The IISc researchers from the department of mechanical engineering (DME), while pointing out that foot injuries or wounds in persons with diabetes heal at a slower rate than in healthy individuals, which increases chances of infection, and may lead to complications requiring amputation in extreme cases, said the specially-designed sandals they’ve developed that could aid faster healing.
The team is collaborating with start-ups Foot Secure and Yostra Labs to commercialise their product.
“Developed by the IISc-led team, the 3D-printed sandals can be customised to an individual’s foot dimensions and walking style. Unlike conventional therapeutic footwear, a snapping mechanism in these sandals keeps the feet well-balanced, enabling faster healing of the injured region and preventing injuries from arising in other areas of the feet,” IISc said.
The institute added that the footwear can be especially beneficial for people who have diabetic peripheral neuropathy — those suffering from nerve damage caused by diabetes, leading to a loss of sensation in the foot.
“Diabetic peripheral neuropathy is one of the long-term complications of diabetes, and its diagnosis is mostly neglected,” Pavan Belehalli, head of the department of podiatry at KIER, and one of the authors of the study published in Wearable Technologies, says. He adds that such loss of sensation leads to irregular walking patterns in diabetic persons.
For example, a healthy person usually places their heel first on the ground, followed by the foot and toes, and then the heel again – this ‘gait cycle’ distributes the pressure evenly across the foot, but due to the loss of sensation, diabetic persons may not always follow this sequence. This means that the pressure is unevenly distributed.
And, regions of the foot where the pressure exerted is high are at greater risk of developing ulcers, corns, calluses and other complications.
Stating that most therapeutic footwear available are ineffective at off-loading the uneven pressure exerted by the ‘abnormal’ gait cycle of diabetic persons, the researchers said, they designed arches in their sandals that ‘snap’ to an inverted shape when a pressure beyond a certain threshold is applied, to address this challenge.
“When we remove the pressure, the arch automatically comes back to its initial position. This is called self-offloading. We consider the individual’s weight, foot size, walking speed and pressure distribution to arrive at the maximum force that has to be off-loaded,” explains the first author, Priyabrata Maharana, a PhD student at IISc’s DME.
Multiple arches have been designed along the length of the footwear to off-load the pressure effectively, IISc said.
Prof GK Ananthasuresh from DME, a senior author of the study, said: “This is a mechanical solution to a problem. Most of the time, people use electromechanical solutions involving use of sensors and actuators that can rack up the price of the footwear.”
Ananthasuresh added that while there are a lot of commercial shoe manufacturers selling costly footwear in the name of giving comfort using what they call memory foam, tests conducted on such footwear show that they “don’t have the required characteristics”.
“…This (IISc) footwear can be used not only by people suffering from diabetic neuropathy, but by others.”