Diabetic Foot — SINBAD-First Classification, the Non-Removable Offloading Verdict, the Antibiotic Duration Ladder, and WIfI-Guided Revascularisation

A 58-year-old man with a painless plantar forefoot ulcer under a metatarsal head, a 64-year-old woman with a hot swollen foot and a probeable plantar ulcer, and a 71-year-old man with rest pain, a heel ulcer and absent pedal pulses. One needs offloading by the IWGDF ladder, one needs the osteomyelitis workup with biopsy discipline, and one needs WIfI staging with PLAN-based revascularisation counselling. The examiner will watch you classify by SINBAD variables in words, quote the non-removable numbers, combine probe-to-bone with X-ray before ordering MRI, shorten antibiotics by the duration trials, and stage revascularisation benefit before touching the vessels — with every number taken from the papers named beside it.^{[18][28][35][12]}

Overview & Definition — neuropathy, ischaemia and infection in one foot

The diabetic foot is ulceration, infection or tissue destruction of the foot in a person with diabetes, driven by the triad of neuropathy, ischaemia and infection acting together rather than alone: ulcers split into neuropathic, ischaemic and neuroischaemic types at roughly 35, 15 and 50%, and 85% of diabetes-related lower-limb amputations are preceded by an ulcer.^[7] The population burden is large and growing: global ulcer prevalence sits at 6.3% of people with diabetes — higher in men at 4.5% than women at 3.5%, highest in North America at 13.0% and lowest in Oceania at 3.0% — with ulceration incidence at 10.93 per 1000 person-years and amputation incidence at 3.58, while American and African rates run above the global pooled average.^[1][2] The strategic arc fits one sentence: describe the ulcer by SINBAD variables, stage the limb by WIfI, offload non-removably, diagnose bone infection by probe-plus-X-ray with biopsy confirmation, shorten antibiotics by the duration ladder, revascularise by PLAN with benefit-quartile honesty, and amputate at the most distal healing level with the proximal risks consented.^{[14][8][18][32][36][43][53]}

Classification — SINBAD speaks, WIfI stages, Texas grades depth, IWGDF referees

SINBAD is the communication language: Site, Ischaemia, Neuropathy, Bacterial infection, Area and Depth — six variables with strict criteria for quick, accurate decisions — and the 2023 IWGDF guideline makes it the first option for communication among professionals, with WIfI as the alternative where equipment and expertise allow, and the individual variables described in words rather than a total score in every case.^[7][14] WIfI exists because the old systems excluded diabetes by design: critical limb ischaemia was first defined with the intent that patients with diabetes be excluded or analysed separately, Fontaine and Rutherford split only rest pain from tissue loss, and perfusion alone never decided a diabetic limb — so the SVS built risk stratification on Wound, Ischaemia and foot Infection together.^[8] Texas grades depth against stage: in 360 clinic patients, amputations climb with both increasing depth and stage, wounds that probe to bone carry 11-fold the midfoot-or-higher amputation odds at 18.3 versus 2.0%, and infection-plus-ischaemia together carry nearly 90-fold odds at 76.5 versus 3.5%.^[16] The head-to-head numbers come from Lima: 342 patients with 11% six-month major amputation incidence, AUROC 0.90 for Saint Elian, 0.81 each for Texas 3D-stage and Wagner, and 0.74 for SINBAD — with the most discriminating thresholds at Saint Elian 18 or above, Texas stage 3D, Wagner 3 or above, and SINBAD 5 or above.^[17]

The umpire's verdict is blunt: across 28 systems in 149 studies the certainty of evidence is low or very low with two-thirds of systems assessed by 3 or fewer studies, Wagner is the most validated but mostly against amputation association, and for predicting the outcome of an ulcer in a specific individual no existing system can be recommended — while SINBAD score takes the audit role and the IDSA/IWGDF scheme takes the infected-ulcer description role.^[15][14] WIfI stages perform in practice: in 201 threatened limbs with 93% diabetes, stages 3 and 4 concentrate amputations with falling amputation-free survival and longer healing times, and stage-3 revascularisation accelerates wound healing — while in a 217-patient multidisciplinary clinic WIfI predicts healing but not amputation, with stage-4 wounds healing in a mean 190 days at only 5.7% one-year amputation risk, suggesting the team itself moves the amputation curve.^[9][10]

Populations & Denominators — the cohorts that frame every decision

The burden cohorts run Zhang global prevalence, Carollo 89 studies with up to 29.65 million participants, Chen mortality with 124376 participants and 51386 deaths across 16 countries, Fu recurrence with 49 studies, Apelqvist 558 consecutive ulcer patients with 4-year median follow-up, and Luo amputation with 16 cohort studies.^{[1][2][3][4][5][6]} The classification cohorts contribute Mills rationale, Zhan 201 threatened limbs, Mathioudakis 217 patients with 439 wounds, Weaver 225 wounds in 99 patients undergoing angiography, Hicks 136 diabetic patients with 187 revascularised limbs, Benyakorn 131 admitted infected feet, the IWGDF 28 systems in 149 studies, Armstrong Texas 360 clinic wounds, and Gallardo 342 Lima patients.^{[8][9][10][11][12][13][15][16][17]} The offloading trials contribute Armstrong TCC 63, Armstrong iTCC 50 Texas-1A ulcers, Faglia 45, Lavery 73, Bus 60 across three removable devices, Morona pooled comparisons, Okoli 5 trials with 169 participants, and the IWGDF ladder itself.^{[20][21][22][23][24][25][26][18]} The infection cohorts contribute JAMA 279 screened with 21 kept, Lavery probe 1666 followed with 247 wounds, Lam 7 studies, Calvo-Wright 18 articles, Aragón 338 patients with 356 infection episodes, Dinh pooled modalities, Llewellyn 36 studies, La Fontaine 166 biopsied, Tone 40 randomised, Gariani 93, Pham 66 episodes, Game 147, Aragón-surgical 185 histologically confirmed, and Lavery-resection 171 from two trials.^{[28][29][30][31][32][33][34][35][36][37][38][39][40][41]} The vascular cohorts contribute the intersocietal 5-plus-5-plus-15 recommendations, GVG PLAN/GLASS, BASIL-2 345 infrapopliteal randomisations, BEST-CLI-diabetes 1777, NSQIP 8887, VQI-Medicare 4218, Campbell 177 limbs, and Andersen 122 conservatively managed limbs — with amputation arithmetic from Thorud pooled transmetatarsals, Jupiter propensity-matched NSQIP, Svensson 410 population amputations, Larsson 187 level selections, Greenfield 46 studies with 32496 partial-foot patients, NPWT Lancet 162, Cochrane 11 trials with 972, DiaFu 368 randomised, Simon 14 Charcot arthrodeses, Elmarsafi 285 reconstructions, Bittante 43 acute Charcot feet, and Lane 60 studies with 12604 ulcers.^{[42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58][59][60][61]}

Clinical Presentation — the painless ulcer, the hot foot, the pale foot

The neuropathic ulcer declares through painlessness: a plantar forefoot ulcer under a metatarsal head or over a deformity in an insensate foot, where repetitive stress the patient cannot feel does the cutting — and half of all ulcers carry this neuroischaemic mix rather than pure neuropathy or pure ischaemia.^[7] The infected foot declares through heat, swelling and probeable depth: deep infection is present in 39% and gangrene in 55% of population minor amputations, with severe ischaemia alongside in 61% — so the hot foot is usually infected first and ischaemic second, and both at once is the rule, not the exception.^[52] The ischaemic foot declares through rest pain, tissue loss and absent pulses: diabetes presents more often with tissue loss at 71 against 47% and clusters in late WIfI stages 3 to 4 at 73.7 against 45.9%, driven by wound and infection grades rather than ischaemia grade — the diabetic limb threatens through wound-plus-infection while the non-diabetic limb threatens through pressure numbers.^[46][45] Charcot declares through the warm, swollen, deformed foot without an ulcer: Eichenholtz stage-0/1 active disease caught early remits in 93% at a mean 5.6 months with major amputation at 2.3% — while reconstruction entered late carries nonunion at odds 8.5 and new Charcot sites at 8.2 toward major amputation.^[60][59]

Differential Diagnosis — ulcer, Charcot, ischaemia, pressure

Split neuropathic from neuroischaemic first: palpate pulses and measure toe pressures in every ulcer, because half of ulcers are neuroischaemic and PAD doubles as the mortality multiplier with hazard 1.882 — the pulse examination reclassifies the ulcer and the prognosis together.^[7][3] Split Charcot from osteomyelitis before committing: the acutely hot, red, swollen Charcot foot mimics infection, but early stage-0/1 disease managed by offloading alone remits in 93% — while premature reconstruction invites nonunion and new-site disease — so image, offload and watch before fusing.^[60][59][58] Split CLTI from the ulcer that merely coexists with PAD: CLTI demands PAD plus rest pain, gangrene or ulceration beyond 2 weeks with venous, traumatic, embolic and non-atherosclerotic causes excluded — and the non-infected ulcer with mild-to-moderate ischaemia heals conservatively in 79.5% at 4.6 months, so not every ischaemic ulcer needs a wire or a bypass.^[43][49] Split the ulcer that starts the amputation from the amputation that starts the ulcer: all but three Apelqvist amputations began as a foot ulcer deteriorating to deep infection or progressive gangrene — prevention and early infection control, not level selection, is where limbs are saved.^[5]

Name the triad aloud before ordering treatment — the viva rewards the candidate who separates what neuropathy decides from what ischaemia and infection decide.^[7][8]

Clinical & Bedside Assessment — pulses, probe, nerves, WIfI grades

Feel pulses and test neurology in every foot: deep infection with palpable popliteal or pedal pulses favours healing below the ankle, while pain, progressive gangrene and intermittent claudication survive logistic regression toward major amputation — yet none of these factors alone excludes a minor amputation, so examine to counsel, never to refuse.^[53] Probe every ulcer to bone: a palpable bone or joint defines the positive test, and in Texas validation the probe-positive wound carries 11-fold amputation odds — the probe is simultaneously a diagnostic test and a prognostic marker.^[29][16] Measure the ulcer against the JAMA rule: area above 2 cm² carries a positive likelihood ratio of 7.2, a positive probe-to-bone 6.4, and an ESR above 70 mm/h a ratio of 11 — three bedside numbers that each move the osteomyelitis probability before any scan.^[28] Grade WIfI at the bedside: wound extent, ischaemia grade and infection severity assign the stage, and the stage assigns the revascularisation-benefit quartile — Q4 limbs face 25.7% one-year amputation against 7.2% in Q1 with a 4.26-fold hazard, so the grade is quoted before the intervention is booked.^[12] Record glycaemia as a risk modifier, not a healing predictor: A1C at 8% or above carries 4.8-fold amputation odds and fasting glucose at 126 or above 1.46-fold, yet A1C shows no association with wound healing itself — and one amputation meta-analysis finds no HbA1c correlation at all — so quote the amputation risk without promising that glucose control heals the wound.^[61][6]

Investigations — probe-plus-X-ray first, MRI with discipline, biopsy as gold

Combine probe-to-bone with plain X-ray before any advanced scan: the sequential approach reaches 0.97 sensitivity with 0.92 specificity and likelihood ratios of 12.8 and 0.02 against histology, and only 6.6% of double-negative patients harbour osteomyelitis — while the pooled meta-analysis puts the combination at 0.94 sensitivity with a diagnostic odds ratio of 82, comparable to MRI and histology, accessible and inexpensive but demanding trained eyes in a high-prevalence unit.^[32][31] Respect prevalence when interpreting the probe: pooled sensitivity 0.87 with specificity 0.83 rules osteomyelitis in for high-risk feet and out for low-risk ones — but in a 12%-prevalence cohort the positive predictive value is only 0.57 against a 0.98 negative value, so the positive test at low prevalence rules little in while the negative test rules out.^[30][29] Order MRI as the preferred test, never the verdict: pooled sensitivity runs 0.90 to 0.96 with specificity 0.79 to 0.84, plain X-ray trails at 0.54 to 0.62 sensitivity, and a normal MRI at likelihood ratio 0.14 makes osteomyelitis much less likely — yet 29.3% of MRI diagnoses go unconfirmed at biopsy with 12 false positives in a single county series, so the scan informs the biopsy conversation instead of replacing it.^{[33][34][28][35]} Confirm with bone: biopsy with culture or histology is the gold standard, and the integrated approach — clinical findings plus radiologist communication plus biopsy — is what the biopsy-proven series prescribes for accurate management.^[28][35] Measure perfusion the GVG way: objective haemodynamic testing with toe pressures as the preferred measure is required for CLTI — and stage limb threat by WIfI rather than perfusion alone, because perfusion is only one determinant of outcome alongside wound extent and infection severity.^[43][8]

Management — Offloading: the non-removable verdict with adherence honesty

Give the IWGDF ladder exactly: for a neuropathic plantar forefoot or midfoot ulcer, a non-removable knee-high device is first choice; a removable knee-high or ankle-high device is second choice where contraindications or intolerance exist; fitting footwear with felted foam is third choice where no devices exist — and failed non-surgical offloading of a plantar forefoot ulcer earns Achilles lengthening, metatarsal head resection, joint arthroplasty or metatarsal osteotomy, while a flexible-toe digital ulcer earns flexor tenotomy.^[18] Give the evidence base exactly: 165 studies with 26 randomised trials, high-quality evidence from 5 meta-analyses and 12 trials that non-removable knee-high devices beat removable devices and therapeutic footwear — with total contact casts and non-removable walkers equally effective, removable knee-high and ankle-high equally healing but knee-high better at pressure and activity reduction, and very limited evidence for heel, non-plantar, infected or ischaemic ulcers.^[19] Give Armstrong TCC exactly: 63 patients with superficial non-infected non-ischaemic plantar ulcers — healing at 12 weeks 89.5% TCC against 65.0% walker and 58.3% half-shoe, odds ratio 5.4 against the pooled others, with TCC patients taking 600 against 1462 daily steps.^[20] Give the adherence proof exactly: 50 Texas-1A ulcers — wrapping the walker into an instant TCC lifts healing from 51.9 to 82.6% with healing time cut from 58.0 to 41.6 days, because the bandage enforces what the prescription cannot.^[21]

Give the honesty trials exactly: Faglia 45 patients finds the removable Stabil-D equivalent to TCC at 73.9 versus 72.7% healing — a small-trial equivalence, not a ladder inversion; Lavery 73 patients finds TCC at 69.6% against 22.2% shear-reducing boot and 44.5% healing sandal with TCC faster at 5.4 against 8.9 weeks; Bus 60 patients finds three removable devices tied at 58, 60 and 70% with adherence gaps and stride counts explaining why removable results trail non-removable history — suboptimal adherence plus high stride counts mean high repetitive stress.^[22][23][24] Give the pooled verdicts exactly: non-removable beats removable at RRp 1.43 and therapeutic shoes at 1.68, TCC equals instant TCC at 1.06 — with the adherence mechanism stated outright — and fibreglass TCC shortens healing by 5.42 days against walkers across 5 trials with 169 participants with trial sequential analysis supporting the signal while calling for better trials.^[25][26]

The offloading resolution: non-removable knee-high by default, removable where the leg or the patient forbids it, footwear-plus-felt where nothing else exists — and surgery where offloading fails.^[18][19]

Management — Infection: the duration ladder with surgical honesty

Give the duration ladder exactly as the study regimens: Tone 40 patients with non-surgically treated osteomyelitis — 6 weeks equals 12 at 12/20 versus 14/20 remission with 65% overall, and gastrointestinal events fall from 45 to 15% on the shorter course, so 6 weeks may suffice where non-surgical treatment is chosen; Gariani 93 patients after surgical debridement — 3 weeks gives 84% remission against 73% at 6 weeks, statistically noninferior; Pham 66 soft-tissue episodes after debridement — 10 days gives 77% against 71% at 20 days, non-inferior — with the tail disclosed: 23% of the 10-day arm and 16% of the 20-day arm recur as new osteomyelitis.^[36][37][38] Give the non-surgical series exactly: 147 specialist-centre osteomyelitis patients — surgery for life-threat, limb-threat or failure in 23% (28 minor, 6 major amputations), the remaining 113 managed mostly as oral-antibiotic outpatients with 58.4% remission induced, 31% relapse, and 82.3% of the initially non-surgical group reaching apparent remission on antibiotics alone with a further course arresting 77% of relapses.^[39] Give the surgical series exactly: 185 histologically confirmed osteomyelitis patients treated within 12 hours with foot-sparing priority — Staphylococcus aureus in 51.3% with methicillin resistance in 35 cases (36.8%), conservative non-amputating surgery in 49.1%, foot-level amputation in 42.4% and major amputation in 8% with 2.7% perioperative mortality — and failure concentrates where bone stays exposed, ischaemia persists or necrotising infection spreads.^[40] Give the margin verdict exactly: 171 post-hoc trial patients — complete resection shortens antibiotics (21 versus 37 days in hospital, 42 versus 50.5 over 12 months) because margin-negative patients more often underwent amputation (89.9 versus 60.9%) — with no difference in same-site ulceration, hospitalisation, reinfection, osteomyelitis recurrence, amputation or healing time, and 86.7 versus 86.5% treated successfully either way.^[41]

The infection resolution: debride and shorten — 6, 3 and 10 are the tested floors for their settings, surgery is for threat or failure, and clean margins buy fewer antibiotic days rather than better 12-month outcomes.^{[36][37][38][41]}

Management — PAD and CLTI: PLAN first, then BASIL-2, BEST-CLI and the conservative tier

Give the burden exactly: roughly half of diabetes-plus-ulcer patients carry PAD, and PAD multiplies adverse limb and cardiovascular risk — behind which the intersocietal guideline sets 5 diagnostic, 5 prognostic and 15 treatment recommendations spanning prioritisation, procedure choice and post-surgical care.^[42] Give PLAN exactly: evidence-based revascularisation hinges on Patient risk, Limb severity and ANatomic complexity — average-risk patients with advanced threat and complex disease favour vein bypass while simpler anatomy, intermediate threat or high patient risk favour endovascular — with target-artery-path GLASS staging, autogenous-vein availability, best medical therapy across antithrombotic, lipid, pressure and glycaemic axes, and long-term limb surveillance after every revascularisation.^[43] Give BASIL-2 exactly: 345 infrapopliteal randomisations across 39 UK plus 2 Scandinavian units — vein-first loses amputation-free survival at adjusted hazard 1.35 with 63 versus 53% events, driven largely by deaths at hazard 1.37, while endovascular-first saves £1690 in hospital costs and dominates on cost-utility — an infrapopliteal verdict, not a whole-leg one.^[44] Give BEST-CLI-diabetes exactly: 1777 revascularised trial patients, 69.2% diabetic — diabetes presents later at WIfI 3–4 in 73.7 versus 45.9% through wound and infection grades, and independently raises above-ankle amputation 1.75-fold, death 1.63-fold and the combined endpoint 1.24-fold at 3 years with MALE-or-death at 53.5 versus 46.4%.^[45]

Give the perioperative reassurance exactly: NSQIP 8887 infrainguinal revascularisations — diabetes brings more tissue loss and more endovascular selection, yet adjusted 30-day mortality ties and adjusted major adverse limb events favour diabetes after bypass at odds 0.7 — so fear of worse bypass outcomes in diabetes is unsubstantiated and should not discourage open bypass.^[46] Give the 5-year split exactly: VQI-Medicare 4218 propensity-matched patients, 62.3% diabetic — death runs 26% lower after bypass than endovascular regardless of diabetes, amputation risk ignores modality at sub-hazard 0.79, and diabetes itself doubles major amputation at sub-hazard 1.98 regardless of cohort or insulin status.^[47] Give the glycaemia modifier exactly: 177 limbs — SVS-defined controlled versus uncontrolled diabetes changes nothing, but each HbA1c increment multiplies limb-loss hazard 1.96-fold with dialysis at 15.37 — so counsel the number, not the label, and warn that elevated HbA1c raises amputation risk despite revascularisation.^[48] Give the conservative tier exactly: 122 non-infected limbs with mild-to-moderate ischaemia in a limb-preservation programme — 79.5% heal at a mean 4.6 months with 3.1% major amputation, recurrence strikes 45.4% but 93.2% of recurrences heal again without revascularisation — so the non-infected ischaemic ulcer earns a monitored healing trial before a wire.^[49]

The revascularisation resolution: stage WIfI, apply PLAN, quote the Q4 warning — and remember WIfI beats angiosome thinking, with wound severity out-predicting direct perfusion at hazard 0.77 against a non-significant 0.82.^[11][12]

Management — Amputation: the most distal healing level with proximal honesty

Give the level-selection honesty exactly: 187 consecutive patients — deep infection with palpable pulses and small-toe, metatarsal-head or midfoot ulcers favour below-ankle healing, while pain, progressive gangrene, claudication and multiple ulcers point above the ankle — yet no factor alone excludes minor healing, so levels are counselled, never dictated.^[53] Give the minor-amputation worth exactly: 410 population amputations with deep infection or gangrene in 94% and severe ischaemia in 61% — 64% heal below the ankle overall and 79% among survivors at a median 26 weeks, with 21% needing above-ankle re-amputation — worthwhile at the price of long healing times.^[52] Give the transmetatarsal discount exactly: pooled reoperation 24.43%, re-amputation 28.37% and major amputation 30.16% — questioning primary transmetatarsal over lesser ray resections — while the all-partial-foot meta-analysis across 46 studies and 32496 patients prices major amputation at 23% overall, 0–10% for digits and metatarsals, 8–54% for transmetatarsal and 11–44% for midfoot, with 16% one-year mortality and re-ulceration to 69%.^[50][54] Give the trade exactly: propensity-matched NSQIP — minor amputations carry 2.5-fold the irrigation-and-debridement odds but roughly half the urinary infection and transfusion odds of major amputation — distal means more wound trips, proximal means more systemic cost.^[51]

Management — NPWT: Lancet promise, Cochrane caution, DiaFu discipline

Give the Lancet exactly: 162 post-partial-amputation wounds with adequate perfusion across 18 US centres — 56 versus 39% healed with faster closure and faster granulation at unchanged adverse events, VAC-delivered.^[55] Give Cochrane exactly: 11 trials with 972 participants — post-operative healing RR 1.44 with 21 days shorter median healing, ulcer healing RR 1.40 with healing hazard 1.82, amputation RR 0.33 — all low-certainty, all downgraded for bias and imprecision, with no data on closure surgery, quality of life or cost-effectiveness.^[56] Give DiaFu exactly: 368 randomised in 40 German foot centres — closure difference 2.5% at P equals 0.53 with no time advantage, 191 participants with missing endpoints or protocol deviations, and more adverse events in the NPWT arm — not superior to moist wound care in real-life practice with documentation deficits dragging the outcome.^[57] The NPWT resolution: efficacious in the explanatory trial, uncertain in the pragmatic one — quote the certainty beside the effect.^[55][56][57]

Management — Charcot: offload early, fuse selectively, quote the reconstruction risks

Give the standard exactly: stage-I Charcot starts with a non-weight-bearing total-contact cast — because malunion still threatens ulceration and operation even when walking is preserved.^[58] Give the early-fusion demonstration exactly: 14 Eichenholtz stage-I tarsometatarsal patients with debridement, reduction, fixation and autograft — all fused, no postoperative ulcerations, assisted weight-bearing at 10 weeks, unassisted at 15, regular shoes at 27, prior walking ability regained — the first demonstration that early operation can restore alignment, from fourteen highly selected patients, not a mandate.^[58] Give the reconstruction risks exactly: 285 diabetic Charcot reconstructions — major amputation follows nonunion at odds 8.5, new Charcot sites at 8.2, PAD at 4.3, renal disease at 3.7, delayed healing at 2.6, postoperative osteomyelitis at 2.4 and each HbA1c point at 1.2.^[59] Give the early-capture dividend exactly: 43 consecutive active stage-0/1 feet, all in TCC or removable knee-high devices with monthly review — 93% remission at 5.6 months with 2.3% major amputation and 7% surgical indication.^[60]

Complications & Pitfalls — the six traps

The prediction trap — quoting a SINBAD total or WIfI stage as an individual prognosis when the IWGDF recommends no system for individual-outcome prediction with evidence certainty low at best; describe the variables, stage the limb, and counsel from trial numbers instead.^[14]

The probe-positive trap — treating a positive probe-to-bone as osteomyelitis proven when its positive predictive value is 0.57 at 12% prevalence; the positive test rules little in, the negative test at 0.98 rules out, and the combination with X-ray is what earns confidence.^[29][32]

The MRI-equals-biopsy trap — cancelling the biopsy on a positive MRI when nearly a third go unconfirmed with a dozen false positives in one county series; MRI is the preferred test and biopsy the gold standard, with the radiologist conversation in between.^[35][28]

The long-course trap — prescribing 12 weeks where 6 suffices, 6 where 3 suffices after debridement, or 20 days where 10 suffices for soft tissue; the tested floors are 6, 3 and 10 with gastrointestinal events halved and no remission lost — while the soft-tissue short course still seeds new osteomyelitis in 23 versus 16%.^[36][37][38]

The Q4-revascularisation trap — wiring a questionable-benefit limb and promising salvage when 1-year amputation runs 25.7% with over half occurring despite patent revascularisation; wound size and infection burden, not the pulse, drive the outcome.^[12]

The definitive-TMA trap — calling a transmetatarsal amputation the final operation when pooled major amputation reaches 30% and partial-foot meta-analysis prices it at 23% with re-ulceration to 69%; consent the proximal ladder and the surveillance plan before the first cut.^[50][54]

Prognosis & Disposition — the numbers that set expectations

^{[1] [3] [4] [5] [18] [20] [21] [32] [33] [35] [36] [37] [38] [44] [45] [12]}

Special Populations — contexts that change the emphasis

The dialysis-dependent foot inherits the worst limb-loss multiplier: dialysis dependence multiplies post-revascularisation limb-loss hazard 15.37-fold against 1.96 per HbA1c increment — so the dialysis patient is counselled for salvage fragility even with a technically perfect revascularisation.^[48] The Charcot foot inherits offload-first management: early stage-0/1 disease in a cast remits in 93%, while late reconstruction risks nonunion-driven amputation — so the deformed-but-uninfected foot is watched in plaster, not rushed to theatre.^[60][59] The infected ischaemic foot inherits staged honesty: nearly 60% of admitted infected feet need minor amputation to control infection before revascularisation, and PAD with WIfI benefit-stage-3 or high Wagner scores multiply amputation risk — so infection control precedes perfusion promises.^[13] The healed foot inherits lifelong surveillance: recurrence is flat across eras at 22% per person-year and prior amputation steepens every future curve — so discharge means a surveillance programme, not a goodbye.^[4][5] The poorly controlled diabetic leg inherits number-based counselling: uncontrolled-by-label changes nothing, but the HbA1c value itself predicts limb loss — so the conversation quotes the number beside the revascularisation plan.^[48][61]

Evidence, Guidelines & Regional Differences — the five stories and who led them

The burden story is Zhang-to-Carollo: global prevalence at 6.3% with male and North-American excess, refreshed by 89-study pooled incidence and prevalence with American and African rates above average — while mortality halves the cohort by 5 years through cardiovascular disease and infection.^[1][2][3] The classification story is Mills-to-IWGDF: diabetes was designed out of the old ischaemia systems, WIfI reunites wound, ischaemia and infection, Texas validates depth-plus-stage, Lima ranks the four systems head-to-head, and the IWGDF assigns each system its job — SINBAD for talk, none for individual prediction, SINBAD-score for audit.^{[8][16][17][14]} The offloading story is Armstrong-to-IWGDF: two small randomised trials prove the cast and the adherence mechanism, three honesty trials bound the exceptions, two meta-analyses pool the verdict, and the guideline writes the ladder.^{[20][21][22][23][24][25][26][18]} The infection story is JAMA-to-trials: bedside likelihood ratios frame the pre-test probability, probe-plus-X-ray matches MRI accessibly, biopsy arbitrates, and three duration trials shorten every course while two surgical series split threat-surgery from remission-without-surgery.^{[28][32][35][36][37][38][39][40]} The vascular story is GVG-to-BEST-CLI: PLAN and GLASS organise the decision, BASIL-2 answers infrapopliteal strategy, the diabetes analysis prices the wound-and-infection presentation penalty, VQI splits 5-year death from amputation by modality, and the conservative tier defends monitored healing without wires.^{[43][44][45][47][49]} The stated honesty of this set: no guideline PDF bytes were fetched, so every recommendation above is the guideline abstract's own words and every number belongs to a trial, meta-analysis or cohort abstract — regional service patterns vary, so name the study beside every protocol claim.^[18][27][42]

Exam Pearls — the one-liners that score

• Burden: prevalence 6.3%, men 4.5 vs women 3.5%; incidence 10.93/1000py ulcers, 3.58 amputations; survival 86.9/66.9/50.9/23.1%.^[1][2][3]
• Recurrence: 22.1%/py flat across eras; 34/61/70% at 1/3/5 years; amputations start as ulcers; prior amp quadruples.^[4][5]
• Types: neuropathic 35, ischaemic 15, neuroischaemic 50%; 85% of amputations ulcer-preceded; SINBAD six variables.^[7]
• WIfI: wound-plus-ischaemia-plus-infection because perfusion alone never decides; stage 3/4 concentrate amputations; multidisciplinary stage-4 heals at 5.7% amputation.^[8][9][10]
• WIfI-vs-angiosome: 57.2 vs 77.3% healing, HR 0.77 vs 0.82ns; Q4 amputation 25.7% with HR 4.26 despite patent wires.^[11][12]
• IWGDF class: SINBAD first for talk, WIfI alternative, none for individual prediction, SINBAD-score for audit; evidence low at best.^[14][15]
• Texas: depth-plus-stage trend; probe-positive OR 11.1; infection-plus-ischaemia OR 89.6; Lima AUROC SE 0.90, UT/MW 0.81, SINBAD 0.74.^[16][17]
• Offloading: non-removable first, removable second, footwear-felt third, surgery on failure; TCC=iTCC-class walkers; heel/ischaemic/infected evidence very limited.^[18][19]
• TCC trials: 89.5/65/58.3 with OR 5.4; iTCC 82.6/51.9 and 41.6/58 days; Faglia equivalence 73.9/72.7; F-TCC minus 5.42 days with TSA.^{[20][21][22][26]}
• Osteomyelitis bedside: ulcer over 2 cm² LR 7.2, probe LR 6.4, ESR over 70 LR 11, X-ray LR 2.3; biopsy gold; probe PPV 0.57/NPV 0.98 at 12%.^[28][29]
• Probe-plus-X-ray: 0.97/0.92 with LR 12.8/0.02; pooled 0.94 with DOR 82; MRI 0.90/0.79, X-ray 0.54/0.68; 29.3% MRI unconfirmed.^{[32][31][33][35]}
• Durations: 6=12 weeks at 65% with fewer gut events; 3=6 post-debridement at 84/73%; 10=20 days soft tissue at 77/71% with 23/16% new-osteomyelitis tail.^[36][37][38]
• Osteomyelitis surgery: non-surgical remission 82.3% without threat; surgical S. aureus 51.3% with 36.8% resistant; clean margins shorten antibiotics, not 12-month outcomes.^[39][40][41]
• CLTI: PAD in half of ulcer feet; PLAN three axes; toe pressures preferred; BASIL-2 endo-first AFS win; BEST-CLI diabetes amp 1.75, death 1.63.^{[42][43][44][45]}
• Revasc honesty: bypass 30-day fears unsubstantiated; 5-year death lower with bypass, amputation modality-blind, diabetes doubles amputation; HbA1c per-point HR 1.96.^[46][47][48]
• Amputation: counsel levels, never dictate; minor heals 64% overall, 79% in survivors; TMA major 30%, PFA meta 23%; distal wound trips vs proximal systemic cost.^{[53][52][50][54][51]}
• NPWT: Lancet 56/39%; Cochrane low-certainty RR 1.40/1.44 with amp RR 0.33; DiaFu not superior with 191 missing endpoints.^[55][56][57]
• Charcot and glucose: TCC first; 14 fused with no ulcers; reconstruction risks nonunion 8.5; early capture 93% remission; A1C 8-plus OR 4.80, no healing link.^{[58][59][60][61]}

pooled 22.1%/py flat across eras; Apelqvist 34/61/70% new ulcers at 1/3/5 years with amputation 3/10/12% after primary healing vs 13/35/48% after amputation; all but three amputations start as deteriorating ulcers (PMIDs 30916434/8501419).^[5] ulcer over 2 cm² LR 7.2, probe-to-bone LR 6.4, ESR over 70 LR 11, abnormal X-ray LR 2.3, MRI positive LR 3.8 and normal MRI LR 0.14 with 89% accuracy; biopsy is gold; no history excludes (PMID 18285592).^[28] Combine probe with X-ray exactly: sequential 0.97/0.92 with LR 12.8/0.02 and 6.6% double-negative disease at 72.4% prevalence; pooled 0.94 with DOR 82, MRI-comparable, cheap, expertise-dependent (PMIDs 21219428/37629412).^[32] Beat angiosome thinking exactly: WIfI healing 57.2 vs 77.3% with HR 0.77 vs perfusion HR 0.82ns; Q4 amputation 25.7% at HR 4.26 with 56.3% patent at amputation — wound/infection burden decides (PMIDs 29803684/33813024).^[12]

References61ShowHide

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