Charcot Arthropathy

8 Interesting Facts of Charcot Arthropathy 

1. Charcot is a progressive, noninfectious, destructive arthropathy that affects weight-bearing joints in patients with distal peripheral neuropathy (DPN), primarily affecting the foot and ankle.
2. •Diabetes is the leading cause for DPN in North America and therefore the most common association with Charcot in the United States.
3. •Charcot affects less than 1% of patients with diabetes.
4. •Although rare, the most common locations affected, in decreasing order, are (1) midfoot; (2) hindfoot; (3) ankle; (4) forefoot.
5. •The natural progression of Charcot typically follows three stages, as described by Eichenholtz (1966):
   • •Stage I: acute or fragmentation phase
   • •Stage II: subacute or coalescence phase
   • •Stage III: consolidation and reconstructive phase
6. •The treatment of Charcot is generally based on the Eichenholtz stage at presentation.
7. •Etiology of Charcot, despite close correlation with DPN, is unclear but likely a combination of the loss of protective sensation, repetitive trauma, upregulated inflammation, and hypervascularity.
8. •If untreated, the foot/ankle will develop a deformity, which then causes pressure points that progress to ulceration and ultimately a deep infection (potentially unbeknownst to the insensate patient).

History

• •Patients often present with no clear history of significant trauma.
• •Because of the neuropathy, pain may be absent or minimal.
• •One of the most common complaints is foot swelling, insidious in onset.
• •Patients may also note the development of foot/ankle deformity.
• •In some cases, the diabetes and/or peripheral neuropathy has not previously been diagnosed—it is critical to pursue these lines of questioning during the history for any patient that presents with unexplained foot/ankle swelling and/or deformity.

Physical Examination

• •Inspect both feet and ankles with socks and shoes off, in a standing posture—take note for presence of asymmetric alignment, swelling, and erythema.
• •The classic presentation in the acute phase of Charcot is a swollen, warm, erythematous foot—the edema characteristically IMPROVES with elevation (does NOT improve with cellulitis).
• •During inspection, look for calluses, ulcerations, and any bony prominences that may reflect deformity and/or neuropathy.
• •Although many patients with Charcot have normal vascularity, always check pedal pulses (dorsalis pedis and posterior tibial).
• •Palpate the foot for warmth, a common finding in the early stages of Charcot.
• •Assess all tendon/motor function, especially in the setting of deformity.
• •Achilles tightness is common and is important to evaluate.
• •Depending on the timing of presentation, the foot/ankle may start to demonstrate lessening of the swelling, warmth, and erythema as the Charcot process goes through healing phases.

Imaging

• MRI may be helpful if there is a concern for abscess or osteomyelitis.
• •CT scan is useful to analyze complex deformity.
• •Because Charcot often causes increased bone signal intensity on MRI (false positive for deep infection), a three-phase tagged white blood cell (WBC) scan may be more sensitive to evaluate for osteomyelitis.

Additional Tests

• •Complete blood count (CBC), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) (infection markers)
• •For diabetic patients, HgbA1C is helpful to assess compliance and consistency of blood sugar control.
• •Vitamin D and calcium deficiency are common and should be tested.

Differential Diagnosis

• •Cellulitis (elevated glucose and infectious markers)
• •Lymphedema

Treatment

• •Ideally, during the course of treatment, the foot/ankle is protected until the Charcot process reaches Stage III, and deformity/ulceration is avoided.
• •Ultimately, surgically or nonoperatively, the goal is to obtain and maintain a plantigrade (near normally aligned) foot/ankle.
• •Early-stage Charcot is treated with cast immobilization and non–weight bearing for up to 3 months.
• •Late stage Charcot is addressed with footwear modification and bracing (depending on level and severity of any residual deformity).
• •Surgical reconstruction is indicated if an unbraceable or unshoeable deformity develops during the course of treatment.
• •If a callus or ulcers persists or recurs despite immobilization, surgery is often indicated to correct the deformity so that the pressure point will resolve.
• •Operative intervention is also necessary if a deep infection develops.

When to Refer

• •Almost all cases of Charcot should be referred to a foot/ankle specialist.

Prognosis

• •The prognosis of Charcot depends on many factors, many of which the surgeon has no control over.
• •Generally speaking, as you move from distal (forefoot) to proximal (ankle), the Charcot process is likely to create a progressively MORE unstable arthropathy, have a HIGHER likelihood of requiring surgery, and a HIGHER risk of complications, including amputation.
• •One of the primary keys to success for Charcot is early recognition and timely treatment, both of which require a heightened sense of awareness from primary care physicians.
• •Patient compliance is also critical for a successful outcome—unfortunately patients with diabetic DPN often have difficulty maintaining non–weight bearing restrictions and adhering to strict serum glucose control.

Troubleshooting

• •Charcot is an extremely complex, poorly understood condition, and many cases require difficult decision making that should always include thoughtful interaction and feedback from the patient.

Patient Instructions

• •One of the most difficult parts about treating Charcot is patient education and managing their expectations.
• •It is critical that the patient understands (1) the lengthy initial treatment process (9–12 months); (2) the importance of compliance; and (3) the lifelong attention required to obtain and maintain a normally aligned and stable foot/ankle.
• •Amputation is not an uncommon (and unfortunate) outcome, and patients should be made keenly aware of this at the time of initial presentation.

Considerations in Special Populations

• •The demographics of patients with Charcot are fairly consistent.
• •For patients that have severe deformity and/or active deep infection and poor compliance, amputation (i.e., below-the-knee) is often the wisest plan of action for a reliable outcome.

Seek Additional Information

• In Coughlin MJ, Saltzman CL, Anderson RB (eds): Mann’s Surgery of the Foot and Ankle., 9th ed 2014. Elsevier, Philadelphia
• Pinzur MS, Schiff AP: Deformity and clinical outcomes following operative correction of Charcot foot: a new classification with implications for treatment. Foot Ankle Int 2018; 39 (3): pp. 265-270.
• Rosenbaum AJ, DiPreta JA: Classifications in brief: Eichenholtz classification of Charcot arthropathy. Clin Orthop Relat Res 2015; 473 (3): pp. 1168-1171.