01OverviewDefinition, clinical context and the essential points that orientate the chapter.
Charcot neuroarthropathy is an inflammatory fracture-dislocation process in a neuropathic foot, usually from diabetes. Ask about timing, minor trauma, temperature or shape change, ulcer, infection, renal replacement therapy, glycaemic control and injury sensation. Pain may be slight and walking can continue after normal initial radiographs. Every unprotected step can worsen fragmentation and deformity.
Compare bare feet. Document temperature at matched sites after acclimatisation and inspect colour, oedema, arch, prominence, callus, ulcer and shoe wear. Test protective sensation, pulses and refill and examine for spreading infection and DVT. Palpate gently without repeatedly stressing an unstable foot. Record ulcer depth and exposed or probe-accessible bone when trained. Assess systemic physiology despite modest pain.
Obtain weight-bearing foot and ankle radiographs when safe because subluxation may appear only under load; never force standing in an unstable patient. Early active disease may show no fracture. MRI detects marrow oedema, microfracture and soft-tissue infection and is preferred when suspicion remains after normal radiographs. CT maps fragmentation for surgical planning. Nuclear imaging has selected use when MRI is contraindicated or infection remains unresolved.
Charcot versus osteomyelitis is not solved by one test. Infection is more likely when an ulcer tracks to the same bone, pus, systemic signs or focal contiguous marrow change exists. Charcot more often affects several joints and periarticular bone with intact skin, yet both can coexist. FBC and CRP may be normal in either early Charcot or infection. When a definitive microbiological diagnosis is needed, aseptically obtained bone for culture and histology is the reference standard, not a superficial swab.
Offloading is immediate treatment. Keep the patient non-weight-bearing initially and arrange safe transport and mobility aids. A trained multidisciplinary service applies a well-moulded non-removable knee-high total-contact cast when suitable, distributing pressure and limiting joint motion. Frequent cast changes accommodate oedema and permit skin inspection. Use a removable knee-high walker when infection monitoring, ischaemia, fluctuating swelling, skin risk or patient safety makes a cast unsuitable, while recognising adherence is critical.
Continue active-phase treatment until warmth and swelling settle and serial specialist measures indicate remission; a single normal temperature reading is not enough. The process often takes months. Gradually reintroduce protected weight-bearing into custom-moulded footwear, an ankle-foot orthosis or Charcot restraint orthotic walker according to location and stability. Inspect the contralateral foot and hands because crutches and load transfer create additional injury. Assess VTE risk during prolonged lower-limb immobilisation.
Antibiotics are used only for clinical infection and selected from NICE diabetic-foot severity, cultures, renal function and local resistance. Drain abscess and debride necrotic tissue promptly; antibiotics cannot correct instability or devitalised bone. NICE does not support routine bisphosphonates as a replacement for immobilisation. Optimise glucose, nutrition, smoking and renal disease and involve vascular services early when perfusion is impaired. Avoid walking programmes and routine physiotherapy loading during active inflammation.
Surgery is complex and multidisciplinary. Indications include non-braceable instability, recurrent ulcer over a prominence, severe non-plantigrade deformity, infection requiring resection and threatened skin. Exostectomy may unload a focal consolidated prominence; arthrodesis and internal or external fixation reconstruct unstable columns. Operate after inflammation and infection control when possible. Hardware failure, non-union, wound breakdown and amputation remain substantial risks, so the goal is a stable plantigrade ulcer-free foot rather than normal anatomy.
Peripheral arterial disease can coexist with a warm foot and falsely normal ankle pressure from calcification. Use Doppler waveforms, toe pressures and vascular input for tissue loss or poor healing. Older or immune-compromised patients may lack fever. Pregnancy changes imaging and thromboprophylaxis, not immediate offloading. Coordinate anticoagulation around casting or surgery without permitting destructive weight-bearing.
Key points
- Suspect active Charcot neuroarthropathy when a person with neuropathy develops unilateral foot warmth, swelling, redness or shape change, often after minor or unremembered trauma and with surprisingly little pain.
- First-line action precedes imaging: make the patient non-weight-bearing, immobilise in a knee-high device and refer to the multidisciplinary foot-care service within one working day.
- Assess infection and perfusion at the same encounter; Charcot disease, ulcer infection, osteomyelitis and peripheral arterial disease can coexist rather than being mutually exclusive.
- First-line imaging is weight-bearing foot and ankle radiography when safe, but normal early films do not exclude active disease; obtain MRI when suspicion remains and radiographs are normal or infection is uncertain.
- A non-removable knee-high total-contact cast is the reference offloading method when trained services, skin and perfusion allow; use a safe removable knee-high alternative when monitoring or contraindications require it.
- Continue immobilisation and offloading until clinical inflammation has resolved and temperature and imaging are stable under specialist criteria, then transition gradually into custom footwear or Charcot restraint orthotic support.
- Do not use antibiotics for warmth alone, and do not use bisphosphonates routinely as a substitute for offloading; treat proven infection with deep sampling and source control.
- Consider reconstruction for instability, non-plantigrade deformity or recurrent ulceration that cannot be accommodated, after active inflammation, infection and perfusion have been addressed.
02AetiologyUnderlying causes, associations and risk factors, with why each one matters.
Diabetic neuropathy
Diabetes is the commonest UK cause, with loss of protective sensation and autonomic and motor changes allowing repetitive injury to continue without warning pain.
Other neuropathies
Alcohol-related, spinal, syringomyelia, leprosy and other sensory neuropathies can produce Charcot joints when protective feedback is sufficiently impaired.
Minor trauma and surgery
An unremembered sprain, fracture, ulcer procedure or foot surgery can initiate inflammatory collapse in an insensate limb.
Renal and bone vulnerability
Renal replacement therapy, osteoporosis, glycaemic burden and previous ulcer or amputation increase foot fragility and complicate healing and reconstruction.
03PathophysiologyThe causal sequence from the underlying abnormality to symptoms and harm.
- 1Unperceived repetitive injury
Loss of pain and proprioception permits continued loading through fractures and ligament injury, creating a cycle of instability and further damage.
- 2Inflammatory bone resorption
Trauma triggers an exaggerated cytokine and osteoclast response, producing osteopenia, fragmentation and rapid joint destruction while the foot remains warm.
- 3Subluxation and collapse
Ligament failure and fractures allow midfoot, hindfoot or ankle joints to dislocate and arch architecture to collapse under continued weight-bearing.
- 4Rocker-bottom pressure
Midfoot collapse creates a plantar bony prominence, concentrating pressure beneath poorly protected skin and leading to callus, ulcer and osteomyelitis.
- 5Remodelling and residual deformity
Inflammation eventually cools and bone consolidates, but fixed malalignment remains and can be unbraceable or recurrently ulcerating without long-term protection.
04Clinical features and red flagsSymptoms, examination findings, patterns of presentation and time-critical warnings.
Unilateral warmth, oedema and erythema with loss of protective sensation is the defining early warning pattern even when pain is mild.
A reproducible difference from the contralateral matched site supports active inflammation and helps monitor trend, but no single cut-off proves diagnosis or remission.
Stage-zero disease can have normal plain films despite MRI microfracture and marrow inflammation, so normal radiographs must not restart weight-bearing.
Midfoot fragmentation and arch reversal create a convex plantar prominence that drives callus, ulceration and difficulty fitting footwear.
An ulcer leading to bone, pus, systemic illness or focal contiguous marrow change raises osteomyelitis, which can exist alongside Charcot destruction.
Warmth does not guarantee adequate arterial supply; tissue loss, weak pulses and abnormal waveforms require vascular assessment.
05InvestigationsWhat to request, why it matters and how to interpret it.
Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.
- 01
First-line bilateral foot and systemic assessmentFirst stepFirst line - Why
- Identify active inflammation, neuropathy, ulcer infection, sepsis and perfusion threat before imaging.
- Interpretation and limitations
- Clinical suspicion alone is enough to begin non-weight-bearing immobilisation; lack of pain or fever is not reassuring.
- 02
First-line weight-bearing foot and ankle radiographs when safeFirst line - Why
- Detect fracture, subluxation, fragmentation, collapse, gas and bony destruction and provide an alignment baseline.
- Interpretation and limitations
- Normal early films do not exclude active Charcot; unsafe or grossly unstable feet should not be forced to stand.
- 03
MRI foot and ankle - Why
- Detect radiographically occult active Charcot change and map marrow, ulcer tract, abscess and possible osteomyelitis.
- Interpretation and limitations
- Diffuse periarticular oedema supports Charcot, while focal contiguous change beneath an ulcer supports infection, but overlap requires multidisciplinary interpretation.
- 04
CT for architecture and reconstruction - Why
- Define cortical fragmentation, joint alignment, fusion surfaces and sequestra when operative planning requires bone detail.
- Interpretation and limitations
- CT is less sensitive for early inflammatory marrow change and does not replace MRI or clinical offloading decisions.
- 05
Reference bone culture and histology when osteomyelitis remains decisive - Why
- Establish microbiology and tissue diagnosis when infection status will change prolonged antibiotics or reconstruction.
- Interpretation and limitations
- Obtain aseptically through intact skin or at surgery when feasible; superficial ulcer swabs are not equivalent to bone sampling.
- 06
Doppler waveform and toe-pressure assessment - Why
- Identify peripheral arterial disease that affects healing, casting and reconstruction.
- Interpretation and limitations
- Medial arterial calcification can make ankle indices falsely high; combine waveforms, toe measures and vascular judgement.
- 07
FBC, CRP, renal profile, glucose and blood cultures - Why
- Assess infection severity, metabolic instability and medicine safety and identify bacteraemia when systemic illness is present.
- Interpretation and limitations
- Normal inflammatory markers do not exclude infection or active Charcot; renal function changes imaging, antibiotic and thromboprophylaxis choices.
06Differential diagnosisRealistic alternatives and the features that help distinguish them.
Cellulitis and deep infection
Skin portal, purulence, systemic illness and focal soft-tissue spread support infection, but absence of fever and normal markers do not exclude it in diabetes.
Osteomyelitis
An ulcer over bone, positive probe-to-bone finding and focal contiguous marrow change increases probability; Charcot and bone infection can coexist and mimic each other on MRI.
Gout or inflammatory arthritis
Acute joint pain and crystals can mimic warmth, but neuropathic architecture, ulcer and infection still require assessment and crystals do not exclude bacteria.
Deep-vein thrombosis
Unilateral leg swelling and thrombotic risk requires venous assessment, especially during immobilisation, although DVT does not explain bony collapse.
Acute fracture or sprain
Trauma in a sensate foot causes proportionate pain, but any fracture in neuropathy may trigger Charcot activity and requires protected specialist care.
07ManagementImmediate care, first-line treatment, alternatives and escalation.
01ImmediateOffload before confirmationFirst stepA neuropathic foot becomes unilaterally hot, swollen, red or newly deformed.+
- 1Stop weight-bearing, provide safe transport and immobilise in a knee-high device that protects current alignment and skin.
- 2Inspect for ulcer and spreading infection and assess systemic physiology, glucose, sensation, pulses and the other foot.
- 3Obtain weight-bearing radiographs only when safe and arrange MRI when films are normal but suspicion remains.
- 4Refer to the multidisciplinary foot-care service within one working day, immediately to acute care for limb- or life-threatening disease.
02Active phaseImmobilise until inflammation resolvesThe multidisciplinary service confirms or continues to suspect active Charcot neuroarthropathy.+
- 1Use a non-removable knee-high total-contact cast when expertise, skin and perfusion permit, with frequent fit and skin review.
- 2Use a removable knee-high walker when clinical monitoring or contraindication requires it and support adherence explicitly.
- 3Monitor temperature trend, oedema, skin, radiographs and device pressure over months rather than using pain as the guide.
- 4Assess VTE, falls, contralateral foot and upper-limb loading risks throughout prolonged immobilisation.
03Infection branchTreat sepsis and preserve tissueUlcer, purulence, systemic illness, abscess, necrosis or suspected osteomyelitis accompanies Charcot change.+
- 1Grade infection and obtain deep tissue or bone cultures when safe without delaying antimicrobials in sepsis.
- 2Drain abscess, debride non-viable tissue and involve vascular services when perfusion limits healing.
- 3Use MRI and bone sampling selectively to distinguish and map infection when management depends on it.
- 4Narrow antibiotics with microbiology and keep mechanical offloading active because infection treatment alone does not stabilise the foot.
04Remission and reconstructionTransition to durable protectionInflammation settles or consolidated deformity remains unstable, ulcerating or unbraceable.+
- 1Confirm clinical and imaging stability under specialist criteria before slowly increasing protected weight-bearing.
- 2Provide custom footwear, total-contact insole, ankle-foot orthosis or Charcot restraint device and inspect all pressure sites.
- 3Consider exostectomy or reconstruction for recurrent ulcer, non-plantigrade deformity or instability after infection and perfusion optimisation.
- 4Maintain lifelong high-risk foot surveillance because neuropathy and recurrence risk persist after cooling or surgery.
Key medicines and prescribing safety2 treatments · regimens, roles and cautions+
Flucloxacillin for selected mild diabetic-foot infection
When clinical infection is mild and oral treatment is appropriate, give flucloxacillin 500 mg to 1 g orally four times daily for 7 days, then review response and microbiology; the 1 g four-times-daily dose is off label.Antibiotics are not indicated for sterile Charcot warmth; admit severe infection, check allergy, liver and renal function and interactions, and obtain drainage, deep samples and vascular care when required.
VTE prophylaxis during immobilisation when risk outweighs bleeding
Use the local prophylactic low-molecular-weight heparin or fondaparinux regimen after weight, renal function, pregnancy, platelet and bleeding review, following NICE NG89 and considering stopping when lower-limb immobilisation continues beyond 42 days.Do not prescribe automatically; review active ulcer bleeding, renal impairment, other antithrombotics, falls and procedures, and give urgent advice for bleeding, calf swelling or breathlessness.
08ComplicationsImportant consequences, why they occur and why they matter clinically.
Rocker-bottom deformity
Midfoot collapse creates an unstable convex plantar surface that is difficult to shoe and vulnerable to recurrent pressure injury.
Ulcer and osteomyelitis
Prominent bone beneath neuropathic skin drives progressive breakdown, contiguous infection and repeated hospital admissions or debridement.
Amputation
Infection, ischaemia, non-reconstructible instability and recurrent ulceration can culminate in major or minor limb loss and increased mortality.
Contralateral injury
Offloading shifts pressure to the opposite foot and upper limbs, risking ulcer, fracture and falls without careful mobility and skin surveillance.
Treatment complications
Casting can cause pressure ulcer, thrombosis and falls, while reconstruction has high risks of infection, hardware failure, non-union and recurrent deformity.
09Monitoring and follow-upTreatment response, safety checks and longer-term review.
- Compare temperature at standard matched sites after acclimatisation, alongside oedema, colour and clinical trajectory rather than one isolated threshold.
- At every cast or walker review, inspect all skin, ulcer sites, device edges, perfusion and contralateral pressure areas.
- Repeat weight-bearing radiographs when safe to follow alignment and consolidation and use MRI for unresolved activity or infection questions.
- Track glucose, renal function, infection markers and cultures when clinically indicated, remembering normal values do not clear the foot.
- Reassess VTE, falls, mobility aids, home access and upper-limb load throughout non-weight-bearing care.
- After remission, maintain lifelong footwear, podiatry and rapid-access review for new warmth, blister, callus, ulcer or shape change.
10Special situationsVariants, exceptions and circumstances that change the usual approach.
Pain is an unreliable guard
Neuropathy removes the symptom that normally stops loading, so modest discomfort can coexist with extensive fractures and joint instability.
Offloading is diagnostic protection
Immobilising immediately prevents avoidable collapse while imaging and multidisciplinary assessment determine whether active Charcot is present.
Warm does not mean well perfused
Inflammatory hyperaemia can coexist with peripheral arterial disease, and calcified ankle vessels can make pressure ratios falsely reassuring.
Charcot and infection coexist
An ulcer can seed osteomyelitis into an already neuropathic collapsing foot, so clinicians should not force a mutually exclusive diagnosis.
The other foot becomes the load foot
Non-weight-bearing transfers stress contralaterally, making daily inspection, footwear and mobility planning essential on both sides.
Cooling is not cure
Inflammation can remit while deformity and neuropathy remain, requiring lifelong accommodation and rapid response to recurrent heat or skin injury.
11Common pitfallsFrequent interpretation and management errors.
- 01
Reassuring from mild pain, normal CRP or normal early radiographs and allowing continued weight-bearing.
- 02
Treating all warmth as cellulitis with antibiotics while failing to immobilise a collapsing foot.
- 03
Assuming Charcot and osteomyelitis cannot coexist beneath an ulcer.
- 04
Using a total-contact cast without adequate perfusion, skin expertise and frequent pressure review.
- 05
Starting bisphosphonate or physiotherapy loading as a substitute for immediate mechanical offloading.
- 06
Ending protection after one cooler visit without specialist confirmation of sustained remission and stable imaging.