Evaluation of Additive Manufacture in the Production of Orthotic Insoles

Efficacy of Additive Manufactured Orthotic Insoles for the Reduction of Forefoot Plantar Pressure in the Diabetic Foot.

This study will assess the ability of different orthotic insole treatments to reduce pressure under the ball of the foot. This is important for people who have diabetes because their feet are at higher risk of foot problems in this area. This study will involve the participants wearing a a range of insoles produced by milling, handmade processes and additive manufacture along with normal orthotic footwear. A researcher will measure the pressures under the feet while the participants walk wearing the orthotic insoles.

The study is divided into multiple appointments over which the investigators assess the performance of the orthotic insoles the participants are using.

Screening Appointment (1 hour): The participants will be asked to come to the orthotics department at the Royal Blackburn Hospital. A clinician will perform a routine clinical foot assessment, which will include taking photographs of the feet, to ensure it is safe for the participants to participate in the study. If the participants are not eligible they will not be able to participate in the study, this will not affect the participants normal orthotic care. If the participants are eligible, information on the shape of their feet will be taken using a 3D foot scanner to allow the investigators to produce suitable insoles.

Supply Appointment (1 hour): When the insole is ready the participants will come in for a supply appointment the investigators will check that the insoles and shoes the participants will receive are the correct shape, design and are suitable to wear. At this appointment the investigators will measure the pressure under the feet whilst walking wearing the insoles to check the insole is working correctly. This is done using a thin layer of flexible sensors which go into the participants shoes. The participants will then receive insoles to take home and wear as normal.

After the participants have been supplied with orthotic insoles, a member of the National Health Service (NHS) clinical team will contact them by telephone. This will be each week for the first 4 weeks and then once a month until six months. The call will last no more than 15 minutes and the participants will be asked about their general health, the NHS foot care services they may have used and about the orthotic insoles. In addition at 3 and 6 months after the participants received their orthotic insoles they will be asked to come back into the clinic for a review appointment which will take approximately 1 hour. At these appointments the investigators will measure the pressure under their feet again, using a thin layer of flexible sensors that go into the participants shoes on top of the orthotic insole.

The investigators will also be asking some participants if they would be willing to take part in focus group discussions which will allow more detailed questions to be asked about the participants experiences wearing the orthotic insoles. The participants can decide whether to be involved in these independent of the primary trial. These will be held at the Royal Blackburn Hospital.

Inclusion Criteria:

• Are aged between 40 and 85
• Have diabetes
• Have all normal foot structures
• Have sensory neuropathy
• Have detectable pulses in feet
• Have non-standard footwear provided by the orthotics department
• Able to walk 50 meters unaided without stopping

Exclusion Criteria:

• Pregnant or Nursing
• Had prior major injuries to the lower limb (eg. Fractures, skin graft)
• Have active persistent foot or leg ulceration within last 2 years.

The participant may also not be suitable to participate if they have any of the following conditions:

• Ischemia or poor blood supply to your feet
• Charcot Arthropathy
• Connective tissue diseases (for example scleroderma, systemic lupus erythematosus).
• Autoimmune diseases (e.g. rheumatoid arthritis).