The Journal of Bone and Joint Surgery (American). 2006;88:140-147.
doi:10.2106/JBJS.F.00454
© 2006 The Journal of Bone and Joint Surgery, Inc.
Nonsteroidal Anti-Inflammatory Drug-Induced Fracture Nonunion: An Inhibition of Angiogenesis?
Mark Murnaghan, MB, BCh, BAO, MRCS(ED),
Gang Li, MB, BS, DPhil and
David R. Marsh, MD, FRCS(Tr&Orth)
Corresponding author: Mark Murnaghan, MB, BCh, BAO, MRCS(Ed) SpR in
Department of Trauma and Orthopaedic Surgery, Queen's University Belfast,
Musgrave Park Hospital, 20 Stockman's Lane, Belfast BT9 7JB, Northern Ireland,
United Kingdom. E-mail address:
m.murnaghan{at}qub.ac.uk
In support of their research for or preparation of this manuscript, one or
more of the authors received grants or outside funding from the Research and
Development Office of the Department of Health and Personal Social Services,
Northern Ireland, UK (grant #EAT/1884/01). None of the authors received
payments or other benefits or a commitment or agreement to provide such
benefits from a commercial entity. No commercial entity paid or directed, or
agreed to pay or direct, any benefits to any research fund, foundation,
educational institution, or other charitable or nonprofit organization with
which the authors are affiliated or associated.
Background: Approximately 5% to 10% of fractures may result in
delayed union or nonunion. The results of research done over the past three
decades have shown that the use of nonsteroidal anti-inflammatory drugs
(NSAIDs) has an inhibitory effect on fracture repair, but the exact mechanism
of action remains to be elucidated. Cancer research has identified that NSAIDs
impede cell proliferation by inhibiting angiogenesis. It is proposed that a
similar mechanism occurs in the induction of NSAID-induced nonunions. This
hypothesis was investigated in a randomized placebo-controlled trial of the
NSAID rofecoxib with use of a murine femoral fracture model.
Methods: Two hundred and forty mice were randomized to receive
either the nonsteroidal anti-inflammatory drug rofecoxib (5 mg/kg orally) in a
0.5% methylcellulose solution (the NSAID group) or the 0.5% methylcellulose
solution only (the control group). Two hundred and thirty-five of the 240 mice
underwent surgery to induce an open transverse middiaphyseal femoral fracture,
which was then treated with use of a custom-made external fixator. Five
additional animals underwent sham surgery with no fracture induced. Outcomes
measures included radiographic assessment, histologic analysis, biomechanical
testing, and use of laser Doppler flowmetry to assess blood flow across the
fracture gap.
Results: Radiography revealed similar healing patterns in both
groups; however, at the later stages (day 32), the NSAID group had poorer
healing. Histological analysis demonstrated that the control animals healed
quicker (at days 24 and 32) and had more callus and less fibrous tissue (at
days 8 and 32) than the NSAID animals did. Biomechanical testing found that
the control animals were stronger at day 32. Both groups exhibited a similar
pattern of blood flow; however, the NSAID group exhibited a lower median flow
from day 4 onward (significant at days 4, 16, and 24). Positive correlations
were demonstrated between both histological and radiographic assessments of
healing and increasing blood flow. NSAID-treated animals exhibited lower blood
flow and poorer healing by all parameters. Regression analysis, however,
demonstrated that the negative effect of NSAIDs on fracture repair is
independent of its inhibitory action on blood flow.
Conclusions: Following the development of a novel method of
analyzing functional vascularity across a fracture gap, we have demonstrated
that the cyclooxygenase-2 (COX-2) inhibitor rofecoxib has a significant
negative effect on blood flow across the fracture gap as well as an inhibiting
effect on fracture repair.
Clinical Relevance: COX-2 inhibitors are marketed as having low
side-effect profiles. We propose that these drugs should be used with caution
in all patients following osseous trauma and, in particular, after injuries
that may already predispose a fracture to a delayed union due to osseous,
vascular, or patient-related factors.

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