When Leonard Francesco's yellow Labrador Retriever, Maxine, jumped to catch a ball and landed funny on her back leg, it was clear to her primary care veterinarian what the problem was: she had injured her common calcaneal tendon, also known as the Achilles tendon. A tendon injury can require major surgery and then a very long, slow recovery. However, Dr. Cara Blake at Penn Vet’s Ryan Hospital had an idea to speed up the process.
When Maxine first came to Ryan Hospital, Dr. Ana Caceres in radiology assessed the extent of her injury. An ultrasound revealed a ruptured tendon.
“It's unusual to see a complete injury of the tendon,” Dr. Caceres said. “It's really hard to restore function to the way it was before.”
A normal tendon fiber alignment resembles “a horse tail,” according to Dr. Blake, Assistant Professor of Small Animal Orthopedic Surgery. The long, wavy fibers attach neatly to the bone, connecting muscle and skeleton. In an ultrasound, the fibers look like hair. In Maxine's case, some of the fibers linked to the bone, but most of them appeared in clumps off to the side. Dr. Caceres also pointed out a round, dark structure nearby: a hematoma, or internal pool of blood. Although the hematoma looked out of place, Dr. Caceres explained that it was key for the healing process.
Blood contains platelets, which contain many growth factors that are thought to help tendons heal. In platelet-rich plasma (PRP), these helpful cells containing the growth factors are concentrated into a small amount of plasma, which can be injected into the injury site. PRP has been used to speed recovery times in human tendon and soft tissue injuries, but there have not been any large, randomized controlled studies evaluating its success in veterinary medicine. Nevertheless, its success in other patients and its presence in veterinary literature encouraged Dr. Blake and Dr. Caceres to proceed. Mr. Francesco was willing to give it a try.
“I thought we'd give it a shot and see,” he said. “I wanted the best for Maxine.”
The first step was for Dr. Blake to operate on Maxine to remove an area of the damaged tendon and suture the tendon back together. Then, she asked Dr. Beth Callan, Professor of Medicine, to prepare the PRP for the next procedure in two weeks, after Maxine had healed enough from the first surgery.
“The advantage here at Penn Vet is that Dr. Callan can actually make the PRP for us. We don't need to buy a system [that will make PRP]. And, we know exactly what we're putting in,” Dr. Blake said.
To make the PRP, Dr. Callan spun Maxine’s blood in a centrifuge on a light spin. She worked in a laminar flow hood, which has a special airflow system, to avoid potential contamination of the PRP. The gentle motion separated the heavier red and white blood cells from the platelets, which stayed at the top, suspended in plasma. She then removed the PRP and centrifuged it further to make a platelet concentrate, maximizing the number of platelets in a smaller volume of plasma appropriate for injection.
As soon as the PRP was prepared, Dr. Caceres and Dr. Blake used ultrasound to inject the PRP into the precise spot around Maxine's tendon where the surgery had taken place.
Since the procedure, Maxine has been healing well, monitored by Dr. Caceres and Dr. Blake. While they can't definitively attribute the success to the PRP without appropriate controls, there is no doubt that Maxine is doing well. Dr. Caceres pointed out healthy soft tissue and strong, well-arranged tendon fibers in Maxine’s last ultrasound.
“The tendon can take six months to a year to heal. Sometimes it's never the same,” she said. “I'm not in a hurry. In just four months, this is incredible progress.”