In 11 cases (10 dogs, 1 cat) in which fractures were repaired with the Jonas intramedullary splint, osteomyelitis developed in 6 and tumors developed in 5. In each case, the tumor originated in close proximity to the splint, at the midshaft of the femur or radius. All implants had been in place for 6 months to 6 years in the case of tumors, and for 4 months to 6 years in the cases involving osteomyelitis. Corrosion was evident in all retrieved implants. The corrosion was attributed to fabrication of the devices with a corrosion-susceptible stainless steel, AISI type 304. The corrosion was believed to have been accelerated by stress effect due to differences in cold work of the sleeve and pin and the difference in composition between the sleeve and spring of the splint. It was concluded that fixation of fractures in small animals should not be performed with the Jonas intramedullary splint.