Shoes and insoles which are custom-made to relieve pressure on the foot could prevent ulcers in people with diabetes. Foot ulcers are a serious complication of the disease and can lead to amputation if they are not managed appropriately. Even a mild injury can cause a foot ulcer.
Researchers wanted to identify design features of footwear which are effective in reducing repetitive pressure.
They found there was no standardised approach for designing footwear for people with diabetes. But some features were effective in reducing pressure on the foot. They included arch supports, cushioned cut-outs around sites at risk of damage (apertures) and cushioning to reduce pressure on the ball of the foot (metatarsal additions).
The researchers recommend that techniques for measuring the pressure on the feet during everyday activities should be used in the design of appropriate footwear for people with diabetes.
What’s the issue?
Foot ulcers (open sores of the feet) are one of the most frequent and serious complications of diabetes. If a foot ulcer is not properly treated and fails to heal, the limb may have to be amputated. Every 20 seconds someone, somewhere in the world, loses a leg because of diabetes.
A major cause of these wounds is poor distribution of pressure over the sole of the foot (plantar pressure) during everyday activities. Diabetes can lead to nerve damage (neuropathy) and a loss of sensation in the feet. This makes it difficult for patients to be aware of repetitive pressure and the damage it can cause.
Reducing pressure on the foot is crucial for healing and preventing foot ulceration. Specialised shoes and insoles for people with diabetes are widely available, but there is a lot of variation. It is not known what the best type of footwear is for these patients.
Researchers analysed over 50 scientific studies which looked at footwear and insoles for people with diabetic neuropathy.
- the shape of the insole, shoe upper and shoe outside
- the materials the insole and shoe were made from
- the techniques used to make the insole and shoe
- modifications made to the insole and shoe after manufacturing
The researchers found there was no standard way of developing shoes and insoles for people with diabetes. But footwear that included arch supports, apertures (cushioned cut-outs) and metatarsal additions (to reduce pressure on the ball of the foot) was effective at reducing plantar pressure and potentially preventing foot ulcers.
There was insufficient evidence for the researchers to recommend techniques for making shoes, or the materials most likely to prevent repetitive pressure. Technology which can measure pressures within shoes is recommended for designers.
Why is this important?
Between five and seven per cent of people with diabetes will have a foot ulcer at some point in their lives, at an estimated cost of £935 million to the NHS. Preventing foot ulcers is therefore important, but there is currently no standard approach for creating shoes and insoles for people with diabetes. It is not clear what features of shoe design or inserts (orthotics) are most effective for offloading pressure on the sole and reducing the risk of a foot ulcer developing or an existing one getting worse.
NICE guidelines recommend that people with diabetes wear appropriate ‘diabetic footwear’ designed to reduce repetitive stresses at all times. The guidelines do not provide information on the most important features to look for.
This study calls for further research into the most appropriate shoes for people with diabetes to be funded. It would help doctors give better recommendations on footwear and help patients make more informed choices.
This information could help manufacturers design better footwear for people with diabetic neuropathy. But further research is needed to evaluate the effectiveness of specific insoles in preventing foot ulcers in patients who are at high risk.
More research on the techniques and materials used to create bespoke footwear is also needed.
The next stage of research is to develop a standard procedure for designing footwear to reduce the risk of ulcers in people with diabetic neuropathy. This is being investigated as part of the Insoles To Ease Pressure (INSTEP) multicentre feasibility randomised controlled study.
You may be interested to read
The full paper: Collings R, and others. Footwear and insole design features for offloading the diabetic at-risk foot—A systematic review and meta‐analyses. Endocrinology, Diabetes and Metabolism. 2020;00:e00132
Collings R, and others. INSoles To Ease Pressure (INSTEP): A multicentre, randomised controlled feasibility study to compare the effectiveness of a novel instant optimised insole with a standard insole for people with diabetic neuropathy: A study protocol. BMJ Open 2019;9:e029185
Fernando ME, and others. Plantar pressure in diabetic peripheral neuropathy patients with active foot ulceration, previous ulceration and no history of ulceration: a meta‐analysis of observational studies. PLoS ONE. 2014;9:e99050
The International Working Group on the Diabetic Foot (IWGDF) produces international, multidisciplinary, evidence-based guidance documents to inform health professionals all over the world on the prevention and management of diabetic foot disease.
The research was funded by the NIHR Research Trainees Coordinating Centre and an NIHR Clinical Doctoral Fellowship.