Comprehensive load-capacity model of diabetic foot ulcer healing

Diabetic foot ulcers pose an enormous burden on individuals and society. Better understanding and faster healing of these ulcers is paramount. With DIALOAD, we aim to unravel underlying biomechanical and behavioural mechanisms of diabetic foot ulcer healing in a comprehensive load-capacity model, and explore design of personalised education based on model outcomes.

DIALOAD is a 20-weeks prospective multicentre observational cohort study at Dutch hospitals (Amsterdam UMC, location AMC and VUmc; ZGT; Isala), including patients with diabetes mellitus and a plantar foot ulcer. Our comprehensive load-capacity model will be based on three key aspects of foot-loading: offloading device biomechanics, daily activity and device adherence.

For offloading device biomechanics, we will perform barefoot and in-device plantar pressure measurements during midgait steps. For daily activity, participants will be applied with an inertial sensor, to obtain detailed individual activity classification and daily-life gait patterns. Temperature sensors placed inside participants’ offloading device are used to measure device usage on a continuous 20-weeks basis, and in combination with gait patterns device adherence will be assessed. Such detailed and long-term biomechanical, activity and adherence profiles will lead to the most comprehensive load-capacity model of diabetic foot ulcer healing currently existing.

Via multivariate regression modelling the association between the model and its components with diabetic foot ulcer healing will be established. Considering these profiles are amenable, based on the model outcomes and qualitative interviews with patients, we will explore the design of personalised education, to bridge this project with clinical applications and future research opportunities.

To unravel underlying biomechanical and behavioural mechanisms of foot ulcer healing in a comprehensive load-capacity model, and design personalized education based on model outcomes.

We hypothesise that:
- Lower cumulative plantar tissue stress shortens the time to ulcer healing.
- A comprehensive load-capacity model to calculate cumulative plantar tissue stress (as described in the summary) better predicts time to foot ulcer healing compared to the current model (Lazzarini et al., 2019).

First measurement (week 0) – hospital-visit: participant provides informed consent. Participant is provided with offloading device, with an adherence sensor added to the device. A MoveMonitor (McRoberts, The Hague) will be provided to register daily activity during one-week following. Furthermore, logbook and fall calendar will be completed.

Second measurement (week 2) – hospital-visit: barefoot and in-shoe plantar pressure measurements during mid-gait steps. Furthermore, questionnaires (SF-36) will be completed.

Last measurement (ulcer healed or week 20) – hospital-visit: Questionnaires (SF-36) will be completed.

Week 0, 4 and 8: daily activity measurements for 1 week.

Entire measuring period (20 weeks): offloading device adherence measurements

If there is a biomechanical change of the foot or change of offloading device, barefoot and in-shoe plantar pressure measurements will be repeated.

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