Limb Health and Socket Pressure in Response to Powered Ankle Protheses

Study Overview
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Brief Summary
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this project seeks to understand and quantify the effects of powered transtibial prostheses on socket loading and direct measures of residual limb health so as to inform the optimization of prosthesis fit.

Detailed Description
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Some estimates suggest that by 2050, as many as 3.6 million people in the United States will be living with limb loss, and at least 60% of them will have had at least a foot removed For military personnel, combat-related amputations remain one of the most common major disabling war-related injuries from modern armed conflict. Technological advancements in active prosthetic devices for individuals with transtibial amputation offer the potential for superior function in key areas that could lead to higher rates of RTD and improved quality of life. Currently intended primarily for individuals with a K-level of 3 or 4, active transtibial prostheses that provide controlled plantar/dorsiflexion in either swing (microprocessor-controlled prostheses) or late stance (prostheses with powered propulsion) are likely to become the gold standard in the future as technology continues to improve Indeed, users of these types of prostheses have higher mobility than those using any of the other four categories of prosthetic ankle-foot mechanisms for unlimited community ambulators. Note that a major insurer has recently declared microprocessor-controlled ankle-foot prostheses medically necessary for members whose functional level is 3 or above.The PROPRIO FOOT® by Ossur, is a microprocessor-controlled prosthesis that regulates the angle of ankle dorsiflexion during the swing phase. This added ankle control of these devices reduces the risk of falls by increasing toe clearance supports more natural standing posture on slopes and improves stair and slope ascent/descent capability by adapting to the change in terrain.On stairs, the PROPRIO FOOT® has been shown to improve affected leg knee kinematics (increased knee flexion) and kinetics (increased knee moment) instance. These improvements also contributed to higher interlimb symmetry reduced energetic cost of slope ascent and higher Amputee Mobility Predictor with a Prosthesis (AMPPRO) scores . Although the ankle of the PROPRIO FOOT® can be controlled in swing, the device does not have adequate power to provide an active propulsion instance. The Empower ankle by Ottobock is a powered prosthesis that provides active propulsion in late stance to mimic the positive work performed by the ankle plantar flexors in push-off. The Empower has been shown to improve affected leg kinematics (increased ankle range of motion and reduced knee flexion) on smooth flat ground ramp ascent and gravel]. In terms of kinetics, the Empower likewise results in increased ankle power on level ground stairs and ramps . Active prostheses like the PROPRIO FOOT® and Empower ankle offer great potential to more completely restore the locomotor capabilities of individuals with transtibial amputation, perhaps enhancing RTD for military personnel. As with all prosthetic components, though, these active devices are of little use if they induce pain and/or injury at the residual limb to the degree that the user will simply not wear them. The investigators will examine how optimal fit of lower limb prostheses can impact individuals comfort and/or reduce irritation.

Official Title
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Limb Health and Socket Pressure in Response to Powered Ankle Prostheses

Conditions
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Pressure Ulcer, Ankle, Prosthesis User, Prosthesis Durability, Mobility Limitation, Skin Wound, Amputation; Traumatic, Foot, Amputation, Limb Deficiencies

Intervention / Treatment
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* Device: PROPRIO FOOT® by Ossur
* Device: Empower ankle by Ottobock


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Ages 18 and above Weight ≤ 280 lb Ambulate at a K3 level or higher-level determined from patient EHR At least 3 months post-amputation per physician discretion Residual limb length greater than 4.5 inches Use of a passive prosthesis Unilateral transtibial amputees Must be able to ambulate without any assistive devices Subjects must be able to follow directions and give informed consent on their own Exclusion Criteria: Conditions and/or co-morbidities that would prevent wearing a prosthetic socket, affect gait, or influence function of the contralateral limb Other amputees Cognitive deficits or mental health problems that would limit ability to consent and participate fully in the study protocol Women who are pregnant or who plan to become pregnant in the near future Individuals diagnosed with renal failure Participants unwilling to wear a cloth face covering for the duration of each visit

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Supportive Care
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Proprio Foot<br>microprocessor-controlled prosthesis that regulates the angle of ankle dorsiflexion during the swing phase | Device: PROPRIO FOOT® by Ossur<br>* Active prostheses like the PROPRIO FOOT® offer great potential to more completely restore the locomotor capabilities of individuals with transtibial amputation, perhaps enhancing RTD for military personnel. The investigators will examine factors of socket loading and direct measures of residual limb health so as to inform the optimization of prosthesis fit. The testing will consist of walking on a treadmill and the use of a 3D motion capture camera to track movement and angles of the participant's upper and lower extremities. Ascending and descending on stairs and ramps with the device will be completed. Participants will also have laser speckle imaging to measure blood flow to skin and transepidermal water loss measurement to check skin health.<br>|
| Active Comparator: Empower Ankle<br>a powered prosthesis that provides active propulsion in late stance to mimic the positive work performed by the ankle plantar-flexors in push-off. The Empower has been shown to improve affected leg kinematics (increased ankle range of motion and reduced knee flexion) on smooth flat ground, ramp ascent, and gravel | Device: Empower ankle by Ottobock<br>* Active prostheses -such as the Empower ankle offer great potential to more completely restore the locomotor capabilities of individuals with transtibial amputation, perhaps enhancing RTD for military personnel. The investigators will examine factors of socket loading and direct measures of residual limb health so as to inform the optimization of prosthesis fit. The testing will consist of walking on a treadmill and the use of a 3D motion capture camera to track movement and angles of the participant's upper and lower extremities. Ascending and descending on stairs and ramps with the device will be completed. Participants will also have laser speckle imaging to measure blood flow to skin and trans epidermal water loss measurement to check skin health.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Effects of use of a powered transtibial prosthesis on socket pressure | effects of a powered transtibial prosthesis on the socket pressure for level-ground walking, stair ascent/descent, and ramp ascent/descent in comparison to a microprocessor-controlled prosthesis and a passive prosthesis | 4 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Skin Perfusion | Changes measured with laser speckle imaging. | 4 weeks | 
| Change in transepidermal water loss | Water loss change is measured via the TEWL device- the reduction in the score denotes improvement in water loss | 4 weeks | 
| Change in PEQ-13 Score | Change in PEQ-13 score over the course of 4 weeks | 4 weeks | 
| Socket Comfort Score | Change in Socket Comfort Score over the course of 4 weeks | 4 weeks |