The authors performed a prospective study to correlate preoperative gadolinium-enhanced MRI scans with postoperative union in 60 patients with established scaphoid nonunions. Scaphoid reconstruction was performed using a non-vascularized bone graft and intramedullary screw fixation. Fracture consolidation was determined in 54 cases (90%) by 12 weeks. Ten of 11 scaphoids with an avascular proximal pole on enhanced MRI united. The authors conclude that there is no significant correlation between preoperative MRI assessment of vascularity and subsequent union of the scaphoid.
Previous studies have provided conflicting information regarding the effectiveness of a preoperative contrast-enhanced MR assessment in predicting the outcome of reconstructive scaphoid surgery (Cerezal et al., AJR 2000; Singh et al., JHS Br 2004). The current study shows a high rate of healing after nonvascularized bone grafting of scaphoid nonunions in cases with avascular proximal poles as defined on contrast-enhanced MRI. Although not specifically addressed in this study, near anatomic fracture reduction and rigid construct stability may have positively influenced the union rate. Alternatively, the MRI scans may have failed to depict minor perfusion of the proximal pole that was sufficient to allow healing.