Magnetic limb-lengthening holds promise for Philly patients

For years, Will Ethington stacked a bunch of credit cards and playing cards in his left shoe to mask the difference in the length of his legs.

The imbalance happened gradually as a result of a slight deformity in his femur after he received chemotherapy at age 3 for childhood lymphoma. He could still play basketball and softball, as well as golf and surf, but one leg grew about an inch and a half longer than the other.

By age 30, pain flared in his hip and back because of the imbalance, and he struggled to walk.

“I felt like I was getting old pretty quick,” said Ethington, an athletic 34-year-old who lives in Mount Laurel.

Even more painful was the leading treatment option, limb-lengthening surgery, which long required breaking the leg bone, then manually stretching it by cranking on rings drilled into the bone. Until recently, the procedure came with a high risk of infection and a long recovery.

Then, in 2021, Ethington became a candidate for a new technique that uses magnets to lengthen limbs. It promised to be more tolerable and less risky, and would allow him to bear weight right after the surgery. What’s more, it would be covered by his insurance and, because of the pandemic, he could recover at home while continuing to work.

“I was like, heck, let’s go for it,” he recalled.

The magnetic internal rod device was a game changer for limb lengthening, said Austin Fragomen, professor of clinical orthopedics at the Hospital for Special Surgery in New York.

An expandable rod is surgically implanted in the bone, and uses the pull of magnets to lengthen bones in the arms or legs gradually over a period of several months.

Limb lengthening with magnetic implants, first introduced in 2012, is now gaining popularity among adults who simply want to be taller. Over the last 17 years, Fragomen’s practice has seen these types of surgeries increase from about a half-dozen a year to about 25. Patients typically need to be 5′5″ or shorter and must be cleared by a psychologist before surgery.

Both legs are done at the same time and can be lengthened up to three inches, the size of the rods. From having the initial surgery to walking independently takes six months.

Insurance doesn’t cover limb lengthening for height, and the procedure can run $100,000 out of pocket, Fragomen said. But medically necessary procedures, such as Ethington’s, are often covered by insurance.

Magnetic limb lengthening still requires breaking the bone, but the process is less painful — patients can typically manage pain with over-the-counter medications after a few days’ hospital stay.

Two weeks after surgery to implant the rod, the patient begins the lengthening process by holding an external magnet over the magnet within the rod to begin lengthening the rod. As space opens up between these two ends, new bone grows to fill in the gap.

The process needs to move slowly, starting with a half-millimeter a day and building up to one millimeter, because the muscles, tendons, ligaments, arteries and nerves also need time to stretch, said Samir Mehta, chief of the orthopedic trauma and fracture service at Penn Medicine, who began using the technology about seven years ago and performs about one procedure a month..

“Part of the reason we go so slowly is that we want these other structures to come along at the correct pace,” said Mehta, who treated Ethington.

The process can take several months. For example, a gain of two inches takes about 50 days and then 100 days more for the bone to completely fill in. There are risks of infection, blood clots, the bone not filling in, or a mechanical malfunction, but they are rare, Mehta said.

The technology is similar for children. Doctors can either lengthen the shorter leg or slow the growth of the longer leg. At the Children’s Hospital of Philadelphia, the procedure is mostly recommended for patients with a discrepancy of at least two inches, said Alexandre Arkader, an associate professor of orthopedic surgery at CHOP.

For a smaller difference in children who are still growing, he recommends slowing growth. Children with a congenital condition that affects the growth plate may need more than one procedure throughout their growth span.

“The reality is that most people don’t want to be shorter than they have to be,” said Arkader, who along with his colleagues, performs about 25 procedures a year.

The success rate is close to 100%, Arkader said, and the child can return to normal activities as soon as the bone has filled in, which can be as soon as three months.

Though certainly less excruciating than the external limb-lengthening procedure would have been, the new technique was also painful, Ethington said.

“The first month or two I regretted it, but now I’m glad I did it,” he said.

While he could walk, getting up and down the stairs to his second-floor condo was tough. During the first two months after surgery, he relied on medication to ease the pain and depended on his family for help with daily tasks.

He’s now back to his active lifestyle, pain free and without a need for a shoe lift. He recently went on a seven-mile hike, an excursion he’d never been able to do before.