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

Study Overview
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Brief Summary
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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.

Detailed Description
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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.

Official Title
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The Effects of Heel Distraction Height on Foot Loading With Carbon Fiber Custom Dynamic Orthoses

Conditions
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Traumatic Lower Limb Injury

Intervention / Treatment
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* Device: Carbon Fiber Custom Dynamic Orthosis (CDO)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Ages 18-50 years Unilateral injury or disease affecting the muscle, bones, or nerves in the lower leg Use a modular carbon fiber custom dynamic orthosis (CDO) Mechanical pain with limb loading (>4/10 on Numerical Pain Rating Scale) Ability to walk 50 feet at a slow to moderate pace Ability to walk without a cane or crutch Ability to read and write in English and provide written informed consent Exclusion Criteria: Diagnosis with a moderate or severe brain injury Diagnosis with a physical or psychological condition that would preclude functional testing (e.g., cardiac condition, clotting disorder, pulmonary condition, etc. Ankle weakness resulting from spinal cord injury or central nervous system pathology Nerve, muscle, bone, or other condition limiting function in the contralateral extremity Rheumatoid or inflammatory arthritis Necrosis of any bones in the foot or ankle Pain of 8/10 or greater during walking Uncorrected visual or hearing impairments Require use of a knee stabilizing device to perform daily activities (i.e., Knee ankle foot orthosis, knee orthosis, etc.) 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 Body mass index greater than 40 kg/m2

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 50 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: In this study, forces acting under the foot (hindfoot, midfoot, forefoot, and total 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. Testing order of the CDO conditions will be randomized to prevent influence of testing order.
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| No Intervention: NoCDO<br>Participants will complete study activities without a CDO | |
| Experimental: 0cm Distraction<br>Participants will complete study activities while wearing a CDO with 0cm of heel distraction height | Device: Carbon Fiber Custom Dynamic Orthosis (CDO)<br>* 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.<br>* Other names: Ankle Foot Orthosis (AFO);|
| Experimental: 1cm Distraction<br>Participants will complete study activities while wearing a CDO with 1cm of heel distraction height | Device: Carbon Fiber Custom Dynamic Orthosis (CDO)<br>* 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.<br>* Other names: Ankle Foot Orthosis (AFO);|
| Experimental: 2cm Distraction<br>Participants will complete study activities while wearing a CDO with 2cm of heel distraction height | Device: Carbon Fiber Custom Dynamic Orthosis (CDO)<br>* 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.<br>* Other names: Ankle Foot Orthosis (AFO);|

What is the study measuring?
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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 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Plantar Force, Ankle Foot Orthosis, Carbon Fiber Orthosis, Biomechanics