Do Adaptable Sockets Improve Military Performance?

Study Overview
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Brief Summary
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This is a repeated measures prospective study and is no greater than a minimal risk study. All study procedures will be conducted at the Center for the Intrepid (CFI) through collaborative efforts of the Military Performance Lab at the CFI and the Sanders lab at the University of Washington. Data collected at the CFI will be coded, compiled, and shared with the University of Washington investigators.The objective of the research is to test if microprocessor-adjusting sockets improve Service member performance in Military specific activities compared to (a) user- operated, motor-driven adjustable sockets (i.e. sockets users adjust themselves), and (b) static (traditional) sockets. Investigators also test if microprocessor-adjusting sockets better maintain socket fit and limb fluid volume, and if self-reported outcomes are more favorable than for user-operated or static sockets. The hypotheses to be tested include: During intense Military specific tasks, compared to the user-adjusted socket and the static socket, the microprocessor-adjusting socket will: minimize translational movement between the residual limb and the prosthetic socket; maintain residual limb fluid volume; and maximize prosthetic socket comfort. When using the microprocessor-adjusting socket compared to the user-adjusted socket and the static socket, participants will: cover the greatest distance during a simulated combat patrol; perform all high intensity Military specific tasks with less pain; perform a simulated combat patrol nearer to uninjured levels of performance; and rank usability at a level similar to the static socket. The specific aims are to: Fabricate microprocessor-adjusting sockets specific for Service members and Veterans with goals of returning to high-level physical activities Evaluate Military task performance in Service members with transtibial amputation using Readiness Assessments, while wearing three socket configurations: microprocessor-adjusting, user-adjusting, and static Simulated combat patrol in a Virtual Realty Environment Military version of a Functional Capacity Evaluation Characterize user preference and usability of different socket configurations

Detailed Description
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The purpose of the proposed research is to evaluate the use of microprocessor-adjusting sockets during Readiness Assessments of Military tasks performed by Service members with transtibial amputation. Participants will come to the Center For the Intrepid (CFI) for up to 10 visits to complete a pre-monitoring session (assess residual limb health and gather information regarding limb fluid volume); socket fitting session(s) (fitting of three sockets- static socket, a user-adjusted socket, and microprocessor-adjusting socket); and for military readiness assessments for each of the three socket conditions. Data across the three socket conditions (static socket, user adjusted socket, and Microprocessor-adjusting sockets) will be tested for normality. When it normality can be assumed, a single factor repeated measures ANOVA will test between socket conditions. Mauchly's Test of Sphericity was be used to test if the variance is significantly different across all of the conditions. If the sphericity condition is violated, a Greenhouse-Geisser adjustment will be applied. When a significance effect is detected, pairwise comparisons using a Tukey post-hoc will be performed to determine which conditions are significantly different. When normality cannot be assumed, a Kruskal-Wallis H test will be used. When a significance effect is detected, pairwise comparisons using a Mann-Whitney post-hoc while adjusting the p-value for multiple comparisons will be performed to determine which conditions are significantly different. Statistical significance will be set to p<0.05

Official Title
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Do Adaptable Sockets Improve Military Performance?

Conditions
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Amputation Stump

Intervention / Treatment
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* Device: Static socket
* Device: User adjusted socket
* Device: Microprocessor-adjusting sockets


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Males and females age 18 - 55 years Authorized to receive care at the Center for the Intrepid Unilateral or bilateral transtibial amputation Have experience performing military relevant tasks (e.g., Active duty Service Member or Veteran) Current prosthesis user Ability to comply with instructions associated with functional testing Able to provide written informed consent Exclusion Criteria: Self-reported inability to safely ambulate for a minimum of twenty minutes continuously and unassisted History of medical or psychological disease that would preclude safe gait, load carriage, physical, or cognitive functional training or testing within a virtual reality environment as determined by the provider screening the subject (i.e. moderate/severe traumatic brain injury, stroke, renal failure, cardiac or pulmonary problems disease, severe anemia, and other medical conditions) Any injury sustained to the upper extremity which would preclude safe physical performance testing Self-reported Blindness Self-reported Pregnancy Self-reported Active infection Weight above 250 lbs (114 kg) Residual limb length shorter than 9cm as this is the minimum distance necessary to attach the bio-impendence sensors Score greater than 20% on the Modified Oswestry Low Back Pain Questionnaire as this will indicate greater than minimal disability due to low back pain.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 55 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: Treatment
Intervention Model: Single Group Assignment
Interventional Model Description: This is a repeated measures prospective study.
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Adaptable Prosthetic Socket<br>Using measurements of limb-socket displacements from sensors embedded within the socket wall, adaptable sockets make small adjustments to socket size so as to maintain consistent displacements while prosthesis users are active. They do not require the user to stop activity or to touch or modify the prosthesis, and they do not distract users from their objectives. | Device: Static socket<br>* For the static socket configuration, both the microprocessor control and user control are disabled, and the panels are positioned in their flush configuration to create the user's as-prescribed socket shape.<br>Device: User adjusted socket<br>* Sockets are configured for user control by disabling automated control and enabling push buttons on the side of the socket to adjust socket size. Each button push effects a socket size change of approximately 0.3% volume. An upper button effects a socket size increase, and a lower button a socket size decrease. The buttons are countersunk so reduce risk of accidental pushes, and they do not function unless the user is stationary. An additional button push will not be executed until motor motion from the prior push has been completed. If a button is continuously held then the motor will continue moving until the button is released. Limits are set on cable length to ensure that sockets sizes threatening to the user's residual limb (too tight) are avoided. The push buttons effect inner-loop control that operates completely within the mechanism, achieving high-resolution adjustment of cable length with minimal error.<br>Device: Microprocessor-adjusting sockets<br>* A strategy for automatically controlling the size of the socket during walking to compensate for unknown changes in limb volume will be used. The controller is essentially a regulator that continuously measures socket fit, and adjusts the socket to maintain a prescribed reference set point. Because the fit is automatically sustained, the prosthesis user is unaware of its operation.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Motion of the Residual Limb in the Socket | Angular movement between the residual limb and the prosthetic socket in the sagittal plane. | Collected during physical performance sessions (Simulated Dismounted Operations (REDoP) and Functional Capacity Evaluation-Military (FCE-M)) Approximately 3 hours. | 
| Motion of Residual Limb in the Socket | Translational movement between the residual limb and the prosthetic socket about the longitudinal axis of the prosthetic socket. | Collected during physical performance sessions (Simulated Dismounted Operations (REDoP) and Functional Capacity Evaluation-Military (FCE-M)) Approximately 3 hours. | 
| Self-report questionnaires of socket comfort | Change in Socket Comfort Score (SCS) across the Readiness Evaluation during Simulated Dismounted Operations (REDoP) and modified Functional Capacity Evaluation-Military (FCE-M), 0-10 scale. | SCS recorded before after after each task during REDoP and FCE-M. Approximately 3 hours. | 
| Readiness Evaluation during Simulated Dismounted Operations (REDoP) performance metrics | Total distance traversed during REDoP assessment. | Assessment administered per condition. Approximately 55 minutes. | 
| Readiness Evaluation during Simulated Dismounted Operations (REDoP) performance metrics | An 11-point (0-10) verbal numerical rating scale (NRS) for pain will be displayed and used to collect the individual's pain level throughout REDoP. | Recorded after each task during REDoP. Approximately 55 minutes. | 
| Functional Capacity Evaluation-Military (FCE-M) performance metrics | Time to complete each sub-task of the FCE-M. | Assessment administered per condition. Approximately 30 minutes. | 
| Functional Capacity Evaluation-Military (FCE-M) performance metrics | An 11-point (0-10) verbal numerical rating scale (NRS) for pain will be displayed and used to collect the individual's pain level throughout FCE-M. | Recorded after each task during REDoP. Approximately 30 minutes. | 
| Total score on the Post-Study System Usability Questionnaire | This is a 19-item instrument for assessing user satisfaction with system usability. The items are 7-point graphic scales, anchored at the ends with the terms Strongly agree for 1, Strongly disagree for 7, and a Not applicable (N/A) point outside the scale. | After each of the sessions with each socket condition, approximately 3 hours. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Readiness Evaluation during Simulated Dismounted Operations (REDoP) performance metrics | Marksmanship during the simulated ambushes. | Recorded after each task during REDoP. Approximately 55 minutes. | 
| Readiness Evaluation during Simulated Dismounted Operations (REDoP) performance metrics | Heart rate. | Recorded during REDoP. Approximately 55 minutes. | 
| Readiness Evaluation during Simulated Dismounted Operations (REDoP) performance metrics | Rating of perceived exertion. A standard 6-20 Borg scale will be used to collect the individual's Rating of Perceived Exertion. Subject's will be asked throughout the session to rate the difficulty of the task based on their fatigue level using the Borg scale. | Recorded after each task during REDoP. 5-10 sec to respond and approximately 55 minutes in total. | 
| Functional Capacity Evaluation-Military (FCE-M) performance metrics | Heart rate. | Recorded during FCE-M. Approximately 30 minutes. | 
| Functional Capacity Evaluation-Military (FCE-M) performance metrics | Rating of perceived exertion. A standard 6-20 Borg scale will be used to collect the individual's Rating of Perceived Exertion. Subject's will be asked throughout the session to rate the difficulty of the task based on their fatigue level using the Borg scale. | Recorded after each task during FCE-M. 5-10 sec to respond and approximately 30 minutes in total. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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amputation, bioimpedance, prosthetic socket, transtibial