VASCULAR RESPONSE TO FRACTURE HEALING IN THE BOVINE

Angiography during metatarsal fracture healing following simple coaptation, stainless steel plating, and allogeneic onlay bone plating was performed in 24 calves. Angiograms obtained during the early stage of fracture healing demonstrated enhanced extraosseous vascularity at and around the fracture site regardless of the technique used for immobilization. However, the increased soft tissue vascularity was more intense in animals with simple coaptation than with metallic or allogeneic onlay bone plating. From four to six weeks the fracture site was vascularized, with visualization of crossover vascular contacts and ramification of vessels supplying the bridging callus. These changes were observed earlier and were more intense following plating. Enhanced soft tissue vascularity persisted longer in animals with delayed union and infection, whereas it regressed to nearly normal by the tenth week in normally healing fractures.