%0 Journal Article
%T Biomechanics of ramp descent in unilateral trans-tibial amputees: comparison of a microprocessor controlled foot with conventional ankle-foot mechanisms
%J Clinical biomechanics
%D 2015
%A Struchkov, Vasily
%A Buckley, John G.
%V 32
%N 
%P 164-170
%X BACKGROUND: Walking down slopes and/or over uneven terrain is problematic for unilateral trans-tibial amputees. Accordingly, 'ankle' devices have been added to some dynamic-response feet. This study determined whether use of a microprocessor controlled passive-articulating hydraulic ankle-foot device improved the gait biomechanics of ramp descent in comparison to conventional ankle-foot mechanisms. <br><br>METHODS: Nine active unilateral trans-tibial amputees repeatedly walked down a 5° ramp, using a hydraulic ankle-foot with microprocessor active or inactive or using a comparable foot with rubber ball-joint (elastic) 'ankle' device. When inactive the hydraulic unit's resistances were those deemed to be optimum for level-ground walking, and when active, the plantar- and dorsi-flexion resistances switched to a ramp-descent mode. Residual limb kinematics, joints moments/powers and prosthetic foot power absorption/return were compared across ankle types using ANOVA. <br><br>FINDINGS: Foot-flat was attained fastest with the elastic foot and second fastest with the active hydraulic foot (P<0.001). Prosthetic shank single-support mean rotation velocity (p =0.006), and the flexion (P<0.001) and negative work done at the residual knee (P=0.08) were reduced, and negative work done by the ankle-foot increased (P<0.001) when using the active hydraulic compared to the other two ankle types. <br><br>INTERPRETATION: The greater negative 'ankle' work done when using the active hydraulic compared to other two ankle types, explains why there was a corresponding reduction in flexion and negative work at the residual knee. These findings suggest that use of a microprocessor controlled hydraulic foot will reduce the biomechanical compensations used to walk down slopes.<p /> <p>Language: en</p>
%G en
%I Elsevier Publishing
%@ 0268-0033
%U http://dx.doi.org/10.1016/j.clinbiomech.2015.11.015