Abstract
Background
Plantar foot pressure is a significant risk factor for ulceration in diabetic feet. However, foot pressure-based ulceration risk prediction has remained confined to the contribution of compressive pressure measured under controlled laboratory conditions for more than 30 years. This ignores the strong evidence that two important shear pressures are critical for tissue damage and ulceration genesis. It also prevents the cumulative effect of free-living behaviors on compressive and shear pressures from being integrated into predictive models of ulceration risk, and therefore risk prediction in real time. To address these fundamental limitations, the primary objective of this study was to assess the functionality of a novel LOMIS insole device that measures both shear and compressive pressure during daily activities over extended periods. The secondary objectives include assessing safety, validity, suitability, and feasibility as a clinical intervention.

Methods
Eighty patients with diabetes (aged 18–85 years, with feet classified as low, moderate, or high risk of ulceration) recruited from three clinical sites. Phase one includes a controlled walking assessment in the laboratory; Phase 2 pilots the device during participants’ free-living activities over five days, and phase three extends this to a three-month longitudinal study of compressive and shear pressure under real-life conditions.

Discussion
This is the first multi-center pilot study of a novel in-shoe pressure and shear measurement system that aimed to continuously measure the risk of foot ulceration. Through iterative testing to establish safety and functionality evidence, this study supports the development of digital healthcare technology and predictive foot ulceration risk models based on free-living data. Testing the feasibility and functionality of the LOMIS device in free-living circumstances will inform subsequent efficacy study designs and the pathway toward implementation in healthcare services.