Plantar foot ulcers are a leading cause of hospitalization, infection, and lower-extremity amputation in people with diabetes, and recurrence is the rule rather than the exception. Roughly 40% of people with a healed diabetic foot ulcer (DFU) develop a new ulcer within one year, and approximately 65% within five years (Armstrong et al., NEJM, 2017). Because most of these recurrences occur at the same plantar site, the surface that a neuropathic foot contacts during walking has become a central target for prevention. Therapeutic footwear and custom-made insoles are the principal tools used to reduce that mechanical risk.
Why Plantar Pressure Matters
In a foot with loss of protective sensation, repetitive elevated pressure under bony prominences—commonly the metatarsal heads, hallux, or a Charcot deformity—produces tissue ischemia and breakdown without the warning of pain. Reducing peak plantar pressure during walking is therefore the mechanistic basis for therapeutic footwear. Two pressure thresholds appear most often in the literature: an absolute peak in-shoe pressure below 200 kPa, and a relative reduction of at least 25–30% from the patient’s baseline at high-pressure sites (Collings et al., Heliyon, 2024). The 2023 International Working Group on the Diabetic Foot (IWGDF) prevention guideline operationalizes this by recommending footwear with a demonstrated pressure-relieving effect at high-pressure locations during walking (Bus et al., Diabetes/Metabolism Research and Reviews, 2024).
What the Evidence Shows
Custom-Made Footwear Reduces Recurrence—When Optimized
A landmark multicenter randomized controlled trial by Bus and colleagues randomized 171 neuropathic patients with a recently healed plantar ulcer to receive custom-made footwear that was iteratively optimized using in-shoe plantar pressure analysis or to receive usual-care custom footwear (Bus et al., Diabetes Care, 2013). On a per-protocol basis, recurrence at 18 months was 26% in patients whose pressure-optimized footwear was worn as prescribed compared with 47% in non-adherent peers—a relative risk reduction of 46%. Intention-to-treat analysis showed only a non-significant 11% reduction, underscoring that the benefit depends on both pressure-relieving design and consistent use.
Adherence Is the Limiting Variable
The same research group quantified how often prescription footwear is actually worn. Using a temperature-based shoe monitor over seven days in 107 high-risk patients, overall daytime adherence was 63%, falling to 59% at home and rising to 74% outside the home (Waaijman et al., Diabetes Care, 2013). A subsequent analysis identified footwear adherence above 80%, in-shoe peak pressure below 200 kPa, and absence of pre-ulcerative lesions as independent protective factors against recurrence. A 2024 review in Diabetic Medicine confirmed that, across studies, mean adherence rarely exceeds two-thirds of weight-bearing time and is consistently lowest indoors—exactly where most steps are taken.
Custom-Made Insoles and Offloading Devices
A 2024 systematic review of custom-made offloading devices found that properly designed insoles can lower forefoot peak pressures by 16–32% compared with flat insoles and reduce ulcer incidence in moderate-to-high-risk patients (Crews et al., Journal of Diabetes Science and Technology, 2024). The IWGDF 2023 update specifically recommends extra-depth shoes, custom-made footwear, custom-made insoles, and/or toe orthoses for individuals with foot deformity, pre-ulcerative lesions, or a previously healed plantar ulcer (IWGDF risk categories 2–3), with a pooled relative risk for ulcer recurrence of 0.53 (95% CI 0.24–1.17) compared with non-therapeutic footwear (Bus et al., 2024).
Emerging Pressure-Feedback Technology
Because adherence and sustained pressure reduction are difficult to achieve with passive footwear alone, sensor-based insoles have entered the prevention conversation. In a proof-of-concept randomized trial published in The Lancet Digital Health, an intelligent insole system that delivered real-time alerts when sustained high pressure was detected reduced plantar ulcer recurrence by 71% in adherent users over an 18-month follow-up (Abbott et al., 2019). Larger confirmatory trials are ongoing, but the signal aligns with the broader principle that continuous, individualized pressure feedback may close the gap between prescribed and actually-delivered offloading.
Practical Principles Supported by the Guidelines
Several practical principles emerge consistently across the literature. Footwear for an at-risk diabetic foot should be assessed and fitted by a clinician trained in diabetic foot biomechanics, because neuropathy compromises the patient’s ability to judge fit. Pressure-relieving performance should be verified objectively—ideally with in-shoe pressure measurement—rather than assumed from design alone. Patients should be counselled that the device only works when worn, including indoors, and that worn-out insoles or compressed top covers lose offloading capacity within months. Finally, regular review at three- to six-month intervals allows deformity progression, weight change, and material fatigue to be addressed before pressure climbs back into the at-risk range.
Conclusion
Therapeutic footwear and custom insoles are among the few interventions with randomized evidence supporting prevention of diabetic foot ulcer recurrence. Their efficacy is mediated through measurable reductions in plantar pressure and is critically dependent on patient adherence—particularly at home. Current IWGDF guidance, supported by RCT data and emerging sensor-based technologies, favours objectively pressure-optimized footwear that is worn consistently, evaluated at regular intervals, and integrated with broader foot-care surveillance.
References
Abbott CA, Chatwin KE, Foden P, et al. Innovative intelligent insole system reduces diabetic foot ulcer recurrence at plantar sites: a prospective, randomised, proof-of-concept study. The Lancet Digital Health. 2019;1(6):e308–e318.
Armstrong DG, Boulton AJM, Bus SA. Diabetic foot ulcers and their recurrence. New England Journal of Medicine. 2017;376(24):2367–2375.
Bus SA, Waaijman R, Arts M, et al. Effect of custom-made footwear on foot ulcer recurrence in diabetes: a multicenter randomized controlled trial. Diabetes Care. 2013;36(12):4109–4116.
Bus SA, Sacco ICN, Monteiro-Soares M, et al. Guidelines on the prevention of foot ulcers in persons with diabetes (IWGDF 2023 update). Diabetes/Metabolism Research and Reviews. 2024;40(3):e3651.
Collings R, Freeman J, Latour JM, Paton J. Plantar pressure thresholds as a strategy to prevent diabetic foot ulcers: a systematic review. Heliyon. 2024;10(4):e26161.
Crews RT, Shen BJ, Campbell L, et al. The efficacy of custom-made offloading devices for diabetic foot ulcer prevention: a systematic review. Journal of Diabetes Science and Technology. 2024.
Waaijman R, Keukenkamp R, de Haart M, et al. Adherence to wearing prescription custom-made footwear in patients with diabetes at high risk for plantar foot ulceration. Diabetes Care. 2013;36(6):1613–1618.
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