When Charcot Reconstructions Fail
Usually, these patients require at least six weeks of parenteral antibiotics in combination with local wound care. If complex wounds are present, the foot and ankle surgeon may elect to repair them during this period or refer patients to a plastic surgeon as indicated. One can exchange antibiotic beads every two weeks to deliver higher loads of antibiotic directly to the infected site. The decision to terminate antibiotic therapy and this convalescent part of the treatment should be based on the clinical appearance of the wound, perfusion of the wound, negative cultures and viability of the wound during debridement. The vascular status needs to be optimal before proceeding.
Subsequent to this, the surgeon can remove the external fixator and lay internal beams to recreate the transverse arches of the foot and the medial and lateral column. In the senior author’s practice, the beams do not attempt to create compression arthrodesis. Beams only facilitate alignment. The surgeons can place an external Ilizarov frame using bent wire technique to compress for fusion. Studies have documented that bent wire compression and internal screws provide synergistic compression superior to using screws alone.5,6
Closure should happen over drains. One should get input from an infectious disease physician as to the length of time to treat the wounds after hardware has been reintroduced.
Generally, patients require monthly laboratory studies including ESR and CRP for six months. Perform a WBC scan every six months or until the results are normal. Repeat X-rays are necessary to follow maturation of the surgical construct.
What To Do For Charcot Patients With Special Circumstances
It has been the senior author’s experience that Charcot ankle reconstruction poses special challenges when a Charcot ankle surgery fails. In many instances, it is due to a hardware failure. Specifically, instances in which tibiocalcaneal nails have fractured through the ankle or calcaneus due to nonunion represent serious failure circumstances. This special class of failure requires removal of all hardware and placement of an Ilizarov external fixator frame with compression. It has been the senior author’s experience that it may be necessary to wait as long as 15 to 26 weeks for a solid fusion or a stable pseudarthrosis to evolve. When there is a failure of the primary ankle fusion in Charcot, the senior author’s preference is external fixation without further hardware introduction.
If after 20 to 26 weeks the ankle is still unstable, the senior author typically adds multiple large diameter stainless steel screws at different angles around the ankle to absorb the bending moments of the ankle. Most tibiocalcaneal nails rely on solid arthrodesis to work successfully over time.
One must take special precautions for patients with end-stage renal disease and abnormalities of bone metabolism associated with renal failure. A useful diagnostic test to determine if patients are capable of mineralizing bone is a serum osteocalcin level. A negative serum osteocalcin level predicts an inability in this population to heal bone and is a worrisome sign. The assistance of an endocrinologist or the dialysis nephrologist to try to correct bone metabolism disease in this population is worthy of consideration. Additionally, these patients have more severe PAD including small vessel diseases, which preclude normal healing.
When a Charcot reconstruction failure develops, one must consider amputation. Before making this decision, one needs to consider factors including the patient’s potential to be a community ambulator, his or her adherence to recommended treatment and, most especially, the viability of the opposite limb.