Incidence and independent predictors of heterotopic ossification after posterior acetabular fixation without routine...

Heterotopic ossification (HO) is a frequent complication of acetabular fracture fixation; however, the optimal strategy for prophylaxis remains controversial. This study aimed to evaluate the incidence and clinical course of HO after posterior acetabular fixation performed without routine prophylaxis, and to identify independent predictors of its development.

A cohort of 257 consecutive patients who underwent acetabular fracture fixation via the Kocher-Langenbeck approach between 2001 and 2023 at a Level I trauma center was retrospectively analyzed. No routine postoperative prophylaxis with non-steroidal anti-inflammatory drugs or radiation therapy was administered. The patients were followed up for a minimum of 12 months (mean, 53 months). HO was graded according to the Brooker classification. Potential risk factors for HO development were examined using univariate and multivariate logistic regression analyses.

HO developed in 34 (13.2%) patients, with 23 (9.0%) demonstrating clinically significant HO (Brooker grade III or IV). Radiographic HO was first detected at a mean of 6.7 weeks postoperatively. Among the patients with HO, seven (20.6%) developed painful ankylosis requiring surgical excision at a mean of 11.5 months after diagnosis: one had Brooker grade III HO and six had grade IV HO. Univariate analysis demonstrated significant associations between HO and traumatic brain injury, mechanical ventilation, traumatic hip dislocation, femoral head fracture, and retained intra-articular debris (all p < 0.05). After adjustment for confounding factors, traumatic brain injury (odds ratio [OR], 6.98; 95% confidence interval [CI] 3.03-16.08), mechanical ventilation (OR, 9.49; 95% CI, 3.70-24.32), and retained intra-articular debris (OR, 7.42; 95% CI, 3.01-18.29) remained independent predictors, whereas hip dislocation and femoral head fracture were no longer significant.

In this cohort, posterior acetabular fixation without routine prophylaxis was associated with a relatively low incidence of clinically significant HO, comparable to the rates reported in a contemporary series. HO development is primarily associated with markers of systemic injury severity and the presence of retained intra-articular debris. These findings suggest that risk stratification based on injury severity and meticulous intra-articular management may be appropriate for determining the need for HO prophylaxis.