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Foot and Ankle FRCS > Diabetic Foot Charcot Neuropathy > Flashcards

Diabetic Foot Charcot Neuropathy Flashcards

1
Q

What is Charcot foot?

A
  • A CHRONIC AND PROGRESSIVE JOINT DISEASE after LOSS OF PROGRESSIVE SENSATION
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2
Q

What does charcot foot lead too?

A
  • Destruction of joints and surrounding bony structures
  • May require Amputation if left untreated
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3
Q

What is the epidemiology of Charcot foot?

A
  • 0.1-1.4% of pt w diabetes
  • 7.5% with diabetes and neuropathy
  • Presents type 1 DM age 5th decade ( 20yrs from DX)
  • Present type 2 - in 6th decade ( 5-10 yrs from DX)

location

  • Foot and ankle
    • 9-35% bilateral disease
  • Shoulder and elbow
  • knee
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4
Q

Which joints does Charcot effect?

A
  • Foot and ankle 9-35% have bilat disease
  • Shoulder and elbow
  • Knee -> ligamentous laxity
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5
Q

What are the risk factors for Charcot ?

A
  • **Diabetic Neuropathy **
  • xs ETOH
  • Leprosy
  • Myelomeningogcele
  • Tabes Dorsalis/Syphilis
  • Syringomyelia
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6
Q

What is the pathophysiology of Charcot?

A
  • NEUROTRAUMATIC
      • insensate joint subjected to REPETITIVE MICRO TRAUMA
    • body unable to adopt mechanism to protect due to abnormal sensation
  • NEUROVASCULAR
    • ​autonomic dysfunction increases blood flow thru Av shunting -> bone absorption and weakness
    • ? INFLAMMATORY CYTOKINES IL10, TNF ALPHA
    • lead to increased production of transcription factorKB, rank/rankl/opg triad pathway
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7
Q

Do you know any classifications?

A
  • EICHENHOLTZ
  • Stage O= Joint oedema, radiographs are negative, bone scan positive in all stages
  • Stage 1 FRAGMENTATION= Joint oedema
    • ​radiographs= osseous fragementation with joint dislocation - see pic
  • ​​​Stage 2= COALESCENCE
    • ​decrease bone oedema
    • xray- coalescence of fragments and absorption of bone debris
  • Stage 3= RECONSTRUCTION
    • no local oedema
    • xray- consolidation & remodelling of fracture fragments
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8
Q

What are the PC of someone with a charcot joint?

A
  • Swollen foot and ankle
  • PAIN 50%,
  • PAINLESS 50%
  • Loss of function
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9
Q

What do you find on examination?

A
  • Acute
    • Swollen
    • Warm
    • Erytherma- decrease with elevation cf infection
  • Chronic
    • Structurally deformed foot
    • rocker bottom deformity- see pic
    • pes planus
    • bony prominence
    • Lack of sensation- semmes- weinstein testing
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10
Q

What do you see on X-rays ?

A
  • Acute- degenerative changes may mimic OA
  • chronic-
    • ​obliterated joint space
    • Fragmentation of bony surface-> subluxation/dislocation
    • HERETROPHIC OSSIFICATION
    • scattered bone in soft tissue swelling
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11
Q

Are bone scans helpful in charot ?

A
  • Yes to identify presence of superimposed osteomyelitis
  • Technetium- maybe positve for neuropathic joint and osteomyelitis
  • Indium wc- cold neuropathic but hot for osteomyelitis
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12
Q

Are MRI scans helpful?

A
  • Yes identify abscess from soft tissue swelling
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13
Q

Are biopsy useful in charot joints?

What investigations are also helpful?

A
  • Yes
  • Can guide antibiotic tx in cases of osteomyelitis or soft tissue abscess
  • FBC/ESR- both elevated in infection/Charcot arthropathy
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14
Q

What are the tx options for charcot arthropathy?

A
  • TOTAL CONTACT CASTING- Cast changed 2-4 wks for 2-4 months
  • Orthotics- charcot restraint walker boot used after contact casting
  • SHOE WEAR MODIFICATIONS- double rocker reduce risk of ulceration
  • Medication- bisphosphonates, topical anaesthetics, antidepressants
  • Outcomes 75% success rate

Operative

  • Resection of bony prominence (exostectomy) & TAL
    • ​Braceable foot w equinus deformity + focal bony prominenece= skin breakdown
    • Joint stability good
    • Aim achieve a plantigrade foot that allows ambulation
  • Arthrodesis and osteotomies
    • ​severe defoemities, unstable joints that are non braceble
    • v high complx rate 70%
  • Amputation
    • ​failed surgery, infection
    • goal is partial/limited amputation if vascularity allows
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15
Q

Describe the surgical technique for arthrodesis in charcot foot?

A
  • Fixation technique
    • Screws/plates & tibiocalcaneal nail
    • ex fix - bone quality poor
    • post op minimal weight bear 3 months
  • High complication rate up tp 70%
    • Infection
    • hardwear malposition
    • recurrent ulceration
    • fracture
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16
Q

What is epidemiology of diabetic foot ulcers?

A
  • 12% of diabetics have foot ulcers
  • most common medical complication causing diabetics to seek medical attention
  • Responsible for 85% of lower extremity amputations
17
Q

What are the risk factors fo diabetic foot ulcers?

What are the varibles predictive of poor healing in daibetic foot ulcers?

A
  • Factors associated with decreased healing potential
    • Uncontrolled Hyperglycaemia
    • inability to offload the affected area
    • poor circulation
    • infection
    • poor nutrition
      *
18
Q

Name the factors associated with increased healing potential?

A
  • Serum albumin >3.0g/L
  • Total lymphoycte count >1,500/mm3
19
Q

What are the varibles predictive of poor healing in daibetic foot ulcers?

A
  • Transcutanous o2 pressure <20mmHg
  • Ankle brachial pressure index <0.45
  • Albumin <3.0g/L
  • Total lyphocytes <1,500/mm3
20
Q

What is the pathophysiology of diabetic foot ulcers?

A
  • Neuropathy
    • largest effect
    • sensory dysfunction-> lack of protective sensation-> ulcer
    • autonomic dysfunction-> drying of skin due to lack of normal glandular function
    • increased mechanical & axial stress on skin more prone to injury due to drying
  • Angiopathy
    • Iesser effect than neuropathy
    • >60% of diabetic ulcers have decreased blood flow due to peripheral vascular disease
21
Q

Name any associated conditions of diabetic foot neuropathy?

A
  • Infection/Osteomyelitis
  • High rates of osteomyelitis 67% if bone is probed or exposed at base of ulcer
  • organisms
    • Usually polymicrobal
    • gram positive- aerobic gram positive cocci- s. aureus- STAPH AUREUS
    • gram negative- found in chronic wounds
    • Anerobes- obligate pathogens with ischaemia/gangrene
22
Q

Can you name and decribe a classification system of diabetic foot ulcers?

A
  • Wagner
  • Grade 0 - skin intact but bony deformities leads to foot at risk
    • shoe modification with serial exams
  • Grade 1- superificial ulcer
    • office debridment and contact casting
  • Grade 2- deeper , full thickness extension
    • Operative formal debridment and contact casting
  • Grade 3- Deep abscess formation/oseomyelitis
    • Operative formal debridment & contact casting
  • Grade 4- Partial Gangrene of forefoot
    • Local vs larger amputation
  • Grade 5- Extensive gangrene
    • Amputation
23
Q

What are the symptoms and signs of diabetic foot ulcer?

A

Symptoms

  • Often painless- unable to feel Semmes- weinstein monofilament 5.07

Signs

  • Depth of ulcer- probe
  • presence of infection- cellulitis, pus, gangrene
  • excess achilles tendon tightness- exacerbate ulcers by fixed plantarlexion
    • Silverskold test-
    • improved ankle dorsiflexion with knee flexion= Gastronemius tightness
    • equivalent ankle dorsiflexion wiht knee flexion/extension = achilles tight
  • Acess circulation
24
Q

What studies may add you in daignosis of diabetic foot ulcer?

A
  • If no peripheral pulses
  • Transcutanous oxygen pressure TcpO2
    • consider gold standard to assess wound healing potential
    • >30mmHG or 40mmhg is good sign healing
  • ​ABIs
    • ​calcification in vessels-> inaccurate reading
    • elevates the ABI due to decreased compliance of calcifiec vessels
    • index of 0.45 & toe pressure >40mmHg are needed to heal an ulcer
25
Q

What imaging may be of assisting in diabetic foot ulcers?

A
  • Xrays
    • AP, lateral , oblique of foot and ankle
  • MRI
    • best in differentiatinb abscess from soft tissue swelling
    • difficult to differentiate infection from Charcot arthropathy on MRI
  • Bone Scan
    • Tc99m
    • useful to ddx soft tissue, infection and charcot arthopathy
26
Q

What is the tx of diabetic foot ulcers?

A

Factors to consider-

  • angiopathic vs neuropathic
  • Deep vs superifical
  • osteomyelitis
  • pyarthrosis

Non operative

  • Shoe modification
    • Deep wide shoes, custom insoles, rocker bottom soles ( reduced plantar pressure on foot)
  • Wound care
    • provide moist environment, absorb excudate, act as barrier, off load pressure on ulcer
  • Total Contact Casting
    • Gold standard for mechanical relief plantar ulceration
    • CI= infection, marginal arterial supply to area, pt unbel to comply / tolerate cast
    • ulcers reoccur 3-4 weeks post cast removal
  • Antibiotics tailored to bone biopsy culture results if osteomyelitis

Operative

  • Surgical debridment, antibiotics , local wound care, total contact casting
    • grade 3 or > undergo I&D w antibiotic tx before casting
    • TTC for 4 months then charcot retraint walker then custom shoe.
  • Osteotomy +/- TAL
    • bony prominence -> internal pressure
  • Partial Calcanectomy +/- TAL
    • ​Large heel ulcers w assoc calcaneal Ostemyelitis
    • preserves limb length & decrease morbdity cf higher level amputations
  • Syme amputation
    • ​I= forefoot gangrene & palpable post tibial artery pulse
27
Q

What does a syme amputation include?

A
  • Ankle disarticulation
  • removal of malleoli
  • anchoring heel pad to weight bearing surface- must have a viable heel pad- branches of posteriot tibial artery= NB important palpable POST TIBIAL PULSE

Foot and Ankle FRCS (31 decks)

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