Effects of botulinum toxin A on fracture healing in rats: an experimental study.

INTRODUCTION Fracture healing is a complex process influenced by intrinsic and extrinsic factors. The aim of the present study was to evaluate the effects of botulinum toxin (BTX) A on fracture healing. MATERIALS AND METHODS Following the induction of bilateral standard closed femoral fractures and relative fixation in 18 Wistar albino rats, 8 IU of BTX A were injected into the right femoral region. After 28 days, all of the rats were sacrificed, the diameter of the callus was measured, and fracture healing was assessed by biomechanical and histopathologic evaluation. RESULTS While an increase in biomechanical and histopathologic healing was noted on the side injected with BTX A, a decrease in callus diameter was observed. CONCLUSION Botulinum toxin A administration increases the healing power in a relatively fixated fracture and decreases the callus diameter, just as if rigid fixation had been performed. The beneficial effect of BTX A on fracture healing might be associated with increased fixation rigidity.