Improving the design of insoles for diabetic foot disease

• Register: ISRCTN
• Last refreshed on: 21 August 2017
• Main ID: ISRCTN19805071
• Date of registration: 21/08/2015
• Prospective Registration: No
• Primary sponsor: Glasgow Caledonian University
• Public title: Improving the design of insoles for diabetic foot disease
• Scientific title: Optimisation of custom insoles for pressure relief in patients with diabetes via finite element modelling
• Date of first enrolment: 01/03/2015
• Target sample size: 20
• Recruitment status: Completed
• URL: http://isrctn.com/ISRCTN19805071
• Study type: Interventional
• Study design: Single-centre randomised repeated measures crossover design (Prevention)

Countries of recruitment

United Kingdom

Contacts

• Name: Scott Telfer

Key inclusion & exclusion criteria

Inclusion criteria: 1. 18-75 years of age
2. Shoe size 5-11 (UK)
3. Able to walk 300m (including ~20m barefoot) safely
4. Diabetes mellitus Type 1 or 2 with duration =10 years
5. Diabetic peripheral neuropathy defined as loss of sensation to 10g monofilament test at one or more forefoot sites
6. Elevated barefoot plantar pressure (>700kPa) measured at the forefoot during walking
Exclusion criteria: 1. Lower limb, foot or digital amputation (at a level proximal to the distal IPJ, or involving the hallux)
2. Severe callus (callus will not result in exclusion if it has been reduced to a level that does not affect sensation of underlying skin)
3. History of medical conditions, injuries or surgical procedures that significantly influence gait, or which cause pain on walking (including Charcot)
4. Severe foot deformity or reduction in ROM that result in abnormal gait or preclude good fit of study shoe (including Charcot)
5. Severe concurrent medical condition that would prevent participation in study procedures (e.g. severe cardiac/pulmonary condition that precludes activity) or with life expectancy = 3 months.
6. Pregnancy

Age minimum:
Age maximum:
Gender: Both

Health Condition(s) or Problem(s) studied

Diabetes with peripheral neurpathy
Nutritional, Metabolic, Endocrine
Diabetes mellitus

Intervention(s)

Three interventions are administered to each participant in a randomised, crossover fashion:
1. Standard, total contact insole with modifications for forefoot offloading (control). This is a traditionally designed insole that is currently the standard device prescribed for at risk diabetic feet.
2. Virtually optimised pressure offloading insole manufactured through direct milling. This is an insole design that has been optimised for pressure offloading using a numerical model simulation and is manufactured via direct milling.
3. Virtually optimised pressure offloading insole manufactured through 3D printing. This is an insole design that has been optimised for pressure offloading using a numerical model simulation and is manufactured via 3D printing.
The study tests the acute effects of the insoles. Each participant will have approximately 5 minutes to acclimatise to each pair of insoles before being data collection. The in-shoe measurement system is a flexible array of sensors that is placed between the foot and the insole and records interface forces. We will collect at least 20 steps of data for each foot.

Primary Outcome(s)

Forefoot peak plantar pressure, measured using an in-shoe plantar pressure measurement system (Pedar, Novel GmbH, Munich) at a single timepoint immediately after the insoles are provided to the patient

Secondary Outcome(s)

Validation of computational models in this patient population comparing the predicted plantar pressures to those measured experimentally

Secondary ID(s)

N/A

Source(s) of Monetary Support

Seventh Framework Programme