Veterinary Orthopedic Surgeon Regrows Dog's Leg Bone

When MaryAnn Lawson finally brought her 2-year-old Yorkshire terrier to the University of California, Davis veterinary hospital, she had already been through an uphill battle to save Ethel’s leg, which had been operated on twice in an effort to properly heal her broken right ulna and radius. Ultimately, Lawson was advised that the best course of action was amputation. The odds were not on Ethel’s side, but thankfully 1 veterinary orthopedic surgeon was.

The turning point in Ethel’s case came after Lawson learned of a novel veterinary procedure that involves regrowing bone with the use of bone morphogenetic protein (BMP). After researching the surgery, Lawson was referred to Amy Kapatkin, DVM, MS, DACVS, an orthopedic surgeon at UC Davis veterinary hospital where BMP has been used since 2012 to regrow canine jaw and leg bones.

Prior to treating Ethel, Dr. Kapatkin had successfully implemented the regrowth strategy in almost 25 cases. She agreed to take on Ethel’s case but remained apprehensive that the procedure would save the dog’s leg. In fact, she estimated the success rate after surgery to be only 1% because, although BMP grows bone effectively, the bone still needs to be stabilized with a bone plate to work. In Ethel’s case, 50% of her distal radius was gone and her remaining bone was smaller than most bone plates.

Still, Dr. Kapatkin forged on with the surgery, with Lawson agreeing to allow for amputation if the use of BMP was determined to be appropriate. Much to Lawson’s delight, the amputation never took place.

“Nonunion after long-bone fracture repair in dogs represents a potentially devastating complication,” said Dr. Kapatkin. “When I first saw Ethel, I estimated that there was very little chance to save the leg—not impossible, though. And MaryAnn is such a dedicated pet owner that she insisted we try the regrowth procedure.”

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The basic premise of the procedure is to remove any dead bone and failed implants. A scaffold—called a compression-resistant matrix (CRM)—saturated with BMP is placed into the bone defect to stimulate growth between the ends of the healthy native bone. Rigid stabilization of the normal bone on either end of the BMP-impregnated CRM is required. The use of CRM and BMP is specifically targeted for large bone defects that lack blood supply to the area after at least 1 failed surgery.

“Like with almost all of the previous regrowth procedures, we had success with Ethel also,” Dr. Kapatkin said. “We are continuing to see exciting results with this procedure and are optimistic that our use in orthopedics will have long-term positive results.”

In most cases, BMP patients are discharged a few days following surgery. For Ethel, however, the veterinary team decided the dog should remain at UC Davis veterinary hospital for observation during recovery.

One postsurgery complication that arose for Ethel was that the bone plate used to stabilize the fracture—which typically remains in the patient forever—started protruding from the dog’s leg due to the limited soft tissue and thin skin in her tiny distal limb. When it was decided that the plate was no longer needed, Dr. Kapatkin removed it to allow Ethel’s tissue to heal completely around the bone.

At Ethel’s 3-month recheck appointment, she was able to run on her new leg.

“This is important work that others can learn from so more dog owners can know this help is available,” Lawson said. “I’m so grateful to them and what they’ve done to help us.”

View additional photos of Ethel here.