Incidence of Heterotopic Ossification Without Additional Long-Term NSAID Prophylaxis After Periacetabular Osteotomy and Concomitant Hip Arthroscopy.

Abstract

Background: Periacetabular osteotomy (PAO) is an established treatment for hip dysplasia and has been increasingly combined with concomitant hip arthroscopy to address additional intra-articular hip pathology. Heterotopic ossification (HO) is a complication of arthroscopic and open hip procedures. Nonsteroidal anti-inflammatory drugs (NSAIDs) have become an established form of HO prophylaxis, but their use may delay bone healing.

Purpose: To examine the incidence of HO without NSAID prophylaxis in patients after PAO with concomitant hip arthroscopy and to evaluate the impact of other variables on the development of HO in these patients.

Study design: Case series; Level of evidence, 4.

Methods: Of 243 hips that underwent PAO with concomitant hip arthroscopy by a single surgeon over 11 years, 182 met the study inclusion criteria. No patients were discharged on NSAIDs for HO prophylaxis, although most took up to 6 weeks of aspirin 81 mg as part of the prophylaxis protocol for deep venous thrombosis. Radiographic images at 2 weeks, 6 weeks, and 3 months postoperatively were reviewed and graded for HO using the Brooker classification. Patient characteristics and surgical variables were recorded. The chi-square and t tests were used to determine HO incidence rates, compare groups, and identify variables associated with the presence of HO.

Results: The incidence of radiographic HO was 6.6% (12/182 hips). Nine hips were Brooker grade 1, 2 were grade 2, and 1 was grade 3. Four patients experienced clinical symptoms of HO- including pain and restricted motion. Only 1 patient required a return trip to the operating room for surgical excision. Male patients were significantly more likely to develop HO than female patients (P = .01). No other demographic or surgical factor influenced the development of HO. There were no cases of nonunion.

Conclusion: There was a low incidence of HO and symptomatic HO in patients who underwent PAO with concomitant hip arthroscopy without using NSAIDs for HO prophylaxis. HO was significantly more likely to develop in male patients. Given the potential risk of NSAID use on bony union, the low incidence found in this study may obviate the need for postoperative HO prophylaxis.