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Novel Design of an Anterior
Cruciate Ligament (ACL)
Injury Prevention Brace
Rachel Porter
Dan Greenshields
Justin Killewald
Lawrence Technological University
BME Senior Projects 1
Dr. Mansoor Nasir, Fall 2013
Faculty Advisor: Dr. Eric Meyer, PhD
Technical Advisor: Ken Cook, P.E.
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Agenda

Problem

Objective

Need Statement

Current progress/Future plans

Background

Research plan

Knee Anatomy

Design Process

Knee Mechanics

Patent

Knee Injuries

Testing

ACL Injuries

Cost & materials

ACL Injury Mechanisms

Timeline

Tasks & responsibilities
Problem

Knee injuries account for approximately 60% of all sports related injuries. Nearly
half of those injuries occur to the ACL [1].

Extensive recovery time ~ 8-12 months
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Need Statement

An improved knee brace for ACL injury prevention could help lower the injury
rate in athletes.


Short term benefits
In turn, this potentially could delay the onset of further knee complications later in
life.

Long term benefits
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Design


ACL braces
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Prevent hyperextension

Prevent valgus bending
Osteoarthritis braces


Unicompartmental loading
Include design characteristics of prevention braces
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Knee Anatomy

Bones

Ligaments

Menisci

Cartilage

Muscles/tendons
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[2] http://www.webmd.com/pain-management/knee-pain/picture-of-the-knee
Knee Motions



Sagittal

Flexion

Extension
Coronal/Frontal

Valgus bending

Varus bending
Axial

Internal rotation

External rotation
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Knee Injuries

Bone fracture

Torn ligament
[7]



ACL

PCL

MCL

LCL
Torn meniscus

Lateral

Medial
Osteoarthritis
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ACL Injuries

200,000 – 300,000 ACL injuries/year in the U.S. [3]

70% of injuries are non-contact [4]

Females are 3-10 times more likely to sustain injury [5]

Stop-jump landing and cutting [5]

Most common injury position: < 30° of flexion
http://bretcontreras.com/wp-content/uploads/q-angle-men-vs-women.jpg
ACL Injury Mechanisms

Internal rotation


Anterior shear of tibia


Compressive force causes tibial slipping (5500 N) [4]
Hyperextension


Foot planted as knee is hit from the front
Axial Load


Foot planted as body twists
Tension on ACL causes tearing
Valgus bending

Knee is angled towards center of body
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Objective

Redesign OA brace hinge to prevent hyperextension, valgus bending, and axial
loading on the knee joint to protect the ACL

Research plan

Hinge design

Patent filing

Human subject testing
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Current ACL Braces

Donjoy Defiance – clinically proven brace
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Decreases ACL strain [6]
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FourcePoint hinge
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Protects against hyperextension and valgus bending

Worn by many college and NFL linemen
http://www.djoglobal.com/products/donjoy/defiance
Osteoarthritis Braces

Commonly used by elderly population

Medial compartment most affected by OA. [8]
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Offload medial compartment to even the distribution on compartments
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Unicompartmental loading
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Medial/lateral
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Modified Hinge Design


Polycentric gears  Spider gears
Hypothesis
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Lateral hinge = polycentric
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Medial hinge = spider gear
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Stainless Steel
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Both hinges – prevent hyperextension
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Medial hinge – shifts loading mechanism

Lateral hinge – prevent valgus bending
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Modified Hinge Design cont.

Polycentric normal action

Compressive loading – flexed action
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Patent Filing Process
http://www.uspto.gov/patents/process/index.jsp
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Current Patent Search


Hundreds of knee brace patents

OA brace

ACL brace
Individual components patented

Hinge - consistent

Strap

Frame
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Future Patent Filing

Our design has not been patented

Two different hinges on our brace

Start process in January
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Finish and file in May
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Could take years to get full patent approval
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Institutional Review Board (IRB)
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Department of Health and Human Services
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Protect the rights and welfare of human subjects
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Monitor research development, testing and evaluation methods

Submitted for IRB approval
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Application
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Consent form

Participant info sheet
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http://www.irbservices.com/irbservices/Choose_IRBS_files/IRBS%20Master%20Logo.png
Current Testing Techniques
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3D motion capture
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20 participants
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Stop-jump landings
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With and without brace
Measured

Knee flexion angle
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Ground reaction forces
[5]
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Experimental Method
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2 participants
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Jump landing trials onto force plates
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3 tests
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Without brace
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With Donjoy Defiance brace
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With redesigned brace

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Measure

Ground reaction force

Segment acceleration
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Joint reaction force
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Moment
Materials

Vicon Nexus

Polygon
http://bjsm.bmj.com/content/early/2010/06/16/bjsm.2009.069351/F2.large.jpg
Cost & Materials


Braces = $1000

Donjoy OA Defiance Brace

1 male and 1 female
Hinge redesign material = $500


Testing supplies = $300


Springs, screws, washers, stainless steel
Velcro, double sided tape
LESA foundation - $1000 granted
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Timeline
Month
Milestone
January
Assemble first prototype brace and begin human subject testing
February
Continue testing prototype and adjust design
March
Adjust design and continue testing
Data analysis
April
Data analysis and interpretation
May
Prepare final report and presentation
File provisional patent
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Anticipated Challenges

Not a significant decrease in compressive load forces

Time restrictions

Failed IRB approval

Patent filing
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Tasks & Responsibilities

Individual tasks

Shared tasks

Rachel Porter
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Prototype design & fabrication
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Testing

Data analysis



Institutional Review Board (IRB) filing
Dan Greenshields
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Existing knee brace patent search
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Presentation creation
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Patent application
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Final report documentation
Justin Killewald
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Hinge design research

Materials used in braces
References
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[1] Rishiraj, Neetu, Jack E. Taunton, Robert Lloyd-Smith, Robert Woollard, William Regan, and D.B. Clement. "The
Potential Role of Prophylactic/Functional Knee Bracing in Preventing Knee Ligament Injury." Sports Medicine 39.11
(2009): 937-60. Print.

[2] http://www.webmd.com/pain-management/knee-pain/picture-of-the-knee

[3]Teng, Phillis S.P., K.F. Leong, P.Y. Huang, and J. McLaren. "The Effect of a Knee-ankle Restraint
on ACL Injury Risk Reduction during Jump-landing." Procedia Engineering60 (2013): 300-06. Print.

[4] Meyer, Eric G., and Roger C. Haut. "Excessive Compression of the Human Tibio-femoral Joint
Causes ACL Rupture." Journal of Biomechanics 38.11 (2005): 2311-316. Print.

[5] Yu, B. "Immediate Effects of a Knee Brace With a Constraint to Knee Extension on Knee
Kinematics and Ground Reaction Forces in a Stop-Jump Task." American Journal of Sports
Medicine 32.5 (2004): 1136-143. Print.

[6] http://www.djoglobal.com/education/patient-education/acl-bracing
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[7] Majewski, M., H. Susanne, and S. Klaus. "Epidemiology of Athletic Knee Injuries: A 10-year
Study." The Knee 13.3 (2006): 184-88. Print.

[8] Gaasbeek, Robert D.A., Brenda E. Groen, Brieke Hampsink, Ronald J. Van Heerwaarden, and
Jacques Duysens. "Valgus Bracing in Patients with Medial Compartment Osteoarthritis of the Knee
A Gait Analysis Study of a New Brace." Gait & Posture26 (2007): 3-10. Print.
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Questions?
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