Sealed Therapeutic Shoe as Treatment of Diabetic Foot Ulcers

Sealed Therapeutic Shoe vs. Total Contact Cast as Treatment of Diabetic Foot Ulcers: a Multicenter RCT

Total contact casts (TCCs) are effective treatment of plantar diabetic foot ulcers because they effectively offload the ulcer and are non-removable, resulting in high adherence to using the device. However, TCCs are not widely used in clinical practice because they negatively impact gait and daily activities. A new treatment concept was invented, sealed therapeutic shoe, where a shoe with a custom-made insole offloads the ulcer, and the shoe is rendered irremovable to be worn day and night, like a TCC. In this multicenter randomized controlled trial (RCT), 150 participants will be recruited and randomized to two treatment arms: TCC or sealed therapeutic shoe. The primary outcome is ulcer healing, secondary outcomes include (but are not limited to) skin complications, glycemic control, body mass index, gait function, balance, quality of life, physical activity, and health economics.

Data for the primary outcome of 112 participants are needed but the aim is to recruit 150, if possible within a reasonable time frame, to take drop-out into account. Participants are randomized (blocked randomization, stratified for ulcer site and study center) to either treatment with a sealed therapeutic shoe or total contact cast. Each participant will be assessed by a cast technician during the treatment period (for ulcer healing and skin complications) and be assessed by a physiotherapist on five occasions: at baseline, approximately 4 weeks into treatment and 1, 6 and 12 months after treatment end. On these occasions the physiotherapist will perform different tests (gait, balance, ankle strength and flexibility, bone mass density in heel bone, etc) and participants will answer questionnaires and have their physical activity measured for 7 days with an activity monitor.

The primary outcome (ulcer healing) will be assessed by a cast technician not blinded to group allocation, but it will be verified from a photograph by a blinded assessor. The statistician comparing the primary outcome between groups will be blinded to group allocation.

Therapeutic footwear including off-the-shelf therapeutic shoes and custom-made insoles. The shoe on the ulcerated foot is "sealed", i.e., made irremovable, with a plastic band.

Defined as complete epithelization, verified on a second occasion at least 14 days later. Primary outcome measure is proportion of ulcers healed in each Group after 12 weeks of treatment.

Number of participants with skin complications through study completion (treatment period, on average 12 weeks)

Physical activity measured with the Swedish National Board of Health and Welfare's indicator questions

3 items (intense activity, moderate activity, sitting time), each with 7 response alternatives (higher score is better)

Internal locus of control measured with two items from Form C of the Multidimensional Health Locus of Control (MHLC-C) scale

Adherence to using therapeutic footwear assessed with 2 self-report questions adapted from the Questionnaire for persons with a transfemoral amputation

The 2 questions assess using time: number of days/week (range 0-7) and number of hours/day (6 categories). Higher score is better.

Number of new foot complications per study group after healing assessed with study-specific questionnaire and patient files

Out-patient health care consumption per participant assessed with study-specific questionnaire and patient files

Study-specific questionnaire with 5 items assessing number of visits (6 response categories, higher is worse) for 5 types of out-patient visits related to the foot ulcer. Patient files will also be used to assess the same variables.

In-patient health care consumption per participant assessed with study-specific questionnaire and patient files

Study-specific questionnaire where participants fill in each hospital admission (and time period) related to the foot ulcer. Also patient files will be used to assess the same variables.

Sick-leave from work (number of days per participant) during treatment period (average 12 weeks) and during the period after treatment end up to 12 months later, assessed with study-specific questionnaire and Swedish Social Insurance Agency's system data

Data from self-report questionnaire and Swedish Social Insurance Agency's system to assess number of days on sick leave

Inclusion Criteria: Diagnosed with diabetes mellitus (any kind) Foot ulcer under metatarsal heads Exclusion Criteria: large ulcer (3-5 metatarsal heads) critical ischemia (defined as toe pressure <30 mmHg or TcPO2 <30 mmHg) uncontrolled infection (IWGDF infection grade 4, or grade 3 if not treatment against infection has been administered) Active Charcot foot foot deformities that necessitate custom-made shoes inability to speak/read Swedish. People with increased risk that side-effects will not be discovered or reported (dementia, abuse of alcohol or drugs, intellectual disability, etc.) if the person do not have appropriate social support, will be excluded.