ORLANDO, Fla. – An imperfect prosthetic alignment might not be readily apparent on a smooth, level surface, but may reveal itself on more challenging terrain, according to Mark Geil, PhD, director of the Center for Pediatric Locomotion Science at Georgia State University.

“There is an area where we don’t see visible gait differences but alignment might not be perfect, particularly in seasoned amputees,” Geil said at the American Academy of Orthotists and Prosthetists Annual Meeting and Scientific Symposium, here.

In a study of three amputees, Geil and colleagues noted their baseline kinematics and kinetics as they walked on a smooth, level lab floor and on another surface of loose gravel. They also asked the patients how they felt when they walked.

Researchers than maladjusted their prosthetic alignment by 4° and 8° medial (internal) for walking on the smooth surface, and by 4° and 8° lateral (external) for walking on the gravel surface. Patients completed five trials of each condition; after the fifth trial they were asked for their feedback.

 

Mark Geil

Amputee walking speed dropped considerably with a lateral perturbation.

“When alignment was slightly off, the gravel really challenged them,” Geil said.

Prosthesis limb step length did not change significantly on the smooth surface regardless of perturbation, he said. However, step length dropped considerably with an 8° lateral perturbation on the uneven surface. Amputees reported varying degrees of comfort during each walking condition.

“We saw drops in either [terrain] but self-reported larger drops on uneven terrain, so there is still some potential to see these differences when you ask ‘how does that feel’ and you’ve challenged gait on an uneven terrain,” Geil said.

He suggested that dynamic alignment should include similar challenges to gait.

For more information:

Geil M. Paper F21. Presented at: American Academy of Orthotists and Prosthetists Annual Meeting and Scientific Symposium. Feb. 20-23, 2013. Orlando, Fla.

Disclosure: Geil has no relevant financial disclosures.