All Broken Bones Are Not Created Equal.
Buddy, a Chihuahua, is 8 months old and weighs about four pounds. He bounces around on his unusually long and skinny legs like a miniature antelope. A few months ago he broke one of his front legs. Tiny dogs, especially Chihuahuas, are prone to broken front legs and sometimes really difficult to repair and slow to heal.
All broken bones are not created equal. Young dogs heal better than old dogs. A bone broken at an angle, like a broken baseball bat, is easier to fix than one broken straight across, like a candy cane might break. A fracture near the middle is easier to fix than a fracture near one end or the other. Bones in tiny little dogs have a smaller marrow cavity and therefore less blood circulation, and take longer to heal.
Dr. Ponozzo at Riverview Animal Clinic in Clarkston has fixed lots of broken bones but she knew she had her work cut out for her with Buddy. He had broken both the bones - the radius and ulna - out near the end of his leg, close to his "wrist." There was not enough room to stabilize the fracture with bone pins and he was too small for a bone plate with screws. There would be little blood supply through the marrow cavity in Buddy's tiny little bones. The only thing he had going for him was his youth. She straightened the fracture pieces and put a good lightweight cast on Buddy's leg.
About three weeks later Buddy showed up at our clinic. His original owner had, for some reason, given Buddy away to someone else. Then those folks decided they didn't want him, or couldn't take care of him, and gave him to Jody. We take care of Jody's other pets so, when Buddy bumped his leg, and then quit walking on it, and the cast started smelling bad, she brought him to us.
X-Rays showed some signs the fracture was healing, but it still had a ways to go. We sedated Buddy and removed the cast. There were no skin sores, no swelling, and it felt like the fracture was healing well. We applied a new splint.
Buddy started using the leg again, and a month later X-Rays showed complete healing. There was a solid looking thickened area - a good bone callus - where the fracture had been. We removed the splint.
There are two risks at this point in treating broken bones. First, after eight weeks in a cast and no weight bearing, bone starts to lose strength. Astronauts have to be careful after long periods of weightlessness or they might break a leg. Second, normal bones flex a little, like a fishing rod, and where the stiffer bone callus is, that flexing can cause a fracture at the edge of the callus.
Ten days after we removed his splint, Buddy broke his leg again. The fracture was right in the middle of the callus, and just a tiny hairline crack. So Buddy got a new splint. That was three weeks ago and his latest X-Rays again show complete healing. We are still holding our breath. It is hard to decide when to remove the splint again. Too soon and we risk a fracture in the callus again, too late and the bones get weaker from disuse and might break somewhere else.
Buddy was lucky that Dr. Ponozzo provided such good initial care, and he was lucky that Jody and her family were there with a good home when he needed it. Let's hope his luck holds up a little longer.