Bilateral pelvic discontinuity: a unique condition characterized by high failure rates of current treatment

BACKGROUND: Bilateral pelvic discontinuity is characterized by complete dissociation of the superior and inferior pelvis secondary to bone loss or fracture. The end result is a freely mobile inferior pelvis at the level of each discontinuity which presents a significant reconstruction challenge. This clinical entity has not been described previously, and the results of surgical treatment are not known. METHODS: We retrospectively reviewed all identified cases of pelvic discontinuity (PD) treated with revision THA at one institution. We identified 133 pelvic discontinuities. Within this group, 6 patients had bilateral simultaneous PDs. Preoperative, intraoperative, and postoperative data and radiographic imaging were reviewed preoperatively and postoperatively for the characteristics of the dissociation and assessing PD healing and fixation of components after surgery. RESULTS: There were no preoperative factors that could distinguish these patients from the rest of the group of discontinuities (3 rheumatoid arthritis, 2 osteonecrosis of the femoral head, 1 developmental dysplasia). The reconstructions performed included 2 cup/cage, 5 posterior plating and uncemented cup, 3 cage alone, and 2 cups only. Ten of 12 hips had at least 1 complication postoperatively. At final follow-up, only 1 patient (17%) had radiographic evidence that both discontinuities had healed (posterior plate with uncemented cup). CONCLUSIONS: Bilateral pelvic discontinuity is rare but presents the surgeon with a major reconstructive challenge. Only 1 patient went on to radiographic healing with current treatment strategies. Continued motion of the contralateral pelvic dissociation may account for the high failure rates. Surgeons should be aware of the challenges presented by this diagnosis and develop strategies to improve outcomes.