Most diabetes-related foot ulcers do not begin with an injury the patient notices. They begin with a nerve that has stopped reporting. Loss of protective sensation (LOPS) — the inability to feel pressure, friction, or minor trauma on the foot — is the single most consistent precursor to ulceration, and it is largely silent. Screening exists to find that silence before the skin breaks.
Why Loss of Protective Sensation Matters
Diabetic foot ulcers affect roughly 4–10% of people with diabetes, and they carry disproportionate consequences: reduced quality of life, elevated mortality, and a substantial share of overall diabetes healthcare expenditure. The three predisposing factors that recur across the literature are peripheral neuropathy, peripheral arterial disease, and trauma — with neuropathy typically the necessary condition that allows the other two to do damage unnoticed (Tentolouris et al., Hormones, 2024).
The clinical implication is straightforward. A patient who can feel a stone in the shoe will remove it. A patient with LOPS will walk on it. Screening is therefore not an academic exercise in neurology; it is the step that determines whether protective behaviour and protective footwear are prescribed at all.
What the Screening Examination Actually Involves
The 2023 International Working Group on the Diabetic Foot (IWGDF) guideline on prevention recommends screening every person with diabetes at very low risk annually for loss of protective sensation and peripheral artery disease, with more frequent screening — and assessment of additional risk factors — for those at higher risk (Bus et al., Diabetes/Metabolism Research and Reviews, 2023).
Bedside tests for sensation
The 10-g Semmes-Weinstein monofilament remains the reference bedside instrument for LOPS. Around it sits a family of tests with differing properties: vibration perception using a 128-Hz tuning fork or biothesiometer, pinprick sensation, thermal discrimination, ankle reflexes, the Ipswich Touch Test, and composite instruments such as the Neuropathy Disability Score. Sudomotor screening tests and plantar pressure or skin temperature measurement have also been examined as adjuncts (Tentolouris et al., 2024).
An important practical finding is that no single bedside test performs well enough alone. In a study of 75 patients admitted with a diabetic foot ulcer, a vibration-based bedside device showed high specificity (84.2%) and positive predictive value (90.3%) against biothesiometry in the contralateral foot, but sensitivity of only 50% — meaning half of the at-risk feet were missed. Combining that device with the 10-g monofilament raised sensitivity to 62.5%, and adding a tuning fork brought it to 64.3% (Pasangha et al., Diabetes & Metabolic Syndrome, 2021). The message for practice is that an abnormal result is highly informative, while a normal result on one test does not clear the foot.
Risk stratification, not simply a pass/fail
Screening output is meant to be a risk category that sets follow-up frequency and preventive intensity. In a cross-sectional study of 220 outpatients stratified by IWGDF categories, 23.6% had sensory neuropathy on 10-g monofilament testing, 36.8% had clinical evidence of peripheral arterial disease, and 43.6% had foot deformities; 27% fell outside the lowest risk group. Retinopathy, hyperkeratosis, and lower educational attainment were independently associated with higher risk categories (Zantour et al., BMC Endocrine Disorders, 2020). Callus and other pre-ulcerative lesions are not cosmetic findings — they are markers of concentrated pressure on an insensate foot.
What Follows a Positive Screen
The systematic review and meta-analysis underpinning the 2023 IWGDF prevention guideline screened 19,349 records and included 40 controlled studies, 33 of them randomised. It found moderate-certainty evidence that at-home skin temperature monitoring reduces plantar ulcer recurrence in high-risk patients (5 RCTs; risk ratio 0.51, 95% CI 0.31–0.84), and comparable moderate-certainty evidence for pressure-optimised therapeutic footwear or insoles. Structured education, therapeutic footwear, flexor tenotomy for non-rigid hammertoe with a pre-ulcerative lesion, and integrated foot care were supported by low-certainty evidence (van Netten et al., Diabetes/Metabolism Research and Reviews, 2023).
A separate meta-analysis of the same body of temperature-monitoring trials, covering 772 participants in IWGDF risk categories 2 and 3, reported the same risk reduction. In all five trials, participants measured skin temperature at six or more sites per foot daily with a handheld infrared thermometer and reduced walking when a difference greater than 2.2°C persisted between matched sites on consecutive days. The authors graded certainty as low, reflecting risk of bias in three of the five trials (Golledge et al., Diabetes/Metabolism Research and Reviews, 2022).
Notably, the 2023 guideline also issues a negative recommendation: nerve decompression surgery is not suggested as a means of preventing foot ulcers (Bus et al., 2023).
Clinical Summary
Loss of protective sensation is detectable well before ulceration, but only if it is deliberately looked for. Annual screening at minimum, more often as risk rises, using more than one bedside test, remains the evidence-based standard. Screening earns its value only when the resulting risk category drives something — education, pressure-relieving footwear, treatment of pre-ulcerative lesions, temperature self-monitoring, and integrated follow-up — since these are the interventions with demonstrated effect on ulcer incidence and recurrence.
References
- 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. 2023;40(3):e3651.
- van Netten JJ, Raspovic A, Lavery LA, et al. Prevention of foot ulcers in persons with diabetes at risk of ulceration: A systematic review and meta-analysis. Diabetes/Metabolism Research and Reviews. 2023;40(3):e3652.
- Tentolouris A, Stergioti A, Eleftheriadou I, Siafarikas C, Tsilingiris D. Screening tools for diabetic foot ulcers: a narrative review. Hormones (Athens). 2024;24(1):71–83.
- Golledge J, Fernando ME, Alahakoon C, et al. Efficacy of at home monitoring of foot temperature for risk reduction of diabetes-related foot ulcer: A meta-analysis. Diabetes/Metabolism Research and Reviews. 2022;38(6):e3549.
- Pasangha E, George B, Jayalakshmi V, Devi P, Ayyar V, Bantwal G. The utility of Vibratip in accurate identification of loss of protective sensation in the contralateral foot of patients admitted with a diabetic foot ulcer. Diabetes & Metabolic Syndrome. 2021;15(3):857–862.
- Zantour B, Bouchareb S, El Ati Z, et al. Risk assessment for foot ulcers among Tunisian subjects with diabetes: a cross sectional outpatient study. BMC Endocrine Disorders. 2020;20(1):128.
- Schaper NC, van Netten JJ, Apelqvist J, et al. Practical guidelines on the prevention and management of diabetes-related foot disease (IWGDF 2023 update). Diabetes/Metabolism Research and Reviews. 2023;40(3):e3657.
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