Pressure is the mechanical engine of the neuropathic plantar ulcer. In a foot that has lost protective sensation, repetitive load during walking drives tissue breakdown and then prevents the wound from closing, no matter how carefully the wound bed itself is managed. This is why international guidelines describe offloading — the redistribution or removal of mechanical stress from the ulcer site — as arguably the single most important intervention in healing a diabetes-related foot ulcer. Despite that consensus, offloading remains one of the most inconsistently delivered elements of diabetic foot care.
Why Mechanical Stress Determines Healing
Diabetes-related foot ulcers affect roughly 18.6 million people worldwide each year and precede approximately 80% of lower-extremity amputations in people with diabetes. Healing is slow and incomplete: only about 30% to 40% of ulcers are healed at 12 weeks, and recurrence after healing is estimated at 42% at one year and 65% at five years (Armstrong et al., JAMA, 2023).
Neuropathy is central to this pattern. Loss of protective sensation removes the pain signal that would normally cause a person to limp, shift weight, or stop walking. Motor neuropathy and limited joint mobility concentrate peak plantar pressures under the metatarsal heads and hallux, and the resulting callus further elevates local pressure. Without a deliberate mechanical intervention, an ulcer is re-injured with every step.
The Evidence Hierarchy: Non-Removable Devices First
The 2023 update of the International Working Group on the Diabetic Foot (IWGDF) offloading guideline, developed through systematic review and meta-analysis using the GRADE framework, sets out a clear stepwise pathway (Bus et al., Diabetes/Metabolism Research and Reviews, 2024). For a neuropathic plantar forefoot or midfoot ulcer, the first-choice intervention is a non-removable knee-high offloading device — a total contact cast or a removable walker rendered non-removable. If contraindications or intolerance exist, a removable knee-high or ankle-high device is the second choice. If no device is available, appropriately fitting footwear combined with felted foam is the third-line option.
The advantage of the knee-high, non-removable design is twofold. It reduces plantar pressure at the ulcer site more effectively than ankle-high devices or footwear, and it removes the decision to wear it from the patient. Australian national guidelines, adapted from the IWGDF recommendations through the ADAPTE and GRADE frameworks and endorsed by ten national peak bodies, reached the same step-down conclusion: non-removable knee-high devices first, then removable knee-high, then removable ankle-high, with medical-grade footwear as a last resort (Fernando et al., Journal of Foot and Ankle Research, 2022).
When Non-Surgical Offloading Fails
Guidelines also address the ulcer that does not respond. When adequate non-surgical offloading fails to heal a plantar forefoot ulcer, the IWGDF recommends considering Achilles tendon lengthening, metatarsal head resection, joint arthroplasty, or metatarsal osteotomy. For a neuropathic ulcer at the apex or plantar surface of a lesser digit secondary to flexible toe deformity, digital flexor tenotomy is recommended. These procedures shift the mechanics of the foot rather than relying on an external device.
Adherence: The Reason Removable Devices Underperform
Removable devices are frequently chosen for practical reasons — wound inspection, bathing, sleep, patient preference — but the evidence shows the trade-off is real. In a prospective multicentre study of 79 people with type 2 diabetes and plantar ulcers, offloading adherence was measured objectively with activity monitors rather than by self-report. Participants wore their removable device during only 59% of their daily activity, and better adherence independently predicted smaller ulcer size at six weeks (Crews et al., Diabetes Care, 2016).
That study also identified a clinically useful predictor of non-adherence: perceived postural instability. Patients who felt unsteady in the device wore it less. Larger and more severe ulcers, more severe neuropathy, and foot pain were associated with better adherence — suggesting that patients with painless, less dramatic-looking wounds may be at particular risk of under-using their device. Anxiety, depression, and illness perception scores were not significantly associated with adherence.
Offloading Within a Broader Care Framework
Offloading does not operate in isolation. The IWGDF practical guidelines frame ulcer management as a combination of pressure relief, wound bed preparation and debridement, treatment of infection, restoration of perfusion where peripheral artery disease is present, and metabolic and structural care (Schaper et al., Diabetes/Metabolism Research and Reviews, 2020). Rearfoot ulcers, non-plantar ulcers, and ulcers complicated by infection or ischaemia require modified offloading approaches rather than the standard forefoot pathway. After healing, pressure-relieving therapeutic footwear demonstrably reduces recurrence compared with usual care (13.3% vs 25.4%; relative risk 0.49, 95% CI 0.28–0.84).
Key Takeaways
Offloading is a mechanical treatment for a mechanical problem, and the evidence hierarchy is consistent across independently developed guidelines. Non-removable knee-high devices are the first-choice intervention for neuropathic plantar forefoot and midfoot ulcers. Removable devices work only when they are worn, and objective monitoring shows they often are not. Perceived instability is a measurable barrier worth assessing when selecting a device. When appropriate offloading fails, surgical offloading procedures are the next evidence-supported step. And because recurrence rates after healing are high, pressure management remains relevant long after the wound has closed.
References
- Bus SA, Armstrong DG, Crews RT, Gooday C, Jarl G, Kirketerp-Møller K, Viswanathan V, Lazzarini PA. Guidelines on offloading foot ulcers in persons with diabetes (IWGDF 2023 update). Diabetes/Metabolism Research and Reviews. 2024;40(3):e3647. doi:10.1002/dmrr.3647
- Armstrong DG, Tan TW, Boulton AJM, Bus SA. Diabetic Foot Ulcers: A Review. JAMA. 2023;330(1):62–75. doi:10.1001/jama.2023.10578
- Crews RT, Shen BJ, Campbell L, Lamont PJ, Boulton AJM, Peyrot M, Kirsner RS, Vileikyte L. Role and Determinants of Adherence to Off-loading in Diabetic Foot Ulcer Healing: A Prospective Investigation. Diabetes Care. 2016;39(8):1371–1377. doi:10.2337/dc15-2373
- Fernando ME, Horsley M, Jones S, Martin B, Nube VL, Charles J, Cheney J, Lazzarini PA. Australian guideline on offloading treatment for foot ulcers: part of the 2021 Australian evidence-based guidelines for diabetes-related foot disease. Journal of Foot and Ankle Research. 2022;15(1):31. doi:10.1186/s13047-022-00538-3
- Schaper NC, van Netten JJ, Apelqvist J, Bus SA, Hinchliffe RJ, Lipsky BA. Practical Guidelines on the prevention and management of diabetic foot disease (IWGDF 2019 update). Diabetes/Metabolism Research and Reviews. 2020;36(Suppl 1):e3266. doi:10.1002/dmrr.3266
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