Abstract
Charcot arthropathy (CA) is an insidious, destructive, and disabling pathology of the foot and ankle. Efficient and effective treatment is therefore required to improve clinical outcomes and to reduce overall mortality risk. The purpose of this case series report is to propose a treatment algorithm for correcting deformity and restoring a plantigrade, shoeable foot in patients with midfoot CA. While there is no clear evidence in the literature favoring either internal or external fixation methods, it may be appropriate to use both techniques during most deformity correction cases. Depending on the presence of ulceration, single-stage and multi-stage reconstruction with either biplanar or aggressive resection can effectively address the presentation of nonviable tissue and a wide degree of variable deformity. Following midfoot reduction, medial column plating and circular external frame can be used together to effectively stabilize and protect the correction and construct. In all cases, the aim is to immediately place the patient into a Charcot Restraint Orthotic Walker boot, with the ultimate goal of transitioning to diabetic shoeing as quickly as possible.
Keywords
Charcot arthropathy (CA) is well established in the literature as a destructive and disabling condition of the foot and ankle.1-4 A defining characteristic of CA is the initial insidious, cumulative onset of clinical symptoms, which are often uncorrelated with negative radiographic observation.2,4 Quite often, affected neuropathic patients are oblivious to recurrent tissue microtrauma, leading to disruption of bony architecture, structural instability, recurrent plantar ulceration, and ultimately increased amputation risk.2,4,5 In its most benign form, the classic rocker-bottom CA midfoot deformity can have a profound negative effect on patient function and quality of life. 5 As an advanced pathology, CA can lead to severe infection and a reported 28% to 37% increase in patient mortality.6-8 Efficient and effective treatment is necessary to significantly improve patient outcomes and to reduce mortality risk. 8
In its most benign form, the classic rocker-bottom CA [Charcot arthropathy] midfoot deformity can have a profound negative effect on patient function and quality of life.
Our current understanding is that the course of CA treatment is highly dependent on specific factors, including the location of deformity, the presence of ulcer, patient comorbidity, and the extent of disease progression.3,5,9,10 Noninvasive measures such as offloading of bodyweight, administration of bisphosphonate drugs, and external bone stimulation have demonstrated some clinical benefits for the treatment of stages 0 and I CA.11-13 However, surgical measures are only warranted once deformity has progressed to stage II or III. Specific techniques to remove bony prominence and reduce tissue strain can include exostectomy and tendo-Achilles lengthening (TAL). However, correction of advanced deformity is most often achieved via internal and external fixation.4,14 While these procedures are relatively common, the superiority of any specific surgical technique has yet to be established. 4 The purpose of the current case series report is to propose a treatment algorithm for achieving a stable, plantigrade, shoeable foot in patients with advanced midfoot CA deformity.
Case Series
Case 1
A 68-year-old diabetic male presented in the clinic with marked swelling of the left foot. The patient had previously undergone several months of infection treatment prior to the initial observation. Furthermore, a history of peripheral vascular disease, coronary artery disease, and respiratory failure was noted. Following clinical assessment, a Brodsky type 1 midfoot pattern was observed at the Lisfranc region. 15 While there was divergent dislocation of the tarsometatarsal joint, no rocker-bottom deformity was initially present.
The patient was first placed into a total contact cast (TCC) and allowed to walk with relatively limited weight-bearing. A series of several TCCs were applied over the following weeks, with gradual transition to a Charcot Restraint Orthotic Walker (CROW) boot. Ultimately, the patient received an accommodative extra-depth diabetic shoe with Plastazote insert (Zotefoams, Inc, Walton, KY) and was released after several months of treatment. At 5 months the patient returned to the clinic presenting with blister formation on the plantar surface of the foot secondary to exostotic bone. Once the wound was debrided and packed, a preoperative evaluation was performed to plan surgical debridement and irrigation following plantar exostectomy and TAL. Intravenous antibiotics were administered prior to surgery. The operation was deemed successful and uneventful.
At 5 months postoperative follow-up, the patient presented once more with a pronounced increase in deformity and reported difficulty with shoe wear. Radiographic analysis revealed continued TMT dislocation with a confirmed rocker-bottom deformity. At this point, amputation was introduced as a potential treatment option. Care was taken to fully inform the patient of the potential benefits and risks associated with both amputation and limb salvage. Despite consideration of amputation, the patient chose to continue with efforts to salvage the limb. At the time of surgery, the medial and lateral portions of the foot were dissected to expose the nonviable neuropathic bone (Figure 1A). A biplanar wedge resection was then completed with Kirschner wires serving as guides (Figure 1B). Following reduction of the underlying deformity, beaming screws (Cannulated Screw; Smith & Nephew, Inc, Memphis, TN) were inserted along the medial and lateral columns of the foot. Next, a large medial column plate with 5.0 mm Osteopenia screws (Smith & Nephew, Inc) was applied with subsequent autograft and closure of the incision. Following tourniquet release, an Ilizarov circular frame (Smith & Nephew, Inc.) was applied to the foot. The frame was removed at 4 months, and at 10 months postoperative follow-up, the patient was able to wear appropriate diabetic shoes and was participating in a cardiac rehabilitation program.
A, Biplanar wedge resection of nonviable bone. B, Kirschner wires placed to assist with aligning reduction of defomity.
Case 2
A 42-year-old diabetic male presented in the clinic with an existing fifth metatarsal fracture. According to the patient, the injury had been reoccurring over a period of 6 months. The clinical assessment revealed a Brodsky type 2 pattern (Figure 2A and B) coupled with cavus structure and a subtalar joint subluxation. 15 The fracture was treated with a TCC, crutches, and limited weight-bearing.
A, AP Pre-operative radiograph of Case 2. B, Lateral Pre-operative radiograph of Case 2.
The patient was lost to initial follow-up, but 4 months later the patient returned to the clinic presenting with dislocation of the subtalar and Chopart’s joints. On assessment, a large wound with probable bone exposure was observed over the now weight-bearing lateral malleolus. Following immediate consultation regarding possible treatment options, the patient desired a limb salvaging procedure. Following hospital admittance, surgical debridement was performed prior to intravenous antibiotic and negative pressure wound therapy (Kinetic Concepts, Inc, San Antonio, TX). Next, a staged reconstruction with midfoot osteotomy and subtalar fusion was performed. During stage 1 of the procedure, the ulcer and compromised bone were resected and aggressive irrigation and debridement were performed. After antibiotic beads were administered to the exposed site, the foot was stabilized by applying an Ilizarov circular frame. During stage 2, the antibiotic beads and frame were removed. A medial column plate with 5.0 mm Osteopenia screws was then used to restore the arch and stabilize the correction (Figure 3A and B). Cannulated screws (Smith & Nephew, Inc) were used to fuse the subtalar joint. The frame was then reapplied to further stabilize and protect the correction and construct. The frame was removed 2.5 months following surgery. At 5 months postoperative follow-up, the patient presented with an excellent clinical outcome. Weight-bearing in a CROW boot was permitted as tolerated. The patient is now 8 months from correction and has made a full transition to diabetic shoes. Lateral and AP postoperative radiographic images may be found in Figure 4A and B.
A, Initial lateral post-operative radiograph of Case 2. B, Initial AP post-operative radiograph of Case 2.
A/B, Final AP and Lateral radiographs of Case 2; 8 months post-operative.
Discussion
The onset of CA is most commonly associated with diabetes mellitus (DM), which currently affects approximately 25.8 million people in the United States alone.16,17 While the insidious nature of CA makes it very difficult to accurately assess prevalence, an estimated 0.08% to 7.5% of all DM patients will be diagnosed with the pathology.2,4,18,19 Moreover, the absolute number of patients presenting with advanced foot deformity is only likely to grow as the overall incidence of DM continues to increase. 20 Therefore, efficient surgical intervention is required to effectively reduce infection, amputation, and mortality risk in this population.6-8 There is still no clear evidence supporting the use of either internal or external fixation methods in CA. 4 However, limb salvage does appear increasingly possible with the advent of modern medial column plating and screwing techniques, coupled with supplemental use of ring and wire frame fixation.
The limb salvage treatment described in this case series is illustrated as an algorithm in Figure 5. Both CA patients were initially treated for varying degrees of observed skeletal deformity and soft tissue damage. Unfortunately, the deformity continued to progress in each case and required surgical reconstruction. The key consideration in this treatment algorithm is whether or not the patient is presenting with ulceration. In the absence of ulcer, it may be appropriate to perform either exostectomy or reconstruction, depending on the level of deformity. During the single-stage reconstruction procedure, bone resection, medial column plating, and external fixation are all performed with the ultimate goal of restoring a well-aligned, plantigrade, shoeable foot once the frame is removed. Furthermore, it is critical for patients to understand that their reconstructed foot will always be different from their contralateral foot. Specifically, CA patients should expect to wear fitted DM shoes with an appropriate insert for the rest of their lifetime to prevent further injury.
Proposed Charcot arthropathy surgical treatment algorithm
In the event there is a soft tissue wound or ulceration, single-stage or multi-stage reconstruction is recommended. During single-stage reconstruction, a more aggressive resection is performed to fully excise nonviable bone and soft tissue. Next, internal and external fixation with subsequent frame removal is performed, with the patient placed into a walking cast or boot, then returned to DM shoes as quickly as possible. In contrast, the multi-staged reconstruction is a more demanding procedure. First, debridement with or without antibiotic beads is performed alongside the application of the external frame to address immediate infection risk and to provide initial stability to the deformity. During the second stage of surgery all antibiotic beads are removed. The deformity is then further stabilized by applying medial column plating and revising the frame. Once healed, the frame is removed and the foot may be considered shoeable.
The patient should be informed that this course of treatment typically requires 4 to 6 months to complete, with full recovery occurring at approximately 1 year postoperatively. However, this combination of internal and external fixation offers a viable option for limb salvage in neuropathic CA patients with severe deformity. Using both methods accentuates the strengths of each technique and supports direct reduction and stabilization of the deformity in multiple planes. Furthermore, this technique allows the external frame to provide strong additional reduction stabilization, with the added benefit of supporting the direct monitoring of the soft tissue envelope.
Conclusion
Effective management of advanced midfoot CA is a challenging problem that demands a creative and flexible surgical approach. The correction of advanced deformity has typically been achieved via either internal or external fixation methods. However, there is little evidence in the literature to support the superiority of either technique. The results of the current case series analysis suggest that the most effective treatment option may actually involve the strategic use of both methods. Specifically, the proposed treatment algorithm constructs a simple and organized surgical protocol that can effectively guide both single-stage and multi-staged reconstruction. Additional cases will be treated with this approach to further assess clinical outcomes following correction of midfoot CA. Furthermore, while ankle CA has not yet been addressed with the current algorithm, we do intend to explore additional clinical indications.