Charcot Arthropathy

Charcot arthropathy, also called Charcot joint or neuropathic joint, is a progressive musculoskeletal disorder characterized by joint subluxation, pathologic fractures, and debilitating deformities. Left untreated, this condition results in progressive destruction cycles of bone and soft tissues at weight-bearing joints. Charcot arthropathy can occur at any joint in the body, but most commonly occurs in the foot and ankle. Any disease that causes sensory or autonomic neuropathy can lead to Charcot arthropathy, while diabetes mellitus is the current leading cause.

Pathophysiology
Charcot arthropathy most likely results as a combination of the following two theories:

Neurotraumatic Theory
The process begins with an unperceived trauma or injury to an insensate joint. The sensory neuropathy renders the patient unaware of the osseous destruction that occurs with ambulation. This microtrauma leads to progressive destruction and damage to bone and joints.

Neurovascular Theory
The underlying condition leads to the development of autonomic neuropathy, causing the extremity to receive increased blood flow. This results in a mismatch in bone destruction and synthesis, leading to osteopenia.

Stages of Charcot Arthropathy
Stages proposed by Eichenholtz in 1966:
 * 1) Development - Inflammation and radiographic visibility of changes. Possible debris formation, fragmentation, subluxation, dislocation, and distention.
 * 2) Coalescence - Decreased inflammation. Absorption of debris and fusion of fragments. Progression slows and transitions into remodeling.
 * 3) Remodeling - Remodeling and consolidation. Structural deformity is likely present and can lead to skin breakdown, infection, and amputation.

Causes and Risk Factors

 * Diabetes mellitus neuropathy
 * Alcoholic neuropathy
 * Cerebral palsy
 * Leprosy
 * Syphilis
 * Spinal cord injury
 * Myelomeningocele
 * Syringomyelia
 * Intra-articular steroid injections
 * Congenital insensitivity to pain

Incidence

 * Estimates of the population affected by Charcot arthropathy range from .1% to 13%
 * Bilateral involvement occurs in less than 10% of patients
 * Recurrence occurs in less than 5% of patients
 * Patients with diabetes and Charcot are 7 times more likely to have an amputation than those with only diabetes
 * Patients with diabetes, Charcot, and an ulcer are 12 times more likely to get an amputation than those with only diabetes

Symptoms

 * Pain occurs in approximately 75% of patients

Signs and Tests

 * Mild to severe swelling depending on stage
 * Erythema
 * Increased skin temperature (3-7 degrees celsius)
 * X-rays may reveal bone resorption and degenerative changes in the joint
 * Bone or synovial biopsy may be necessary to differentiate Charcot arthropathy from osteomyelitis

Treatment
Although surgical treatment is an option, treatment is primarily nonoperative. Conservative treatment of Charcot arthropathy relies on halting the destructive phase of progression, and then protecting and supporting the joints throughout the healing process. Treatment plans can be broken into two phases, acute and postacute:

Acute Treatment Phase (Onset until Charcot is inactive, 3-6 months after onset)
Immobilization to prevent further destruction. Immobilization methods include: Reduction of stress on the joint to allow for faster healing. Stress reduction methods include:
 * Total contact casting
 * Metal or plastic immobilizing AFOs (May prolong healing time)
 * Total non-weight bearing
 * Partial weight bearing with assistive devices
 * Full weight bearing (May prolong healing time)

Postacute Treatment Phase (End of acute phase through 1-2 years after onset)
Following acute treatment phase, it is necessary to protect the foot throughout the remainder of the healing process. Protection methods include:
 * Charcot restraint orthotic walker (CROW)
 * Patellar-tendon bearing AFO
 * Double upright metal AFO
 * Accommodative footwear with rigid soles and shanks
 * Rocker bottoms to relieve stress on plantar ulcers
 * Accommodative foot orthoses to protect insensate feet

Prognosis
Affected joints may be fully healed within 1-2 years of treatment, however lifelong care should be taken to prevent recurrence. This includes preventing injury, noting temperature changes, checking feet regularly, reporting trauma, and receiving professional foot care as necessary.