Occult isolated fracture of the trapezoid diagnosed by ultrasonography.

PURPOSE: To describe a patient with an occult isolated trapezoid fracture of the wrist. Isolated trapezoid fractures are very difficult to detect without advanced radiological imaging, since the fragment displacement does not occur in the sagittal plane. A discussion regarding the investigation of trapezoid fractures utilizing multiple imaging modalities includes the first demonstration of its detection via ultrasonography (US). METHODS: A 26-year-old male presented to a chiropractic teaching clinic with pain involving the left wrist, after vaulting over the handlebars of his bicycle 2 days prior. The mechanism of injury was hyperflexion of the left wrist. Left wrist pain, reduced range of motion, and dorsal soft tissue edematous changes were identified at examination. Although the initial radiographic examination was negative, elevated clinical suspicion triggered an US examination 4 days later. The US exam demonstrated an isolated 1.8 mm dorsal trapezoid fracture, which was minimally displaced by 0.7 mm. RESULTS: Following the US diagnosis of an isolated trapezoid fracture, the wrist was immobilized. The patient elected to not pursue an orthopedic consultation. Conservative care included ice and Class IV therapeutic laser therapy. The patient reported complete alleviation of clinical symptoms after approximately 2 weeks of splinting and treatment. CONCLUSION: We emphasize the limitations of radiography in the diagnosis of this fracture. To our knowledge, this is the first case to describe the use of US in the diagnosis of an isolated trapezoid fracture.