High-energy shock waves for the treatment of nonunions: an experiment on dogs

Several surgical as well as nonsurgical modes of treatment of nonunions have been advocated in the literature. In an effort to achieve bony union in a new noninvasive way, we experimentally investigated the treatment of nonunions with extracorporeally induced high-energy shock waves. With use of a modified canine nonunion model, two randomized groups of five dogs each were set up to obtain a treatment and a control group. Shock waves were applied with the Osteostar (Siemens A.G., Germany), a specially designed, experimental, transportable, high-energy shock wave apparatus. Each of the dogs in the treatment group received 4000 shock waves of 0.54 mJ/mm2 (14.5 kV), which were applied at four preselected sites, lying symmetrically on the dorsal and ventral sides of the nonunion. During the course of the experiments, the dogs were monitored radiographically. Immediately after the shock wave treatments no radiographic changes could be detected. All of the treatment group dogs reached radiographically observable bony union 12 weeks after the shock wave treatment. In the control group, four dogs had radiographically persistent nonunions at termination of the study. Statistical analysis with Fisher's exact test (two-sided; P < or = 0.05) demonstrated the significance in outcome between the two groups. We conclude that hypertrophic nonunions in dogs can be treated successfully with extracorporeally induced high-energy shock waves. The results of this study may justify the application of shock waves for the treatment of certain types of nonunions, provided a specially designed shock wave apparatus is used for this purpose. We think that it may become a reliable, nonsurgical, alternative for the treatment of certain types of nonunions.