Summary Diabetic Charcot Neuropathy is a chronic and progressive disease that occurs as a result of loss of protective sensation which leads to the destruction of foot and ankle joints and surrounding bony structures. Diagnosis can be made clinically with a warm and erythematous foot with erythema that decreases with foot elevation. Radiographs often reveal obliteration of joint space and fragmentation of both articular surfaces of a joint leading to subluxation or dislocation. Treatment is a trial of total contact casting for acute charcot deformities without skin breakdown. Operative management is indicated for recurrent infections, deformities, and severe skin breakdown. Epidemiology Incidence 0.1-1.4% of patients with diabetes 7.5% of patients with diabetes and neuropathy Demographics age bracket type 1 diabetes typically presents in 5th decade (20-25 years following diagnosis) type 2 diabetes typically presents in 6th decade (5-10 years following diagnosis) Anatomic location foot and ankle (diabetic Charcot foot) 9-35% have bilateral disease shoulder and elbow knee often leads to ligamentous instability and bone loss Risk factors diabetic neuropathy alcoholism leprosy myelomeningocele tabes dorsalis/syphilis syringomyelia Etiology Mechanism and pathophysiology theories neurotraumatic insensate joints subjected to repetitive microtrauma body unable to adopt protective mechanisms to compensate for microtrauma due to abnormal sensation neurovascular autonomic dysfunction increases blood flow through AV shunting leads to bone resorption and weakening molecular biology inflammatory cytokines may cause destruction IL-1 and TNF-alpha lead to increased production of transcription factor-kB RANK/RANKL/OPG triad pathway Associated conditions orthopaedic manifestations foot ulcerations Classification Brodsky Classification Type 1 Involves tarsometatarsal and naviculocuneiform joints Collapse leads to fixed rocker-bottom foot with valgus angulation 60% Type 2 Involves subtalar, talonavicular or calcaneocuboid joints Unstable, requires long periods of immobilization (up to 2 years) 10% Type 3A Involves tibiotalar joint Late varus or valgus deformity produces ulceration and osteomyelitis of malleoli 20% Type 3B Follows fracture of calcaneal tuberosity Late deformity results in distal foot changes or proximal migration of the tuberosity < 10% Type 4 Involves a combination of areas < 10% Type 5 Occurs solely within forefoot < 10% Eichenholtz Classification Stage 0 Joint edema Radiographs are negative Bone scan may be positive in all stages Stage 1 Fragmentation Joint edema Radiographs show osseous fragmentation with joint dislocation Stage 2 Coalescence Decreased local edema Radiographs show coalescence of fragments and absorption of fine bone debris Stage 3 Reconstruction No local edema Radiographs show consolidation and remodeling of fracture fragments Presentation Symptoms swollen foot and ankle pain in 50%, painless in 50% loss of function Physical exam acute Charcot neuropathy inspection swollen warm average of 3.3 degrees C warmer than contralateral side erythema often confused with infection erythema will decrease with elevation in Charcot arthropathy, but is unchanged in infection chronic Charcot neuropathy inspection structurally deformed foot bony prominences rocker bottom deformity collapse of medial arch motion may be ligamentously unstable neurovascular Semmes-Weinstein monofilament (5.07) testing sensitivity of 40-95% in diagnosing neuropathy Imaging Radiographs views obtain standard AP and lateral of foot, complete ankle series findings early changes degenerative changes may mimic osteoarthritis late changes obliteration of joint space fragmentation of both articular surfaces of a joint leading to subluxation or dislocation scattered "chunks" of bone in fibrous tissue surrounding soft tissue edema joint distension by fluid heterotopic ossification Bone scan indications useful to help determine presence of superimposed osteomyelitis type of study technetium bone scan may be positive for a neuropathic joint and osteomyelitis indium WBC scan negative (cold) for neuropathic joints and positive (hot) for osteomyelitis MRI indications best for differentiating abscess from soft-tissue swelling most sensitive in diagnosing soft tissue and/or osteomyelitis limitations difficult to differentiate infection from Charcot arthropathy on MRI Studies Laboratory inflammatory markers ESR and WBC elevated in both infection and Charcot arthropathy wound healing levels absolute lymphocyte count >1500/mm3 serum albumin >3.0g/dL Biopsy may be used to guide antibiotic therapy in cases of associated osteomyelitis or soft tissue abscess Histology synovial hypertrophy detritic synovitis (cartilage and bone distributed in synovium) Treatment Nonoperative total contact casting, shoewear modifications, medications indications first line of treatment technique contact casting casts changed every 2-4 weeks for 2-4 months orthotics Charcot restraint orthotic walker (CROW) boot can be used after contact casting shoe modifications in Eichenholtz stage 3 double rocker shoe modifications will best reduce risk for ulceration at the plantar apex of the deformity medications bisphosphonates neuropathic pain medications antidepressants topical anesthetics outcomes 75% success rate Operative resection of bony prominences (exostectomy) and TAL indications "braceable" foot with equinus deformity and focal bony prominences causing skin breakdown technique goal is to achieve plantigrade foot that allows ambulation without skin compromise deformity correction, arthrodesis +/- osteotomies indications severe deformity that is not "braceable" outcomes very high complication rate (up to 70%) amputations indications failed previous surgery (unstable arthrodesis) recurrent infection technique goal is for a partial or limited amputation if vascularity allows Techniques Arthrodesis technique fixation techniques internal fixation screw, pins, plates, tibiocalcaneal nail external fixation used when bone quality is poor or soft tissues are compromised post-operative care minimal weight-bearing for three months cons high complication rate (up to 70%) infection hardware malposition recurrent ulceration fracture