title: Interface pressures during ambulation using suction and vacuum-assisted prosthetic sockets.
abstract: Interface pressures were measured during ambulation with a normal total-surface weight-bearing suction socket and a vacuum-assisted socket. The vacuum-assisted socket has been shown to eliminate daily volume loss. Urethane liners were instrumented with five force-sensing resistors to measure positive pressures and one air pressure sensor at the distal end of the liner to document negative pressures. Nine unilateral transtibial amputees participated in the study. The vacuum-assisted socket created significantly lower positive-pressure impulse (42.8, 39.6 kPa x s) and peak pressures (83.5, 80.0 kPa) during the stance phase. The pressure impulse (-10.5, -13.3 kPa x s), average (-21.2, -26.5 kPa), and peak (-28.5, -36.3 kPa) negative pressures during swing phase were significantly greater in magnitude with the vacuum-assisted socket. We believe that lower positive pressures seen during stance using the vacuum-assisted socket reduces the fluid forced out and greater negative pressures seen during swing increases the amount of fluid drawn into the limb, thereby preventing volume loss.
authors.affiliation: Human Performance Laboratory and the Department of Mechanical and Manufacturing Engineering, St. Cloud State University, MN, USA.
authors.forename: Tracy L
authors.initials: TL
authors.lastname: Beil
authors.forename: Glenn M
authors.initials: GM
authors.lastname: Street
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Covey
mesh_terms: D000328:Adult; D000368:Aged; D000672:Amputation Stumps / Q000503:physiopathology*; D001186:Artificial Limbs; D006801:Humans; D007866:Leg; D008875:Middle Aged; D011312:Pressure; D011474:Prosthesis Design; D017755:Prosthesis Fitting; D016138:Walking / Q000502:physiology*; D016474:Weight-Bearing / Q000502:physiology