Improving the Lives of Amputees

Mar 08, 2016, 16:07 ET from Orthopaedic Research Society

ROSEMONT, Ill., March 8, 2016 /PRNewswire-USNewswire/ -- In the United States, there are hundreds of thousands of amputees caused by trauma alone, and this number is expected to steadily rise as the population continues to grow.

Although socket-type prostheses are the most common, an optimal fit is difficult to achieve, often resulting in painful sores and other complications. Socket prosthetic devices also lack stability due to their inefficient integration with the body. This has led to an increased interest in improving the methods of attaching prosthetic devices to amputees.

One approach gaining popularity is the integration of a prosthetic implant directly with the amputees' residual bone. This implant penetrates the skin to connect to a prosthetic limb. This direct prosthesis-bone interface allows for a more stable connection to the skeleton enabling greater control of the prosthesis and heightened sensory feedback of the environment while eliminating pain and sores experienced with socket prosthetics.

Although this type of prostheses offers promise, it is not without issues. "Unfortunately, these implants face several challenges which prevent their approval by the FDA outside of clinical trials," explains David Ruppert, a researcher at the University of North Carolina at Chapel Hill and North Carolina State University. "The implants need to conform to patients' specific anatomy; the skin penetration of the implant is susceptible to infection; and a 12 month rehabilitation period is required to produce a stable bone-implant interface."  Ruppert, along with his collaborators, are currently conducting research focused on addressing the patients' specific anatomy as well as reducing the lengthy rehabilitation period.

"Our findings showed that rough textured implants created though 3D printing exhibit stronger bone integration than machine threaded counterparts," says Ruppert.  "This highlights the superiority of using 3D printing to not only produce custom designs, but also custom surfaces that interface with amputees' residual bones."

In addition, the team of scientists found that vibrating the whole body at low-magnitude and high-frequency at a specific amplitude range can increase bone density around the implant. These results demonstrate that whole-body vibration can be used to minimize bone loss during rehabilitation.

Previous work investigating fracture healing has indicated that low intensity pulsed ultrasound (LIPUS) can be beneficial to bone healing through as yet undetermined mechanisms. It is also unclear if sufficient levels of the stimulus can reach the inner surfaces of the bone to stimulate bone healing. "In our future work we'll investigate the effects of LIPUS on bone integration into an implant to see if further improvement on the rehabilitation period can be made," Ruppert explains.  "We will also investigate whether there is a cumulative effect of using LIPUS in conjunction with vibration. Finally, we aim to validate additional methods of 3D printing to the one used in our study to improve the level of detail in implant design.  Ultimately, we hope to improve the quality of life for amputees."

Ruppert's work was recently presented at the Annual Meeting of the Orthopaedic Research Society. Founded in 1954, the Orthopaedic Research Society strives to be the world's leading forum for the dissemination of new musculoskeletal research findings.  The musculoskeletal system provides form, support, stability, and movement to the body.

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SOURCE Orthopaedic Research Society