Emerging Concepts In Fixation For Charcot Midfoot Reconstruction

Author(s): 
Lawrence M. Fallat, DPM, FACFAS

Given the challenges with reconstructive surgery for patients with Charcot neuroarthropathy, this author reviews the different fixation options and offers step-by-step pearls on the use of intramedullary screw fixation.

Charcot neuroarthropathy is a dynamic non-infectious destructive process, which can affect the bones and joints of the foot and the ankle. Diabetes with pronounced neuropathy is the most common etiology of this condition but any neuromuscular disorder that damages the peripheral nerves can result in Charcot foot pathology.

   This includes multiple sclerosis, syringomyelia, cerebral palsy and Charcot-Marie-Tooth disease. Other conditions such as leprosy, syphilis and rheumatoid arthritis can also result in Charcot neuroarthropathy. Trauma to the peripheral nerves and prolonged exposure to toxic substances such as alcohol can also result in Charcot neuroarthropathy.

   The basic goal for surgery of the deformed Charcot foot is to create a stable, braceable, plantigrade foot. One can accomplish this by correcting the foot deformity through wedging osteotomies, removing bony prominences and performing an arthrodesis. Surgery should result in no pressure points on the foot and should prevent amputation.

Key Insights On ‘Superconstructs’

In 2009, Sammarco developed the concept of “superconstructs” to describe the use of surgical techniques when the normal principles of internal fixation are abandoned to reduce the likelihood of failure of the procedure.1

   Superconstructs are defined as follows:

1) fusion that extends beyond the zone of injury to include joints that are not affected to improve fixation;
2) bone resection performed to shorten the extremity to allow for adequate reduction of the deformity without undue tension on the soft tissue envelope;
3) use of the strongest fixation device that can be tolerated by the soft tissue envelope; and
4) application of the fixation devices in a position that maximizes mechanical function.

   Surgeons use superconstructs in situations in which they expect technical problems in achieving a successful outcome and in patients with bone loss, dysvascular bone, severe osteoporosis and major deformity correction. Podiatric surgeons may also use these superconstructs when patients have comorbidities that would adversely affect healing.

Assessing The Pros And Cons Of Plantar Plating And Locking Plates

   Surgical reconstruction with fixation of the neuropathic Charcot foot deformity can be difficult and challenging to the surgeon. In addition to correcting a severe foot deformity, the bone is usually of poor quality and the ability to heal may be impaired.

   The bone may be fragmented and unable to hold a screw. When you combine this with premature ambulation, it can result in a loss of fixation and correction. Even with stable fixation, the incision site may be prone to dehiscense, ulceration, infection and osteomyelitis, which could further weaken the bone.

   Current fixation options for the Charcot foot include plantar plating, locking plates, external fixation and intramedullary screws.

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