NSAIDs and Fracture Healing
by Michael Hwang
In a recent review on orthopaedic research by Rodeo et al (1), the authors assert
that, “It has been well established that nonsteroidal anti-inflammatory drugs can inhibit
bone-healing.” However, contrary to what many believe, the literature does not support
such a unanimous conclusion.
The first experiments on the effect of NSAIDS on fracture healing occurred in
animals. One of the earliest was a randomized controlled trial in rats by Allen et al in
1980 (2). The authors took 210 rats and subjected them to fractures of their right ulna
and radius. These rats were then divided into seven groups of 30 and given varying doses
of indomethacin and aspirin with one group left as the control. After 22 days, the rats
were sacrificed and histologic sections of the fracture sites were examined in a blinded
fashion for healing. The result was a dose-related response with increased doses relating
to delayed fracture healing in the indomethacin group. There was a similar response in
the aspirin group, though this was not statistically significant.
Since then, there have been several other studies in animals that demonstrated
delayed bone healing. Hogevold et al (3) took 72 rats and assessed the healing of
intramedullary pinned osteotomies of the femur. He found that the group given
indomethacin showed statistically significant decreases in bone strength, absorbed
energy, and bending rigidity when mechanically tested in cantilever bending. Similarly,
Altman et al (4) studied the effects of ibuprofen and indomethacin on rats with femur
fractures. These results demonstrated evidence of delayed healing in both groups both by
mechanical testing and histological evaluation. In addition, there are many other studies
in animals that support such results.
However, there are also studies in animals that have shown negative results,
though these studies are fewer in number. More et al (5) examined 28 rabbits who were
given tibia fractures. Six were given flunixim, an NSAID used in veterinary medicine,
and six each were given low-dose and high-dose peroxicam. The remaining ten served as
controls. After three weeks, there was no statistically significant difference in the healed
fractures as measured by ankle stiffness or tibia torsional strength. Huo et al (6)
examined 152 rats with femur fractures. Half were given ibuprofen and the other half
were given nothing. Animals were sacrificed at intervals over twelve weeks, and the
study found no significant differences between the treated and control groups with
regards to biomechanical testing as well as histologic study.
In contrast to studies using animal subjects, studies examining the effects of bone
healing with NSAID therapy in humans are much fewer in number. Giannoudis et al (7)
looked retrospectively at 377 patients treated with intramedullary nailing for femoral
shaft fractures. Nonunion had occurred in 32 of them. Out of the remaining, the authors
selected 67 patients similar in sex and age. They then examined differences, including
postoperative NSAID use, between the two groups and found that a larger number of
patients (62.5% vs. 13.4%) used NSAIDs in the nonunion group (p value = 0.000).
Similarly, Butcher et al (8) retrospectively examined 94 patients who had sustained tibial
fractures. He found that those who received NSAIDs as part of their treatment had an
average length of time to union 7.6 weeks greater (p value = 0.0003) from 16.7 to 24.3
weeks.
As for prospective studies in humans, there have only been two to date, and they
have decidedly different conclusions. Burd et al (9) studied 112 patients who received
ORIF of acetabular fractures and who also had concomitant long bone fractures. Those
at risk for heterotopic ossification based on the surgical approach were randomized to
receive either radiation or indomethacin; the remaining served as controls. The results
demonstrated a higher incidence of nonunion of a long bone fracture in the indomethacin
group (11 of 38 patients or 29%) versus in the non-indomethacin (radiation and control)
group (5 of 74 patients or 7%).
Adolphson et al. (10) conducted a randomized, double-blind, placebo-controlled
trial examining 42 postmenopausal women with displaced Colles’ fracture. After closed
reduction, patients were randomized to receive either piroxicam or placebo. Those who
had received piroxicam were found to have no difference in fracture healing as measured
by clinical function; they did, however, note significantly less pain.
For those who do believe that NSAIDs delay fracture healing, even the
mechanism is uncertain. NSAIDs are thought to either act locally at the fracture site or
through hormonal effects. Zhang et al (11) reviewed the literature on cyclooxygenases
and their role in bone repair. In his review, he states that the enzymes are implicated in
key steps in bone repair including, chondrogenesis, chondrocyte differentiation, and
osteoblast differentiation. In contrast, Edwall et al (12) demonstrated in rats that insulinlike growth factor I (IGF-I) was increased at 8 days after fracture and that this level was
depressed by indomethacin administration, implicating both a role of IGF-I in fracture
healing and indomethacin’s inhibitory response.
In conclusion, there is theoretical reason to believe that NSAIDs may retard
fracture healing, and animal studies have largely borne this out. Human studies, on the
other hand do not wholly support this conclusion. While retrospective studies have
mostly confirmed the results of animal studies, only two prospective studies have been
conducted, and they reached opposing conclusions. While it may be likely that NSAIDs
do, in fact, retard fracture healing, more research in humans needs to be done, especially
if we are to deny patients the analgesic effects of NSAIDs.
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