Amputation, Prosthesis User
Conditions
Keywords
Lower limb prosthesis, Transtibial amputation, Below knee amputation, Biomechanics
Brief summary
The aim of this research is to identify the prosthetic foot that results in improved walking performance when individuals with lower limb amputation carry infants, toddlers, or other loads.
Detailed description
The natural lower limbs provide important biomechanical functions such as body weight support, forward propulsion, and balance control during ambulation. When the loads borne by the lower limbs change, lower limb muscle activation responds accordingly to enable seamless continuation of biomechanical function. These loads can change suddenly, such as when carrying an infant, toddler, or other load like a heavy backpack. For individuals with a lower limb amputation, these sudden changes to weight-bearing loads can be problematic because they can negatively impact walking performance. One reason walking performance may suffer is that the properties of most prosthetic limbs, such as their stiffness, are constant and do not change to suit varying load conditions. Another reason is that the most widely prescribed prosthetic feet do not have motors, sensors, or brain-like controllers that act to replace the neuromuscular system of the amputated limb. Regardless of the reason, no evidence exists to guide prescription practice for veterans who walk with a prosthesis and experience sudden load changes. The aim of this research is to identify the prosthetic foot that results in improved walking performance when individuals with lower limb amputation carry infants, toddlers, or other loads. The investigators will conduct a human subject experiment with help of twenty individuals with below-knee amputations. Study participants will walk on a treadmill with no added load and four added load conditions using a weighted pack (13.6 kg or \ 30 lbs) to simulate an infant, toddler, or other load. The four conditions include the pack strapped to their front, their back, and carried with their arms on the intact limb side and the prosthetic limb side. Each participant will wear a usual prosthetic foot, this same foot with a heel-stiffening wedge, the same prosthetic foot but one category stiffness higher, a new-to-market dual keel prosthetic foot intended for load carrying situations, and a powered ankle foot prosthesis. The results from these experiments will aid clinicians in specifying the best prosthesis for individuals with lower limb amputations who frequently carry infants, toddlers, or other loads. For individuals who wear a lower limb prosthesis while carrying infants, toddlers, or other loads, this research will provide evidence to support prosthesis prescription practice that reduces undesirable compensatory responses to load carriage. The objective is to help clinicians select among currently available solutions to enable individuals with lower limb loss to achieve their life and work goals.
Interventions
DEVICEStandard-of-care prosthetic foot
Widely prescribed prosthetic foot of stiffness category appropriate to the participant's body weight and activity level.
DEVICEStandard-of-care prosthetic foot with heel-stiffening wedge
Widely prescribed prosthetic foot with a wedge inserted between the heel and foot keels intended to stiffen the behavior of the heel.
DEVICEStandard-of-care prosthetic foot of one category greater stiffness
Widely prescribed prosthetic foot of one stiffness category greater than usually prescribed based on the participant's body weight and activity level.
DEVICEDual keel prosthetic foot
A prosthetic foot with two forefoot keels intended for load carriage applications.
DEVICEPowered ankle-foot
A powered prosthetic ankle-foot.
Sponsors
VA Puget Sound Health Care System
Study design
Allocation
RANDOMIZED
Intervention model
FACTORIAL
Primary purpose
TREATMENT
Masking
SINGLE (Subject)
Masking description
A sock and foot cover to blind the participants to the study prostheses when possible (use of the powered ankle-foot will be obvious).
Intervention model description
This study will employ a within-subject experimental design. Each participant will wear, in randomized order, a standard-of-care prosthetic foot, this same prosthetic foot with a heel-stiffening wedge, this same prosthetic foot but one category stiffer, a dual keel prosthetic foot intended for load carriage applications, and a powered ankle-foot purported to adapt to changing loads. All study prostheses are commercially available. Each participant, wearing each of the study prostheses, will walk overground with no added load and four added load conditions of 13.6 kg: anterior, posterior, intact-side carry, and prosthetic-side carry. The load condition will be presented in block randomized order.
Eligibility
Sex/Gender
ALL
Age
18 Years to 70 Years
Healthy volunteers
No
Inclusion criteria
1. Unilateral transtibial amputee 2. Have been fitted with and used a prosthesis for at least six months 3. Do not use heel stiffening wedges or bumpers in their as-prescribed prosthesis 4. Wear their prosthesis for at least four hours per day 5. Are moderately active by self-report 6. Can be fitted with the study prostheses (prosthetic foot size, stiffness category and build heights)
Exclusion criteria
1. Do not have a proper fit and suspension and one cannot be achieved with clinical resources 2. Presence of disorder, pain, or injury other than amputation that interferes with gait
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Anterior Ground Reaction Force Impulse (Normalized) | During study visit (approximately 3 hours) | A measure of body forward propulsion. Normalized by body mass, including the mass of the load when applicable. |
| Vertical Ground Reaction Force Impulse (Normalized) | During study visit (approximately 3 hours) | A measure of body support. Normalized by body mass, including the mass of the load when applicable. |
| Peak-to-peak Range of Sagittal Plane Whole-body Angular Momentum (Normalized) | During study visit (approximately 3 hours) | A measure of balance control primarily for anterior and posterior added load conditions. Normalized by body mass (kg) including the mass of the load when applicable, body height (m), and \[gravity\*body height\]\^0.5 (m/s) resulting in a unitless number. |
| Peak-to-peak Range of Coronal Plane Whole-body Angular Momentum (Normalized) | During study visit (approximately 3 hours) | A measure of balance control primarily for intact-side added load conditions. Normalized by body mass (kg) including the mass of the load when applicable, body height (m), and \[gravity\*body height\]\^0.5 (m/s) resulting in a unitless number. |
| Net Positive Ankle Joint Mechanical Work Over the Prosthetic Limb Gait Cycle (Normalized) | During study visit (approximately 3 hours) | Positive ankle joint mechanical work over the prosthetic limb gait cycle is a measure of propulsion capability. A prosthetic foot with greater propulsion capability may enhance gait efficiency during everyday ambulation. Normalized to body mass and the added load mass when applicable. |
Countries
United States
Contacts
PRINCIPAL_INVESTIGATORGlenn Klute, PhD
VA Puget Sound Care System
Participant flow
Pre-assignment details
One enrolled participant decided they were no longer interested in participating after the first visit (alignment and acclimation) but before the second visit (randomization).
Baseline characteristics
| Characteristic | — |
|---|---|
| Age, Continuous | 46 years STANDARD_DEVIATION 15 |
| Ethnicity (NIH/OMB) Hispanic or Latino | 3 Participants |
| Ethnicity (NIH/OMB) Not Hispanic or Latino | 8 Participants |
| Ethnicity (NIH/OMB) Unknown or Not Reported | 1 Participants |
| Race (NIH/OMB) American Indian or Alaska Native | 0 Participants |
| Race (NIH/OMB) Asian | 0 Participants |
| Race (NIH/OMB) Black or African American | 1 Participants |
| Race (NIH/OMB) More than one race | 3 Participants |
| Race (NIH/OMB) Native Hawaiian or Other Pacific Islander | 0 Participants |
| Race (NIH/OMB) Unknown or Not Reported | 2 Participants |
| Race (NIH/OMB) White | 6 Participants |
| Sex: Female, Male Female | 2 Participants |
| Sex: Female, Male Male | 10 Participants |
Adverse events
| Event type | EG000 affected / at risk |
|---|---|
| deaths Total, all-cause mortality | 0 / 12 |
| other Total, other adverse events | 0 / 12 |
| serious Total, serious adverse events | 0 / 12 |
Outcome results
None listed