Acetabulum fractures: classification and management.

Twenty-two years of experience in this field allow us to say that a perfect open reduction is the method of choice to treat displaced acetabular fractures. But difficult cases require experience. Late follow-up of hips treated by open reduction and internal fixation supports the contention that a satisfactory outcome can be expected if the fracture reduction is perfect. The converse applies, and in some instances it would have been better to accept the result which might have been obtained by conservative methods. The type of fracture dictates the choice of approach, but the indication for operative treatment as well as the result of acetabular fracture treatment is the degree of congruence achieved between the acetabulum and the femoral head. Incongruence may be total, partial or apparent. Total incongruence is seen in both persistent posterior or central dislocation in which, on all three standard radiographs, the fragments of the acetabulum are seen separated from the femoral head. The situation may exist from the moment of trauma or following attempts at reduction. In all instances, operative treatment is indicated. With partial incongruence, the femoral head lies well centered beneath an undisplaced fragment of roof, but other fragments of articular surface remain displaced. A very good clinical result cannot be expected in more than 55% of hips left in this state, and neglecting operative complications, the same can be expected following conservative management. A small degree of incongruence can be accepted but one of the difficulties lies in determining the size of the fragment "roof" left in situ. Certainly, congruency seen on one standard radiograph and not in the others must not be accepted, and surgical treatment is indicated. With apparent congruence, the fragments of shattered acetabulum have regrouped around a displaced femoral head and exhibit a fair degree of congruence in this displaced position. Examples like this can often be treated conservatively because while surgery may achieve a better true congruence, this cannot be guaranteed and will be accompanied by the risks of operation. Further, the result could be worse. In nine acetabular fractures, it has been possible to achieve an apparent congruence by reconstituting displaced acetabular fragments around the femoral head but accepting the overall displacement. Seven of these obtained very good clinical results but it should be emphasized that the need to resort to this approach has been very infrequent.