ABSTRACT
The etiology of Kienbock's disease is not clear definitely. Lunate blood supply, its shape and ulnar variance have been counted as the etiologies of this disease. For years, ulnar variance supposed to be an important predisposing factor for Kienbock's disease. There are controversies on the role of ulnar variance in Kienbock's disease and it has recently been stated that negative ulnar variance is not a risk factor for Kienbock's disease. The aim of this study was to elucidate the role of the negative ulnar variance in Kienbock's disease in Iranian patients. In this study, ulnar variance was measured in standardized condition in 90 normal wrists and in 67 patients with Kienbock's disease who had undergone surgery over the past 15 years. The correlation between age, sex and ulnar variance was assessed. We tried to determine the role of ulnar variance in the development of Kienbock's disease. Mean ulnar variance in the control group was 0.477 millimeter and in the group with Kienbock's disease, it was -0.995 millimeter. Regarding age, both groups were similar and after stratification by sex, we found that sex had no role in the development of disease. The correlations between age and ulnar variance, and sex and ulnar variance in the control group were not statistically significant. However, comparing case and control groups, we found statistically significant correlation between negative ulnar variance and Kienbock's disease. In spite of recent reports, negative ulnar variance is a predisposing risk factor for the development of Kienbock's disease