Ulnar Variance in Scaphoid Nonunion

Beckground: Negative ulnar Variance can be a risk factor in Kienbock's disease, wrist instability, and scaphoid bone fracture, This Study focused on the ulnar variance-in wrists with scaphoid bone nonunion. Method: We retroapectively reviewed posteroanterior Wrist radiographs of. 65 patients who were diagnosed as established scaphoid nonunion and-underwent open reduction and bone grafting between 2006 and 2010. We used reference. radiographs from contralateral wrists of 65 consecutive skeletally- mature patients with distal radius-fracture-as the control group and then measured ulnar variance and compared it in both groups. Results: Ulnar variance was measured in standard posteroanterior wrist X-rays of 65 scaphoid nonunion and 65 normal controls. Twenty five patients (38.5%) in the scaphoid nonunion group had negative ulnar variance, and mean value was -0.26 (+/- 1.24) mm (range: -3, +2). in the control group, 15 subjects (23.1 %) had en ulnar minus wrist, and the mean ulnar variance was + 0.54 (+/- 1.47) mm (range: -3, +4) The difference in ulnar variance was significant between the two groups (P-value = 0.001). Conclusion: Ulnar variance may influence developing of nonunion-process in scaphoid bone fracture.