A point/counterpoint on expandable endoprostheses vs. rotationplasty
The adage “children are not small adults” is never more relevant than in the surgical treatment of malignant bone tumors. Because osteosarcoma often develops in the distal femur in skeletally immature patients, the growth plate must be removed along with the tumor for local disease control. As a result, significant limb length inequality develops as the uninvolved extremity continues to grow.
Controversy exists regarding how best to treat these patients. One method is amputation with rotationplasty, in which the leg is amputated above the knee and the tibia, foot, and ankle are rotated 180 degrees. The tibia is then re-attached to the proximal femur, allowing the ankle joint to act as the knee joint (Fig. 1). Another option is to reconstruct the limb using an expandable endoprosthesis (Fig. 2).
Dempsey Springfield, MD, a supporter of rotationplasty, and Michael D. Neel, MD, an advocate for endoprostheses, explored both treatment options in a session moderated by Valerae O. Lewis, MD, as part of the Musculoskeletal Tumor Society (MSTS) Specialty Day.
The case for rotationplasty
Dr. Springfield said the surgeon’s main goal is not saving the patient’s limb, but “returning the patient to health with as little disruption in adolescent development as possible.” According to him, rotationplasty is the best way to accomplish that goal.
“Patients who have undergone rotationplasty do extremely well,” he said. “They function at a high level. At least one long-term follow-up study of patients who had rotationplasty showed that quality of life remained extremely high 10 years after the procedure was performed.”
He acknowledged that rotationplasty may not be as cosmetically pleasing as an endoprosthesis; however, patients with endoprostheses are not able to participate in as many activities and sports as children with rotationplasties.
“Anybody who has seen pediatric patients with rotationplasties knows that they can participate in every single activity,” he said, pointing to a photo of a group of young basketball players with prosthetic limbs. He noted that the only boy in the photo who is not playing is the one with the endoprosthesis; he is the coach.
It may be easier for patients and their families to accept the idea of a rotationplasty if, prior to surgery, they interact with a patient who has undergone the procedure.
“To the best of my knowledge, no one has been able to show any psychological benefit to limb salvage,” he stated. “There’s no evidence that saving the patient’s limb makes them psychologically better in any way.
“I would say this is particularly important in children because they are trying to develop their personalities,” he said. “Child development is difficult and important, and we have to think about how our efforts to save their limb can affect the child’s development.”
Another issue, according to Dr. Springfield, is the rate of complications. Limb salvage has a high complication rate.
“The trauma surgeons are ahead of us,” he said. “Most will not attempt limb salvage in a patient with a grade IIIB tibia fracture—a severe, open fracture with extensive damage to the tissue as well as nerves and/or arteries. Limb salvage is possible for these patients, but experience has shown that patients treated with limb salvage have a high rate of issues such as job loss and drug dependency. As a result, most trauma surgeons opt for early amputation and rehabilitation for these patients.”
Dr. Springfield noted that survival of expandable prostheses is an important issue.
“Every patient who lives to adult life is going to need a revision procedure—likely, more than once,” he said. “The fact that the surgeon can go back and do an amputation on a patient who has a failed prosthesis is not a very good reason to use an expandable prosthesis.”
Finally, he said, rotationplasty is a “definitive solution.”
“I think amputations or rotationplasties should be the standard of care, and expandable prostheses should only be done in an institutional review board-approved, nationally registered study,” he said.
In support of endoprostheses
“I realize I can’t convince everyone that an expandable implant is better than amputation,” said Dr. Neel.
Early in his career, Dr. Neel performed several rotationplasties that had successful outcomes; however, when he moved his practice, he encountered resistance to the procedure from his new patients and their families.
“I was forced to consider other options, so I started looking at expandable endoprostheses,” he said.
Rotationplasty has good functional and oncologic results, he said, but expandable endoprostheses offer a valid alternative (Fig. 2). Data from multicenter studies have shown that expandable prostheses are successful and that the results are reproducible using devices from different manufacturers.
“Functional results, even in the very young, rival those of adults,” he said. “It’s common for patients to reach skeletal maturity with equal leg lengths, and implant survival is improving as new designs are developed and surgeons gain more experience.”
Design options for expandable endoprostheses include modular, minimally invasive, and noninvasive devices.
“The modular devices have midsections that are exchanged as the other leg lengthens,” he explained. “Minimally invasive devices are implanted with small incisions and have a crank or insertion device that lengthens the implant. With noninvasive devices, periodic treatments with electromagnetic fields are used to expand the prosthesis.”
A study presented at the 2009 combined meeting of the International Symposium of Limb Salvage and the MSTS evaluated children younger than 10 years who had undergone limb salvage. The study, which had a mean follow-up of 4.9 years, found that 84 percent of limb salvage patients maintained their limb.
“The researchers believed that most limbs could be successfully salvaged without adverse effects on survival and local disease control,” he said.
Another study on emotional acceptance and satisfaction following limb salvage surgery with a non-invasive device showed that mean transfer and mobility scores were good.
“It showed that limb salvage in very young children is successful from an emotional and oncologic standpoint,” said Dr. Neel.
Even a 1995 study, he said, “concluded that endoprosthetic replacement in children and adolescents gives results comparable to those obtained in adults, and that it provides a reasonable alternative to rotationplasty, although with more operations.”
A study on the use of prostheses in skeletally immature patients from 1976 to 2005 found a mean follow-up of 96 months from date of surgery to date of last review or death.
“Researchers found that limb lengths were nearly equal in most patients,” said Dr. Neel. “They felt that the results were clinically successful and that the technology was promising.”
Unfortunately, “most studies are small and/or short in follow-up, and cost is also an issue,” he said.
Dr. Neel said the next generation of non-invasive technology is available in Europe. Devices to regenerate bone around a prosthesis and restore skeletal length are also being developed.
“Future directions hold promise that mechanical failures will be reduced as designs evolve, but endoprostheses are not for everybody,” he said. “Orthopaedic surgeons need to adequately educate their patients about this treatment method.”
Disclosure information: Dr. Neel —Wright Medical Technology, Inc; Dr. Springfield—Stryker, Zimmer, Inc.
Jennie McKee is a staff writer for AAOS Now. She can be reached at email@example.com
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- Abudu A, Grimer R, Tillman R, et al: The use of prostheses in skeletally immature patients. Orthop Clin North Am 2006; 37:75-84.
- Steensma M, Healey J, Boland P et al: Limb preservation in children under 10 years of age for lower extremity bone sarcomas. 2009 Combined Meeting of the International Symposium of Limb Salvage and the Musculoskeletal Tumor Society, Session 6: Pediatrics, http://www.isolsmsts2009.org/
- Letson GD, Henderson ER, Pepper AM et al: Emotional acceptance and satisfaction following pediatric limb salvage with a noninvasive expandable endoprosthesis. 2009 Combined Meeting of the International Symposium of Limb Salvage and the Musculoskeletal Tumor Society, Session 6: Pediatrics, http://www.isolsmsts2009.org/