Healing a Hawk’s Humerus

Aug 24, 2015 / Student Blogs

Hawk's Humerus

This beautiful red-tailed hawk was brought to the Wildlife Medical Clinic by one of the rehabilitation centers we work with (The Illinois Raptor Center) with an open fracture of the left humerus (the bone between the shoulder and the elbow). The term “open fracture” indicates that there is a break in the skin over the site of the fracture. This is important to know because it makes infection much more likely and alters our treatment plan.

The student volunteers were very careful when cleaning the tissue and exposed bone. In birds, the humerus is a pneumatic bone; this means that it has a connection to the animal’s respiratory system, and as such, flushing with large amounts of fluid can be dangerous (think drowning). After the fracture site was cleaned and bandaged, a wing and body wrap were applied to immobilize the fracture to minimize pain and additional soft tissue trauma. Here is a basic diagram to give you an idea of how it looks. The bird was fully assessed to rule out other injuries or illness, and when he was stable, he was taken to surgery.

red-tailed hawk

After the red-tailed hawk heals, he will go to the Illinois Raptor Center for further conditioning. The top photo shows a radiograph of the wing after surgery; the long piece of metal is the IM pin and the shorter ones are the cross pins.

Bird bones often cannot handle heavy surgical implants like plates for fracture repair; at the Wildlife Medical Clinic, we predominately rely on pins and wire to repair avian bones. For this hawk, we elected to place a pin through the center of the bone to keep it straight and prevent bending; this is called an intramedullary (IM) pin. But an IM pin alone is not sufficient to counteract all of the forces at work on the damaged bone. We also have to eliminate tension and compression as well as shear (the fragments sliding past one another) and rotation of the separate bone fragments. For this, we placed pins perpendicular to the bone both above and below the fracture site. To finish, we connected the end of the IM pin and the cross pins together with an epoxy putty to keep everything in place.

The finished product is a bit Frankenstein-ish, but it does the job of holding the bone pieces where they should be without weighing the bird down. In fact, just a couple of days after surgery, we were able to remove the wing wrap that we placed to support the (very sore!) wing after surgery, and the hawk has been holding the wing normally ever since. He is healing well and the physical therapy we perform is showing that that range of motion of the wing is near normal. This is all good news, and we hope to have all of the hardware out in a few weeks’ time so he can return to the Illinois Raptor Center for the conditioning he’ll need before release.

Do you have questions or comments? I’d love to hear! Follow me on Twitter @NickiRosenhagen or post to the Wildlife Medical Clinic account on Facebook or @WildlifeatIL.

Nicki Rosenhagen, DVM