Pete cocked his head and fixed his sharp eyes on the people gathered to watch him. The blue-crowned mealy Amazon parrot had been through a lot in his 34 years, but he gave no indication on this late August day that he knew something remarkable was happening.
The stump of what remained of Pete’s left leg rested in a boot-like prosthesis, just one day after he was introduced to the latest in a line of 3D-printed plastic prototypes made just for him. It was an excellent sign that the bird was not only already starting to accept the prosthetic, but that he also understood he was supposed to place his weight on it.
“That in itself is revolutionary for a bird,” said La’Toya Latney, service head and attending clinician of the Exotic Companion Animal Medicine & Surgery at the University of Pennsylvania School of Veterinary Medicine’s Ryan Hospital, known as Penn Vet. “He gets it.”
Pete isn’t the first animal to get a 3D-printed body part — dogs, horses and at least one duck have been beneficiaries of the technology in recent years. But his new foot is the first created by Penn Vet, which previously had created only more traditional prosthetics for animals, and it is something of a test: Prosthetic legs, feet and beaks have been made for birds with mixed success. One of the biggest challenges is whether the recipient will tolerate the artificial device.
Pete’s road to Penn Vet — which is paying for his rehab and prosthetics in exchange for his remarkable willingness to help the institution learn more about recovery in birds — began on a warm evening in September last year. Pete had climbed up the wire mesh on the side of his six-sided aviary on the patio of his Allentown, Pa., home. That left his curled toes outside the enclosure, vulnerable to a predator lurking in the darkness.
“I heard this incredible screaming in the back yard,” recalled Ben Spalding, whose wife, Stacey Gehringer, 56, has owned Pete since he was less than a year old. Spalding looked outside, saw a fox at the aviary and bolted outside.
“The fox got his left foot and ripped it off,” said Spalding. He and Gehringer immediately jumped in the car with Pete in his portable cage to go to the nearest emergency veterinary clinic, calling ahead as they drove. But because it had no avian specialist on staff at night, the couple ended up driving more than 60 miles south to Penn Vet, one of the few veterinary facilities in the Philadelphia region that takes emergency bird cases after hours. Penn Vet’s exotic animal service sees about 1,000 animals a year, and nearly 40 percent are birds.
The emergency room staff stabilized Pete and treated a wound on his chest, and Latney later amputated his mangled leg below the knee. Pete’s prognosis was guarded initially. But his bird metabolism, which reproduces red blood cells much faster than humans’ do, helped get him through the ordeal, Latney said.
“Birds are pretty unique in that they can sustain a significant blood loss and do pretty well,” she said.
But could Pete — who may live into his 60s — carry on with just one leg? Examples of large birds surviving after losing a leg are few and far between, because birds that weigh more than 100 grams usually experience pain and severe arthritis in the remaining leg due to the additional strain, Latney said. Pete weighs 570 grams, or just over a pound.
Latney had read a 2016 article in the Journal of Avian Medicine and Surgery that chronicled one of the very few success stories about a macaw that lived for 2½ years after the amputation of one of its legs due to cancer; it died from an unrelated issue. So Latney knew surviving was certainly possible, although a large bird’s ability to thrive with such a handicap was uncertain. And if cases of large birds living with one leg are scarce, examples of them successfully adapting to a prosthetic are even rarer, she said.
Nevertheless, Latney decided that Pete’s intelligence and the composed, mature personality of an older bird made him a good candidate for a prosthetic. Resting his stump on a prosthesis for even a few hours a day would be beneficial to the long-term health of his remaining leg and foot. Without the artificial support, the stress to Pete’s foot could lead to painful arthritis. What’s more, the parrot’s beak was already showing signs of wear because he was using it steady himself by grabbing the bars of his cage.
“When Dr. Latney suggested they would like to give [a prosthetic] a try — we were all in,” Spalding, 57, said.
Latney turned to Jonathan Wood, a staff veterinarian in neurology and neurosurgery, who had experience using 3D-printed models for teaching and planning surgeries. Wood, in turn, brought in the University of Pennsylvania School of Design’s Fabrication Lab to make the prosthetic.
It hasn’t been an easy fix. Spalding and Gehringer have left Pete in Latney’s care at Penn Vet for a few days at a time so she and Wood can figure out what works best for the bird. The first
prototype resembled a bird’s foot but couldn’t support Pete’s weight. Later models, made from extruded polymer resin, were based on more functional, stable designs, and looked more like a boot. The next challenge was to figure out how to securely and comfortably keep the prosthetic attached to Pete’s stump.
Latney had a lightbulb idea that required a needle, thread and a trip to Home Depot. She attached a magnet to a piece of foam that she put inside the prosthetic and sewed another magnet to a soft fabric sleeve that she created to cover Pete’s stump and fasten to a harness known as a “flight suit.” The question was how Pete would handle the contraption.
At a recent appointment, Latney kissed Pete on the top of his head and massaged the stump of his leg to release any tension before she began putting the flight suit on him. As Pete briefly flapped his wings and fussed, a vet tech stepped in to hold him while Latney adjusted the harness.
“Everything I’m doing is because he’s letting me,” she said.
Ultimately, Pete put his weight on the prosthetic, stood that way for more than an hour and even tried to take a step with it. The magnets and sleeve didn’t hold together when the bird moved the boot, but Latney considered it a win
“Pete is onboard with the idea of it, and that’s the biggest hurdle,” she told Gehringer and Spalding.
The couple says Pete’s bond with Latney is nearly as impressive as the bird’s progress.
“The way Dr. Latney handles Pete is absolutely amazing. No fear, [just] respect — and my sense is that’s reciprocated from Pete’s perspective,” said Spalding, who typically communicates with Pete through whistles and other noises, but not when the bird is with Latney. During those appointments, Spalding said he lets Pete focus on the fitting.
The right solution for Pete might take a few months more months to perfect. While Pete goes back home with Spalding and Gehringer, Latney and Wood will be fine-tuning the prosthetic and attachment system, and also creating a second prosthetic that the bird could potentially use to walk.
“He’s making big strides quite quickly,” Latney said. “All of this makes me very happy.”