Midfoot Charcot Reconstruction: Current Concepts and Techniques for Successful Stabilization and Fusion

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Charcot neuroarthropathy is a condition characterized by a non-infectious, destructive process affecting the bones and joints of the foot and ankle. While diabetes with pronounced neuropathy is the most common cause of Charcot, other neuromuscular disorders such as multiple sclerosis, syringomyelia, cerebral palsy, and Charcot-Marie-Tooth disease can also lead to this condition. In addition, factors such as trauma to peripheral nerves and prolonged exposure to toxic substances such as alcohol can contribute.

Surgical treatment of the deformity can present with challenges due to the dynamic nature of the destruction. It is essential to understand that the primary goal with any Charcot reconstructive surgery is to achieve a stable, braceable, plantigrade foot. Surgical correction of the foot deformity is based on techniques involving wedge osteotomies, resection of bony prominences, and arthrodesis. The ultimate objective of surgery is to prevent pressure points on the foot and thus avoid or delay the need for amputation.

Figure 1

What You Should Know About Superconstructs

The superconstruct is a surgical concept developed by Sammarco in 2009 to describe the use of techniques that deviate from normal principles of internal fixation in order to reduce the likelihood of procedure failure.¹ These techniques include fusion or stabilization beyond the zone of injury to include unaffected joints, bone resection to shorten the extremity, use of the strongest fixation device that the soft tissue envelope will tolerate, and application of fixation devices in a position that maximizes mechanical function.

Surgeons may choose to use superconstructs in situations when technical problems are expected or in patients with bone loss, dysvascular bone, severe osteoporosis, major deformity correction, and for patients with comorbidities that may affect healing.

Figure 2

A Closer Look at Fixation Options

Correcting the Charcot foot deformity through surgical reconstruction presents unique, significant challenges to surgeons. In addition to the severity of the bony destruction, the bone’s poor quality and impaired healing ability make the procedure and fixation even more difficult. The bone may be fragmented and unable to hold a screw, which, combined with premature ambulation, can result in loss of fixation and correction. Moreover, even with stable fixation, the incision site may be susceptible to dehiscence, ulceration, infection, and osteomyelitis, further compromising bone integrity.

To address these challenges, current fixation options for the Charcot foot center around external fixation, intramedullary screws, and medial column plating.

External fixation. External fixators are versatile in providing distraction, compression, and stability and can be used in osteoporotic bone. We find early weight-bearing may be possible in some cases, and ex fix can also be used in the presence of a localized infection by positioning the wires away from the infected area. However, we also note that external fixators can result in complications such as pin tract infection, cellulitis, osteomyelitis, loosening of half pins, or breaking of wires, which may require repositioning or removal of the frame. In our observation, proper patient selection is important as some individuals may not be able to tolerate an external fixator. Thus, alternative fixation methods must become a consideration in patients who are not candidates for external fixation.

Intramedullary screws. Intramedullary screw fixation is commonly employed in Charcot reconstruction. In our experience, intramedullary screws provide the advantage of more minimally invasive incisions. Screws can be inserted through a small percutaneous incision, thus avoiding a more extensive dissection. However, intramedullary screws do present with their own disadvantages commonly encountered once the patient begins weight-bearing. With full weight-bearing, especially in patients with a higher body mass index (BMI), we have noted that an increased load gets applied to the screws and over time breakage of the screws can occur. The cannulated screws often break in a patient with increased BMI or in cases of non-adherence. Even with strong bolts, solid screws, or large diameter screws, the modulus of elasticity is much higher than that of bone and results in the bolts/screws backing out of the bone causing ulcer formation. If failure of the intramedullary screw fixation construct occurs, we find that displacement of the osteotomy/arthrodesis site often follows.

Figure 3

What We Do Now: Column Plating

Medial column plating provides a strong fixation construct that we find especially beneficial in Charcot midfoot reconstruction. This plating technique bridges areas of weakened or grafted bone and can be anchored into stronger bone distally, proximally, and laterally. The addition of locking plates and screws provides an advantage to surgeons as the screw is attached to the plate rather than directly to the bone. This type of fixation is less dependent on the quality of the bone compared to conventional plates and screws, making it effective in softer osteoporotic bone. Bicortical fixation can further increase screw resistance to pull-out in this system. The current design of medial column plates consists of stronger, thicker plate constructs combined with the utilization of screws extending more lateral to encompass multiple bones. Of note, we prefer to use 4.0-mm screws and on average a length of 40 mm.

Several studies evaluated the outcomes of medial column plate fixation fusion for Charcot surgery. A systematic review and meta-analysis by Wu and colleagues in 2021 included 13 studies with a total of 379 patients who underwent medial column plate fixation fusion.² The study found that the overall fusion rate was 93%, and the overall complication rate was 25.1%. The most common complications were nonunion, infection, and implant failure. The authors concluded that medial column plate fixation fusion is a safe and effective technique for the treatment of Charcot arthropathy.

Another study by El-Gafary and colleagues in 2019 evaluated the outcomes of medial column plating in 40 patients with Charcot arthropathy.³ The study found that the fusion rate was 92.5%, and the mean time to fusion was 14.6 weeks. The authors concluded that medial column plating is a reliable technique for Charcot surgery, with good outcomes and a low complication rate.
A retrospective study by Wukich and colleagues in 2019 evaluated the outcomes of medial column plating in 65 patients with Charcot arthropathy.⁴ The study found that the fusion rate was 97%, and the mean time to fusion was 16.8 weeks. The authors concluded that medial column plating is a viable option for Charcot surgery, with high fusion rates and low complication rates.

Figure 4

Steps in the Authors’ Approach to Midfoot Charcot Reconstruction

When carrying out Charcot midfoot reconstruction, it is important to ensure supine patient placement for easier access the medial and lateral parts of the foot.

The first step in Charcot reconstruction involves correcting the associated equinus deformity either via a gastrocnemius recession or an Achilles tendon lengthening. An equinus contracture often results in a neutral or negative calcaneal angle. One must release enough of the contracture to be able to dorsiflex the foot to at least a 90-degree angle to the leg and to reduce a negative calcaneal angle.

In some cases, percutaneous insertion of a large Steinmann rod into the posterior aspect of the heel may become necessary to assist with correcting the calcaneal inclination angle and to correct a breach in the navicular-cuneiform joint. By inserting the Steinmann rod into the heel, the surgeon can use the rod as a joystick to dorsiflex the calcaneus and the talus. If a negative calcaneal inclination angle persists, the posterior capsule of the ankle joint and/or subtalar may necessitate release.

To ensure appropriate incision placement, careful planning is necessary, particularly when there is a rocker bottom deformity. This deformity involves a collapse of the medial column and often an abducted foot, resulting in fracture or dislocation at one or more of the midfoot joints.

A medial incision provides excellent exposure to all of the involved medial joints. One must take care to identify both the tibialis anterior and tibialis posterior tendons. The surgeon transects the tibialis anterior tendon and tags it for later suturing to allow access to the bone for plate application.

In feet with a rocker bottom deformity with abduction of the forefoot, one should take a wedge of bone from the midfoot at the apex of the deformity. The biplane osteotomy should extend from medial to lateral, typically at the level where the most pathology exists. After removing an appropriate wedge of bone with the base facing medially and plantarly, the surgeon can extend the osteotomy laterally as needed to correct the deformity.

Once you have removed the wedge and closed the arthrodesis site, you can address abduction and plantarflex the forefoot with correction of the rocker bottom deformity.

In situations with severe dislocation of the lesser metatarsals where the medial wedge osteotomy cannot fully correct the displacement, it may be necessary to perform osteotomies through the individual metatarsal cuneiform base or cuboid joint to enable reduction.

Once the osteotomy sites have been aligned and the deformity corrected, the surgeon must follow basic principles to perform an arthrodesis, which involves removing all cartilage and preparing the osteotomy site to ensure good alignment and a uniform fit of the bone surfaces with no strain on the soft tissue envelope. One may use a 0.062-inch Kirschner wire to provide temporary stability and maintain the alignment.

The surgeon may then attach the medial column plate after contouring the medial bone surfaces to accept the plate. It is vital that the plate spans not only the apex of the deformity but also extends proximally and distally to allow screw fixation into the stronger unaffected bones/joints, at times used as a bridge plate. A combination of locking and nonlocking screws can be utilized to fixate the reduction.

Additional implementation of prophylactic fixation is possible by inserting a transarticular subtalar joint screw percutaneously from the calcaneus into talus to stabilize the subtalar joint.

In Conclusion

Charcot foot deformity reconstruction is a challenging procedure that is susceptible to numerous complications, such as wound dehiscence, infection, osteomyelitis, and amputation.

The concept of medial column fixation utilizes the strength of the multiple screw fixation points and spanning to areas of stronger bone to stabilize the medial column. In our experience, this form of fixation has demonstrated superior outcomes and increased strength compared to other fixation methods.

Dr. Fallat is a Diplomate of the American Board of Podiatric Surgery and is a Fellow of the American College of Foot and Ankle Surgeons. He is the Director of the Podiatric Surgical Residency at Beaumont/Corewell Wayne in Wayne, MI.

Dr. Qanita Ali is a PGY-3 Podiatric Foot and Ankle Surgery resident at Beaumont/Corewell Wayne in Wayne, MI.

References
1.    Sammarco VJ. Superconstructs in the treatment of Charcot foot deformity: plantar plating, locked plating and axial screw fixation. Foot Ankle Clin N Am. 2009;14(3):393-407.
2.     Wu C, Zhao Y, Wang Q, Li Z, Huang H. Medial column plate fixation fusion for Charcot surgery: a systematic review and meta-analysis. J Orthop Surg Res. 2021; 16(1): 1-10.
3.     El-Gafary KA, El-Sayed MA, El-Assal MA. The outcomes of medial column plating in Charcot foot arthropathy. Foot Ankle Spec. 2019; 12(3):222-229.
4.     Wukich DK, Lowery NJ, McMillen RL, Frykberg RG, Hiatt WR. Medial column plating for Charcot neuroarthropathy: a retrospective review of 65 patients. Foot Ankle Int. 2019; 40(3):270-277.