Understanding How Powered Componentry Impacts K2-Level Transfemoral Amputee Gait

Not Applicable

Recruiting

• Conditions: Amputation; Amputation of Knee; Amputation; Traumatic, Limb; Amputation, Traumatic
• Interventions: Device: SRALAB Hybrid Knee + Passive Ankle; Device: Ottobock CLeg4 + Ottobock foot; Device: Ottobock CLeg 4 + Polycentric Ankle; Device: SRALAB Hybrid Knee + Polycentric Ankle

• Registration Number: NCT06433648
• Lead Sponsor: Shirley Ryan AbilityLab

Brief Summary

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.

Detailed 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.

Study Timeline

• Study Start: 2023-05-01
• Status Verified: 2024-05
• Study First Submitted: 2024-05-16
• Study First Submitted QC: 2024-05-28
• Last Update Submitted: 2024-05-28
• Study First Posted: 2024-05-30
• Last Update Posted: 2024-05-30
• Primary Completion: 2028-06-30
• Study Completion: 2029-06-30

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 20

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.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
Transfemoral Amputee participants: Ottobock CLeg4 + Polycentric Ankle, Hybrid Knee + Passive Ankle	SRALAB Hybrid Knee + Passive Ankle	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.
Transfemoral Amputee participants: Ottobock CLeg4 + Polycentric Ankle, Hybrid Knee + Passive Ankle	Ottobock CLeg 4 + Polycentric Ankle	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.
Transfemoral Amputee participants: SRALAB Hybrid knee + Polycentric Ankle, Ottobock Cleg4 + OB foot	Ottobock CLeg4 + Ottobock foot	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.
Transfemoral Amputee participants: Ottobock Cleg4 + Ottobock foot; Hybrid Knee + Polycentric Ankle	SRALAB Hybrid Knee + Polycentric Ankle	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.
Transfemoral Amputee participants: SRALAB Hybrid knee + Polycentric Ankle, Ottobock Cleg4 + OB foot	SRALAB Hybrid Knee + Polycentric Ankle	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.
Transfemoral Amputee participants: Ottobock Cleg4 + Ottobock foot; Hybrid Knee + Polycentric Ankle	Ottobock CLeg4 + Ottobock foot	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.

Primary Outcome Measures

Name	Time	Method
Amputee Mobility Predictor with Prosthesis (AMPRO) score	Completed at visit during week 5, week 10, week 11, week 14, week 15, week 18, week 35 and week 38.	The AMPRO measures the ambulatory potential of lower limb amputees. It is used to assess functional mobility through a standardized sequence of mobility tests while using a prosthesis. Individual tasks are scored and combined, resulting in a total assessment score out of a possible 47; the minimum score is zero. Higher scores indicate better mobility.; The AMPPRO is a reliable performance measure that has been validated for those with lower limb loss; it measures several functional mobility tasks that are needed during activities of daily living; it has been used to identify limitations in prosthetic mobility, including tasks that require both vertical mobility (sit/stand), horizontal mobility (walking), and balance. The AMPPRO scores have been shown to differentiate between Medicare K-levels and to provide information to guide therapeutic exercise techniques and document change after clinical instruction.

Secondary Outcome Measures

Name	Time	Method
Metabolic Testing	Completed at visit during week 5, week 10, week 11, week 14, week 15, week 18, week 35 and week 38	Subjects will be instrumented with the COSMED® K5 system (COSMED, Rome, Italy). Baseline metabolic data prior to each walking bout will be recorded for 2 minutes of sitting and quiet rest. Metabolic data will then be collected during 6 minutes of walking at a constant self-selected walking velocity on a treadmill. After each walking bout, subjects will rest for 20 minutes to allow their heart rate to return to their baseline level.
Timed Up and Go (TUG)	Completed at visit during week 5, week 10, week 11, week 14, week 15, week 18, week 35 and week 38.	The Timed Up and Go Test (TUG) assesses mobility, balance, walking ability, and fall risk in older adults.
6 Minute Walk Test (6MWT)	Completed at visit during week 5, week 10, week 11, week 14, week 15, week 18, week 35 and week 38.	The 6 minute walk test (6MWT) assesses distance walked over 6 minutes as a sub-maximal test of aerobic capacity/endurance.
Four Square Step Test (FSST)	Completed at visit during week 5, week 10, week 11, week 14, week 15, week 18, week 35 and week 38.	A test of dynamic balance and coordination that clinically assesses the participant's ability to step over objects forward, sideways, and backwards.

Trial Locations

Locations (1)

Shirley Ryan AbilityLab; 🇺🇸 Chicago, Illinois, United States