Deformation of femoral intramedullary nails. A clinical study

Deformation of femoral intramedullary nails is a common complication, occurring in 78% of fractures. Presenting as curvature or angulation, deformation is attributable to either elastic or plastic bending of the nail at the time of introduction of the nail. Generally, deformation is not associated with clinical complications. Angulation can be plastic deformation associated with delayed fracture union, and is induced by weight-bearing on fractures with cortical weakness (comminution or deficiency), especially if the nail is of small diameter. Malunion, also associated with angulation, was not a clinical problem, because the maximum displacement was only 10 degrees. Theoretically, larger displacement are possible. Attempts to prevent angulation by protecting the limb in a weight-relieving caliper were unsuccessful. The best method of prevention is a careful selection of patients to avoid nailing those comminuted fractures in which angulation is likely to occur. If angulation occurs, it may be a prognostic sign of delayed union.