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Published in Under the Rainbow on December 01, 2013
Rebekah Cannada, who recently underwent limb-lengthening surgery on her left leg, is happy to be able to ride her bike again.
Rebekah Cannada, who recently underwent limb-lengthening surgery on her left leg, is happy to be able to ride her bike again.

Innovative Technology Assures Rebekah Cannada Will Reach New Heights

By Jennifer Hospodor

Eleven-year-old Rebekah Cannada of Vicksburg broke one of the bones in her lower left leg and nearly broke the other leg while playing on a trampoline. It’s not an uncommon story, but that’s not where Rebekah’s story ends.  

Rebekah walks with one of her grandfather's horses.
Rebekah walks with one of her grandfather's horses.

Six weeks later, while hobbling around on crutches at her grandmother’s house, Rebekah fell and broke her left femur. Over the next eight months, Rebekah’s leg gradually became shorter and started curving outward.

“It was driving me crazy to see my grandbaby walking around like that when she was a perfectly healthy child,” said Sharon Forbes, Rebekah’s grandmother.

Luckily for Rebekah, her story takes a turn for the better thanks to Dr. Craig Robbins, a limb deformity specialist at Batson Children’s Hospital. Robbins is one of a handful of physicians in the country using a new technology called the PRECICE Intramedullary Limb Lengthening System to lengthen shortened arms and legs, which he says is one of many steps in fixing limb irregularities like Rebekah’s.

“Rebekah had an unfortunate injury with an unfortunate consequence,” said Robbins, assistant professor of pediatric orthopedics. “The fracture occurred partly through the growth plate near her knee and permanently damaged it.  Because she was only nine at the time of the injury, the deformity would become progressively worse until skeletal maturity in her early teens.”

Dr. Craig Robbins, pediatric orthopedic surgeon
Dr. Craig Robbins, pediatric orthopedic surgeon

Rebekah’s injury caused her femur to grow slower and become bowed. The stunted growth caused genu valgum, a condition commonly known as knock knee. Rebekah couldn’t straighten her leg and was having trouble walking. 

Robbins said often by the time patients get to him, traditional methods of healing have not worked. 

“If the normal stuff doesn’t work – plates, screws and rods – I’m the guy of last resort,” he said. 

And he certainly was that for Rebekah. Her mother, Rhiannon, said that months of healing time and physical therapy had not helped, so they looked into what the University of Mississippi Medical Center had to offer. 

When they met with Robbins and he presented the PRECICE system as an option, Rhiannon said she was initially concerned because the procedure was relatively new, but she and Rebekah researched the system before agreeing it was the best option.
“We chose PRECICE because we have such confidence in Dr. Robbins,” she said. “He sent us home with several websites and videos on the procedure. We then decided that the PRECICE nail was the way to go.” 

Robbins shows Rebekah an x-ray of her leg after surgery and explains how the PRECICE Limb-Lengthening System works.
Robbins shows Rebekah an x-ray of her leg after surgery and explains how the PRECICE Limb-Lengthening System works.

Robbins said Rebekah has been a dream patient. 
“She’s very involved in this process and participates in the discussions and decision-making,” he said. “Her family is incredibly supportive and understanding and they are an integral part of our team.”

Any limb-lengthening process, including the PRECICE system, begins with cutting through the bone and then slowly, deliberately pulling apart – or distracting – that bone. This slow distraction process allows new bone to form in the cut and the surrounding soft tissue to respond.

The device typically used for this process distracts the bone by manipulating a sort of framework of rings, pins and wires attached to the bone from outside the leg.

PRECICE uses a telescopic rod to distract the bone. That rod is surgically placed within the bone, leaving nothing attached outside the leg. The rod is manipulated by a handheld magnetic device, called an External Remote Controller (ERC), which can be used at home, offering greater mobility and freedom to patients during the lengthening process.

Robbins performs between 50 and 60 limb-lengthening surgeries each year and said most will use the external method because the PRECICE rods require a minimum bone size and deformity characteristics.

“This new internal device has much narrower indications for use than the industry-standard external device, but when they’re there, hallelujah, because it’s much easier for everyone,” said Robbins.

Robbins approached Rebekah’s deformity in several steps.  Her first surgery was an attempt to remove the damaged growth plate cells to prevent further deformity, but the damage was too great. Robbins then approximated the amount of leg shortening at the predicted time of skeletal maturity.

“Because this was much more than an inch or so, I suggested limb lengthening,” Robbins said. 

Rebekah had her second surgery in March to implant the rod within her femur and despite the pain, returned to school less than two weeks later, anxious to get back to a normal life. 

Rhiannon said using the ERC four times a day was hard for Rebekah at first. 

“The more she healed, the easier it became for us to use the magnet,” she said.

Although lengthening her leg only took two months, Rebekah had a long way to go.

“In general you can lengthen about one inch per month on the fast side, but it takes twice as long to heal, so to gain an inch really takes at least three months,” Robbins said. 

Rebekah is one of four patients he has used the system on since its approval by the Food and Drug Administration in late 2011. According to Scientific American, only about 100 surgeons in the United States perform limb-lengthening procedures. Robbins says even fewer use this new technology.

“When possible, the internal method is preferred and is a new technique that not many people are doing.  I’m part of a very small group of surgeons who use these techniques in general to treat our patients.”

Now that her legs are the same length, the next chapter in Rebekah’s story includes another surgery to remove the internal rod and correct the crookedness in her leg. 

“As well, the final step in her deformity correction after the lengthening will be to acutely cut and reposition the crooked part of the bone.

“We are excited and terrified at the same time,” said Rhiannon. “We are so thankful that Dr. Robbins has been able to help us, and that soon Rebekah’s leg will be good as new.”