Effectiveness of indomethacin in preventing Heterotopic Ossification: a systematic review and meta-analysis of randomized controlled trials

Heterotopic ossification (HO) is a frequent complication of joint trauma or surgery, commonly occurring after hip replacements, acetabular or other joint injuries, or surgeries. Indomethacin has long been used to prevent HO and is considered the first-line therapy. However, its effectiveness and necessity for HO prevention are still debated due to mixed evidence about its efficacy and potential side effects.

Following PRISMA guidelines, this systematic review and meta-analysis evaluated randomized controlled trials using the PICO framework. Searches were conducted across PubMed, Embase, Cochrane Library, and Web of Science. Data were extracted and assessed based on the evidence levels of the selected articles. This study was registered with the International Platform of Registered Systematic Review and Meta-analysis Protocols (INPLASY).

This analysis included 665 patients, with 347 in the Indomethacin group and 318 in the No Indomethacin group. The outcomes analyzed—HO, Gastrointestinal Side Effects, and Bone Ununion—indicated that indomethacin effectively prevents HO. The meta-analysis revealed that the Indomethacin group experienced a significant reduction in the occurrence of grade I-II HO compared to the No Indomethacin group, but not for grade III-IV HO. Gastrointestinal side effects were notably higher in the Indomethacin group. The incidence of bone nonunion was higher in the Indomethacin group, although not statistically significant.

The meta-analysis suggests that indomethacin is effective in preventing HO, particularly for Brooker grade I-II, rather than Brooker grade III-IV. Special attention should be given to gastrointestinal complications when using indomethacin. Further prospective randomized controlled studies are required to confirm these findings.