Radiation Therapy for Heterotopic Ossification: A Systematic Review

Heterotopic ossification (HO) is a benign disorder characterized by ectopic bone formation in soft tissues that can lead to functional loss in patients. We conducted a systematic review of the evidence on the use of radiation therapy (RT) for the prevention or treatment of HO.

Literature searches were conducted using Medline (via PubMed), Embase, and ClinicalTrials.gov until April 1_, 2023. Medical subject headings and free text terms relevant to HO and RT were used. In brief, eligible study participants were ≥18 years of age with HO and were treated with low-dose external RT. Two reviewers screened relevant abstracts and extracted full-text data for analysis. The review followed the Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines.

Ten studies evaluating the effect of RT for either the prevention or treatment of HO met the inclusion for evidence synthesis. Nine randomized controlled trials did not clearly report their methods and had a medium risk of bias. The studies were conducted between 1988 and 2008, with follow-up ranging on average from 3 to 59 months posttreatment. A total of 1530 participants were analyzed, and 566 were treated with RT following fracture fixation, total hip arthroplasty, or total hip replacement. In pooled data from 8 randomized controlled trials, there was a nonsignificant but clinically meaningful reduction in the presence of HO at follow-up for patients who received RT versus comparators (pooled odds ratio, 0.47; 95% CI, 0.19, 1.17). There was minimal evidence of adverse events.

This systematic review found a clinically, but not statistically, significant benefit of prophylactic RT for HO at follow-up. These findings are tempered by a moderate risk of bias. While practice patterns vary, RT for HO prophylaxis in high-risk patients may have benefits that outweigh the risks.