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Prototype Testing:

B. Memory Foam with Ziploc Bag• Held the shape of a square wooden block after air was removed• Rounded edges were not desired by Sole Supports, Inc.

C. Play-Doh in Rubbermaid Container• Captured and held the foot shape and arch height• Very dense, required lots of applied force to cast the foot• Play-Doh stuck to patient’s foot after casting

D. Moist Sand in Sole Supports, Inc. Casting Box• Captured and held the foot shape and arch height• Depth of cast limited due to sand compaction• Scan of sand cast met Sole Supports, Inc. specifications

A. Memory Foam with Latex Exterior and Check Valve• Memory foam absorbed liquid latex instead of creating a vacuum tight exterior layer

Development of a Reusable Casting Apparatus for Custom Made Foot Orthotics

Keegan Compton, Ryan Cook, Michelle SauerBiomedical Engineering, Vanderbilt University, Nashville, TN 37235

Sole Supports, Inc., Lyles, TN 37098

RESULTS

Special thanks to Dr. Paul King, Mr. Matt Moore, Dr. Hak-Joon Sung, and Mr. Brad Compton for their help with this project. We also appreciate the support of the Vanderbilt Biomedical Engineering Department and Sole Supports, Inc. Laboratory.

RESULTS CONTINUED

Sole Supports, Inc.. spends $500,000 annually to ship foam casting boxes to their clients. Clients cast the arch of their patients’ feet in the foam and then send a scan of the cast via the Internet to Sole Supports, Inc.. for manufacturing of the patients’ custom foot orthotics. The foam material currently used for casting can only be utilized once and then must be thrown out. Our project is to develop a reusable casting apparatus that:

1. Maintains Sole Supports, Inc.'s casting technique2. Easily returns to its original shape3. Is cost effective4. Is environmentally friendly

1. Generate List of Possible Reusable Casting Materials2. Research and Select Most Promising Reusable Casting Materials for Testing3. Test Memory Foam Properties4. Build and Test Prototypes5. Conduct an Economic Analysis

Investigation of Memory Foam Properties:

Memory Foam Type Green Green Yellow Yellow Pink Pink

Temperature (°F) 72 47 72 49 72 NA

30 Second DepressionRetraction Time (s) 9 6.6 6.5 11 31 NA

60 Second DepressionRetraction Time (s) 9 3 8 8.8 33 NA After testing several different prototypes it was concluded the dual-compartment

sandbox system (Prototype F) is the least expensive casting method that maintains the requirements for Sole Support, Inc.’s casting technique. It is easily reusable. All materials used to construct the dual-compartment sandbox system (Prototype F) are inexpensive, can be found at a local home improvement store, and are recyclable. Therefore, all of the project objectives have been achieved with the dual-compartment sandbox system (Prototype F).

Sand can get messy, especially when transporting it from the bottom catch box back to wire grated top box. • Readjust catch-box size• Use a funnel to minimize spilling

Moisture levels in sand should be measured and standardized

• If sand is too dry the shape of the foot cannot be maintained• If sand is too wet the sand compacts too much to cast the foot

1 “Corrective Paradigm: Mass Position” http://www.solesupports.com/visitorhome/theoryandresearch.apsx

2 Dr. Stu Currie, “Advancements in Custom Orthotics” http://www.solesupports.com/visitorhome/theoryandresearch.apsx

3 http://www.solesupports.com

Economic Analysis:

• Changes in retraction time due to decreases in temperature were inconclusive because water caused memory foam to loose its memory capabilities

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CONCLUSION

FUTURE WORK

REFERENCES

ACKNOWLEDGEMENTS

E. Moist Sand Piled in the Center of a Wooden Box• Captured and held foot shape and arch height• Sand displaced laterally under applied force

3D Scans:Left: Sand castRight: Sole Supports, Inc. current foam cast

F. Moist Sand in a Dual-Compartment Wooden Box System• Captured and held foot shape and arch height.• Sand displaced vertically into bottom catch box under applied force• Depth of cast increased due to reduction in sand compaction

Prototype Testing Continued:• Retraction time increases as time of applied force increases and density of memory foam increases

BACKGROUND

ABSTRACT

PURPOSE

METHODS

Introduction• Sole Supports, Inc. spends ~$500,000 annually to ship their foam casting box• Goal: Develop an economically advantageous reusable casting apparatus

• Methods• Design and test a number of different casting devices• Brainstorm a number of solutions; perform research on these solutions• Build and test a number of prototypes• .Finalize sand design and test the device using Sole Supports, Inc.’s laser scanners to

verify the effectiveness of our design

Results and Conclusion• Building and testing a number of our designs we were able to conclude that there were

many limitations to the memory foam and modeling clay designs• Dual-compartment sandbox system had limited problems and proved to satisfy all of

the objectives that were set forth for this project, resulting in a successful design of a reusable casting apparatus

Foot Orthotics• Support the arches of the patient’s feet • Correct the function of the foot muscles• Used with patients suffering from collapsed arches caused by aging or disease

MASS Position Theory• Maximum Arch Supination Stabilization• Deficient supination of the foot arch during midstance to forefoot loading 1

Full Contact Orthotics• Remain in full contact with the arch at all

times throughout the gait cycle.2

Gait Referenced Casting• Follows the biomechanics of the foot as if

the patient were going through their normal gait cycle. 3

Foot Orthotic

MASS Position (grey)

Neutral Position (red)

Full Contact Orthotic

Gait Referenced Casting

• Total Saving: $543,000• Must use dual-compartment sandbox system 4 times to break even

Sole Supports, Inc. Foam Casting Boxes Materials Cost/Unit Annual

Boxes $2.45 $73,487 Foam $0.92 $27,595 Shipping $16.00 $480,000 Total $19.37 $581,082

Dual-Compartment Sandbox SystemMaterials Cost/Unit Annual

Labor $20.00 $10,000 Sand $5.00 $2,500 Hardware $30.00 $15,000 Shipping $20.00 $10,000 Total $75.00 $37,500