Obvious radiographic scapholunate dissociation: X-ray the other wrist.

Obvious radiographic scapholunate dissociation seen on plain radiographs may seem to establish the diagnosis in a patient who presents with wrist pain. This diagnosis, however, is based on the assumption that scapholunate dissociation is caused only by trauma. In questioning this assumption, we present 6 cases of obvious radiographic scapholunate dissociation with similar radiographic findings in both wrists. These cases illustrate the pitfalls of using unilateral wrist radiographs to diagnose traumatic scapholunate dissociation. We chose these cases as representative of more than 75 bilateral cases we are studying. We describe medical histories, physical findings, radiographs, other diagnoses, treatments, and outcomes. These patients' injury histories and clinical presentations were not necessarily suggestive of wrist instability. All the patients were asymptomatic in the contralateral, uninjured wrist, despite similarity in radiographic findings. Traumatic scapholunate dissociation cannot be diagnosed with unilateral radiographs, no matter how obvious the findings or suggestive the history of trauma.