Reliability of Force Measurement Within the Carbon Fiber Orthosis Proximal Cuff (CuffForce)

The primary purpose of this research study is to determine if forces within carbon fiber custom dynamic orthoses (CDOs) can be reliability assessed using Loadpad and Loadsol force measuring sensors (Novel GMBH, St. Paul, MN). An improved understanding of the forces acting within orthoses may help to guide future orthosis related research studies, provision methods, and patient education.

Study participants will consist of three groups; 1) healthy, able-bodied adult participants using generic sized CDOs, which consist of a proximal cuff that wraps around the leg just below the knee, a posterior carbon fiber strut that runs the length of the leg and bends to store and return energy, and a semi-rigid footplate that acts as a lever arm to bend the posterior strut, 2) individuals without peripheral neuropathy who use AFO(s) regularly, and 3) individuals with peripheral neuropathy who use AFO(s) regularly. .

Group 1 participants will be asked to fasten the proximal cuff to a self-selected cuff tightness 'SSCT', as well as three different predefined force levels; 'Loose' where the proximal cuff is loosely fastened around the participants leg, 'Moderate' where the proximal cuff is fastened with moderate tightness, and 'Tight' where the proximal cuff is tightly fastened around the participants leg. Testing in the predetermined force levels (Loose, Moderate, Tight) will occur in a randomized order. Group 2 and Group 3 participants will be asked to fasten their AFO(s) to a self-selected 'SSCT' tightness.

For all groups, forces acting on the leg, within the proximal cuff, will be measured using wireless Loadpad sensors and forces acting on the foot will be measured using wireless Loadsol insoles. Testing will include collection of force data as participants sit quietly, stand quietly, and walk and completion of questionnaires.

Study Overview

• Status: Recruiting
• Conditions: Healthy; Peripheral Neuropathy; Ankle Foot Orthosis (AFO)
• Intervention / Treatment: Device: Carbon Fiber Custom Dynamic Orthosis (CDO)

Detailed Description

Ankle foot orthoses (AFOs) are medical devices often used to support the foot and ankle during daily activities. Carbon fiber custom dynamic orthoses (CDOs), one subset of AFOs, that consist of a proximal cuff that wraps around the leg just below the knee, a posterior carbon fiber strut that runs the length of the leg and bends to store and return energy during gait, a semi-rigid carbon fiber footplate that acts as a lever arm to bend the posterior strut, and in some cases a foam heel wedge placed between the footplate and the shoe. Different CDO design characteristics, such as posterior strut stiffness, device alignment, and heel cushion height and stiffness have been studied in the past. While different design characteristics have been studied previously, there is little information available concerning the proximal cuff and how it impacts patient outcomes. Different types of AFOs and CDOs have been used in an effort to offload the limb for years. Both CDOs and patellar tendon bearing (PTB) style AFOs have been shown to reduce forces acting on the plantar surface of the foot. While multiple studies have indicated the importance of fastening the proximal cuff, few have actually investigated the forces acting within the proximal cuff. A loose proximal cuff has been associated with pistoning of the limb, where the limb translates down within the proximal cuff during loading, potentially increasing forces acting on the foot and reducing the offloading effects of the orthosis. Only one study investigated the effects of altering forces within the proximal cuff by adding more padding to the proximal cuff, which was shown to improve limb offloading.

A better understanding of the forces acting within the proximal cuff, and how these effect patient outcomes would help to guide future AFO related research studies, provision, and patient education. At this point in time there is little guidance available to inform patients how tightly they need to secure the proximal cuff when wearing an AFO, many clinicians recommend tightening it so that it's secure, but not uncomfortable. The ability to measure forces within the proximal cuff and an idea of the range of forces seen in a clinical setting will act as a first step to better understanding how forces acting within the proximal cuff impact patient outcomes.

• Study Type: Interventional
• Enrollment (Estimated): 60
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Jason M Wilken, PT, PhD; Phone Number: 3193356857; Email: jason-wilken@uiowa.edu
• Study Contact Backup: Name: Kirsten M Anderson, PhD; Phone Number: 3193530431; Email: kirsten-m-anderson@uiowa.edu

Study Locations

• United States
  • Iowa
    • Iowa City, Iowa, United States, 52241
      • Recruiting
      • University of Iowa
      • Contact: Jason M Wilken, PT, PhD; Phone Number: 3193356857; Email: jason-wilken@uiowa.edu
      • Contact: Kirsten M Anderson, PhD; Phone Number: 3193530431; Email: kirsten-m-anderson@uiowa.edu

Participation Criteria

Eligibility Criteria

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

Description

Group 1 - Able Bodied Participants

Inclusion Criteria

• Between the ages of 18 and 65
• Healthy without current complaint of lower extremity pain, spine pain, open wounds or active infections, or medical or neuromusculoskeletal disorders that have limited their participation in work or exercise in the last 6 months
• Able to hop without pain
• Able to perform a full squat without pain
• Ability to read and write in English and provide written informed consent
• Ability to fit in a generic sized CDO

Exclusion Criteria

• Diagnosed with a moderate or severe brain injury
• Lower extremity injury resulting in surgery or limiting function for greater than 6 weeks
• Injuries that would limit performance in this study
• Diagnosed with a physical or psychological condition that would preclude functional testing (e.g. cardiac condition, clotting disorder, pulmonary condition)
• Visual or hearing impairments that limit walking ability or limit the ability to comply with instructions given during testing
• Require use of an assistive device
• Unhealed wounds (cuts/abrasions) that would prevent AFO use
• BMI > 40
• Pregnancy

Group 2 - AFO Users without Peripheral Neuropathy

Inclusion Criteria:

• Between the ages of 18 and 90
• Use an AFO(s) for daily activities
• The AFO(s) proximal cuff is compatible with loadpad sensors
• Have used their AFO(s) for a minimum of 2 weeks
• Ability to walk 50 feet without use of an assistive device (e.g. cane, crutch, etc.)
• Ability to read and write in English and provide written informed consent

Exclusion Criteria

• Diagnosis or indication of peripheral neuropathy determined using Semmes Weinstein Filaments
• Medical or psychological condition that would preclude functional testing (ex. Moderate or severe brain injury, stroke, heart disease)
• Requirement of a knee stabilizing device (e.g. KAFO, KO) to preform daily activities
• Visual or hearing impairments that limit walking ability or limit the ability to comply with instructions given during testing
• BMI > 40
• Pregnancy

Group 3 - AFO Users with Peripheral Neuropathy

Inclusion Criteria:

• Between the ages of 18 and 90
• Use an AFO(s) for daily activities
• The AFO(s) proximal cuff is compatible with loadpad sensors
• Have used their AFO(s) for a minimum of 2 weeks
• Ability to walk 50 feet without use of an assistive device (e.g. cane, crutch, etc.)
• Diagnosis or indication of peripheral neuropathy determined using Semmes Weinstein Filaments
• Ability to read and write in English and provide written informed consent

Exclusion Criteria

• Medical or psychological condition that would preclude functional testing (ex. Moderate or severe brain injury, stroke, heart disease)
• Requirement of a knee stabilizing device (e.g. KAFO, KO) to preform daily activities
• Visual or hearing impairments that limit walking ability or limit the ability to comply with instructions given during testing
• BMI > 40
• Pregnancy

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Single

Number of Arms

5

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
No Intervention: NoCDO; Participants will complete study activities without wearing a CDO
Experimental: SSCT; Participants will complete study activities while wearing a CDO fastened to their self-selected proximal cuff tightness	Device: Carbon Fiber Custom Dynamic Orthosis (CDO); The carbon fiber custom dynamic orthosis (CDO) will consist of a semi-rigid carbon fiber footplate, a carbon fiber posterior strut, and a proximal cuff that wraps around the leg below the knee that is fastened to different tightness's; Other Names: Ankle Foot Orthosis (AFO)
Experimental: Loose; Participants will complete study activities while wearing a CDO fastened to a loose proximal cuff tightness	Device: Carbon Fiber Custom Dynamic Orthosis (CDO); The carbon fiber custom dynamic orthosis (CDO) will consist of a semi-rigid carbon fiber footplate, a carbon fiber posterior strut, and a proximal cuff that wraps around the leg below the knee that is fastened to different tightness's; Other Names: Ankle Foot Orthosis (AFO)
Experimental: Moderate; Participants will complete study activities while wearing a CDO fastened to a moderate proximal cuff tightness	Device: Carbon Fiber Custom Dynamic Orthosis (CDO); The carbon fiber custom dynamic orthosis (CDO) will consist of a semi-rigid carbon fiber footplate, a carbon fiber posterior strut, and a proximal cuff that wraps around the leg below the knee that is fastened to different tightness's; Other Names: Ankle Foot Orthosis (AFO)
Experimental: Tight; Participants will complete study activities while wearing a CDO fastened to a tight proximal cuff tightness	Device: Carbon Fiber Custom Dynamic Orthosis (CDO); The carbon fiber custom dynamic orthosis (CDO) will consist of a semi-rigid carbon fiber footplate, a carbon fiber posterior strut, and a proximal cuff that wraps around the leg below the knee that is fastened to different tightness's; Other Names: Ankle Foot Orthosis (AFO)

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Modified Socket Comfort Score (Comfort)	Comfort scores range from 0 = most uncomfortable to 10 = most comfortable	Baseline
Numerical Pain Rating Scale	Pain will be assessed using a standard 11-point numerical pain rating scale, in which 0 = no pain and 10 = worst pain imaginable	Baseline
Proximal Cuff Force	Proximal cuff forces (N) will be measured as participants sit, stand, and walk without a CDO and in each CDO condition.	Baseline
Peak Plantar Force	Plantar forces (N) will be measured across the total foot, the hindfoot, midfoot, and forefoot as participants sit, stand, and walk without a CDO and in each CDO condition.	Baseline
Plantar Force Impulse	Plantar force impulse (Ns) across the total foot, the hindfoot, midfoot, and forefoot will be calculated using the integral of the force over the stance phase as participants sit, stand, and walk without a CDO and in each CDO condition.	Baseline

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Modified Socket Comfort Score (Smoothness)	Smoothness scores range from 0 = least smooth to 10 = most smooth	Baseline

Collaborators and Investigators

• Sponsor: University of Iowa
• Investigators: Principal Investigator: Jason Wilken, PT,PhD, University of Iowa

Study record dates

Study Major Dates

• Study Start (Actual): March 1, 2024
• Primary Completion (Estimated): December 31, 2026
• Study Completion (Estimated): December 31, 2026

Study Registration Dates

• First Submitted: November 6, 2023
• First Submitted That Met QC Criteria: November 6, 2023
• First Posted (Actual): November 13, 2023

Study Record Updates

• Last Update Posted (Actual): December 31, 2025
• Last Update Submitted That Met QC Criteria: December 29, 2025
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Keywords: Ankle Foot Orthosis; Plantar Force; Carbon Fiber Orthosis
• Additional Relevant MeSH Terms: Nervous System Diseases; Neuromuscular Diseases; Peripheral Nervous System Diseases; Anti-Infective Agents; Anti-Infective Agents, Local; Carbon Fiber
• Other Study ID Numbers: 202212359

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.: No