Evaluation of hip stability after simulated transverse acetabular fractures.

One of the major goals in managing acetabular fractures is the prevention of posttraumatic arthrosis. Unreduced fractures involving the weightbearing portion of the acetabulum may lead to posttraumatic arthrosis, whereas fractures outside this area portend a better prognosis. The purpose of this study was to help distinguish among fractures that require operative reduction, those that can be treated with traction, and those that require even less aggressive treatment. A model was developed to test hip stability after simulated transverse acetabular fractures. The results from this investigation suggest that transverse fractures with a roof arc angle of 90 degrees do not affect the weightbearing portion of the acetabulum. Fractures with a roof arc angle of 60 degrees begin to infringe on the weightbearing area, and those with roof arc angles of less than 60 degrees are clearly in the weightbearing region. Hip stability was significantly affected by the roof are angle and by the interaction of the roof arc angle and the angle of hip abduction or adduction. The data from the current study suggest that the area of the acetabulum considered to be weightbearing in transverse acetabular fractures may be more expansive than previously thought. The model developed may be used to investigate anterior and posterior column fractures.