In-shoe Pressures Associated With Footwear Fit Guidelines

Overview

One in five foot ulcers are caused by the footwear worn by people with diabetes, yet there is a lack of consensus around footwear fit. Recommended toe gaps (the gap between the longest toe and the inside of the shoe) vary depending on the footwear guidance referred to but no research to date has assessed the recommendations' effectiveness in minimising in-shoe pressures. The investigators will carry out a pilot study in 60 people with diabetes and loss of foot sensation (neuropathy). In this study, the investigators will measure in-shoe pressures whilst participants walk at the same pace to the beat of a metronome. An insole placed inside participants' shoes will measure in-shoe pressures. Participants will wear the same (standardised) type of footwear. The study is designed to detect a difference in pressure within this made-to-measure footwear whose fit conforms to Standard 1 guidance compared with footwear whose fit conforms to Standard 2 guidance. Differences between Standards 1 and 2 with Standard 3 will be considered secondary analyses. Standards are simplified to three non-overlapping recommended toe gap ranges of 0.5-1.0cm; 1.5-2.0cm and 1.0-1.5cm. The investigators will also analyse the heat images taken with a thermographic camera before and after walking in standardised footwear whose fit confirms to these standards (this is known as the plantar thermal stress response to walking). Footwear fit will be determined by measuring the dimensions of participants' feet and that of participants' footwear and comparing the two. The investigators will also measure footwear fit and associated in-shoe pressure/plantar thermal stress response in participants' habitual footwear during walking at paced and self-selected speeds.

The investigators will recruit 60 participants with diabetes, neuropathy and a history of ulceration. The investigators will set a minimum target recruitment number for each sex (25 minimum for each). People with diabetes and neuropathy will be recruited through the Leicester General Hospital Multi-disciplinary Foot Team (MDFT). Leicestershire Partnership NHS Trust (LPT) will be used as a PIC site which runs 24 Community Podiatry clinics to identify possible participants. Our CODEC database (an ongoing trial looking at the effect of sleep patterns on blood glucose control) where participants agreed to be contacted regarding other studies will also be used to identify possible participants. Participants who consent to participate in the study, will have foot measurements. These foot measurements taken at baseline are both relevant to footwear fit and necessary to order comfortable, custom fit standardised house shoes aimed at those with diabetes who are at risk. Those participants assigned to footwear fit Standards which are within the IWGDF recommended range of 1.0-2.0cm toe gap will also be permitted to retain their made-to-measure standardised footwear - a house shoe designed for people with diabetes with at-risk feet. Participants assigned footwear with a non-IWGDF compliant footwear fit (i.e. a short toe gap of less than 1.0cm) will not be permitted to retain their standardised footwear given uncertainty regarding their suitability for long-term use. The air-conditioning will be switched on to control the ambient temperature. Participants will be asked to bring everyday (i.e. most frequently used) footwear or prescribed footwear. Participants' habitual footwear will then be photographed by a member of the research team using a CE-marked digital camera and the footwear style, condition and materials are recorded by a researcher using the Footwear Assessment Form (FAF). Footwear fit will then be determined by measuring the internal length of the shoe using a special gauge and measuring internal shoe width using a calliper-type device. Heel height will also be measured using a ruler. Carbon impression sheets will be used to measure foot posture by capturing the outline of the foot. The participant will be asked to remove any socks with assistance to help with this if necessary. A special insole that measures pressure will be slipped into the participant's footwear.The participant will walk within habitual footwear at normal everyday walking pace and paced using a metronome at a specific normal walking pace. In-shoe pressures will be monitored and recorded throughout. The participant will then walk whilst wearing standardised footwear (identical for all participants) again with metronome pacing. The participant will then complete a few questionnaires to say how comfortable and easy to use both the trainers and habitual footwear are. The participant will be asked to stand upon a carbon sheet which captures an impression of feet whilst standing in a relaxed posture. Thermal images of participants' feet are taken after ten minutes of acclimatization. Participants will don the thin, seamless cotton socks provided. The pressure monitoring insoles are then placed in the participant's habitual footwear. The participant will be asked to complete 4 walks at a self-selected pace during which in-shoe pressures are measured. The participant will then be asked to walk some additional steps until reaching a total of 200 steps. A thermal image is then taken of the feet immediately after removal of both habitual footwear and socks. Participants are then asked to repeat this process, except this time the participant is paced by the sound of a metronome to walk at a pre-selected pace. On completion, a thermal image is again taken of participants' feet immediately after removal of habitual footwear and socks. Participants will be asked to rate the comfort of habitually worn footwear by completing a survey. A member of the research team will be on hand to answer any questions participants may have regarding the survey. Participants will rate habitually worn footwear using usability and comfort surveys. As before, a member of the research team will be available to answer any questions regarding the survey. After putting on the thin, seamless cotton socks provided, pressure monitoring insoles are then placed in the standardised footwear provided for the participant. Participants will now be asked to put on standardised footwear and assisted if necessary. Participants will be given some time to acclimatize to the new footwear. The participant will be asked to rate the comfort of the standardised footwear using the Comfort Survey before beginning the walking trial. Assuming there are no problems, the walking trial will proceed. The participant will once again walk to the beat of the metronome for a total of 200 steps (split into 4 trials capturing midgait steps, plus additional steps). On completion, a thermal image is again taken of their feet immediately after they have removed both habitually worn footwear and socks. If a participant has trouble with the pacing, the investigators may ask the participant to walk more additional trials but these will not exceed the total of 200 steps. After a short foot check, participants will then put any socks and habitually worn footwear back on. Participants will rate standardised footwear using the usability survey. As before, a member of the research team will be available to answer any questions regarding the survey. This completes participants' tasks in the study. Where in-shoe pressures within study participants' habitual footwear are found to be in excess of 200 kPa threshold associated with an increased risk of ulceration, the investigators will refer the participant to the Podiatry Service enclosing an in-shoe pressure image depicting the location of the highest pressure regions to assist in devising offloading measures such as therapeutic insoles and orthotics. This referral does not form part of the study.