Researchers have been studying osseointegration since the 1950s, although much of that early work focused on dental implants. The first surgery to fit a human patient with an osseointegrated prosthetic leg was performed in Gothenburg, Sweden, in 1990. The design and attachment of weight-bearing limbs is still relatively new, particularly on people—only about 120 humans have undergone the procedure, many of whom live in Europe, Harrysson says.
This is the group's third animal surgery using the technique, and their first on a dog. The first two procedures were on cats, and the implant design evolved from the first to second, Harrysson says, but with exception of size, Cassidy's implant design closely resembles that of the one used on the second feline.
After almost four hours of surgery, the surgeons completed the tedious process of suturing Cassidy's soft tissue to the titanium by threading the needle through preset holes on the sides of the implant. From there, he was wheeled off to get x-rays that will help the vets determine the exact placement of the prosthetic.
Nearly one month after his surgery, which cost the family about $5,000, the Posovskys report that Cassidy has bounced back. In late October they will again drive to Raleigh, where the N.C. State team will finally unite Cassidy with his new limb. For now, Cassidy remains unfazed by his important roll in medical history. "He's hopping around like he was before," Posovsky says. "It's as if he never got anything done."