Baby Bootie: Clubfoot Orthotic Device

University of PittsburghSenior Design – BioE 1160/1161

Erika J. FranzenWilliam L. Porter

Alexis C. Wickwire

April 13, 2004

Mentor: Morey S. Moreland, MD

Overall Goal

• To create an improved device design as a means of treatment of corrective therapy for clubfoot deformity

Overview• Background

Prevalence Treatments and Methods

• Specific Objectives• Design

Considerations Development

• Results• Milestones• Future

Background: Clubfoot

• Congenital, idiopathic foot deformity

• Affects bones, joints, muscles, and blood vessels

• Ankle equinus, heel varus, midfoot cavus, and forefoot adduction

Foot position is pointing downwards and twisted inwards

Anterior view of infant’s left foot

http://www.drfoot.co.uk/pictures/clubfootrepair.jpgFaulks et al. 2005

Prevalence• Prevalence

~1/1,000 births in the US 100,000 cases annually 5-7 times greater in

developing countries• 80% of all cases

• Up to 50% bilateral cases

• Family history in 24% patients (familial)

• Twice as prevalent in males than females 3-Day Infant w/ bilateral clubfoot

http://www.drfoot.co.uk/pictures/clubfootrepair.jpgFaulks et al. 2005

Current Treatment• Surgical

Soft-tissue

Bone

Combination

• Non-surgical Soft-tissue manipulation

Cont. passive motion

Strapping

Casting

Normal Clubfoot

http://www.mgh.harvard.edu/ortho/ClubFoot.htm

Non-Surgical Methods

Plaster Casts

• Achieve proper position of foot Dorsiflexion, ER, eversion

• Normal quality of life can be achieved with correction

• Most popularly use a combo. of casts, braces US$200 - $300 / brace US$3,000 for 12 months

Ponseti Method

Corrective Braces

http://www.orthoseek.com/articles/img/club2.gifhttp://www.mgh.harvard.edu/ortho/ClubFoot.htm

Ponseti Method

1. Brief manual manipulation

2. Casting @ maximum correction

3. Percutaneous heel cord release

4. Final cast (3 weeks)

5. Maintain correction with brace

• Full time: 3 months

• 14-16 hours/nightwear: up to 4 y/o

~5 times

(1 week each)

Need for Improvement

• Costly Complexity Production

• Knee immobility

• Foot-to-foot constraint

• Parental misuse Placement

Removal

Objective

3 Primary Design Requirements:

1. Low production cost

2. Improve comfort and effectiveness during wear/use Improve foot-brace interface Unilateral

3. Adaptable Simplistic design Economic considerations

Economic Considerations

Significantly lower price wrt US competitive standards

• Materials

• Labor

• Simple design

• Available resources

• Unilateral

• Hazard Risk

• Resilience/Wearability

• Material cost, availability

• No mechanical parts

• No plastic molded components

Initial Design Considerations

Prototype Development

V 1.0

(Lateral View)

V 2.0

(Anterior View)

V 1.0 Concerns

V 1.0

(Lateral View)

• Knee constraint Comfort

Muscle, tendon atrophy and shortening

• How to maintain position of thigh unit?

Prototype Version 2

V 2.1 V 2.2 V 2.3

V 2.0

(Anterior View)

(Lateral View)

Proposed Solution

V 2.4

• Longer gauntlet

• Removed sole

• Removed ankle strap

• Material buckling

• Strap attachment points

(Lateral View)

Fabrication Limitations

• Inaccessibility to patients

• Mold adult foot Non-representative casting size

Reduced ankle flexibility, rotation

Healthy foot (no clubfoot)

Prototype

Anterior

Posterior

Lateral

Medial

Materials: Gauntlet

•Outside - Calfskin (light weight) tanned black

•Inside - Horsehide (lightweight) pearl tanned

•Padding – polyethylene foam closed cell Moisture barrier

•Nylon laces through brass eyelets

•Polyethylene stay

•Stainless steel bone

Materials: Strapping

•1” Velcro straps backed with light polyester Dacron webbing

•Z69 bonded nylon thread

•AA eyelets

•Big double headed rapid rivet nickel plated brass

Posture Correction

DorsiflexionExternal Rotation

Validation: Independent Evaluation

• Feedback Pediatric Orthopedic Surgeons

O&P manufacturer

• Initial Reaction: FAVORABLE

• Wearability

• Ease of use

• Positioning

• Concern: scalability

Cost Analysis

• Custom to patient: US $160

• Mass produced: US $80

Wearability

• Unilateral

• Knee mobility

• Open heel, toe Growth and development

Verify correct wear/placement

• Ankle lace-up Provides intimate fit

Adaptability

US $200-300

US $12 http://www.mgh.harvard.edu/ortho/ClubFoot.htm

Competitive Analysis

• Denis-Browne Bar Bilateral US $200-$300 Adaptable

• Wheaton Brace Unilateral Knee constraint US $200-$300 Not adaptable

http://www.mgh.harvard.edu/ortho/ClubFoot.htm http://www.orthoseek.com/articles/img/club2.gif

Competitive Analysis

DBB Wheaton Our Design

Low Cost XUnilateral X XAdaptable X X

Ease of Use X XMobility X

Project Milestones

• Contacted project mentor @ Children’s Hospital (Dr. Moreland)

• Prototype designs• Contacted potential manufacturer at Hanger

Prosthetics and Orthotics, Inc. (Bob Mawhinney)

• Fabricated 2 prototypes Evaluation/Validation

• Submitted business proposal to the Enterprize Business Competition

• Compiled Design History File

Future

• Fabricate properly scaled brace• Establish standardized sizes• Adapt parallel design for in developing

countries• Further evaluation

Patients Clinicians

Acknowledgements

• Generous gift of Drs. Hal Wrigley and Linda Baker

• Dr. Moreland

• Dr. Mendelson

• Bob Mawhinney

• Department of Bioengineering, University of Pittsburgh

Thank You!