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: 1. minimize translational movement between the residual limb and the prosthetic socket; 2. maintain residual limb fluid volume; and 3. maximize prosthetic socket comfort. When using the microprocessor-adjusting socket compared to the user-adjusted socket and the static socket, participants will: 1. cover the greatest distance during a simulated combat patrol; 2. perform all high intensity Military specific tasks with less pain; 3. perform a simulated combat patrol nearer to uninjured levels of performance; and 4. rank usability at a level similar to the static socket. The specific aims are to: 1. Fabricate microprocessor-adjusting sockets specific for Service members and Veterans with goals of returning to high-level physical activities 2. 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 3. Characterize user preference and usability of different socket configurations
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
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Enrollment
15
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.
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.
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.
Brooke Army Medical Center, Center for the Intrepid
Fort Sam Houston, Texas, United States
Motion of the Residual Limb in the Socket
Angular movement between the residual limb and the prosthetic socket in the sagittal plane.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: After each of the sessions with each socket condition, approximately 3 hours.
Readiness Evaluation during Simulated Dismounted Operations (REDoP) performance metrics
Marksmanship during the simulated ambushes.
Time frame: Recorded after each task during REDoP. Approximately 55 minutes.
Readiness Evaluation during Simulated Dismounted Operations (REDoP) performance metrics
Heart rate.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: Recorded after each task during FCE-M. 5-10 sec to respond and approximately 30 minutes in total.
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