On December 3rd of 2022 a young red-tailed hawk was hunting along the side of Hwy 20 when she was struck by a vehicle and left stunned with a broken wing on the side of the road near Albany. Luckily for her, a good samaritan saw the young hawk and brought her to Chintimini Wildlife Center that same day, where she was admitted as our 1462nd patent of the year.
Upon examination, the staff at Chintimini palpated a fracture around the radius and ulna of the left wing. They placed the wing in a figure 8 wrap and set the hawk up with a plan for pain management (metacam, tramadol, and gabapentin) until the veterinarian could assess it the next day. The hawk had some blood in its mouth and its breathing was a little gurgly (a sign of potential internal bleeding), so it was also started on clavamox and itraconazole to prevent a respiratory infection.
The next day I (Dr. Peterson) confirmed a closed mid-diaphyseal fracture of the left ulna by palpation. The bone would likely heal as the radius was still intact, however there was a risk of the two bones healing together in the callus (called “synostosis”) - this condition would inhibit essential movement and rotation of the wing and affect the hawk’s ability to fly. If that happened, the hawk would likely not be a successful hunter or be releasable. Due to this risk, the decision to treat this fracture surgically instead of just with external coaptation (splints and bandages) was made.
So on December 4th the hawk underwent surgery. Premedications included buprenorphine (0.1 mg/kg), midazolam (0.5 mg/kg), meloxicam (1 mg/kg), and enrofloxacin (15 mg/kg). Subcutaneous fluids (LRS with vitamin B complex) were given before and after the procedure. The patient was maintained on isoflurane and intubated; monitoring included physical parameters (heart and respiratory rates) as well as capnography.
First the wing was assessed in further detail and the fracture was found to have broken through the skin, so the wound area was flushed with dilute betadine and then closed with 4-0 monocryl suture. An intramedullary pin was placed normograde into the caudal aspect of the ulna (between the secondary feathers), taking care to avoid the elbow. The pin was then pushed forward (“normograde”) towards the wrist until it was seated in both pieces of the bone. This intramedullary pin prevents bending of the bones from the fracture sites, but the pieces will still be able to move a bit rotationally (turning around each other) or pulling away or towards each other. The fracture pieces should be held completely still with no movement as this will allow the fastest healing with the smallest callus (so less chance of synostosis), and that means additional pins need to be placed. A pin was then placed perpendicular to the bone in the proximal piece of the ulna, and a second similar pin was placed in the distal piece of the ulna. The intramedullary pin that was sticking out of the bone is then bent at a 90 degree angle so it lines up with the other two pins. Connecting all three pins with a “bar” then stops any movement of the two bone pieces, so they can heal together. There are different ways to make this bar, my preference is with a material called “aquaplast” - a plastic material that I cut to size and softened in very hot water. Once soft, I folded the material three times to make a “bar” shape. While softened from the water, it’s possible to poke the three pin ends through to connect it all into one cohesive structure. Once the plastic has dried and cooled it becomes hard again. To ensure the pins are seated firmly in the plastic, I dot each spot with a tiny bit of super glue (Zap a Gap is my favorite), being sure to protect against any of the glue dripping onto the hawk’s skin or feathers. About 1-2 cms is ideally left between the bar and the skin to allow for swelling of the surgical site and the ability to clean this area if needed while the bone is healing.
This contraption, called a “Tie-In External Fixator” (because the external fixator part is connected or “tied in” to the intramedullary pin) is often the preferred surgical method of fixing fractured avian long bones as it allows the fracture site to stay stable without the need of a bandage. Because a bandage is not needed on the wing, the bird is able to move its wrist, elbow, and shoulder - helping to prevent tightening up of these joints that can happen in a tight wing wrap and that would need additional physical therapy. In general, I’ve found that most birds do not mess or try to pick at these fixators with their beaks. I’ve had birds pull out pins if I’ve just placed one (like an intramedullary pin), and I suspect this is because the fracture pieces still have movement without the whole tie-in fixator. I suspect that with the full fixator the bone fragments are held so well together that it limits pain and discomfort so the patients tolerate the fixator really well. If they are picking at it, I worry about infection or a pin slipping out and movement that may be causing discomfort. These fixators are left in for around 4 to 8 weeks depending on how the fracture is healing on radiographs (x-rays).
For our red-tailed hawk, x-rays were taken at about 2 and ½ weeks post surgery. The radius is well away from the healing callus between the two fractured pieces of the ulna, which is what we wanted - no synostosis! The pins are all still in place and the bone is well aligned, and signs of the bone healing with a callus is seen. The pins were then removed under anesthesia at about 4 and ½ weeks. Sometimes I will remove only the two perpendicular pins and leave the IM pin for a few more weeks if the fracture appears to need more support while healing. However, for this fracture and patient, everything palpated solid so I removed the entire fixator and IM pin at the same time. X-rays are shown from about 2 weeks after pin removal.
The hawk was healing well and slowly weaned off of pain medications, and the fracture continued to be monitored with x-rays. After about 5 weeks after the pin removal, she was moved into a larger room-sized enclosure. After gaining strength there for a few weeks, she was then moved to a full-sized flight cage (30 feet by 60 feet) to gain further strength in flying. She was prey tested with live mice and easily proved her hunting ability in the pen. By the end of February she was flying at full strength and I could find no difference between the performance of her two wings. Her flight and turning skills were strong, and she was in an excellent body condition weighing in over 1300 grams.
She was happily released on March 1st of 2023 near where she was originally found. What an honor to give this tough hawk a second chance at life in the wild.
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Dr. Peterson can be reached with questions about cases or this case at ClaireAPeterson@gmail.com