Effects of extracorporeal shock wave therapy and radial pressure wave therapy on elasticity and microstructure of equine cortical bone

Objective - To measure changes in the modulus of elasticity (E) and describe histologic findings after extracorporeal shock wave therapy and radial pressure wave therapy on equine cortical bone specimens. Sample Population - 16 bone specimens from the proximodorsal cortex of an equine third metacarpal or metatarsal bone. Procedure - Baseline E was determined by the density (ρ) and unidirectional ultrasound transmission velocity (C) of each specimen according to the equation E = ρC². Eight specimens were treated with 500 pulses of 0.15 mJ/mm² of extracorporeal shock wave therapy, and 8 specimens were treated with 500 pulses of 0.16 mJ/mm² of radial pressure wave therapy. After treatment, C was determined again. Four treatment sessions resulted in 2,000 pulses and 5 C measurements. The ρ of each sample was measured again. Mean post-treatment E was calculated for each group. Nondecalcified sections of all specimens were stained with toluidine blue or basic fuchsin for histologic evaluation. Results - Overall treatment group effect was not significant for C or E. Final E was not different from baseline values for extracorporeal shock wave therapy and radial pressure wave therapy. No histologic changes could be attributed to either treatment modality. Conclusions and Clinical Relevance - Extracorporeal shock wave therapy and radial pressure wave therapy did not affect the material properties of equine bone at the energy and pulse values used in this study.