This piece is a companion to Pain Control and Healing: Using Anti-inflammatory Medications Wisely. That article covers what a general reader needs to know about anti-inflammatories during recovery. This one is for anyone who wants to see why the underlying science is genuinely unsettled, not just simplified for the sake of a shorter article.
The Mechanism Behind the Disagreement
Anti-inflammatory drugs like ibuprofen and indomethacin work by blocking an enzyme called COX-2, and COX-2 also happens to be required for bone-forming cells to develop properly. That’s a real, well-understood mechanism, and it’s the reason orthopedic surgeons have worried about these drugs for decades.
But the actual clinical evidence in humans has never resolved into a clear answer. A 2016 systematic review published in JBJS Reviews set out to explain why the research on this topic has stayed so divided for so long, by grading the quality of the studies themselves rather than just tallying their conclusions.
The Review’s Findings
Marquez-Lara and colleagues’ results are more revealing than a simple “the evidence is mixed.” Using a validated methodology scoring system, the review found that studies concluding NSAIDs harm bone healing were, on average, meaningfully lower quality than studies concluding NSAIDs are safe. Of the twelve human clinical studies included, only three were randomized controlled trials; the rest were retrospective reviews, a much weaker design for answering this kind of question. None of the twelve scored as high quality overall.
There’s also a citation pattern worth noting. Literature reviews that recommended avoiding NSAIDs cited, on average, far fewer clinical studies than reviews that concluded NSAIDs are safe to use. The three individual studies cited most often across all the reviews were all studies with negative conclusions, regardless of how strong those particular studies actually were on their own methodological merits. In other words, some of the caution around NSAIDs may reflect which studies got cited and repeated most, not necessarily which studies were most rigorous.
Timing and dose kept showing up as the variable that actually mattered, more than a simple yes-or-no on the drug class. In one of the better-designed studies included in the review, a short course of an anti-inflammatory wasn’t associated with higher nonunion risk, while a much longer course of the same drug was.
Outside the Scope of This Review
This particular analysis deliberately excluded a few related but distinct questions: heterotopic ossification (bone forming where it shouldn’t, common after hip replacement) and osseous ingrowth around metal implants. Those are real and separate bodies of research, with their own separate evidence base, and this review doesn’t speak to them directly. If your procedure involved implanted hardware, that distinction matters.
Further Reading
The original review: Marquez-Lara A, Hutchinson ID, Nuñez F Jr, Smith TL, Miller AN. “Nonsteroidal Anti-Inflammatory Drugs and Bone-Healing: A Systematic Review of Research Quality.” JBJS Reviews. 2016;4(3):e4.
- Publisher page: https://journals.lww.com/jbjsreviews/subjects/basic%20science/fulltext/2016/03000/nonsteroidal_anti_inflammatory_drugs_and.4.aspx
- PubMed abstract: https://pubmed.ncbi.nlm.nih.gov/27500434/
A related, freely accessible critical analysis on the same question: Pountos I, Georgouli T, Calori GM, Giannoudis PV. “Do Nonsteroidal Anti-Inflammatory Drugs Affect Bone Healing? A Critical Analysis.” ScientificWorldJournal. 2012. Full text: https://pmc.ncbi.nlm.nih.gov/articles/PMC3259713/