When Charcot Reconstructions Fail

William P. Grant, DPM, FACFAS, Bryan Barbato, BS, Lisa Grant, BS

   Although earlier literature postulated that patients with a Charcot diabetic foot by definition had satisfactory or even hyperemic circulation, clinical practice has proven this theory false in many cases.3 Patients with diabetic Charcot frequently have significant peripheral arterial disease (PAD).4 When a Charcot reconstruction fails due to wound dehiscence or infection, it is mandatory to reevaluate the vascular status as soon as possible, performing non-invasive studies including toe pressures and the ankle brachial index (ABI), and giving early consideration to angiogram and endovascular attention by vascular specialists.

   It has been the senior author’s experience that patients who had intact circulation preoperatively and were cleared by vascular specialists can go on to have an occluded superficial femoral artery, tibial artery or other vessels during the perioperative period, producing resultant significant infection and/or wound dehiscence.

What You Should Know About Post-Op Infection In The Charcot Foot

Serious postoperative infections compromise the outcome and cause failure in diabetic Charcot reconstructions. One must have a high level of suspicion for infection for this population of patients. These types of patients need very frequent follow-up throughout the perioperative period, more so than other patients. If the patient is home, there should be evaluation by home health nurses at least twice a week as well as a visit to the office. This may preclude a failure by early intervention.

   A general rule that the senior author has used is that a postoperative diabetic foot infection is generally twice as bad as it looks on the surface. The surgeon needs to remember that neither an elevated white blood cell (WBC) count nor an elevated temperature is necessarily associated with a serious diabetic foot infection. Better measures of the severity of the infection include erythrocyte sedimentation rate (ESR) and the C-reactive protein (CRP). These are two tests that one must obtain and can use during therapy to identify progress or the lack thereof. As a rule, failure of Charcot reconstruction with infection requires prompt hospitalization. Infectious disease consultation is mandatory. Typically, imaging studies for Charcot include plain films and WBC labeled scans.

   Implanted hardware, which one typically sees postoperatively in Charcot, negates magnetic resonance imaging (MRI) as a diagnostic tool to assess the severity of an infection. Furthermore, even if the patient had no hardware implanted whatsoever, MRI cannot discern between Charcot and infection.

   Once one has diagnosed the infection clinically, the patient requires prompt surgery to remove all hardware, which is potentially infected. Obtain deep cultures during the surgery as well as a bone biopsy. All defects should receive pulse lavage. The surgeon needs to remove all avascular and dead bone. There are a variety of choices for wound management including VAC Therapy (KCI), wet-to-dry dressings or the use of antibiotic beads loaded with vancomycin or tobramycin. When possible, one can consider closure of the wound over the antibiotic beads with a drain. In some instances in which skin necrosis precludes primary closure, the physician may use a combination of antibiotic beads and VAC Therapy.

How External Fixation Can Provide Stability And Help Speed Healing

In these complex instances, placement of an external fixator is extremely beneficial. The frame provides access to the wounds, which a cast prevents. The fixator provides stability, which diminishes edema and the spread of infection, and it maintains normal architecture during healing.

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