title: Effect of alignment changes on socket reaction moments while walking in transtibial prostheses with energy storage and return feet.
abstract: BACKGROUND
  Energy storage and return feet are designed for active amputees. However, little is known about the socket reaction moments in transtibial prostheses with energy storage and return feet. The aim of this study was to investigate the effect of alignment changes on the socket reaction moments during gait while using the energy storage and return feet.
  
  
  METHODS
  A Smart Pyramid™ was used to measure the socket reaction moments in 10 subjects with transtibial prostheses while walking under 25 alignment conditions, including a nominal alignment (as defined by conventional clinical methods), as well as angle malalignments of 2°, 4° and 6° (flexion, extension, abduction, and adduction) and translation malalignments of 5mm, 10mm and 15mm (anterior, posterior, lateral, and medial) referenced from the nominal alignment. The socket reaction moments of the nominal alignment were compared with each malalignment.
  
  
  RESULTS
  Both coronal and sagittal alignment changes demonstrated systematic effects on the socket reaction moments. In the sagittal plane, angle and translation alignment changes demonstrated significant differences (P<0.05) in the minimum moment, the moment at 45% of stance and the maximum moment for some comparisons. In the coronal plane, angle and translation alignment changes demonstrated significant differences (P<0.05) in the moment at 30% and 75% of stance for all comparisons.
  
  
  CONCLUSIONS
  The alignment may have systematic effects on the socket reaction moments in transtibial prostheses with energy storage and return feet. The socket reaction moments could potentially be a useful biomechanical parameter to evaluate the alignment of the transtibial prostheses.
authors: Orthocare Innovations, Mountlake Terrace, WA, USA. Electronic address: tkobayashi@orthocareinnovations.com.
authors: Toshiki
authors: T
authors: Kobayashi
authors: Department of Engineering and Computer Science, Seattle Pacific University, WA, USA.
authors: Adam K
authors: AK
authors: Arabian
authors: Orthocare Innovations, Mountlake Terrace, WA, USA.
authors: Michael S
authors: MS
authors: Orendurff
authors: Orthocare Innovations, Mountlake Terrace, WA, USA.
authors: Teri G
authors: TG
authors: Rosenbaum-Chou
authors: Orthocare Innovations, Mountlake Terrace, WA, USA.
authors: David A
authors: DA
authors: Boone
mesh_terms: D000328:Adult; D000368:Aged; D000674:Amputees; D001186:Artificial Limbs; D001696:Biomechanical Phenomena / Q000502:physiology; D001703:Biophysics; D005260:Female; D005684:Gait / Q000502:physiology*; D006801:Humans; D008297:Male; D008488:Medical Illustration; D008875:Middle Aged; D016059:Range of Motion, Articular / Q000502:physiology; D013977:Tibia; D016138:Walking / Q000502:physiology*; D016474:Weight-Bearing / Q000502:physiology
keywords: Amputation; Direct measurement; Kinetics; Load; Malalignment