The benefit of magnetic resonance imaging for patients with posttraumatic radial wrist tenderness.

PURPOSE: To describe fractures revealed by magnetic resonance imaging (MRI) in a series of skeletally mature patients with radial wrist pain after an acute injury and clinically suspected to have a scaphoid fracture. Additionally, we attempted to assess the diagnostic value of radiographs and computed tomography (CT) in patients with scaphoid and other carpal fractures verified by MRI.

METHODS: We conducted the study prospectively over a 3-year period on skeletally mature patients presenting at our emergency department with tenderness on the radial side of the wrist after an injury. A total of 300 wrists in 296 patients underwent clinical and radiographic examination. We performed low-field, 0.23-T MRI of all injured wrists within 3 working days from inclusion in the study. If the radiographs or MRI revealed a scaphoid fracture, we immediately carried out a supplementary 16-slice CT scan of the wrist. We calculated the sensitivity and specificity of radiographs and CT for the diagnosis of scaphoid fractures using MRI as the reference standard.

RESULTS: We diagnosed a total of 224 fractures in 196 wrists using MRI; 42% were scaphoid fractures, 15% were distal radius fractures, 6% were triquetrum fractures, and 5% were capitate fractures. The most commonly found fracture combinations were that of the scaphoid and distal radius, followed by scaphoid and capitate fracture. The sensitivity of radiographs for visualization of scaphoid fractures was 70% and the specificity was 98%. Radiographic sensitivity for other fractures was less than 60%. The sensitivity of CT for visualization of scaphoid fractures was 95%, and between 75% and 100% for other fractures.

CONCLUSIONS: Low-field MRI showed a high incidence of fractures in patients with posttraumatic radial wrist tenderness and demonstrated more fractures than radiographs and CT. A scaphoid fracture was by far the most common injury. However, it is not clear whether diagnosis of subtle injuries only demonstrated on MRI improves outcomes.

TYPE OF STUDY/LEVEL OF EVIDENCE: Diagnostic I.