Diabetic Charcot arthropathy

• diabetic neuroarthropathy (Charcot arthropathy) of the foot resulting from acute fractures, subluxations, or dislocations can cause permanent disfiguring foot deformity (1)
  
  
  • this condition can be a very difficult complication to manage because of the increased risk for skin breakdown and lower-extremity amputation
  • delay in the early recognition and initiation of treatment can negatively affect healing times as well as the ultimate therapeutic outcomes, thereby further contributing to deformity and long-term disability
  • approximately 0.1-5% of diabetics with neuropathy develop neuropathic or Charcot's joint (2)
    • usually involving the tarsal or tarsometatarsal joints
    • other sites including the wrist, knee, hip and spine have been reported (3)
      
      
  • initial diagnosis of acute Charcot arthropathy is often clinical, based on profound unilateral swelling, increased skin temperature, erythema, joint effusion and instability, and bone resorption
    
    • medial longitudinal arch is often collapsed
    • pain is generally mild, often even missing
      
      
  • investigation and diagnosis
    • diagnosis remains primarily clinical, particularly in the early stages, and the purpose of investigations is to distinguish charcot arthropathy from other conditions that cause pain and swelling of the foot, such as osteomyelitis, inflammatory arthritis, cellulitis, trauma, deep vein thrombosis or gout
      • in chronic charcot arthropathywith foot ulcers, accurate diagnosis of underlying osteomyelitis can be difficult but is clearly important in the management of patient care (3)
    • plain X-ray
      • neither sensitive nor specific for separating Chacor arthorpathy changes from infection - forefoot can show demineralisation, bone destruction and periosteal reaction, typically the triad of uncomplicated osteomyelitis but in the context of diabetes could be atrophic neuropathy and fracture without infection
    • radionuclide imaging can be a useful investigative tool in some instances
    • magnetic resonance imaging
      • extremely sensitive, having a 100% detection of abnormalities and thus the most sensitive modality - also has a specificity rate of 80% for osteomyelitis and has a good negative predictability when there are equivocal radiographs or bone scans (3)
        
        
• longstanding recommended therapy for acute Charcot foot arthropathy is strict non-weight bearing, cast immobilization for a period of 3 months (1)
  • acute Charcot arthropathies of the ankle, hindfoot, or midfoot take longer to heal by than arthropathies localized to the forefoot
  • evidence that adherence to partial weight bearing with assistive devices during casting and early institution of cast immobilization are critical factors associated with shorter healing times using total contact casting (1)
  • NICE state (4):
    • suspect acute Charcot arthropathy if there is redness, warmth, swelling or deformity (in particular, when the skin is intact), especially in the presence of neuropathy or renal failure. Think about acute Charcot arthropathy even when deformity is not present or pain is not reported
    • to confirm the diagnosis of acute Charcot arthropathy, refer the person within 1 working day to the multidisciplinary foot care service for triage within 1 further working day. Offer non-weight-bearing treatment until definitive treatment can be started by the multidisciplinary foot care service
    • if the multidisciplinary foot care service suspects acute Charcot arthropathy, offer treatment with a non-removable offloading device
      • if a non-removable device is not advisable because of the clinical, or the person's, circumstances, consider treatment with a removable offloading device
    • do not offer bisphosphonates to treat acute Charcot arthropathy, unless as part of a clinical trial
    • monitor the treatment of acute Charcot arthropathy using clinical assessment
      • should include measuring foot-skin temperature difference and taking serial X-rays until the acute Charcot arthropathy resolves. Acute Charcot arthropathy is likely to resolve when there is a sustained temperature difference of less than 2 degrees between both feet and when X-ray changes show no further progression
    • people who have a foot deformity that may be the result of a previous Charcot arthropathy are at high risk of ulceration and should be cared for by the foot protection service

Reference:

1. J Diabetes Complications. 1998 Sep-Oct;12(5):287-93.
2. Tomas MB et al.The diabetic foot. Pictorial review. Br J Radiol 2000;73: 443-450.
3. Diabetologia. 2002 Aug;45(8):1085-96
4. NICE (August 2015). Diabetic foot problems: prevention and management