Biological effects of extracorporeal shockwave in bone healing: a study in rabbits

Introduction This study is an investigation of the biological effects of extracorporeal shockwave treatment (ESWT) on bone healing in a rabbit model. Materials and methods Sixteen 12-month-old New Zealand white rabbits with body weight ranging from 2.5 to 3.5 kg were used in the study. An intra-medullary pin was inserted retrograde into the femur canal. A closed fracture of the femur was created with a three-point bend method. The animals were randomly divided into the study group and the control group with eight rabbits in each group. The study group received shockwave treatment, whereas the control group did not. The animals were killed at 12 weeks, and a 5-cm long femur bone including the callus was harvested. The specimens were subjected to biomechanical study, histomorphological examination, and immunohistochemical analysis. Results The shockwave group showed significantly better bone strength in biomechanical study, more cortical bone formation in histomorphological examination and higher number of neo-vessels and angiogenic and osteogenic growth markers including VEGF, eNOS, PCNA, and BMP-2 on immunohistochemical stains than the control group. Conclusion ESWT significantly improved bone healing after fracture of the femur in rabbit. ESWT promoted the formation of cortical bone what might have been associated with increased biomechanical results. ESWT-promoted bone healing was associated with increased neovascularization and up-regulation of angiogenic and osteogenic growth factors.