Early Postoperative Displacement of Combined Pelvic Ring Injury With Acetabular Fracture

Combined pelvic ring and acetabular injuries present a management challenge. The literature on this topic is scarce, with few outcomes studies available. This retrospective study assessed whether the incidence of postoperative displacement and loss of reduction is higher with combined injuries compared with isolated pelvic ring injuries and isolated acetabular fractures. The charts and radiographs of 33 patients with combined pelvic ring and acetabular fractures treated operatively during a 7-year period at a single institution were reviewed. Pelvic ring and acetabular displacements were measured during the early postoperative period and compared with final follow-up measurements (minimum 5 months after surgery). Measurements also were compared with those from isolated pelvic ring fractures (n=33) and isolated acetabular fractures (n=33). Groups were matched for injury pattern and were propensity-matched by age and Injury Severity Score. Patients with combined injuries and patients with isolated pelvic ring injuries had similar initial pelvic ring reductions on anteroposterior and outlet view radiographs. By final follow-up, the combined injury group had experienced significant additional pelvic ring displacement. The presence of combined injury was an independent risk factor for postoperative pelvic ring displacement. Initial postoperative acetabular displacement was higher in the combined injury group compared with the isolated acetabular fracture group (2.6 +/- 1.8 vs 1.1 +/- 1.1 mm). By final follow-up, apparent displacement decreased significantly for both groups. Patients with combined pelvic ring and acetabular fractures were more likely to have poorer acetabular reduction and additional displacement of the pelvic ring component during the postoperative period compared with patients with isolated injuries.