SCAPHOID NONUNIONS

Abstract

Our ability to treat scaphoid nonunions has improved dramatically. The degree of collapse and bone loss can be accurately assessed in waist fractures using sagittal images on CT scans. These nonunions require reduction and bone grafting to re-establish the normal geometry of the scaphoid. Magnetic resonance imaging helps evaluate whether or not avascular necrosis is present in the proximal pole. Because of the poor prognosis of conventional bone grafts, a vascularized bone graft is recommended as the primary treatment when AVN is present. The volar collapse of the humpback deformity is best corrected with a volar approach and the proximal pole nonunion is best approached using a dorsal approach. Nearly all proximal pole nonunions require a vascularized bone graft and all acute proximal pole fractures require open reduction and internal fixation. Using specially designed cannulated screws, the nonunions can be stabilized accurately to decrease the time to resolution of the nonunion and minimize the amount of time in a cast. Stable fixation requires that the screw fixation target the central portion of the scaphoid regardless of the type of screw design used. Using these techniques, the hand surgeon should be able to provide a reasonable prognosis for patients presenting with a scaphoid nonunion, and the treatment should result in functional range of motion, grip strength, and relief of pain.