocartilage Tear.  Radiological Society of North America 2005 Scientific Assembly and Annual Meeting, November 27 - December 2, 2005 ,Chicago IL. http://archive.rsna.org/2005/4412971.html