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The physical characteristics of materials used in the manufacture of orthoses for patients with diabetes.
Paton J, Jones RB, Stenhouse E, Bruce G. Foot Ankle Int. 2007 Oct;28(10):1057-63.
Quote:
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((R)) (Rogers Corp., Gent, Belgium), 3.2-mm Poron((R)), three densities of 12-mm Ethylene Vinyl Acetate (EVA), 12-mm low-density plastazote, two depths (6.4-mm, 3.2-mm) of Clerontrade mark (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((R)) 96 (6-mm) and Poron((R)) 4000 (6-mm). High density EVA (Algeo Ltd., Liverpool,~UK) and Lunacell Nora((R)) 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.
Physical properties, durability, and energy-dissipation function of dual-density orthotic materials used in insoles for diabetic patients.
Brodsky JW, Pollo FE, Cheleuitte D, Baum BS. Foot Ankle Int. 2007 Aug;28(8):880-9.
Quote:
BACKGROUND: Patients with neuropathic conditions may develop plantar bony deformities through neuropathic collapse, frequently placing the skin and soft tissues at risk. Orthoses have been used to accommodate and distribute plantar pressures over a large surface area, thereby minimizing peak loading pressures in small regions and reducing the risk of ulceration.
METHODS: A previously described bony prominence model (Brodsky et al.) was used to test the pressure-absorbing and force-transmission properties of various orthotic material combinations used in our outpatient clinic. Six materials were tested in five combinations of materials for their compressive properties: [MS]: medium plastazote (M) + soft plastazote (S); [MN]: medium plastazote (M) + nickelplast (N); [NP] nickelplast (N) + Poron (P); [MO] medium plastazote (M) + Spenco (O); and [MC] medium plastazote (M) + P-cell (C). Materials were tested for 100,000 cycles using a materials-testing system (MTS) apparatus (MTS Systems Corporation, Cary, NC) and software. Stress-strain curves comparing the measured peak pressure to the elastic deformation, or the percentage of compression a material experiences with respect to its original thickness, were plotted for each orthotic combination.
RESULTS: For MS, MN, MO, and to a lesser extent, MC, a trend was noted for decreased elastic deformation with increased testing. Additionally, the peak pressures before and after testing for each 10,000 testing cycle for each of the orthotic combinations were plotted. For both MN and NP, no demonstrable difference was noted in the peak pressures in the pretesting and post-testing for the 100,000 cycles. The MO showed a trend for increased peak pressures after each testing cycle. Both the MC and MS peak pressures markedly increased with respect to pretesting value. Also, the MN, MO, and MS all showed an overall trend for increased load cell values with increasing cycles at fast loading.
CONCLUSIONS: These data showed that some orthotic combinations are more effective than others at reducing peak pressures during compression testing using our bony prominence model. Further studies are needed to test the orthotic combinations for shear and combined shear and compression modes.
Materials used for diabetic insoles
Linear Mode
