Kate Jorgenson has played volleyball and basketball and swum competitively without her left arm, which she lost above the elbow in an ATV accident two years ago.

But then there are tasks such as eating a Dairy Queen Blizzard.

To dig out the thick, cookie dough ice cream, the 13-year-old from Westbrook, Minn., had to steady the cold cup between her knees, sometimes making a mess in the process.

“It’s things like that you and I take for granted,” said her father, Jim.

And that’s where a new type of bionic prosthesis — aided by a surgery that reassigns nerves in the arm — has made a big difference in the teenager’s life. While she is still learning to master the prosthesis, Jorgenson can now use it to mix muffin batter, zip up a jacket and carry shopping bags while texting friends.

“She hadn’t zipped a zipper for almost two years,” said her mother, Nikki Jorgenson. “She had to ask us to do it. For teenagers, that’s frustrating.”

Hastened by advances in neurology and robotics — and tragically by the spike in U.S. soldiers returning from Iraq and Afghanistan without limbs — a new era of prosthetics has emerged, using signals from the brain to evoke an increasing variety of movements from bionic limbs.

Jorgenson is one of about 50 patients worldwide — and the youngest, so far — to undergo a surgery called targeted muscle reinnervation, in which severed nerve endings in her arm were reassigned to control muscles that would trigger sensors in the bionic arm. With the surgery, which was performed last year at the Mayo Clinic, she also became the first to have six nerves rewired, giving her the ability at will to move the robotic elbow up and down, rotate the wrist, and open and close the hand.

Prosthetics aren’t simple

Traditional myoelectric devices use two nerve signals from the intact biceps and triceps arm muscles to trigger movements. But they require users to turn switches on their prosthetics whenever they want to control the hand or wrist or elbow, explained Pat Prigge, clinical manager of Advanced Arm Dynamics of Maple Grove, which provided the prosthetic and training for Jorgenson.

People often give up, or use their prosthetics less, because of the clunky switching, which can turn a simple chore into a three-step “robotic” process, Prigge said.

“If it’s difficult to use and its slow, its not going to get used that much … We’re trying to get prosthetics so easy to control that people use them fluidly,” he said.

On Wednesday, Jorgenson was practicing at Advanced Arm Dynamics’ Maple Grove facility, where she travels with her parents for regular therapy appointments to adjust and expand on her use of the bionic arm. Physical therapist Jennifer Peterson had Jorgenson lay out a tablecloth, then transplant a pepper plant into a new pot.

“I might crush it!” Jorgenson exclaimed.

Learning how to signal the proper muscles to trigger movements from the bionic arm happened quickly, Jorgenson said, but mastering it is taking time.

“Sometimes when I raise my arm up,” she said, “the hand will start twisting around.”

When it closes, the hand can create a grip-crushing 22 pounds of force, but it can also be delicate enough to hold a paper cup. So developing control has proved crucial. After daring her older brother to let her squeeze his nose, she tried it on herself. She squeezed too tightly and found herself unable to release the hand because the shock caused her muscles to tense up.

But on Wednesday, she transplanted the plant, filled the pot with soil, and cleaned the mess with a dustpan — all with little to no delay between the time she wanted her prosthetic to move and when it did.

“It’s pretty amazing how intuitive she has become,” her father said.

Her next step will be triggering two motions at once — such as moving the elbow while closing the hand — but she is comfortable enough to start wearing the bionic arm to school. The eighth-grader had delayed until now, because her school lacks air conditioning and the prosthetic can become uncomfortable in high heat.

Love and support

Across southern Minnesota, people came to the Jorgensons’ support when news of the June 2013 accident spread. The girl had been picking rocks from a family field, but hit loose gravel on the drive back and flipped her weighted-down ATV.

Friends and neighbors organized fundraisers when the family’s health insurance initially denied coverage of approximately $215,000 in costs for the prosthetic and therapy and maintenance sessions, though the preparatory surgery was covered. A clause in the health plan allowed for coverage of an unapproved device if Jorgenson proved she could use it, so Advanced Arm donated a trial prosthetic for her last year so she could prove its worth.

Coverage by Blue Cross and Blue Shield of Minnesota has since been approved, and Jorgenson has her own prosthetic, which she recently covered with a striped decorative sleeve she carefully picked out.

“That was a whole day at Jo-Ann Fabrics,” her mother said.

Insurance coverage is almost always denied at first, because the devices are viewed as luxuries over standard myoelectric limbs, Prigge said. “They equate it with heated seats and power steering in a car.”

But traditional prosthetic arms can cause complications. Lack of use can cause back problems or overuse injuries for the other arms, for example. Prigge said he believes more success stories like Jorgenson’s will expand insurance coverage. In a statement, Blue Cross said it was “pleased” with Jorgenson’s success, and that coverage discussions with the family have been “instrumental” in educating the insurance company on how to work with families in these situations in the future.

Prigge also said technological improvements are sure to come along to allow for more sensitive movements.

Jorgenson, for example, is able to pick up corn on the cob and bring it to her mouth. She just wishes the prosthetic would provide that subtle rolling of the wrists for easy eating.