HomeR&DResearch ProjectsSponsoredMinistry of TextilesCompleted ProjectsMoT completed projectsDevelopment of functional spacer fabrics for medical inlays in orthopedic shoes

Development of functional spacer fabrics for medical inlays in orthopedic shoes

Investigators: Dr. K. P. Chellamani and Mr. M. K. Vittopa


The number of patients with diabetes increases year by year. As per available statistics, more than 40 million diabetics are there in India and most of them have the risk of lesions on the lower extremities. An advanced stage of the disease is the reduced feel for ‘Aches’.

Necessary steps useful for diabetic patients are,

i) Pressure release & soft bedding of the foot,  ii) Measures to prevent infections


  • To develop 3D spacer fabrics as base material for shoe-inlays, particularly for diabetic patients
  • Identification and application of appropriate antimicrobial finishes to shoe-inlays

Major findings

 At present, many of the diabetic shoes are with MCP (Micro Cellular Polymer) insole and MCP liners. The essential quality attributes for a diabetic shoe are:

i) Cushioning energy     ii) Compression set   iii) Water absorption & water desorption    iv) Anti Microbial property

These quality characteristics were evaluated for MCP. MCP insoles were inferior in terms of compression set & water absorption characteristics. In addition, they are not amenable to any anti-microbial treatment.

            In order to make appropriate diabetic insoles/liners SITRA has undertaken the following necessary steps,

  • Warp knitted spacer fabrics (6mm thickness) were made using texturised silver coated nylon threads
  • Warp knitted spacer fabrics (6 mm thickness) were made using 100% texturised polyester filament yarns.

The study has shown that silver coated nylon threads are ideal candidates for making diabetic shoe insoles. Texturised polyester filaments are also suitable for making insoles, provided they are given anti microbial treatment.

A large number of shoe insoles were made using 100% Silver coated Nylon threads as well as 100% Polyester (with antimicrobial finish) texturised filament yarns. Incorporating these insoles, shoes were made and they were given to a large number of diabetic patients. Based on the opinion expressed by the patients, the material compositions of the insoles were altered.

 In general, insoles are made with thickness in the range of 25 mm. SITRA has made insoles using MCP material at the bottom (18 mm thickness) and dyed silver coated nylon spacer fabrics as the top layer (6mm thickness), so that the insole has a total thickness of 24 mm (SITRA insole). Liners were made using wrap knitted fabrics made out of silver coated nylon threads (thickness 0.5mm) (SITRA liners).

Using SITRA insoles and SITRA liners, 20 pairs of shoes /slippers were made and they were given to 20 diabetic patients, as advised by Diabetic Foot Wear Centre, Coimbatore.

Views of the diabetic patients with regard to the suitability or otherwise of the shoes/slippers made using SITRA insole/SITRA liner materials were obtained.

The suitability of the shoes/slippers is evaluated with reference to 12 different characteristics viz,

1) Too heavy/light

2) Looks likes hospital shoe (Aesthetic effect)

3) Comfortable to wear (soft feel)

4) Sweat absorption during walking/running

5) Walking feel/running feel (foot pain)

6) Water absorption/desorption (quick drying)

7) Cushioning effect (compressional set)

8) Insole back to original position (creep property)

9) Thermal comfort (heat/cool)

10) Comfort walk during rainy time (outdoor)

11) Itching character/body compatibility

12) Leg ulcer curing time for diabetic patients.

Most of the patients have rated shoes made using SITRA insole/SITRA liner as superior as compared to the conventional shoes (made using MCP materials).

Research Reports/Publications: Available at SITRA