Wiberg's center-edge angle in patients with slipped capital femoral epiphysis.

Wiberg's center-edge (CE) angle was measured in 104 patients with slipped capital femoral epiphysis (SCFE) to determine whether it correlates with a deeper acetabulum. Initially, the radiographs of 45 pre- and mild slip patients (group I) were measured using the contour of the femoral head to determine the head center (point C) as described by Wiberg's original article and, alternatively, using the acetabular line (Visser's method). In addition, the radiographs of 59 patients with moderate and severe slip (group II) were measured in both ways. The measurements were not statistically different between both methods and between the two groups. In 78 unilateral slips, the Mann-Whitney test did not show statistical differences between the normal side and the affected hip (p > 0.05). The Wiberg's CE angle of 58 patients was compared with that of a group control of the same age, gender, and race. The Wiberg's CE angle was significantly higher in patients with SCFE (p < 0.05), the same being true when comparing the white and nonwhite patients separately (p < 0.05 and p < 0.05, respectively). Theories involving biomechanical stress in the adolescent hip can explain the majority of slips occurring in an otherwise healthy child. The femoral head with a better coverage yields more shearing stress across the epiphyseal line. This, associated with hormonal disorders, trauma, or another deleterious factor, can progress to its failure.