Evaluating Mobility Interventions in the Real World

• Lower limb prostheses (Device), also known as Low-profile foot, Energy-storing foot, Hydraulic ankle, Microprocessor ankle: Standard commercially available prostheses for participants with lower-limb amputation. Specific prostheses will be determined at the time of the study, but they will include prostheses that are fully passive such as energy storage-and-return (ESR, Agilix) feet and low-profile foot (LP, Pacifica LP), ESR feet with mobilized ankles such as passive hydraulic ankles (PHA, Kinterra), and ESR feet with microprocessor-controlled ankles (MPA, Kinnex).
• Orthoses for Drop-foot (Device), also known as carbon fiber ankle foot orthosis (caAFO), functional electrical stimulation (FES): Standard commercially-available orthoses or standard-of-care custom orthoses as well as standard commercially-available electrical stimulation neuro-orthoses. Sprystep for the caAFO, Bioness L300 Go for the FES

Primary outcomes

• Minimum Foot Clearance With Different Prostheses [Weekly time points for Prosthetic interventions (baseline, 1, 2, 3, and 4 weeks), data collected anytime up to 12 weeks on study]: Minimum Foot Clearance with different prostheses, participants crossover to each of 4 different conditions at different study visits, data collected up to 12 weeks on study.
• Minimum Foot Clearance With Different Orthoses [Baseline, 10 days, and 20 days for Orthotic interventions]: Minimum Foot Clearance with different orthoses, participants crossover to each of 3 different conditions at different study visits, data collected up to 20 days on study.

Secondary outcomes

• Behavioral Gait Function as Measured From Daily Stride Count [Weekly time points for Prosthetic interventions (baseline, 1, 2, 3, and 4 weeks), data collected anytime up to 12 weeks on study]: Behavioral gait function will be measured by daily stride count (strides per sensor hour, Prosthetics only), participants crossed over to each of 4 different conditions at different study visits, data collected up to 12 weeks on study.
• Behavioral Gait Function as Measured From Stride Speed During Walking Bouts of Different Durations [Weekly time points for Prosthetic interventions (baseline, 1, 2, 3, and 4 weeks), data collected anytime up to 12 weeks on study]: Behavioral gait function will be measured by average stride speed, participants crossover to each of 4 different conditions at different study visits, data collected up to 12 weeks on study.
• Prosthetic Limb Users Survey of Mobility Score [up to 12 weeks]: The Prosthetic Limb Users Survey of Mobility (PLUS-M) is a 12 item questionnaire. It is a self-report instrument for measuring mobility of adults with lower limb amputation. PLUS-M instruments measure prosthetic users' mobility (i.e., the ability to move intentionally and independently from one place to another). PLUS-M questions assess respondents' perceived ability to carry out actions that require use of both lower limbs, ranging from household ambulation to outdoor recreational activities. The described activities relate to two primary forms of movement, locomotion (i.e., movement in a continuous, repeatable pattern) and/or postural transitions (i.e., movement from one position to another or one type of activity to another). PLUS-M instruments provide a T-score that averages 50 with a standard deviation of 10. A higher PLUS-M T-score corresponds to greater mobility.
• Change in Movement Quality as Determined by Stride Width: Prosthesis [Weekly time points for Prosthetic interventions (baseline, 1, 2, 3, and 4 weeks), data collected anytime up to 12 weeks on study]: Change in movement quality will be determined by stride width, participants crossover to each of 4 different conditions at different study visits, data collected up to 12 weeks on study. Stride width is the absolute value of the lateral distance from a line that is fit to the foot placements of 3 strides previous and 3 strides after the current stride, to the foot placement location of the current stride.
• Change in Movement Quality as Determined by Stride Width: Orthoses [Baseline, 10 days, and 20 days for Orthotic interventions]: Change in movement quality will be determined by stride width, participants crossover to different conditions at different study visits, data collected up to 20 days on study. Stride width is the absolute value of the lateral distance from a line that is fit to the foot placements of 3 strides previous and 3 strides after the current stride, to the foot placement location of the current stride.
• Change in Gait Performance as Determined by Average Speed [Weekly time points for Prosthetic interventions (baseline, 1, 2, 3, and 4 weeks), data collected anytime up to 12 weeks on study]: Change in gait performance as determined by speed of the participant, participants crossover to each of 4 different conditions at different study visits, data collected up to 12 weeks on study.
• Gait Performance as Determined by Stride Frequency at Identical Speed [Weekly time points for Prosthetic interventions (baseline, 1, 2, 3, and 4 weeks), data collected anytime up to 12 weeks on study]: Gait performance as determined by stride frequency at identical speed (included strides with walking speeds between 0.75-1.25 meters per second). Participants crossover to each of 4 different conditions at different study visits, data collected up to 12 weeks on study.
• Change in Gait Performance as Determined by Ground Reaction Forces [Baseline, 10 days, and 20 days for Orthotic interventions, weekly time points for Prosthetic interventions (baseline, 1, 2, 3, and 4 weeks), data collected anytime up to 12 weeks on study]: Ground reaction force is force applied by the body to the ground. Peak forces and shape of the force vs. time trajectory are commonly used to assess gait quality. Forces closer to "normal" are usually considered better, but this goal does not apply in participants with amputation.
• Change in Gait Performance as Determined by Socket Torques [Baseline, 10 days, and 20 days for Orthotic interventions, weekly time points for Prosthetic interventions (baseline, 1, 2, 3, and 4 weeks), data collected anytime up to 12 weeks on study]: Socket torque (also termed "socket moment") is the amount of twisting or bending torque applied to the prosthetic socket. Peak socket torque and cumulative socket torque are measures commonly used to assess gait quality in persons with lower limb amputation.
• Change in Functional Gait Assessment Score [Baseline, 10 days, and 20 days for Orthotic interventions]: The Functional Gait Assessment Score will be measured for the sub-population of participants with Multiple Sclerosis (MS). The total score ranges from 0-30 with higher scores indicating increased impairment in gait. Participants crossover to each of three conditions at different study visits.
• Change in 6 Minute Walking Test Distance [Baseline, 10 days, and 20 days study visits to test conditions for Orthotic interventions]: The sub-population of participants with MS will undergo a 6 minute walking test for distance. Each participant will crossover to three conditions over three study visits: No intervention, the carbon fiber ankle foot orthosis (cfAFO), and a functional electrical stimulation (FES) device). Reported here are the difference from No intervention for the cfAFO and FES orthoses, a positive number shows an increase in distance walked due to the intervention.
• Stride Length at Identical Walking Speed [Weekly time points for Prosthetic interventions (baseline, 1, 2, 3, and 4 weeks), data collected anytime up to 12 weeks on study]: Walking speeds from 0.75 to 1.25 meters per second were analyzed, participants crossover to each of 4 different conditions at different study visits, data collected up to 12 weeks on study.

Sex: All, ages: 18 Years to 75 Years, accepts healthy volunteers

Inclusion Criteria:

Target Populations:

* Participants with amputation must have used a prosthesis for more than 6 months, and wear it for at least 8 hours per day.
* Participants must be more than 6 months past their most recent surgery (if any).
* Participants must be free of musculoskeletal and cardiovascular conditions that would limit their ability to safely complete testing.
* Participants should consider themselves in good health; be able to wear their prostheses or orthoses all day long; be able to perform all of their activities of daily living (ADL) with their prostheses or orthoses as appropriate; have a comfortably fitting functional prosthesis (if applicable) that does not cause any skin problems; and have a stable residual limb (or impaired limb).
* Participants may use a narrow-base cane (single point, narrow tripod base, etc.) as an ambulatory aid but not a small-base quad cane or walker.
* Participants must be able to walk with their prostheses or orthoses for 30 minutes (total) and stand for 30 minutes (total), in individual bouts of at least 6 minutes, without becoming fatigued, feeling dizzy, having chest pain or shortness of breath, or experiencing claudication symptoms.
* Participants involved in running tests must be able to run for 30 minutes (total) in bouts of at least 6 minutes, without becoming fatigued, feeling dizzy, having chest pain, or experiencing claudication symptoms.
* Participants must have no known cognitive disability.
* Participants must be fluent in spoken and written English.
* Running portions of the study will be limited to participants who self-report regular engagement in recreational or competitive running.
* Participants in the branch that uses only their own prostheses must have at least a daily use prosthesis and a running-specific prosthesis; additional prostheses may also be included

Multiple Sclerosis group:

* For the specific subgroup targeting Multiple Sclerosis, participants must have a clinical diagnosis of Multiple Sclerosis and a clinician must determine they are experiencing foot drop.
* Participants must be able to comfortably wear and ambulate with both study devices with effective management of foot-drop, without significant discomfort
* Participants must be able to perform all of their activities of daily living (ADL) with only minimal use of ambulatory aids. Subjects may use a narrow-base cane (single point, narrow tripod base, etc.) as an ambulatory aid in any amount. Use of more comprehensive ambulatory aids (e.g. a small-base quad cane, wide-base quad cane or walker) must be limited to no more than 20% of their walking time when not at home. Participants who do use an assistive device occasionally should report a threshold for use of greater than 100 feet, i.e., they are unlikely to use their device unless they anticipate ambulating greater than this distance.

Exclusion Criteria:

Target Populations:

* Allergy to electrode gel, surgical tape and metals.
* Participants who currently use the Bioness L300 Go or similar neuro-orthoses or use a carbon fiber ankle-foot orthosis at the time of the study will be excluded to avoid biasing results for one device or the other. Participants with past experience not currently using these devices will be eligible.
* Participants enrolled in physical therapy or other rehabilitative care for treatment of gait, balance, or lower extremity strength or coordination at the time of the study will be excluded to avoid confounding effects from therapy and device-based management of their condition.
* For the orthotics study, participants with peripheral neuropathy impacting control of the tibialis anterior muscle via the peroneal nerve will be excluded.
* Participants under treatment for infectious diseases will be excluded from the study.
* Women who are pregnant or planning to become pregnant during the course of the study will be excluded.
* Symptomatic musculoskeletal conditions that prevent unaided walking, such as back pain or knee arthritis.
* Cardiovascular conditions that make moderate exercise unsafe, including (but not limited to) history of angina, peripheral vascular disease, congestive heart failure, history of myocardial infarction, and history of stroke. Potential participants will be excluded if they self-report that a physician has told them to avoid moderate exercise.
* History of chest pain, shortness of breath, or claudication symptoms during ambulation
* History of significant neuropathy with altered balance
* History of serious residual limb pain or phantom limb pain within the past six months.
* History of chronic skin breakdown.
* Inability to perform the tasks involved in the study.

Participant flow

Outcome results

• Minimum Foot Clearance With Different Prostheses (Primary), Mean, meters: Prosthesis User With Transtibial or Transfemoral Amputation 0.02117 +/- 0.005247
• Minimum Foot Clearance With Different Orthoses (Primary), Mean, centimeters: Orthoses User With Drop-foot 0.56469 +/- 0.662561
• Behavioral Gait Function as Measured From Daily Stride Count (Secondary), Mean, strides per sensor hour: Prosthesis User With Transtibial or Transfemoral Amputation 264.9 +/- 177.0
• Behavioral Gait Function as Measured From Stride Speed During Walking Bouts of Different Durations (Secondary), Mean, meters per second: Prosthesis User With Transtibial or Transfemoral Amputation 0.4685 +/- 0.049
• Prosthetic Limb Users Survey of Mobility Score (Secondary), Mean, T-score: Prosthesis User With Transtibial or Transfemoral Amputation 56.5 +/- 7.665246245
• Change in Movement Quality as Determined by Stride Width: Prosthesis (Secondary), Mean, meters: Prosthesis User With Transtibial or Transfemoral Amputation 0.1328 +/- 0.03138
• Change in Movement Quality as Determined by Stride Width: Orthoses (Secondary), Mean, meters: Orthoses User With Drop-foot 0.045 +/- 0.010 (p 0.649)
• Change in Gait Performance as Determined by Average Speed (Secondary), Mean, meter per second: Prosthesis User With Transtibial or Transfemoral Amputation 0.8376 +/- 0.1332
• Gait Performance as Determined by Stride Frequency at Identical Speed (Secondary), Mean, strides per minute: Prosthesis User With Transtibial or Transfemoral Amputation 67.47 +/- 3.237
• Change in Gait Performance as Determined by Ground Reaction Forces (Secondary)
• Change in Gait Performance as Determined by Socket Torques (Secondary)
• Change in Functional Gait Assessment Score (Secondary), Mean, score on a scale: Orthoses User With Drop-foot 16.09 +/- 5.230
• Change in 6 Minute Walking Test Distance (Secondary), Mean, meters: Orthoses User With Drop-foot 394.94 +/- 123.83
• Stride Length at Identical Walking Speed (Secondary), Mean, meters: Prosthesis User With Transtibial or Transfemoral Amputation 1.196 +/- 0.1434

Adverse events

Time frame: participants were on study up to 12 weeks

• Study Protocol and Statistical Analysis Plan (PDF, 2023-09-21)
• Informed Consent Form (PDF, 2023-10-02)

• Peter G Adamczyk, Ph.D., Principal investigator, University of Wisconsin, Madison