Heterotopic ossification prophylaxis after acetabular fracture fixation using a posterior approach: a retrospective study at a level 1 trauma center

Background: Heterotopic ossification (HO) is a known complication of acetabular fracture repair. After surgery, standard methods for HO prevention involve observation, radiation therapy, or a course of nonsteroidal antiinflammatories (indomethacin). Methods: A retrospective chart review was performed to analyze the effectiveness of radiation and indomethacin as HO prophylaxis after acetabular fracture surgical repair. Data were analyzed from 117 patients who underwent stabilization of the acetabulum utilizing a posterior approach from 2016 to 2020. Patients were classified into three groups based on the postoperative therapy received: radiation therapy, indomethacin therapy, or no prophylaxis. Grade of HO for each patient was determined by examining pelvic radiographs using the Brooker classification system at the most recent follow-up. Incidence of total and severe HO was recorded for each group and compared. Demographics, follow-up time, injury severity, and other trauma characteristics also were reported. Statistics were calculated using a combination of analysis of the variance (ANOVA), chi square, and Kruskal-Wallis testing. Results: The indomethacin group was younger than the other two groups with a shorter average follow-up time. The radiation group demonstrated a lower incidence of severe and total HO compared to the control group. The indomethacin group had significantly less total HO than the control group. Conclusions: With a decreased incidence of severe HO in the radiation group compared to no prophylaxis, this study supports the utility of radiation therapy as HO prophylaxis following acetabular fracture repair using a posterior approach. It shows a trend indicating that indomethacin also may be useful. Level of Evidence: Level III.