TY - JOUR
T1 - Mass and mass distribution of below-knee prostheses
T2 - Effect on gait efficacy and self-selected walking speed
AU - Lehmann, Justus F.
AU - Price, Robert
AU - Okumura, Ramona
AU - Questad, Kent
AU - De Lateur, Barbara J.
AU - Négretot, Alain
PY - 1998/2
Y1 - 1998/2
N2 - Objective: To study mass and mass distribution effect on function of below-knee prostheses. Design: Design modifications were done to produce proximal center of mass location versus distal center of mass location variations, and prosthesis weight was modified from 42% to 70% of normal limb weight. Work across joints of affected and unaffected extremities was compared to assess the ability of the prosthesis to substitute for function loss. Setting: University biomechanics laboratory. Participants: Fifteen volunteers with below-knee amputations, residual limb length greater than 8.3cm, but excluding Syme amputations. Interventions: Patients walked with all configurations at self-selected walking speeds and 120m/min. Main Outcome Measures: Self-selected walking speed and metabolic efficiency. Work across the joints of affected and unaffected sides was compared. Results: Proximal center of mass location produced a more efficient gait. Weight change from 42% to 70% of normal had no significant effect. Mechanical studies show that the prosthesis is a relatively poor substitute for the normal limb; most work is done by the nonamputated side. Particularly, the prosthesis failed to produce effective forward impulses on the body, resulting from push-off and deceleration of the swing leg. Conclusions: For a proximal center of mass, lightweight distal components (eg, feet) should be used; it is questionable whether further expenditure to develop ultralightweight prostheses would be cost effective for level walking.
AB - Objective: To study mass and mass distribution effect on function of below-knee prostheses. Design: Design modifications were done to produce proximal center of mass location versus distal center of mass location variations, and prosthesis weight was modified from 42% to 70% of normal limb weight. Work across joints of affected and unaffected extremities was compared to assess the ability of the prosthesis to substitute for function loss. Setting: University biomechanics laboratory. Participants: Fifteen volunteers with below-knee amputations, residual limb length greater than 8.3cm, but excluding Syme amputations. Interventions: Patients walked with all configurations at self-selected walking speeds and 120m/min. Main Outcome Measures: Self-selected walking speed and metabolic efficiency. Work across the joints of affected and unaffected sides was compared. Results: Proximal center of mass location produced a more efficient gait. Weight change from 42% to 70% of normal had no significant effect. Mechanical studies show that the prosthesis is a relatively poor substitute for the normal limb; most work is done by the nonamputated side. Particularly, the prosthesis failed to produce effective forward impulses on the body, resulting from push-off and deceleration of the swing leg. Conclusions: For a proximal center of mass, lightweight distal components (eg, feet) should be used; it is questionable whether further expenditure to develop ultralightweight prostheses would be cost effective for level walking.
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U2 - 10.1016/S0003-9993(98)90293-3
DO - 10.1016/S0003-9993(98)90293-3
M3 - Article
C2 - 9473997
AN - SCOPUS:0031882333
VL - 79
SP - 162
EP - 168
JO - Archives of Physical Medicine and Rehabilitation
JF - Archives of Physical Medicine and Rehabilitation
SN - 0003-9993
IS - 2
ER -