Analysis of Joint Mechanics in Response to Gait Modifications and Cutaneous Stimulation
Phase: NA
Conditions: Osteoarthritis, Knee
Sponsor: Stanford University

 
 
 
Gait Modifications and Cutaneous Stimulation 
NCT: 02884414 
November 2, 2016 
 
 
 
Study Protocol and Statistical Analysis Plan 
 
 

Purpose.  The purpose of this study is to quantify differences in joint mechanics between 
different types of walking in healthy individuals and individuals with knee pathology. We will 
determine how modifying gait through feedback and/or cutaneous stimulation changes joint 
loading. Such modifications may be simple, low cost solutions to treat knee pathology. 
Scientific Rationale.  Neuromuscular dysfunction such as decreased quadriceps muscle 
strength and voluntary activation has been demonstrated in patients with osteoarthritis and 
with other joint pathologies including ligament injuries and meniscectomy (Childs et al. 2004, 
Lewek et al. 2004). Physical therapy, braces, elastic wraps, and taping have been commonly 
used to treat many types of these musculoskeletal conditions. For example, rehabilitative 
programs including quadriceps strengthening have been shown to reduce pain and disability in 
subjects with knee osteoarthritis. Quadriceps strengthening, however, may require complex 
clinic-based regimens or machinery not readily available to patients, and can have poor 
adherence rates. Further, despite aggressive rehabilitation programs directed at improving 
quadriceps function following ACL injury and reconstruction, a condition leading to accelerated 
joint degeneration, a universally accepted effective treatment approach to reverse this muscle 
weakness has yet to be identified. The quadriceps weakness following ACL injury has been 
shown to be related to the potential for re-injury and development of knee OA (Becker et al. 
2004, Bodor 2001, Lewek et al. 2002). Thus, while available interventions have achieved some 
clinical success, it is often the case that the results are not sustained due to limitations 
associated with compliance in using the therapy or continuing to the wear a particular 
intervention.  
Knee injuries and disease cause substantial pain and disability, and their high prevalence 
necessitate simple interventions. Clinical guidelines for management of knee OA and 
associated joint injuries emphasize the importance of non-pharmacological conservative 
strategies. Gait modification through cutaneous stimulation offers a low cost alternative to 
rehabilitation programs and current treatments to address deficient muscle activation in knee 
OA and conditions related to development of the disease.  
This study will address the gap in current research, and will evaluate gait modifications that 
include cutaneous stimulation (e.g. vibratory, tactile), in both healthy individuals and patients 
with knee pathology. 

Focus. This study aims to examine the differences in joint mechanics between different types 
of walking in healthy individuals and individuals with knee pathology. We will determine how 
modifying gait through feedback and/or cutaneous stimulation changes joint loading.  
Anticipated Impact.  Knee injuries and disease cause substantial pain and disability, and their 
high prevalence necessitate simple interventions. Clinical guidelines for management of knee 
OA and associated joint injuries emphasize the importance of non-pharmacological 
conservative strategies. Gait modification through cutaneous stimulation may offer a low cost 
alternative to rehabilitation programs and current treatments to address deficient muscle 
activation in knee OA and conditions related to development of the disease. This study will 
address the gap in current research and will evaluate gait modifications which may help 
decrease disability from knee joint pathologies. 
Methods. We plan to recruit up to 90 individuals at Stanford and the VA Palo Alto.  The 
participants will be individuals with knee pain or pathology and healthy volunteers with no 
known knee pain or pathology. Participants to be recruited will be 18 years or older. Both 
males and females will be recruited. Individuals below the age of 18 years old are excluded as 
they may not have yet reached skeletal maturity. 
Departmental clinicians will identify potential subjects with joint pathology meeting the inclusion 
and exclusion criteria. Departmental clinicians will notify potential subjects about the study and 
ask permission to have a clinical coordinator contact him/her with more information. If 
permission is granted, study staff will follow-up in person at the clinic or by phone to arrange 
for informed consent. Asymptomatic subjects will be recruited by responding to flyers 
advertising the study. Subjects with joint pathology may also be recruited by responding to 
flyers advertising the study or by referral from their clinician. 
Following informed consent, information about the subject's health history will be collected. 
The information to be collected includes: age, gender, weight, height, medical and joint-health 
history. Pregnant subjects will be excluded from the study. 
On the testing day, each subject may be asked to walk at a variety of speeds. Subjects will 
also be asked to walk while receiving external feedback/stimulation. Outdoor testing may occur 
in a selected outdoor location that is also safe and unobstructed. Feedback and stimulation 
(for example: audio, video, tactile, vibratory) may be provided to improve gait modification and 

muscle activation abilities. Subjects may be asked to respond to feedback/stimulation, but not 
required to respond. There is little to no risk to the subjects beyond the normal risks associated 
with walking.  
Kinematic and kinetic gait measurements: A motion capture system consisting of infrared 
cameras and small reflective balls (markers) attached to the subjects using small double sided 
stickers and force platforms embedded in the floor will be used estimate subjects kinematics 
and kinetics during gait following the point cluster method protocol and standard inverse 
kinetics calculations. Pressure sensors may also be used to provide a 2 dimensional map of 
the pressure distribution in the stance phase of gait. EMG may be used to provide information 
on muscle activation. Additionally, inertial sensors may be placed on the bodies of the subjects 
to measure their kinematics. The markers and sensors will be placed on the bodies so that 
they do not impede the subject's movements in any way. Moreover, these elements do not 
impart excessive force. Ideally, the subject will forget that they are wearing the system.  
Subjects may also be asked to complete questionnaires regarding pain, function, and physical 
activity. Subjects may be asked to return for a repeated testing session. 
Statistical Analysis Plan. Normality of data will be checked using Shapiro-Wilks tests. Within-
test differences in joint loading parameter (peak knee flexion moment) between experimental 
conditions and walking speeds will be analyzed using paired Student’s t-tests or non-
parametric alternative if non-normally distributed.