Heterotopic ossification (HO) has historically been a common radiographic finding after total hip arthroplasty (THA), with an incidence 10–40%. It is a potentially serious complication, with patients reporting pain and restricted motion. Perioperative protocols have changed over the years and now universally include tranexamic acid (TXA) and non-steroidal anti-inflammatories (NSAIDs). There is evidence that TXA and NSAIDs can help inhibit the development of HO. The primary objective of this study was to determine what the true incidence of HO is in modern THA and whether routine perioperative medications influence this. We secondarily aimed to understand whether there was a difference in HO formation between surgical approaches to the hip (direct anterior, posterior, direct lateral). A retrospective cohort was developed consisting of 315 consecutive patients undergoing total hip arthroplasty during the period of April 2023-June 2024 at a single academic centre. This cohort was then divided by surgical approach with 105 allocated to each group (direct anterior, posterior, lateral). Patients were included if they had an elective primary THA and had radiographs taken at 6 month or 1 year follow-up. A standard perioperative protocol is established at this institution with patients receiving between 1g–1.5g of preoperative and postoperative oral TXA. Patients also receive 14 days of celecoxib if no contraindications to this exist. Radiographs were independently assessed by 2 authors for the presence of HO and were graded according to the Brooker classification. Patient demographics, comorbidities and perioperative medications were collected. Regression was then performed to identify predictors of HO formation. 315 patients (105 direct anterior, 105 direct lateral, 105 posterior) underwent THA during the period of data collection. 5.5% (17/315) developed HO on a postoperative radiograph at 6 months or 1 year follow-up. Only 1.6% (5/315) of patients developed more than Brooker grade 1 HO, with all of these occurring in the direct lateral group. No patients with HO required any further intervention. Patients were significantly more likely to develop HO if they had a direct lateral approach to the hip or did not receive postoperative celecoxib due to a reported sulfa allergy or chronic kidney disease. Patients undergoing THA are unlikely to develop clinically meaningful HO with modern perioperative protocols. The use of celecoxib combined with a more muscle sparing surgical approach appeared to be associated with less development of HO in this series.
Sniderman et al. (Wed,) studied this question.