Research brief · 2026-09-09
Do NSAIDs Slow Tendon and Bone Healing?
Nonsteroidal anti-inflammatory drugs work by blocking cyclooxygenase enzymes that drive inflammation. Because inflammation is also an early step in tissue repair, researchers have long asked whether these drugs get in the way of healing. The answer splits sharply depending on whether you look at rats or people.
In rats, the evidence is consistent. Cohen's 2005 study in the American Journal of Sports Medicine performed rotator cuff repairs on 180 rats, then gave groups celecoxib, indomethacin or plain chow for 14 days. At two, four and eight weeks, both drug groups showed significantly lower failure loads than controls, with worse collagen organization. Five NSAID-treated repairs failed to heal at all, versus none in controls. A 2025 study by Bektas and colleagues found naproxen and celecoxib produced worse histological healing scores than acetaminophen.
The human evidence, focused on bone rather than tendon, is far less settled. Borgeat's 2018 systematic review in the Journal of Clinical Anesthesia found 16 human studies, only three randomized, covering 12,895 patients. They varied so much in drug, dose, duration and how nonunion was assessed that they could not be pooled, and overall quality was rated low. The reviewers concluded no clinical recommendation could be made.
Zura's 2016 analysis in JAMA Surgery examined insurance claims covering 309,330 fractures. The overall nonunion rate was 4.9 percent. Combined NSAID and opioid use carried an odds ratio of 1.84 for nonunion, but that variable measured the two together, not NSAIDs alone, and sat alongside smoking, diabetes and osteoporosis as risk factors.
The central limit is that every tendon-healing study in this record was conducted in rats. No human trial has measured NSAID effects on a healing tendon repair, no safe duration or dose has been established in a controlled human study, and nobody has reconciled the strong rat signal with the weak human one. Decisions about pain medication after an injury belong with a physician.
Sources
- Cohen DB et al. Indomethacin and celecoxib impair rotator cuff tendon-to-bone healing
- American Journal of Sports Medicine 2005
- Borgeat A et al. The effect of nonsteroidal anti-inflammatory drugs on bone healing in humans: a qualitative, systematic review
- Journal of Clinical Anesthesia 2018
- Zura R et al. Epidemiology of Fracture Nonunion in 18 Human Bones
- JAMA Surgery 2016
- Bektas E et al. Comparative effects of COX-2 selective and nonselective NSAIDs and acetaminophen on rotator cuff tendon-bone healing in a rat model
- Acta Orthopaedica et Traumatologica Turcica 2025
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