The Effects of Heel Distraction Height on Foot Loading With Carbon Fiber Custom Dynamic Orthoses (CDODistract)

Carbon fiber custom dynamic orthoses (CDOs) and unloading ankle foot orthoses (AFOs) have shown varying levels of success in reducing forces acting on different regions of the bottom of the foot during gait. CDOs and unloading AFOs have shown differing offloading capabilities across different regions of the foots (hindfoot, midfoot, forefoot) which may be related to a distinct difference between CDOs and unloading AFOs: CDOs do not suspend, or distract, the foot away from the footplate. The purpose of this study is to determine the effects of CDOs and heel distraction height (the distance between the heel and the footplate) on foot loading during gait as well as patient reported pain, comfort, and smoothness.

Study Overview

• Status: Not yet recruiting
• Conditions: Traumatic Lower Limb Injury
• Intervention / Treatment: Device: Carbon Fiber Custom Dynamic Orthosis (CDO)

Detailed Description

Carbon fiber custom dynamic orthoses (CDOs) have been used to improve function, reduce pain, and offload the foot and ankle for individuals with a number of conditions affecting the lower extremity. CDOs consist of a proximal cuff that wraps around the leg just below the knee, a posterior carbon fiber strut that bends to store and return energy during mid to late stance, a semi-rigid carbon fiber footplate, and, in some cases, a foam heel wedge placed in the shoe. Unloading ankle foot orthoses (AFOs) have also been used for a number of lower extremity conditions, including traumatic injuries, in effort to reduce forces and pressure acting under the foot. Unloading AFOs have been created using many different designs, which include a proximal cuff just below the knee, a rigid strut (made of metal, plastic, etc.), and some sort of foot component (footplate, shoe, etc.).

Both CDOs and unloading AFOs have shown varying levels of success in reducing forces acting on different regions of the bottom of the foot during gait. Based on previously published data and initial data collections, CDOs have been shown to successfully offload the forefoot during gait but have had differing results for the hindfoot and midfoot. Offloading AFOs have shown to reduce plantar pressures in the midfoot and hindfoot with some increases observed in the forefoot. The differences in loading may be related to a distinct difference between CDOs and unloading AFOs: CDOs do not suspend, or distract, the foot away from the footplate.

The purpose of this study is to determine the effects of CDOs and heel distraction height (the distance between the heel and the footplate) on foot loading as well as patient reported pain and comfort. In this study, forces acting under the foot will be measured using wireless Loadsol insoles (Novel GMBH, St. Paul, MN) as participants walk without an orthosis (NoCDO) and with a CDO with three different posterior strut lengths resulting in three different levels of heel distraction (0cm, 1cm, 2cm) at self-selected and controlled speeds. Participants will be provided a lift for the contralateral limb to reduce the effects of leg length discrepancies during walking. Loadpad force measuring sensors (Novel GMBH, St. Paul, MN) will be used to measure forces within the CDO proximal cuff, ensuring it is fastened the same across testing conditions. After walking in each condition, participants will complete questionnaires concerning pain and orthosis comfort.

• Study Type: Interventional
• Enrollment (Estimated): 20
• 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, BSE; Phone Number: 3193530431; Email: kirsten-m-anderson@uiowa.edu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Ages 18-50 years
2. Unilateral injury or disease affecting the muscle, bones, or nerves in the lower leg
3. Use a modular carbon fiber custom dynamic orthosis (CDO)
4. Mechanical pain with limb loading (>4/10 on Numerical Pain Rating Scale)
5. Ability to walk 50 feet at a slow to moderate pace
6. Ability to walk without a cane or crutch
7. Ability to read and write in English and provide written informed consent

Exclusion Criteria:

1. Diagnosis with a moderate or severe brain injury
2. Diagnosis with a physical or psychological condition that would preclude functional testing (e.g., cardiac condition, clotting disorder, pulmonary condition, etc.
3. Ankle weakness resulting from spinal cord injury or central nervous system pathology
4. Nerve, muscle, bone, or other condition limiting function in the contralateral extremity
5. Rheumatoid or inflammatory arthritis
6. Necrosis of any bones in the foot or ankle
7. Pain of 8/10 or greater during walking
8. Uncorrected visual or hearing impairments
9. Require use of a knee stabilizing device to perform daily activities (i.e., Knee ankle foot orthosis, knee orthosis, etc.)
10. Pregnancy; Per participant self-report. Due to the expected small number of pregnant individuals and resulting inability to account for its effect on resulting outcomes, participants will be withdrawn from the study
11. Body mass index greater than 40 kg/m2

Study Plan

How is the study designed?

Design Details

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

Number of Arms

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
No Intervention: NoCDO; Participants will complete study activities without a CDO
Experimental: 0cm Distraction; Participants will complete study activities while wearing a CDO with 0cm of heel distraction height	Device: Carbon Fiber Custom Dynamic Orthosis (CDO); The carbon fiber custom dynamic orthoses (CDOs) used in this study 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. The CDO will be modular in design which will allow three carbon fiber struts of the same stiffness and differing lengths to be used to implement 0cm, 1cm, and 2cm levels of heel distraction height. A longer posterior strut will move the carbon fiber footplate away from the participants foot to create the heel distraction height.; Other Names: Ankle Foot Orthosis (AFO)
Experimental: 1cm Distraction; Participants will complete study activities while wearing a CDO with 1cm of heel distraction height	Device: Carbon Fiber Custom Dynamic Orthosis (CDO); The carbon fiber custom dynamic orthoses (CDOs) used in this study 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. The CDO will be modular in design which will allow three carbon fiber struts of the same stiffness and differing lengths to be used to implement 0cm, 1cm, and 2cm levels of heel distraction height. A longer posterior strut will move the carbon fiber footplate away from the participants foot to create the heel distraction height.; Other Names: Ankle Foot Orthosis (AFO)
Experimental: 2cm Distraction; Participants will complete study activities while wearing a CDO with 2cm of heel distraction height	Device: Carbon Fiber Custom Dynamic Orthosis (CDO); The carbon fiber custom dynamic orthoses (CDOs) used in this study 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. The CDO will be modular in design which will allow three carbon fiber struts of the same stiffness and differing lengths to be used to implement 0cm, 1cm, and 2cm levels of heel distraction height. A longer posterior strut will move the carbon fiber footplate away from the participants foot to create the heel distraction height.; Other Names: Ankle Foot Orthosis (AFO)

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Peak Force (forefoot)	Plantar forces (N) will be measured across the forefoot (distal 40% of sensor) as participants walk without a CDO and with each CDO.	Baseline
Force Impulse (forefoot)	Plantar force impulse (Ns) across the forefoot (distal 40% of sensor) will be calculated using the integral of the force over the stance phase as participants walk without a CDO and with each CDO.	Baseline
Peak Force (hindfoot)	Plantar forces (N) will be measured across the hindfoot (proximal 30% sensor) as participants walk without a CDO and with each CDO.	Baseline
Force Impulse (hindfoot)	Plantar force impulse (Ns) across the hindfoot (proximal 30% sensor) will be calculated using the integral of the force over the stance phase as participants walk without a CDO and with each CDO.	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
Modified Socket Comfort Score	Comfort scores range from 0 = most uncomfortable to 10 = most comfortable, and from 0 = least smooth to 10 = most smooth	Baseline

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Peak Force (total foot)	Plantar forces (N) will be measured across the total foot (100% of sensors) as participants walk without a CDO and with each CDO.	Baseline
Force Impulse (total foot)	Plantar force impulse (Ns) across the total foot (100% of sensors) will be calculated using the integral of the force over the stance phase as participants walk without a CDO and with each CDO.	Baseline
Peak Force (midfoot)	Plantar forces (N) will be measured across the midfoot (middle 30% of sensor) as participants walk without a CDO and with each CDO.	Baseline
Force Impulse (midfoot)	Plantar force impulse (Ns) across the midfoot (middle 30% of sensor) will be calculated using the integral of the force over the stance phase as participants walk without a CDO and with each CDO.	Baseline

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Semi-Structured Interview	Participants will be asked a number of open ended questions to help determine what factors influenced their perception of each study condition.	Baseline

Collaborators and Investigators

• Sponsor: University of Iowa
• Collaborators: Fabtech Systems
• Investigators: Principal Investigator: Jason M Wilken, PT,PhD, University of Iowa

Study record dates

Study Major Dates

• Study Start (Estimated): July 1, 2024
• Primary Completion (Estimated): May 1, 2025
• Study Completion (Estimated): September 1, 2025

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): April 3, 2024
• Last Update Submitted That Met QC Criteria: April 2, 2024
• Last Verified: April 1, 2024

More Information

Terms related to this study

• Keywords: Biomechanics; Ankle Foot Orthosis; Plantar Force; Carbon Fiber Orthosis
• Additional Relevant MeSH Terms: Wounds and Injuries; Leg Injuries; Anti-Infective Agents, Local; Anti-Infective Agents; Carbon Fiber
• Other Study ID Numbers: 202302397

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