Trial Outcomes & Findings for Effects of Wearing a Powered Ankle-Foot Prosthesis on Amputee Walking (NCT NCT00869947)

Results Overview

We measured and compared gross rates of oxygen consumption and carbon dioxide production using a portable metabolic analysis system (Cosmed K4b2, IT) while participants walked at five constance velocities (0.75, 1.00, 1.25, 1.50 and 1.75 m/s) on a level treadmill (SoleFitness F85). We calculated average steady-state metabolic power in Watts (W) from 4-6 min of each trial using a standard equation. Then, we divided the metabolic power by each participant's weight and velocity to calculate the metabolic cost of transport (J/Nm).

Recruitment status

COMPLETED

Study phase

NA

Target enrollment

16 participants

Primary outcome timeframe

1 year

Results posted on

2014-02-25

Participant Flow

Participant milestones

Participant milestones
Measure	Prosthesis Subjects with transtibial amputation using a powered and passive ankle-foot prosthesis	Non-amputees Non-amputees
Overall Study STARTED	8	8
Overall Study COMPLETED	8	8
Overall Study NOT COMPLETED	0	0

Reasons for withdrawal

Withdrawal data not reported

Baseline Characteristics

Effects of Wearing a Powered Ankle-Foot Prosthesis on Amputee Walking

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Prosthesis n=8 Participants Subjects with transtibial amputation using a passive ankle-foot prosthesis	Non-amputee n=8 Participants Non-amputees	Total n=16 Participants Total of all reporting groups
Age, Continuous 18 - 65 years	46 years STANDARD_DEVIATION 8 • n=5 Participants	49 years STANDARD_DEVIATION 9 • n=7 Participants	47.5 years STANDARD_DEVIATION 8.5 • n=5 Participants
Sex: Female, Male Female	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants
Sex: Female, Male Male	8 Participants n=5 Participants	8 Participants n=7 Participants	16 Participants n=5 Participants
Region of Enrollment United States	8 participants n=5 Participants	8 participants n=7 Participants	16 participants n=5 Participants

PRIMARY outcome

Timeframe: 1 year

We measured and compared gross rates of oxygen consumption and carbon dioxide production using a portable metabolic analysis system (Cosmed K4b2, IT) while participants walked at five constance velocities (0.75, 1.00, 1.25, 1.50 and 1.75 m/s) on a level treadmill (SoleFitness F85). We calculated average steady-state metabolic power in Watts (W) from 4-6 min of each trial using a standard equation. Then, we divided the metabolic power by each participant's weight and velocity to calculate the metabolic cost of transport (J/Nm).

Outcome measures

Outcome measures
Measure	Participants With an Amputation Using a Passive Prosthesis n=7 Participants	Participants With an Amputation Using a Powered Prosthesis n=7 Participants	Non-amputees n=7 Participants
Metabolic Cost of Transport 0.75 m/s	4.76 J/Nm Standard Deviation 0.30	4.57 J/Nm Standard Deviation 0.66	4.68 J/Nm Standard Deviation 0.65
Metabolic Cost of Transport 1.00 m/s	4.11 J/Nm Standard Deviation 0.37	3.77 J/Nm Standard Deviation 0.31	3.71 J/Nm Standard Deviation 0.42
Metabolic Cost of Transport 1.25 m/s	3.95 J/Nm Standard Deviation 0.34	3.57 J/Nm Standard Deviation 0.41	3.41 J/Nm Standard Deviation 0.45
Metabolic Cost of Transport 1.50 m/s	4.15 J/Nm Standard Deviation 0.18	3.78 J/Nm Standard Deviation 0.34	3.60 J/Nm Standard Deviation 0.39
Metabolic Cost of Transport 1.75 m/s	4.59 J/Nm Standard Deviation 0.35	4.09 J/Nm Standard Deviation 0.49	3.69 J/Nm Standard Deviation 0.35

SECONDARY outcome

Timeframe: 1 year

We determined preferred walking velocity by incrementally increasing and decreasing treadmill velocity until each participant ascertained the velocity that they felt most comfortable.

Outcome measures

Outcome measures
Measure	Participants With an Amputation Using a Passive Prosthesis n=7 Participants	Participants With an Amputation Using a Powered Prosthesis n=7 Participants	Non-amputees n=7 Participants
Preferred Walking Velocity	1.16 m/s Standard Deviation 0.17	1.42 m/s Standard Deviation 0.15	1.41 m/s Standard Deviation 0.25

SECONDARY outcome

Timeframe: 1 year

We calculated step-to-step transition work, the work done by each individual leg on the center of mass during transitions, using the individual limbs method described by Donelan et al. 2002. Trailing leg step-to-step transition work quantifies the amount of push-off work done by the trailing leg when both feet are on the ground during walking. Work (J) is normalized to each subject's mass (kg).

Outcome measures

Outcome measures
Measure	Participants With an Amputation Using a Passive Prosthesis n=7 Participants	Participants With an Amputation Using a Powered Prosthesis n=7 Participants	Non-amputees n=7 Participants
Trailing Leg Step-to-step Transition Work 1.75 m/s	0.148 J/kg Standard Error 0.014	0.217 J/kg Standard Error 0.016	0.259 J/kg Standard Error 0.012
Trailing Leg Step-to-step Transition Work 0.75 m/s	0.114 J/kg Standard Error 0.011	0.155 J/kg Standard Error 0.016	0.165 J/kg Standard Error 0.012
Trailing Leg Step-to-step Transition Work 1.00 m/s	0.125 J/kg Standard Error 0.008	0.194 J/kg Standard Error 0.013	0.179 J/kg Standard Error 0.007
Trailing Leg Step-to-step Transition Work 1.25 m/s	0.123 J/kg Standard Error 0.006	0.199 J/kg Standard Error 0.013	0.199 J/kg Standard Error 0.010
Trailing Leg Step-to-step Transition Work 1.50 m/s	0.131 J/kg Standard Error 0.006	0.239 J/kg Standard Error 0.017	0.240 J/kg Standard Error 0.014

Adverse Events

Prosthesis

Serious events: 0 serious events

Other events: 0 other events

Deaths: 0 deaths

Non-amputees

Serious events: 0 serious events

Other events: 0 other events

Deaths: 0 deaths

Serious adverse events

Adverse event data not reported

Other adverse events

Adverse event data not reported

Additional Information

Dr. Alena Grabowski

Eastern Colorado Healthcare System

Phone: 303-492-5208

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee
Publication restrictions are in place