Incidence of bilateral scapholunate dissociation in symptomatic and asymptomatic wrists.

Purpose: Scapholunate dissociation (SLD) is thought to be a common cause of both acute and chronic wrist pain. Classically, this condition is attributed to a traumatic event and is thought to inevitably lead to the development of degenerative arthritis. Bilateral findings should thus be infrequent. The purpose of the present study was to determine the incidence of bilateral radiographic SLD and associated arthritic changes.

Methods: Demographic, radiographic, and clinical data were obtained from 124 patients with abnormal x-ray findings in at least 1 wrist. Radiographs reviewed included posteroanterior, lateral, and Moneim views of both symptomatic and asymptomatic wrists. Pathology was defined as a scapholunate gap ≥ 5 mm and/or a scapholunate angle ≥ 60°. Arthritic changes were assessed.

Results: A majority of the 124 patients (51%) were unable to recall any specific injury to their wrist. On the symptomatic side, 101 (81%) patients had a pathologic measurement for their scapholunate gap, and 109 (88%) had an abnormal angle measurement. On the asymptomatic side, 64 (52%) of the gap measurements and 87 (70%) of the angle measurements were pathologic. Ninety-nine patients (80%) had abnormal radiographic findings bilaterally for at least 1 variable on each side. Only 13 patients (11%) had a clinical instability pattern typical of SLD. Half the patients had radiographic degenerative changes at presentation.

Conclusions: Bilateral radiographic SLD is much more common than previously assumed, is often asymptomatic, and does not inevitably lead to degenerative arthritis. These findings should call into question the assumption of a uniquely traumatic etiology. Further, most patients presented with pathologies unrelated to the scapholunate articulation. Surgical intervention chosen on the basis of radiologic findings, in the absence of clinical instability, might not be the best course of action, unless criteria are established to determine which patients eventually develop arthritic changes or become symptomatic.

Type Of Study/level Of Evidence: Therapeutic III.