Pelvic dissociation in revision total hip arthroplasty: diagnosis and treatment.

Pelvic dissociation is a distinct but uncommon condition, which occurs in association with total hip arthroplasty, in which the superior aspect of the pelvis is separated from the inferior aspect by fracture. Because radiodense implants and cement can obscure pelvic discontinuity on plain radiographs, not all dissociations can be diagnosed preoperatively; therefore, a high index of suspicion for this condition should be maintained. In selected patients, CT angiography may be indicated. Successful treatment requires achieving initial stability of the socket, establishing conditions for long-term stability of the socket, stabilizing the pelvic dissociation, and producing conditions favorable for healing. Applying a posterior pelvic reconstruction plate to the ilium and ischium will achieve stabilization of the dissociation in most patients if sufficient posterior wall and column are present. Occasionally, if there is adequate space, a second plate may be applied. In selected patients, it may be feasible to place anterior column fixation screws using image guidance, which is the preferred technique of the authors rather than the alternate option of using anterior column plating through an anterior exposure. Residual bone loss is then reevaluated and possible options such as a hemispherical socket, a jumbo cup, or a highly porous metal component and augment can be considered. If there is not enough room for a posterior pelvic reconstruction plate, a cup-cage construct with or without an allograft can be used as a reconstruction option.