Understanding How Powered Componentry Impacts K2-Level Transfemoral Amputee Gait

Shirley Ryan AbilityLab

Status: Enrolling

Conditions: Amputation, Traumatic; Amputation; Traumatic, Limb; Amputation of Knee; Amputation

Treatments: Device: Ottobock CLeg 4 + Polycentric Ankle; Device: Ottobock CLeg4 + Ottobock foot; Device: SRALAB Hybrid Knee + Polycentric Ankle; Device: SRALAB Hybrid Knee + Passive Ankle

Study type: Interventional

Funder types: Other

Identifiers

NCT06433648

STU00217960

Details and patient eligibility

About

The goal of this study is to understand how providing power at the knee or ankle individually, or providing power at both the knee and ankle, impacts ambulation for K2 level transfemoral amputees.

Aim 1: measure functional performance of K2 level ambulators when using a commercially available passive microprocessor knee prosthesis (Ottobock Cleg/Ottobock foot) or a powered knee and ankle prosthesis (SRALab Hybrid Knee and SRAlab Polycentric Powered Ankle.

Aim 2: Participants will be evaluated on the contribution of adding power at the knee only or the ankle only.

Aim 3: The investigators will evaluate the functional performance after intensive clinical gait training on the powered knee and ankle prosthesis (SRALab Hybrid Knee and SRALab Polycentric Powered Ankle).

Our hypothesis is that providing powered componentry will improve function and that intensive training will magnify those improvements.

Full description

Amputation of the lower limb causes profound disability, significantly limiting mobility, independence, and the ability to pursue employment or leisure activities. Nearly 90% of all lower limb amputations in the United States occur in older persons, mostly due to vascular disease, and this population is expected to triple by 2050. After lower limb loss, individuals walk more slowly and more asymmetrically are less stable, and expend more metabolic energy during walking than persons with intact limbs. Even when using state-of-the-art microprocessor-controlled prostheses (typically a microprocessor knee with a passive ankle), persons with transfemoral amputations expend approximately 60% more energy than able-bodied individuals during ambulation. In addition to the physical limitations caused by the amputation, the increased energy requirements affect performance of everyday activities, including getting up out of a chair or off the toilet, or stepping up or down a curb.

Most commercially available prosthetic legs are passive. The movement of a passive prosthetic joint relies on the properties of its mechanical components, such as hydraulic or pneumatic valves or sliding joints, together with compensatory adjustments made by the user. Since these computerized prostheses are passive, the user cannot efficiently negotiate stairs, an incline, or the numerous other functions that require net knee and/or ankle power.

Powered prostheses can actively generate joint torque, allowing easy and efficient performance of more demanding activities, such as ascending stairs and hills. Powered knees and ankles, may allow for better outcomes in both older and younger individuals with transfemoral amputation; this powered componentry may enable more energy efficient walking, allow users to stand up from a seated position with ease, and enable them to walk across more challenging terrains-such as up and down hills, ramps, and stairs-safely and with more normal and symmetric gait kinematics and kinetics.

This study will demonstrate the functional benefits of adding power at an individual joint. This knowledge will be critical for prioritizing future device development and will provide valuable information for clinicians and individuals on selecting appropriate componentry for transfemoral K2 amputees.

Enrollment: 20 estimated patients

Sex: All

Ages: 18 to 95 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Ages 18-95
• A unilateral transfemoral amputation
• At least 6 months since definitive prosthesis fitting
• Able to walk 50 meters (55 yards) with a prosthesis without the assistance of another person.
• Medically cleared by physician to participate in study
• English speaking

Exclusion criteria

• Weight greater than 250 pounds
• Significant new injury that would prevent use of a prosthesis: The ability to consistently wear a prosthesis and perform activities of daily living and specific performance tasks is necessary to evaluate the relative benefits of the interventions.
• Cognitive impairment sufficient to adversely affect understanding of or compliance with study requirements, ability to communicate experiences, or ability to give informed consent: The ability to understand and comply with requirements of the study is essential in order for the study to generate useable, reliable data. The ability to obtain relevant user feedback through questionnaires and informal discussion adds significant value to this study.
• Significant other comorbidity: Any other medical issues or injuries that would preclude completion of the study, use of the prostheses, or that would otherwise prevent acquisition of useable data by researchers.

Trial design

Primary purpose: Basic Science

Allocation: Randomized

Interventional model: Crossover Assignment

Masking: None (Open label)

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20 participants in 3 patient groups

Transfemoral Amputee participants: Ottobock Cleg4 + Ottobock foot; Hybrid Knee + Polycentric Ankle

Active Comparator group

Description:

Participant is fit with the commercially available device (Ottobock Cleg 4/Ottobock foot), they will receive standard of care clinical training for 3-4 sessions over 4 weeks, plus 1 session for outcome assessments. Participant is then fit with the SRALAB Hybrid knee and SRALAB Polycentric Ankle prosthesis, they again will receive clinical training for 3-4 sessions over 4 weeks, plus 1 session for outcome assessments.

Treatment:

Device: SRALAB Hybrid Knee + Polycentric Ankle

Device: Ottobock CLeg4 + Ottobock foot

Transfemoral Amputee participants: Ottobock CLeg4 + Polycentric Ankle, Hybrid Knee + Passive Ankle

Experimental group

Description:

For this arm, transfemoral amputees will participate in an AB/BA randomized crossover study. Before each arm of the cross-over, baseline data will be taken with the Ottobock Cleg 4/Ottobock foot or their clinically prescribed microprocessor knee unit/foot. Condition A is CLeg + Polycentric Ankle Condition B is SRALab Hybrid knee + Passive Ankle Subjects will participate in 2 sessions over 2 weeks, each lasting 2-3 hours to have the device tuned for the specific condition (A or B). On the third week, they will participate in 2 visits to complete functional outcome measures, biomechanical and metabolic assessments. They will then switch conditions, and repeat the protocol for the second condition. There will not be a washout period between conditions, but subjects will complete outcome measures with the Ottobock Cleg 4/Ottobock foot or their clinically prescribed microprocessor knee unit/foot prior to each arm of the crossover to obtain baseline data.

Treatment:

Device: SRALAB Hybrid Knee + Passive Ankle

Device: Ottobock CLeg 4 + Polycentric Ankle

Transfemoral Amputee participants: SRALAB Hybrid knee + Polycentric Ankle, Ottobock Cleg4 + OB foot

Experimental group

Description:

During this arm, participants will receive intensive clinical training with the SRALAB Hybrid knee + Polycentric Ankle twice per week over 8 weeks, lasting 2-3 hours. Training will include patient-driven therapy to achieve participants' individual therapy goals, functional mobility and community skills. At the end of the 8-week training period, subjects will complete the same set of functional outcome measures, biomechanical and metabolic assessments in previous arms. To complete this arm, participants will again complete training and outcome measures with the Ottobock Cleg4/Ottobock or their clinically prescribed microprocessor knee unit/foot over 3 visits.

Treatment:

Device: SRALAB Hybrid Knee + Polycentric Ankle

Device: Ottobock CLeg4 + Ottobock foot