Understanding How Powered Componentry Impacts K2-Level Transfemoral Amputee Gait

Overview

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.

Interventions

• Device Ottobock CLeg4 + Ottobock foot
  Commercially available Ottobock CLeg 4 microprocessor knee unit and Ottobock foot.
• Device SRALAB Hybrid Knee + Polycentric Ankle
  Experimental powered prosthesis: SRALAB Hybrid Knee and powered polycentric ankle.
• Device SRALAB Hybrid Knee + Passive Ankle
  Experimental powered prosthesis: SRALAB Hybrid Knee and passive ankle.
• Device Ottobock CLeg 4 + Polycentric Ankle
  Commercially available Ottobock CLeg 4 prosthetic knee and SRALAB powered polycentric ankle.

Primary outcome measures

• Amputee Mobility Predictor with Prosthesis (AMPRO) score [Time frame: Completed at visit during week 5, week 10, week 11, week 14, week 15, week 18, week 35 and week 38.]

Secondary outcome measures (4)

• 6 Minute Walk Test (6MWT) [Time frame: Completed at visit during week 5, week 10, week 11, week 14, week 15, week 18, week 35 and week 38.]
• Timed Up and Go (TUG) [Time frame: Completed at visit during week 5, week 10, week 11, week 14, week 15, week 18, week 35 and week 38.]
• Four Square Step Test (FSST) [Time frame: Completed at visit during week 5, week 10, week 11, week 14, week 15, week 18, week 35 and week 38.]
• Metabolic Testing [Time frame: Completed at visit during week 5, week 10, week 11, week 14, week 15, week 18, week 35 and week 38]

Eligibility criteria

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.

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

Randomized

Model

Crossover

Masking

Open label

Primary purpose

Basic science

Study locations

United States · 1 center

• Shirley Ryan AbilityLab — Chicago

Publications

• Ziegler-Graham K, MacKenzie EJ, Ephraim PL, Travison TG, Brookmeyer R. Estimating the prevalence of limb loss in the United States: 2005 to 2050. Arch Phys Med Rehabil. 2008 Mar;89(3):422-9. doi: 10.1016/j.apmr.2007.11.005. PMID 18295618
• Gailey RS, Wenger MA, Raya M, Kirk N, Erbs K, Spyropoulos P, Nash MS. Energy expenditure of trans-tibial amputees during ambulation at self-selected pace. Prosthet Orthot Int. 1994 Aug;18(2):84-91. doi: 10.3109/03093649409164389. PMID 7991365
• Hafner BJ, Sanders JE, Czerniecki J, Fergason J. Energy storage and return prostheses: does patient perception correlate with biomechanical analysis? Clin Biomech (Bristol). 2002 Jun;17(5):325-44. doi: 10.1016/s0268-0033(02)00020-7. PMID 12084537
• Burger H, Marincek C. The life style of young persons after lower limb amputation caused by injury. Prosthet Orthot Int. 1997 Apr;21(1):35-9. doi: 10.3109/03093649709164528. PMID 9141124
• Fey NP, Simon AM, Young AJ, Hargrove LJ. Controlling Knee Swing Initiation and Ankle Plantarflexion With an Active Prosthesis on Level and Inclined Surfaces at Variable Walking Speeds. IEEE J Transl Eng Health Med. 2014 Jul 25;2:2100412. doi: 10.1109/JTEHM.2014.2343228. eCollection 2014. PMID 27170878
• Adamczyk PG, Kuo AD. Mechanisms of Gait Asymmetry Due to Push-Off Deficiency in Unilateral Amputees. IEEE Trans Neural Syst Rehabil Eng. 2015 Sep;23(5):776-85. doi: 10.1109/TNSRE.2014.2356722. Epub 2014 Sep 12. PMID 25222950

Identifiers

NCT: NCT06433648 · STU00217960

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗