Five cases of early dissociation between the bipolar hip endoprosthesis cup components; either spontaneously or during reduction maneuvers.

Bipolar hemiarthroplasty is frequently used in the treatment of intracapsular hip fractures. Dissociation of the bipolar components can happen during the hip dislocation, the reduction maneuvers, or spontaneously without any dislocation. Here we report early dissociation between bipolar components in two cases during the attempt of closed reduction maneuvers and three cases with spontaneous dissociation without any trauma. To prevent or minimize this complication; the reduction of dislocated hips must be achieved very gently under general anesthesia with fluoroscopic control. During the initial operation the surgeons must be sure that the bipolar components are locked to each other and after final reduction, especially in osteoarthritic acetabulums, that the cup position is not in varus position.