Heel Wedges and Carbon Fiber Custom Dynamic Orthoses to Control Knee Biomechanics
Phase: NA
Conditions: Adult ALL, Healthy
Sponsor: University of Iowa

 
 
 
 
 
Title: Heel Wedges and Carbon Fiber Custom Dynamic Orthoses to Control Knee Biomechanics 
NCT Number: NCT05209360 
Date: October 19, 2023 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Study Protocol  
Purpose and Procedures:  
The primary purpose of this line of research is to investigate the effects of combined carbon fiber custom 
dynamic orthosis (CDO) and medial-lateral wedge use on biomechanics during gait in an effort to reduce 
unilateral knee compartment loading. In this research study, pilot data will be collected from a cohort of 
healthy adult participants with no history of lower limb injuries or functional deficits. Participants will be 
evaluated using a series of study measures under each of the four conditions; without a brace (NoCDO), 
with a brace and no wedge (CDO), with a brace and a medial wedge placed in the shoe (Medial), and with 
a brace and a lateral wedge placed in the shoe (Lateral). Testing order will be randomized for each 
participant. Participants will walk on a level-ground walkway at self-selected and controlled speeds. 
Physical performance measures will incorporate tests of agility, speed, and lower limb power to ensure 
that the device and wedge don’t negatively affect physical function. Questionnaires will be used to 
evaluate participants’ pain and perception of comfort and smoothness for each condition. 
Objectives and Specific Aims: 
Specific Aim 1: Determine the effect of CDO alignment on lower limb mechanics during gait in a cohort 
of healthy individuals. 
Specific Aim 2: Determine the effect of CDO alignment on physical function and patient reported 
outcomes in a cohort of healthy individuals. 
Background and Significance: 
Osteoarthritis (OA) affects nearly 27 million people in the United States alone, and accounts for 
approximately $2,600 - $7,500 in out of packet expenses each year.[2] Knee OA can affect the medial, 
the lateral, or both compartments of knee. Treatment of OA can include a number of options such as 
medial-lateral wedging under the foot, knee orthoses, or ankle foot orthoses (AFOs). In the case of 
unilateral medial compartment knee OA unloader knee braces are commonly used to decrease knee 
adduction moments in an attempt to offload the knee. Similar efforts have been completed with the use of 
medial-lateral wedge placed in the shoe under the heel of the foot. Wedging was shown to stabilize 
biomechanics over time, preventing increases in knee adduction moment over a one-year period 
compared to neutral wedging. In another study, an ankle foot orthosis with a lateral strut was used in an 
effort to move the center of pressure position, thereby altering frontal plane knee moment. Use of this 
AFO resulted in improved pain, stiffness, and physical function scores when assed using the Western 
Ontario and McMasters Universities Arthritics Index (WOMAC). 
CDOs consist of a cuff that falls just below the knee, a carbon fiber spring that runs the length of the calf 
and bends to store and return energy during gait, and a footplate the acts as a lever arm to bend the 
posterior strut. CDOs stabilize the ankle, and this may allow for greater affects at the knee when frontal 
plane alignment is adjusted. Similar to application of medial-lateral heel wedges in the shoe, placing 
medial-lateral wedges under a CDO may also reduce knee adduction moments. The purpose of this study 
is to determine if medial-lateral wedging combined with CDO use alters knee biomechanics, physical 
function, and patient reported outcomes. 
Inclusion Exclusion Criteria: 
Patient Inclusion Criteria 
1) Between the ages of 18 and 45 
2) 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 
3) Able to hop without pain 

4) Able to perform a full squat without pain 
5) Ability to speak and understand English 
Patient Exclusion Criteria 
1) Medical or neuromusculoskeletal disorders that have limited their participation in work or exercise in 
the last 6 months 
2) Diagnosed with a moderate or severe brain injury 
3) Lower extremity injury resulting in surgery or limiting function for greater than 6 weeks 
4) Injuries that would limit performance in this study 
5) Diagnosed with a physical or psychological condition that would preclude functional testing (e.g. 
cardiac condition, clotting disorder, pulmonary condition) 
6) Uncorrected visual or hearing impairment(s) 
7) Require use of an assistive device 
8) Unhealed wounds (cuts/abrasions) that would prevent CDO use 
9) BMI > 35 
10) Pregnancy 
Design and Methods: 
Personal/demographic and anthropometric information will be used to fully characterize the study 
participants. We will collect multiple variables that have been previously associated with outcomes, 
including race, ethnicity, and education to characterize the cohort. Anthropometric and demographic 
information, such as age, biological sex, height, weight, leg length, shoe type, shoe length and width will 
also be used to characterize the cohort. 
Patient-reported outcomes questionnaires will be used to evaluate participant pain and comfort and 
smoothness. Comfort and smoothness will be assessed using a modified version of the Socket Comfort 
Score, a reliable, valid, and sensitive measure of device fit and comfort.[3] These measures have been 
shown to effectively capture patient perception, are responsive to simple modifications to CDO device 
function, and will be applied in a manner consistent with a prior publication by the research team.[1] 
Participant will be asked to report their pain using a standard 11-point numerical pain rating scale, in 
which 0 = no pain and 10 = worst pain imaginable, at the start of session and at multiple points during 
testing.[4, 5] Semi-structured interviews will also be used to fully capture the participants perspectives, 
experience, and opinions associated with the study testing conditions.  
Physical performance measures provide an objective and responsive assessment of an individual’s 
functional mobility. Activities of daily life require performance of a range of functional tasks that require 
balance, agility, speed, and power. The four square step test (4SST) is a standardized and widely used test 
of functional mobility that requires rapid changes in direction that are often problematic following lower 
limb injury. The measure has good to excellent reliability and validity across multiple patient populations 
and groups and is a key dependent measure in most CDO-related studies to date and has demonstrated 
ability to detect changes in function in individuals with limb trauma and CDOs.[6-8, 9] The sit to stand 5 
times (STS5) test is a well-established measure of lower limb muscle strength, endurance, and 
mobility.[10] The STS5 test has excellent reliability and good validity across a broad range of patient 
populations.[10-20]  
Ground reaction force and motion capture data will be used to evaluate the motion and loading of the 
lower limb as participants walk on an over ground walkway at self-selected speed and a controlled speed 
based on leg length.[21, 22] The ability to collect reliable data across sites has been previously 

demonstrated.[23] Previously established methods will be used to assess lower limb motion and 
moments.[22] 
Statistical Analysis Plan 
Analysis Methods: 
All the primary dependent variables will be evaluated using similar statistical approaches within each 
group. One-way repeated measure ANOVAs will be used to evaluate the effect of CDO alignment. Paired 
t-tests with Bonferroni-Holm correction will be used for post-hoc comparisons. Multiple trials will be 
collected for each condition during testing. 
Power Analysis: 
The number of participants proposed for this study are consistent with those from prior investigations by 
Dr. Wilken related to CDO design. Thirteen participants was sufficient to detect differences associated 
with AFO stiffness in a recent study by Dr. Wilken (PMID: 25193884). 
 
 

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