Surgical resection of severe heterotopic ossification after open reduction and internal fixation of acetabular fractures: a case series of 18 patients

Abstract

Objective: To evaluate the clinical results of surgical resection of severe heterotopic ossification (HO) after the open reduction and internal fixation (ORIF) of acetabular fractures.

Methods: A retrospective chart review was performed between October 2005 and November 2010 on patients undergoing severe HO resection following an acetabular fracture ORIF. Our primary outcome was functional status evaluated by the Harris hip score (HSS). HO resection and hip release was performed using a Kocher-Langenbeck approach in all cases, and a combined radiation and indomethacin regimen was used to prevent HO recurrence. Plain radiographs were also used to evaluate the hip joint for arthritic changes and HO recurrence.

Results: A total of 18 patients (17 males and 1 female) were included in our study analysis. The mean patient age was 36.8 (range: 22-54 years old) when HO resection surgery was performed. The mean time interval between acetabular fracture ORIF and HO resection was 9.9 months (range: 3-30 months): it was within 6 months in 7 patients, 6-12 months in 8 patients, and >12 months in 3 patients. The HO was graded as Brooker grade III in 8 patients and grade IV in 10 patients. The mean time interval between HO resection and the latest follow-up was 4.5 years (range: 2.1-7.8 years). The mean Harris hip score (HHS) was 84.5 (range: 38-100), with a clinical outcome rating of excellent in 9 patients, good in 3 patients, fair in 4 patients, and poor in 2 patients (good and excellent rating accounted for 66.7%). The mean hip joint motion arc was 194° (range: 90-260°). Complications included one intraoperative femoral neck fracture, 1 sciatic nerve injury, 2 femoral head avascular necrosis, and 6 mild HO recurrences (33.3%). There was 28.6% recurrence if HO resection was within 6 months and 36.4% if >6 months. There were no cases of severe HO recurrence, wound infections, deep vein thrombosis, or pulmonary embolism.

Conclusion: The early surgical resection of severe HO after an acetabular fracture ORIF can provide satisfactory results, however the complication rate is relatively high.

Keywords: Acetabular fracture; HO; HO resection; Heterotopic ossification; ORIF; Resection.