Adaption to appropriate prosthesis associated with stride fluctuation

CHICAGO — Stride-to-stride fluctuations are related to an amputee’s adaptation level to an appropriate prosthesis, according to a Thranhardt lecture finalist at the American Academy of Orthotists and Prosthetists Annual Meeting, here.

Shane Wurdeman, PhD, CP, a prosthetist at Advanced Prosthetics Center, Omaha, and instructor at the University of Nebraska, presented data from a randomized study that sought to determine relationships between stride-to-stride fluctuation before and after an adaptation period for both a “more appropriate” prosthesis and a “less appropriate” prosthesis.

In the study, 21 unilateral, transtibial amputees initially wore either a more appropriate or less appropriate prosthesis and walked on a treadmill at a self-selected speed for 3 minutes, then continued to wear the prosthesis for 3 weeks. After 3 weeks, they repeated the process with the other prosthesis. To determine a prosthesis’ appropriateness, researchers matched and mismatched components based on the K-levels of the amputees.


Shane Wurdeman

Using motion capture data, the researchers noted sagittal plane ankle flexion/extension angle of the prosthetic and sound ankle, calculated the largest Lyapunov exponent, and used Pearson product moment correlation to compare both the prosthetic ankle initial fitting vs. end of adaptation and the sound ankle at the study’s start vs. prosthetic ankle at the end.

Data showed a significant, strong relationship for the more appropriate prosthetic ankle design before and after adaptation. For the sound ankle, the more appropriate design also showed a moderately strong relationship.

The data supporting that the more appropriate prostheses show “a stronger relationship than smoking and mortality,” he said.

“We are looking at this as a prescriptive tool, and we are also examining for purposes of outcomes assessment,” Wurdeman said, acknowledging a limitation of the study in that it did not include amputees lower than a K-3 level. “If we had a way to quantify activity level as well as the components’ activity level, we might not be talking about more appropriate, we might be talking about the most appropriate prosthesis.”

For more information:

Wurdeman S. Paper TL2. Presented at: American Academy of Orthotists and Prosthetists Annual Meeting and Scientific Symposium. Feb. 26-March 1, 2014. Chicago.

Disclosure: Wurdeman has no relevant financial disclosures.

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