Magnetic resonance imaging to assess vascularity of scaphoid nonunions.

The unreliability of current methods of assessing of bone vascularity is well documented, precluding any prospective analysis of its influence on bone healing. In hopes of accurately predicting scaphoid vascularity, magnetic resonance imaging was used prospectively in patients with radiographic evidence of nonunion. Magnetic resonance imaging scans were compared to plain radiographs, tomograms, and the operative impressions of the surgeon. The diagnostic accuracy of each test was determined by a pathologist's interpretation of histological sections. Ten of thirteen surgical specimens were available for analysis. The magnetic resonance imaging scan accurately predicted scaphoid viability in all ten cases (three viable, seven avascular). This compared with diagnostic errors in six of ten plain radiographs, one of seven tomographs, and two of ten surgical assessments. Magnetic resonance imaging can accurately predict the vascularity of the ununited scaphoid. With further follow-up of these patients, the capability of the avascular scaphoid to heal will become evident. Definitive preoperative determination of the healing potential of scaphoid nonunions may then be possible, thereby aiding the surgeon's choice of the appropriate surgical procedure.