When David and I were studying podiatry at Cardiff Metropolitan University, we spent a lot of time looking at how mechanical pressure alters the skin on the bottom of the foot. Whether it is a painful, stubborn corn, chronic hyperkeratosis (callus), or the burning ache of metatarsalgia, the underlying culprit is almost always the same: concentrated, unyielding pressure and friction over a small surface area.
As podiatrists, our traditional answer to this has always been offloading. If you remove the pressure, you give the tissue a chance to repair, and relieve the pain.
However, we noticed a gap in the treatment options available. On one end, you have traditional felt padding, which is excellent in the short term but flattens quickly, cannot be washed, and can cause skin irritation if left on too long or applied too frequently. On the other end, you have fully bespoke orthotics, which are highly effective but take weeks to manufacture, require specialist equipment, and come with a price tag that doesn't suit every patient's budget. Modified off the shelf insoles have not traditionally been easily customisable, requiring grinding machines, glue stations, and heat guns. For a busy practitioner, the time and equipment required are not always practical to offer to all patients.
We knew there had to be a way to bridge that gap. We wanted a professional-grade, immediate offloading tool that could be
customised on the spot, whether in a busy NHS clinic, a private practice, or by a patient at home. So, we set up a 3D print
ing and CAD operation right in our living room and spent years prototyping.
The result of that research is ZeroSole.
Engineering the Hexagonal Grid
The core innovation of ZeroSole lies on its underside. Instead of a solid block of foam or gel, the insole is engineered with a patented, interlocking grid of hexagonal segments made from highly durable silicone.
The geometry here matters. Hexagons are nature's most efficient shape for distributing load across a surface. By interlocking these cells, the insole provides structured, resilient support across the entire foot. But more importantly, these individual segments are designed to be removed cleanly without the need for scissors or specialist tools.
If a patient has a painful corn under a metatarsal head, the heel, or anywhere under the plantar surface of the foot, a practitioner (or the patient themselves) can simply locate the corresponding hexagons directly beneath the lesion and pull them out.
By creating a precise void beneath the painful area, the mechanical load is immediately transferred away from the vulnerable tissue and redistributed across the surrounding healthy structure of the foot. Because the silicone is highly resilient, the void stays true; it won’t collapse under weight or flatten out after a few miles of walking.
What the Clinical Data Shows
We believe that breakthrough innovation must be grounded in rigorous science, not just clever marketing. To ensure ZeroSole delivered measurable outcomes, we partnered with university research teams at the University of Wales Trinity Saint David and Cardiff Metropolitan University podiatry school to put the insoles through independent pressure-mapping and clinical testing.
The laboratory testing confirmed two critical mechanical functions:
Targeted Pressure Reduction: When segments were removed beneath the ball of the foot, high-resolution pressure sensors confirmed a significant drop in pressure precisely at the target site.
No Edge Effect (Ring Oedema): One of the hidden risks of amateur or poorly designed offloading is that by cutting a hole in a material, you can inadvertently create a high-pressure "ring" right around the edge of the void. This traps fluid and causes localised swelling (ring oedema). The specific taper and flex of the ZeroSole hexagonal walls completely avoids this, ensuring a smooth transition of pressure in a similar way to back-bevelling.
Beyond the technical data, the impact on patient comfort was stark. During clinical studies, patients tracking their pain on a Visual Analogue Scale (VAS) reported a dramatic reduction in discomfort before any clinical debridement (scalpel treatment) had taken place.
Independent pressure-mapping and clinical-based studies In one notable case, a participant’s pain score dropped from an 8/10 (severe, limiting pain) down to a 0/10 immediately when wearing the customised ZeroSole inside their shoes. By protecting the area between podiatry appointments, it stops the rapid re-accumulation of hard skin, keeping patients comfortable for much longer.
A Practical Tool for Both Sides of the Clinic
ZeroSole was designed to integrate seamlessly into busy practitioners' daily workflows. It requires no grinding machines, no heat guns, no glue stations and no waiting around. You can adapt it in seconds during a treatment session, even during domiciliary (home) visits where your equipment is more limited.
Targeted pain relief: The modular design allows precise customisation based on individual patient needs, supporting both treatment of existing lesions/pain points and prevention of pressure-induced complications.
Quick customisation: No specialist equipment or manufacturing is required so ZeroSole can be instantly customised in any clinical or domiciliary environment.
Cost-effective solution: ZeroSole provides durable, professional-grade therapeutic benefits at an affordable price point, addressing real clinical needs without financial barriers.
Easy to fit: ZeroSole can be worn within most enclosed footwear. Perfect for work boots, trainers and everyday footwear. TIP: remove any pre-existing shoe inserts before fitting ZeroSole for additional space.
We didn't design ZeroSole to replace custom orthotics when they are clinically necessary. We designed it to be a reliable, evidence-based, immediate answer to pressure-related foot pain. It is technical precision balanced with genuine practicality, keeping people on their feet, comfortably.
Professional Recognition and Validation
Since founding Kaydiar Ltd in 2018, we have been fortunate to have secured substantial professional validation, including the Welsh ESTnet Technology Prize and significant funding through Innovate UK and Smart Cymru grants, and with ZeroSole now available on the NHS supply chain. The £1.2M funding round we secured in 2024 enabled us to transition from university research to clinical availability.
Ongoing collaborations with university research partners ensure continuous refinement of our products, with a new custom-orthotic material currently in development through additional Innovate UK SMART Grant funding.