[Bone fracture and the healing mechanisms. Application of the extracorporeal shock wave on treatment of fracture].

We developed a new and unique extracorporeal shock waves (ESW) generator for bone application in 1992. ESW was applied to the canine's femurs. Gross fracture was not seen in any of the dogs. Detachment of the periosteum and subperiosteal bleeding were seen. Callus formation was seen beneath the periosteum at the focusing surface of the cortex and inner surface of the cortex. We applied ESW to eight patients with delayed union of the fracture. The sites of the ESW application were 4 tibiae, 2 humerus, one radius, one femur. ESW was applied to the delayed union site avoiding a metal plate, major vessels, and peripheral nerves. Five out of 8 cases achieved bone union. Average period until fusion achieved after ESW was 4.3 months. There was no complication except mild subcutaneous hemorrhage that disappeared within a week. We conclude that ESW is a safe and effective procedure for the treatment of delayed union of the fracture.