Dexterous Partial Hand Prosthesis Outcomes

Liberating Technologies, Inc. (LTI) has developed a dexterous prosthetic fingertip that will be fit onto an i-Digits™ partial hand prosthesis and allow for an additional fine grasp. The device will interface with research participants' existing prostheses and use the same control strategy that is used for their everyday use. Each participant's prosthesis will be restored to their original configuration by the end of their testing period.

Study Overview

• Status: Completed
• Conditions: Amputation; Prosthesis User; Amputation; Traumatic, Hand; Upper Limb Amputation at the Hand; Limb; Absence, Congenital, Upper
• Intervention / Treatment: Device: Pointdexter

Detailed Description

Liberating Technologies, Inc. (LTI) has developed a dexterous prosthetic fingertip that will be fit onto an i-Digits™ partial hand prosthesis and allow for an additional fine grasp. The device will interface with research participant's existing prostheses and use the same control strategy that is used for their everyday use. Each participant's prosthesis will be restored to their original configuration by the end of their testing period.

The study will focus on design feasibility testing and will compare performance of hand functional outcome tests on an i-Digits™ prosthetic partial hand with and without the investigational Pointdexter modification. Our primary hypothesis is that subjects using the investigational device will show better performance on objective functional outcomes measures than those using a standard i-Digits™ partial hand prosthesis, particularly in the manipulation of small objects.

The investigators will explore multiple outcomes measures as options, but our primary endpoint will be performance on the Small Common Objects subtask of the Jebsen-Taylor Hand Function Test, which assesses a broad range of unimanual hand functions required for ADLs. The primary quantitative measure of the Jebsen-Taylor task will be completion time of each subtask. Qualitative evaluation will be conducted by an occupational therapist via observation, and by the user through a self-assessment questionnaire, such as the Patient Specific Functional Scale (PSFS). The investigators will be performing repeated measures on each individual subject to reduce the variance as well as having each subject act as their own control. New and existing i-Digits™ partial hand prosthesis users will be recruited for the study and consented with an approved protocol. Research participants will schedule a time to conduct the testing and be informed of study details.

The investigational device being tested is a novel prosthetic finger with a built-in split gripper. The device is an index finger which can drop in place of existing digits on an i-Digits™ partial hand prosthesis. The investigational device is controlled with the same signals as the conventional digits.

This study will pilot test the dexterous fingertip prosthesis with a small number of subjects (up to 12). Research participants will be consented and will test the device at home and/or in-lab. Subjects will be introduced to the partial hand prosthesis configuration and be instructed on how to operate it to complete their testing session.

The in-lab testing will be conducted in a single site visit at Össur Academy in Dublin, Ohio or LTI in Holliston, MA. Subjects may be asked to come back for an additional site visit if data collection is incomplete. For this study, the index finger of each participant's existing everyday prosthesis will be temporarily disconnected and replaced with the investigational device. The prosthesis will be restored to its original configuration when the test session has been completed. At the start of the study session, subjects will prepare for testing in their first configuration (investigational or comparator). If investigational, subjects will doff their prosthesis and investigators will replace the usual i-Digits™ index finger with the investigational device. If comparator, subjects will don their usual unmodified prosthesis. Subjects will be trained on how to operate the investigational device and be allowed a minimum of 30 minutes to practice using it until they are comfortable with proceeding. The subjects will be guided to conduct functional outcome tests that involve picking up and manipulating everyday objects (beans, coins, pegs, spoon, cloth, etc.), such as the tasks outlined in the Jebsen-Taylor and Peg Board functional tests. Each sub-task in the functional test will be scored by occupational therapist standards. After a round of functional testing is done, subjects will fill out the PSFS survey and subjective questionnaire. Subjects will then doff the prosthesis and don the next device configuration. The PSFS survey as well as user and clinician feedback are both exploratory outcome measures as the design is still in very early prototype stages. The intent of this feedback is to help iterate the design to assist in further development of the final product. Subjects will repeat the functional tests and surveys with each device configuration. After the final condition, the subject will have completed the study and their prosthesis will be restored to its usual configuration. The study session should span 3-5 hours.

A subset of subjects will take home the investigational device for up to 4 weeks to provide feedback of the device when used in everyday tasks. Investigators will restore the user's prosthesis at the end of the testing period and surveys will be conducted to capture feedback. Two site visits may be required: one to initialize the study and configure the prosthesis, and two to restore the prosthesis at the study end. This feedback is also an exploratory outcome measure due to the design being in very early prototype stages.

Both new and existing i-Digits™ partial hand prosthesis users will be invited to participate in the study. Research participants will schedule a time to conduct the testing and be informed of study details. Participants will be given as much time as needed to review and question the informed consent form before signing.

Two different technologies will be assessed:

• Investigational Device: i-Digits™ partial hand prosthesis with dexterous fingertip modification
• Comparator Baseline: unmodified i-Digits™ partial hand prosthesis

Persons with partial hand limb absence who are new or current i-Digits™ prosthesis users will be recruited for this study through the LTI and Össur clinician network. Prosthetists may be contacted with the need for research subjects and, if interested, will be given flyers to hand out to their patients. If subjects are interested in participating, they can call the number on the flyer to speak with investigators. In addition, previous research participants who have given permission to be contacted for future studies may be contacted directly to assess interest in participating in this study. Enrollment will be open to people of all ages, genders, races, and ethnicities. Participants must be new or current users of i-Digits™ partial hand prostheses. The user must have an absent index finger at minimum. Patients who have 4-5 digit and/or thumb involvement will be preferred.

Based on subject population and availability, a convenience sample of up to 12 subjects will be recruited for this pilot study.

• Study Type: Interventional
• Enrollment (Actual): 4
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Massachusetts
    • Holliston, Massachusetts, United States, 01746
      • Liberating Technologies, Inc.
  • Ohio
    • Dublin, Ohio, United States, 43017
      • Össur Academy - Touch Solutions

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Must have an upper limb partial hand absence.
• Must be new or current i-Digits prosthesis users.
• Must have an absent index finger at minimum.
• Must be able to understand spoken and written English in order to be properly consented and provide feedback to the study personnel.
• Must be willing and able to complete outlined tasks and provide feedback on the intervention.

Exclusion Criteria:

• The risks to pregnant women and fetuses are unknown and therefore pregnant women should not participate in the study.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Device Feasibility
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
No Intervention: Comparator Baseline; The subject's usual partial hand prosthesis
Experimental: Pointdexter; The subject wears a modified version of their usual partial hand prosthesis. The modification replaces the usual index finger of the partial hand prosthesis with the investigational Pointdexter device.	Device: Pointdexter; i-Digits partial hand prosthesis modified with the investigational pointdexter finger in place of the usual index finger.; Other Names: Dexterous Partial Hand Prosthesis; Gripper

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Jebsen-Taylor Small Common Objects Functional Test	During the in-lab portion of the study, subjects will be asked to complete the 'small common objects' subtask of the Jebsen-Taylor Hand Function Test, which assesses a broad range of unimanual hand functions required for ADLs. The primary quantitative measure of the Jebsen-Taylor task will be completion time of each subtask. The maximum time allotted for each task was 120 seconds, at which point the subject was told to stop the task and the time was reported as the maximum 120 seconds. This test will be used to evaluate the feasibility of the device design as compared with a baseline condition. This was the only primary outcome measure collected for this study. There were no secondary outcome measures, only exploratory measures as this is a very early prototype design that is still in the design iteration stages.	4 hours at a single site visit

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Patient-Specific Functional Scale (PSFS) Survey	This short questionnaire asks the patient to identify up to five important activities they are unable to perform or are having difficulty with as a result of their upper limb difference. They are asked to rate the current level of difficulty associated with each activity on a scale of 0 (Unable to perform activity) to 10 (Able to perform activity at the same level as before injury or problem).	Duration of study: (In-Lab: ~4 hours, Take-home: ~4 weeks).

Collaborators and Investigators

• Sponsor: Liberating Technologies, Inc.
• Collaborators: Össur Iceland ehf
• Investigators: Principal Investigator: Todd Farrell, PhD, Liberating Technologies, Inc.

Study record dates

Study Major Dates

• Study Start (Actual): July 15, 2021
• Primary Completion (Actual): April 28, 2022
• Study Completion (Actual): April 28, 2022

Study Registration Dates

• First Submitted: June 1, 2021
• First Submitted That Met QC Criteria: August 31, 2021
• First Posted (Actual): September 9, 2021

Study Record Updates

• Last Update Posted (Actual): March 25, 2025
• Last Update Submitted That Met QC Criteria: January 16, 2025
• Last Verified: January 1, 2025

More Information

Terms related to this study

• Keywords: prosthesis; amputee; prosthetist; upper limb amputee; partial hand prosthesis user; i-Digits; upper limb loss; gripper; dexterous fingertip; index finger prosthesis
• Additional Relevant MeSH Terms: Wounds and Injuries; Amputation, Traumatic
• Other Study ID Numbers: 20212193

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: Yes
• product manufactured in and exported from the U.S.: Yes