Effects of Malleo-Lok Stiffness on Lower Limb Mechanics (MalleoLokStiff)

The primary purpose of this research study is to determine if the stiffness of a commercially available ankle foot orthosis (Malleo-Lok, Bio-Mechanical Composites, Des Moines IA) impacts gait biomechanics and overall joint level stiffness. Previously published research suggests that AFO stiffness can affect gait biomechanics and patient preference. However, previous studies have focused on traditional posterior strut devices with the strut aligned in the frontal plane to allow sagittal plane deflection. The Malleo-Lok is a novel, low-profile carbon fiber device with two laterally positioned struts aligned in the sagittal plane. The proposed study will provide insight that can be used by certified prosthetists orthotists (CPOs), physical therapists, and physicians to select the device that bests meets their patients' needs.

Study Overview

• Status: Completed
• Conditions: Healthy; Adult ALL
• Intervention / Treatment: Device: Malleo-Lok

Detailed Description

Healthy adult individuals will be invited to participate in this study, at the University of Iowa, that involves one visit lasting 3-4 hours. The primary purpose of this work is to determine the effects of Malleo-Lok stiffness on gait biomechanics and ankle joint stiffness. Previous work has highlighted the effects of ankle foot orthosis stiffness on gait using devices with a traditional single posterior strut opposed to the Malleo-Lok, which has two laterally positioned struts. Orthosis stiffness is an important factor to consider during device prescription and manufacturing. The ability to tune overall joint level stiffness by determining the combined effects of biological limb stiffness and orthosis stiffness will enhance precision medicine when treating individuals who require an orthosis for daily activities. The secondary purpose of this research study is to determine the within session repeatability of a novel approach for in-vivo AFO stiffness testing. AFO stiffness testing is typically performed using mechanical testing systems without accounting for the interaction of the individual and the device.

During the visit to the University of Iowa campus participants will review a list of inclusion and exclusion criteria to determine their eligibility for this study. Eligible participants will review an informed consent document and have the chance to ask any questions they may have. Study staff will thoroughly explain the informed consent document and answer all questions. Upon signing the informed consent document study activities will begin. Participants will complete all study activities wearing no brace and two braces of differing stiffness's. Anthropometric and demographic information will be collected from each participant. The investigators will also use a motion capture system to evaluate gait biomechanics and ankle joint stiffness. Participants will walk at a self-selected and a controlled speed to evaluate gait biomechanics, and will stand in the motion capture system and bring their knee forward over the foot to evaluate ankle joint stiffness. Participants will be provided visual feedback of muscle activity to minimize lower limb muscle activity during ankle stiffness testing.

Results from the proposed study will provide information about the effects of orthosis stiffness on gait biomechanics and ankle joint stiffness. Study results will be made available to clinicians to use when prescribing and fitting individuals with ankle foot orthoses.

• Study Type: Interventional
• Enrollment (Actual): 20
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Iowa
    • Iowa City, Iowa, United States, 52242
      • University of Iowa

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 45 years (Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Between the ages of 18 and 45
• 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 speak and understand English

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
• History of recurrent ankle sprains or chronic ankle instability
• Diagnosed with a physical or psychological condition that would preclude functional testing (e.g. cardiac condition, clotting disorder, pulmonary condition)
• Uncorrected visual or hearing impairment(s)
• Require use of an assistive device
• Unhealed wounds (cuts/abrasions) that would prevent AFO use
• BMI > 35
• Pregnancy

Study Plan

How is the study designed?

Design Details

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

Number of Arms

6

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Compliant, NoCDO, Stiff; Participants will be tested while wearing a moderate stiffness device (Compliant), then while wearing no brace (NoCDO), then while wearing a stiff device (Stiff).	Device: Malleo-Lok; The Malleo-Lok is a novel, low-profile carbon fiber device with two laterally positioned struts aligned in the sagittal plane.; Other Names: Ankle Foot Orthosis; Carbon Fiber Custom Dynamic Orthosis
Experimental: Compliant, Stiff, NoCDO; Participants will be tested while wearing a moderate stiffness device (Compliant), then while wearing a stiff device (Stiff), then while wearing no brace (NoCDO).	Device: Malleo-Lok; The Malleo-Lok is a novel, low-profile carbon fiber device with two laterally positioned struts aligned in the sagittal plane.; Other Names: Ankle Foot Orthosis; Carbon Fiber Custom Dynamic Orthosis
Experimental: NoCDO, Compliant, Stiff; Participants will be tested while wearing no brace (NoCDO), then a moderate stiffness device (Compliant), then while wearing a stiff device (Stiff).	Device: Malleo-Lok; The Malleo-Lok is a novel, low-profile carbon fiber device with two laterally positioned struts aligned in the sagittal plane.; Other Names: Ankle Foot Orthosis; Carbon Fiber Custom Dynamic Orthosis
Experimental: NoCDO, Stiff, Compliant; Participants will be tested while wearing no brace (NoCDO), then while wearing a stiff device (Stiff), then while wearing a moderate stiffness device (Compliant).	Device: Malleo-Lok; The Malleo-Lok is a novel, low-profile carbon fiber device with two laterally positioned struts aligned in the sagittal plane.; Other Names: Ankle Foot Orthosis; Carbon Fiber Custom Dynamic Orthosis
Experimental: Stiff, Compliant, NoCDO; Participants will be tested while wearing a stiff device (Stiff), then while wearing a moderate stiffness device (Compliant), then while wearing no brace (NoCDO).	Device: Malleo-Lok; The Malleo-Lok is a novel, low-profile carbon fiber device with two laterally positioned struts aligned in the sagittal plane.; Other Names: Ankle Foot Orthosis; Carbon Fiber Custom Dynamic Orthosis
Experimental: Stiff, NoCDO, Compliant; Participants will be tested while wearing a stiff device (Stiff), then while wearing no brace (NoCDO), then while wearing a moderate stiffness device (Compliant).	Device: Malleo-Lok; The Malleo-Lok is a novel, low-profile carbon fiber device with two laterally positioned struts aligned in the sagittal plane.; Other Names: Ankle Foot Orthosis; Carbon Fiber Custom Dynamic Orthosis

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Ankle Joint Stiffness	Ground reaction force and ankle motion data were collected simultaneously using the force measurement and motion capture systems as participants wore no brace (NoCDO), a moderate stiffness orthosis (Compliant) and a stiff orthosis (Stiff) in a randomized order. The ankle motion data was plotted against the ankle moment data and the slope of the corresponding line was the resulting ankle joint stiffness (Nm/degree).	In-vivo ankle joint stiffness was measured for each condition before and after short bouts of walking (~15-20 minutes).
Ankle Joint Power	Peak ankle joint push-off power (W/kg) was calculated during gait and normalized to participant body weight as participants wore no brace (NoCDO), a moderate stiffness orthosis (Compliant) and a stiff orthosis (Stiff) in a randomized order.	Ankle joint power was measured for each condition during short bouts of walking (~15-20 minutes).
Ankle Joint Moment	Peak ankle plantarflexion moment (Nm/kg) was calculated during gait and normalized to participant body weight as participants wore no brace (NoCDO), a moderate stiffness orthosis (Compliant) and a stiff orthosis (Stiff) in a randomized order.	Ankle joint moment was measured for each condition during short bouts of walking (~15-20 minutes).

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Numerical Pain Rating Scale	Participants were asked to rate their pain on a standard 11-point numerical pain rating scale, in which 0 = no pain and 10 = worst pain imaginable. Participants were asked to rate their pain after completing testing in no brace (NoCDO), a moderate stiffness orthosis (Compliant) and a stiff orthosis (Stiff) in a randomized order.	Participants were asked to rate their pain after completing in-vivo ankle stiffness testing and walking trials in all conditions.
Modified Socket Comfort Score: Comfort	Study participants were asked to rank the smoothness of each orthosis on a scale from 0-10 where 0 = least smooth and 10 = most smooth orthosis. Participants were asked to rate the comfort of each orthosis after completing testing in a moderate stiffness orthosis (Compliant) and a stiff orthosis (Stiff) in a randomized order.	Participants were asked to rate their comfort after completing in-vivo ankle stiffness testing and walking trials in Compliant and Stiff conditions.
Modified Socket Comfort Score: Smoothness	Study participants were asked to rank the smoothness of each orthosis on a scale from 0-10 where 0 = least smooth and 10 = most smooth orthosis. Participants were asked to rate the smoothness of each orthosis after completing testing in a moderate stiffness orthosis (Compliant) and a stiff orthosis (Stiff) in a randomized order.	Participants were asked to rate the orthosis smoothness after completing in-vivo ankle stiffness testing and walking trials in Compliant and Stiff conditions.

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Center of Pressure Velocity Timing	Timing of peak center of pressure velocity (percent stance) during gait.	Baseline
Center of Pressure Velocity Magnitude	Magnitude of peak center of pressure velocity (m/s) during gait.	Baseline
Soleus Muscle Activity (Electromyography)	Electromyography of soleus activity during in-vivo ankle stiffness testing was used as visual feedback for participants during testing.	Baseline
Medial Gastrocnemius Muscle Activity (Electromyography)	Electromyography of medial gastrocnemius activity during in-vivo ankle stiffness testing was used as visual feedback for participants during testing.	Baseline
Tibialis Anterior Muscle Activity (Electromyography)	Electromyography of tibialis anterior activity during in-vivo ankle stiffness testing was used as visual feedback for participants during testing.	Baseline
Peroneus Longus Muscle Activity (Electromyography)	Electromyography of peroneus longus activity during in-vivo ankle stiffness testing was used as visual feedback for participants during testing.	Baseline

Collaborators and Investigators

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

Study record dates

Study Major Dates

• Study Start (Actual): March 11, 2021
• Primary Completion (Actual): October 20, 2021
• Study Completion (Actual): October 20, 2021

Study Registration Dates

• First Submitted: March 11, 2021
• First Submitted That Met QC Criteria: March 16, 2021
• First Posted (Actual): March 19, 2021

Study Record Updates

• Last Update Posted (Actual): June 15, 2023
• Last Update Submitted That Met QC Criteria: May 22, 2023
• Last Verified: May 1, 2023

More Information

Terms related to this study

• Keywords: Biomechanics; Gait Analysis; Carbon Fiber; Ankle Foot Orthosis
• Additional Relevant MeSH Terms: Anti-Infective Agents, Local; Anti-Infective Agents; Carbon Fiber
• Other Study ID Numbers: 202004402

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