The Physical Characteristics of Materials Used in the Manufacture of Orthoses for Patients with Diabetes

Abstract

Background: Neuropathic diabetic foot ulceration may be prevented if the mechanical stress transmitted to the plantar tissues can be modified. Orthotic therapy is one practical method commonly used to maintain tissue integrity. Orthotic design must consider the materials chosen for use in fabrication and profile of the device because both aspects influence the performance and durability of the device. Published research evaluating the physical properties of materials commonly used in the manufacture of orthoses for patients with diabetes is limited. This study investigated the physical properties of materials used to fabricate orthoses designed for the prevention of neuropathic diabetic foot ulcers. Methods: Fifteen commonly used orthotic materials were selected for testing: four specifications of 6.4-mm Poron® (Rogers Corp., Gent, Belgium), 3.2-mm Poron®, three densities of 12-mm Ethylene Vinyl Acetate (EVA), 12-mm low-density plastazote, two depths (6.4-mm, 3.2-mm) of Cleron™ (Algeo Ltd., Liverpool, UK), Professional Protective Technology (PPT), and MaxaCane (Algeo Ltd, Liverpool, UK). The density, resilience, stiffness, static coefficient of friction, durability, and compression set of each material were tested, ranked, and allocated a performance indicator score. Results: The most clinically desirable dampening materials tested were Poron® 96 (6-mm) and Poron® 4000 (6-mm). High density EVA (Algeo Ltd., Liverpool, UK) and Lunacell Nora® EVA (Freudenberg, Weinhein, Germany) possessed the properties most suitable to achieve motion control. The data present a simple and useful comparison and classification of the selected materials. Conclusions: Although this information should not be used as a single indicator for assessing the suitability of an orthotic material, the results provide clinically relevant information relating to the physical properties of orthotic materials commonly used in the prevention of neuropathic diabetic foot ulcers.

Keywords

Diabetes Materials Orthoses Physical Characteristics

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References

Abbott

Vileikyte

Williamson

Carrington

Boulton

: Multicenter study of the incidence of and predictive risk factors for diabetic neuropathic foot ulceration. Diabetes Care 21:1071–1075, 1998.

Armstrong

Peters

Athanasiou

Lavery

: Is there a critical level of plantar foot pressure to identify patients at risk for neuropathic foot ulceration? J. Foot Ankle Surg. 37:303–307, 1998.

Avison

: The World of Physics, Thomas Nelson and Sons Limited. Surry. London, 1984.

Bennett

Stocks

Whittam

: Analysis of risk factors for neuropathic foot ulceration in diabetes mellitus. J. Am. Podiatr. Med. Assoc. 86:112–116, 1996.

Boulton

Betts

Franks

: Abnormalities of foot pressure in early diabetic neuropathy. Diabet. Med. 4:225–228, 1987.

Brodsky

Kourosh

Stills

Mooney

: Objective evaluation of insert material for diabetic and athletic footwear. Foot Ankle Int. 9:111–116, 1988.

Campbell

Newell

McLure

: Compression testing of foamed plastics and rubbers for use as orthotic shoe insoles. Prosthet. Orthot. Int. 6:48–52, 1982.

Caselli

Pham

Giurini

Armstrong

Veves

: The forefoot to rearfoot plantar pressure ratio is increased in severe diabetic neuropathy and can predict foot ulceration. Diabetes Care 25:1066–1071, 2002.

Cinats

Reid

Haddow

: A biomechanical evaluation of sorbothane. Clin. Orthop. 222:281–288, 1987.

10.

Ctercteko

Dhanendran

Hutton

Quesne

: Vertical forces acting on the feet of diabetic patients with neuropathic ulceration. Br. J. Surg. 68:608–614, 1981.

11.

Foto

Birke

: Evaluation of multidensity orthotic materials used in footwear for patients with diabetes. Foot Ankle Int. 19:836–838, 1998.

12.

Janisse

: A scientific approach to insole design for the diabetic foot. The Foot. 3:105–108, 1993.

13.

Kastenbauer

Sauseng

Sokol

Auinger

Irsigler

: A prospective study of predictors for foot ulceration in type 2 diabetes. J. Am. Podiatr. Asso. 91:343–350, 2001.

14.

Kuncir

Wirta

Golbranson

: Load-bearing characteristics of polyethylene foam: an examination of structural and compression properties. J. Rehabil. Res. Dev, 27:229–238, 1990.

15.

Lavery

Armstrong

Wunderlich

Tredwel

Boulton

: Predictive value of foot pressure assessment as part of a population based diabetes disease management program. Diabetes Care 26:1069–1073, 2003.

16.

Lavery

Vela

Ashry

Lanctot

Athanasiou

: Novel methodology to obtain salient biomechanical characteristics of insole materials. J. Am. Podiatr. Assoc. 87:266–271, 1997.

17.

Lewis

Tan

Shiue

: Characterization of the performance of shoe insert materials. J. Am. Podiatr. Assoc. 81(8):418–424, 1991.

18.

Macfarlane

Jeffcoate

: Factors contributing to the presentation of diabetic foot ulcers. Diabet. Med. 14:867–870, 1997.

19.

Ogrodnik

: Fundamental engineering mechanics, Addison Wesley Longman Limited, Essex, 1997.

20.

Peters

Lavery

: Effectiveness of the diabetic foot risk classification system of the international working group on diabetic foot. Diabetes Care 24:442–1447, 2001.

21.

Pratt

Rees

Rodgers

: Assessment of some shock absorbing insoles. Prosthet. Ortho. Int. 10:43–45, 1986.

22.

Rome

: A study of the properties of materials used in podiatry. J. Am. Podiatr. Med. Assoc. 81:73–83, 1991.

23.

Sanders

Greve

Mitchell

Zachariah

: Material properties of commonly-used interface materials and their static coefficients of friction with skin and socks. J. Rehabil. Res. Dev. 35:161–176, 1998.

24.

Shiba

Kitaoka

Cahalan

Chao

: Shock-absorbing effect of shoe insert materials commonly used in management of lower extremity disorders. Clin. Orthop, 310:130–136, 1995.

25.

Stess

Jensen

Mirmiran

: The role of dynamic plantar pressures in diabetic foot ulcers. Diabetes Care 20:855–858, 1997.

26.

Tyrsell

: Orthotic intervention in patients with diabetic foot ulceration. Wound Care 8:530–532, 1999.

27.

Veves

Murray

Young

Boulton

: The risk of foot ulceration in diabetic patients with high foot pressure: a prospective study. Diabetologia. 35:660–663, 1992.

28.

Watkins

: Structure and function of the musculoskeletal system, Human Kinetics, United States, 1999.