Dean D. Morgan, DVM; Scott McClure, DVM, PhD, DACVS; Michael J. Yaeger, DVM, PhD; Jim Schumacher, DVM, MS, DACVS; Richard B. Evans, PhD Journal of the American Veterinary Medical Association May 1, 2009 234 9 1154-1161 Objective—To evaluate the effects of focused, extracorporeal shock wave therapy (ESWT) on the healing of wounds of the distal portion of the limbs in horses. Design—Randomized controlled trial. Animals—6 healthy adult horses. Procedures—In each horse, a 4-cm-diameter full-thickness wound that included underlying periosteum was created on the dorsomedial aspect of each metacarpus and two 3-cm-diameter full-thickness wounds that included underlying periosteum were created on the dorsomedial aspect of each metatarsus. One randomly selected metacarpal wound and a randomly selected pair of metatarsal wounds were treated once weekly with ESWT at an energy flux density of 0.11 mJ/mm2. For metacarpal wounds, swab specimens were collected for bacterial culture on days 1, 2, and 3 and area of epithelialization and extent of wound contraction were measured at 3- to 4-day intervals. Metatarsal wounds were biopsied after 2 and 4 weeks, and immunohistochemical staining for vascular endothelial growth factor, transforming growth factor-β1, and insulin-like growth factor-1 was performed. Results—Results of bacterial culture, area of epithelialization, and percentage of wound contraction did not differ between treated and untreated wounds; however, healing time for treated wounds (mean, 76 days) was significantly shorter than healing time for untreated wounds (90 days). Staining intensity of growth factors did not differ significantly between treated and untreated wounds. Conclusions and Clinical Relevance—Findings suggested that ESWT may stimulate healing of wounds of the distal portion of the limbs in horses, although the mechanism by which healing was stimulated could not be identified.