Connect TF - An Investigation of Function and Usability of a New Adaptable Socket System

Design:

This clinical investigation will be of a single group non-randomized open label prospective repeated measures (ABBA) design comparing subject´s current conventional socket and the CONNECT TF. The subjects will be asked to use the CONNECT TF as their primary prosthesis for up to six weeks. Subject will be fitted with the same foot-pylon-knee prosthetic system as used with their current conventional socket, with the CONNECT TF socket.

Procedures:

There are four scheduled study events. At the initial visit, the first study event, for each subject a qualified researcher will obtain an informed consent. Prior to fitting the patient subject to CONNECT TF he/she will be asked to provide feedback and perform tasks on/using their current conventional prosthetic socket. The patient subjects will be fitted with the CONNECT TF within the standard methods of prosthetic fitting, alignment, introduction, training and walking on various terrain.

The CPO (Certified Prosthetis/Orthotist) will conduct the fitting and aligning of the CONNECT TF.

A Co-Investigator will time the fitting procedure; from unpacking the device until it is correctly adjusted and properly fit to the subject.

Data on initial feedback on the device will be collected from the subjects using the instruments specified above. Afterwards an appointment at 2 weeks is made and the subjects leave the clinic on the device.

If the fitting of CONNECT TF fails, i.e. the PI/CPO does not manage to fit the device properly or the subject cannot use the device as intended during training at the clinic, a new appointment is made, if the subject is willing to continue participation.

The second event will be according to the appointment scheduled 2 weeks earlier. During this visit the same set of information will be gathered from/on the subjects as at the initial visit using the conventional socket. A 6 week follow up (6WFU) visit is scheduled and the subject leaves on the CONNECT TF socket.

The third event will be according to the appointment scheduled at the previous visit. During this visit set of information will be gathered from/on the subjects as at the initial visit using the conventional socket. A final 6WFU visit is scheduled and the subjects are fitted back to and leave on their current conventional socket.

The fourth event will be according to the appointment scheduled at the previous visit. During this visit set of information will be gathered from/on the subjects as at the initial visit using the conventional socket. End of study.

Data analysis:

The dataset will be assessed with inferential statistics based on the acceptance criteria for the data, as applicable.

Outcomes at each time point will be visually inspected for normality using histograms and qq-plots. If the data are deemed to be normal the hypothesis will be tested using a two-tailed, paired, student's t-test for 2WFU evaluation and mixed models for the 6WFU evaluation. Non-normal data will be tested using the Wilcoxon signed-rank test.

• CONNECT TF adaptable socket system (Device): Prefabricated, adaptable socket system
• Any conventional handmade socket (Device): Subjects current socket

Primary outcomes

• Comprehensive Lower-limb Amputee Socket Survey (CLASS) Total Score [Visit 1 (Baseline), Visit 2 (2 weeks), Visit 3 (6 weeks), and Visit 4 (12 weeks)]: The Comprehensive Lower-limb Amputee Socket Survey (CLASS) is a participant-reported measure of prosthetic socket satisfaction for individuals with lower-limb amputation. The questionnaire evaluates perceived socket stability, suspension, comfort, and appearance during common activities. Responses are combined to generate a total score, which is converted to a percentage of the maximum possible score. Scores range from 0% to 100%, with higher percentages indicating greater satisfaction and better perceived socket performance.

Secondary outcomes

• Residual Limb Health Subscale Score (PEQ-RLH) [Visit 1 (Baseline), Visit 2 (2 weeks), Visit 3 (6 weeks), and Visit 4 (12 weeks)]: The Residual Limb Health (RLH) subscale of the Prosthesis Evaluation Questionnaire (PEQ) is a participant-reported outcome measure assessing perceived residual limb health while using a prosthesis. The RLH subscale consists of 6 items addressing issues such as perspiration, odor, swelling, skin irritation, and other residual limb problems. Each item is rated on a 0-10 Likert-type scale. Item scores are summed and converted to a percentage of the maximum possible subscale score, resulting in a score ranging from 0% to 100%, where higher percentages indicate better residual limb health and fewer residual limb problems.
• Prosthesis Evaluation Questionnaire (PEQ) Sounds Subscale Score [Visit 1 (Baseline), Visit 2 (2 weeks), Visit 3 (6 weeks), and Visit 4 (12 weeks)]: The Sounds subscale of the Prosthesis Evaluation Questionnaire (PEQ) assesses the participant's perception of sounds generated by the prosthesis during use. The subscale consists of 2 items. Responses are averaged to produce a subscale score. Scores range from 0 to 10 likert scale, where higher scores indicate a more favorable outcome (less bothersome prosthetic sounds/noise).
• Mobility (2-Minute Walk Test) [Visit 1 (Baseline), Visit 2 (2 weeks), Visit 3 (6 weeks), and Visit 4 (12 weeks)]: The 2-Minute Walk Test (2MWT) is a performance-based measure of walking capacity. Participants were instructed to walk as far as possible in 2 minutes. The total distance walked during the test was recorded in meters. Greater distances indicate better mobility and walking endurance.
• Balance During Ambulation (Timed Up and Go Test [TUG]) [Visit 1 (Baseline), Visit 2 (2 weeks), Visit 3 (6 weeks), and Visit 4 (12 weeks)]: The Timed Up and Go (TUG) test is a performance-based measure of functional mobility and balance. Participants were instructed to stand up from a chair, walk 3 meters, turn around, walk back to the chair, and sit down. The time required to complete the task was recorded in seconds. Lower completion times indicate better mobility and balance performance.

Sex: All, ages: 18 Years to any

Inclusion Criteria:

* Lower limb amputees
* Uni- or bilateral TF amputees
* 40 < body weight < 125Kg
* Activity level: K1-K2;
* Liner size: 28-45;
* Max 1 user in sizes 28 and 45, respectively
* Residual limb parameters; perineum to distal end: 205 to 280 mm
* Older than 18 years
* Prosthetic users for more than 3 months
* Components of conventional socket functionally compatible to Össur components (foot-pylon-knee combination)
* Users understanding the function of the device
* Willing and able to participate in the study and follow the protocol

Exclusion Criteria:

* Other amputees
* 40> body weight > 125Kg
* Amputees with broken skin on the residual limb
* Younger than 18 years
* Prosthetic users for less than 3 months
* Using no liner
* Using a microprocessor controlled prosthetic knee not manufactured by Össur
* Users not understanding the function of the device

Participant flow

Outcome results

• Comprehensive Lower-limb Amputee Socket Survey (CLASS) Total Score (Primary), Mean, percentage: CONNECT TF 66.55 +/- 20.56
• Residual Limb Health Subscale Score (PEQ-RLH) (Secondary), Mean, percentage: CONNECT TF 82.29 +/- 14.42
• Prosthesis Evaluation Questionnaire (PEQ) Sounds Subscale Score (Secondary), Mean, scores on a scale: CONNECT TF 7.5 +/- 3.42
• Mobility (2-Minute Walk Test) (Secondary), Mean, meters: CONNECT TF 52.04 +/- 37.43
• Balance During Ambulation (Timed Up and Go Test [TUG]) (Secondary), Mean, seconds: CONNECT TF 53 +/- 53.75

Adverse events

Time frame: over the course of the study, up to 12 weeks

• Study Protocol and Statistical Analysis Plan (PDF, 2020-10-08)

• Sashwati Roy, PhD, Principal investigator, Indiana University