Radiotherapy for the prophylaxis of heterotopic ossification after total hip arthroplasty: A systematic review and meta-analysis of randomized controlled trails.

Heterotopic ossification (HO) refers to the formation of lamellar bone in soft tissues and is a significant complication after total hip arthroplasty (THA). Radiotherapy has been proven as an effective prophylaxis especially for those patients with high risk of HO after THA. However the dose, timing, and frequency of radiation have yet to be determined. To compare HO progressions with different radiotherapy strategies and explore an optimal radiation option. We systematically searched PubMed, Embase, and Cochrane Library for randomized controlled trails (through December 1, 2019; no language restrictions) collecting patients who accepted prophylaxis radiation for whom HO progression outcomes were reported. Of 87 identified studies, 10 randomized controlled trails including 1203 patients and 1268 hips were taken to this analysis. Compared with the low biologically effective radiation dose group (biologically effective dose [BED] < 20 Gy), the medium biologically effective radiation dose group (20 Gy ≤ BED ≤ 24 Gy) had statistically significant difference on the prophylaxis of HO (p = 0.003). But for overall incidence of HO, there was no statistically significant difference between low BED group and high BED group (BED > 24, p = 0.21). There was statistically significant reduction in the prophylaxis of HO progression with multiple fractions as opposed to single fraction radiotherapy (p = 0.04). Hips with preoperative radiation were no more likely to observe HO progression than those with postoperative radiotherapy (p = 0.43). Radiotherapy with medium dose (20 Gy ≤ BED ≤ 24 Gy) after THA is an effective dose for preventing HO. In the prophylaxis of HO, multiple fractions seem to be more effective than single fraction radiation. Preoperative radiotherapy could prevent HO progression with the same efficacy postoperative.