[Bulge of the scapholunate ligament: an arthro-CT sign of traumatic scapholunate instability].

Tears of the scapholunate ligament are usually diagnosed during an arthro-CT or arthro-MRI examination. Typically, the contrast agent passes from one joint to the other. In certain cases, fibrous scar tissue devoid of any mechanical effect may block the passage and lead to an erroneous interpretation of the images. We reviewed retrospectively patients who underwent arthroscopic treatment for scapholunate tears and who had normal arthro-CT images. We searched for specific aspects suggestive of ligament injury. Analysis of the arthro-CT images demonstrated that a bulge of the scapholunate ligament could be noted in patients whose diagnosis of scapholunate ligament injury was established arthroscopically. We propose that appropriate lecture of wrist images can identify scapholunate ligament injury in patients wrongly considered to be free of wrist injury, but who actually have an occult injury to the scapholunate ligament.