A Novel Limb Salvage Technique for Midfoot Charcot Reconstruction Complicated by Osteomyelitis
Charcot neuroarthropathy is a challenging and debilitating condition, particularly when considering limb salvage options for patients with diabetic Charcot neuroarthropathy of the foot. This condition was first described by Jean Martin Charcot in 1868 in neuropathic patients with syphilis, first presenting as painless bony and articular destruction of the foot.1 Diabetic Charcot arthropathy can result in foot deformities that lead to ulceration due to unevenly distributed forces acting on the foot. These chronic ulcers can progress to osteomyelitis due to the limited soft tissue protection over these ulceration sites, making them a significant threat to limb preservation.
Traditionally, osteomyelitis treatment options have included surgical resection of the infected bone and long-term antibiotic therapy. Severe diabetic Charcot foot arthropathy is a major contributor to amputations worldwide. Therefore, the primary goals of treating Charcot arthropathy have focused on preventing the progression of foot ulcers by unloading pressure sites, creating/maintaining a stable plantigrade foot, and preserving patient mobility. Several classification systems describe the anatomic location and stage of osseous breakdown in Charcot arthropathy, including the Eichenholtz classification, Sanders and Frykberg classification, and Brodsky classification. These systems help surgeons plan and quantify the most appropriate treatment options based on the extent of the disease.
In the context of surgical reconstruction, timing is critical. Attempting reconstruction in Eichenholtz stages I and II may pose challenges due to inadequate bone stock, thus increasing the risk of fixation failure and infection. Our research and clinical experience suggest that Eichenholtz stage III, characterized by osseous stability, resolution of edema and erythema, and radiological evidence of osseous union, is the ideal stage for definitive foot reconstruction.
However, the complexity of Charcot neuroarthropathy is often compounded by local or systemic infections, further complicating treatment strategies and the potential for limb salvage. Accurate diagnosis of infection is crucial, as relying solely on magnetic resonance imaging (MRI) findings can be misleading, with noninfected Charcot arthropathy often appearing similar to osteomyelitis on imaging.2 Thus, it is essential to combine clinical, laboratory, and advanced imaging modalities with bone biopsy to definitively diagnose osteomyelitis in patients with this condition.
In cases of osteomyelitis associated with diabetic Charcot neuroarthropathy, aggressive treatment is imperative and typically involves debridement, temporary external fixation, and therapeutic antibiotics. The use of external fixators offers several advantages, including stabilizing affected bones without traversing the infected area and minimizing the risk of hardware-related infections.2
This article aims to explore a reproducible surgical option for patients with Charcot neuroarthropathy who present with a significant deformity in the midfoot complicated by chronic ulcerations that have progressed to osteomyelitis. In this piece, we describe a midfoot Charcot reconstruction technique utilized at our institution and present representative case studies.
Background on the Patient Cases
This retrospective review looked at 3 patients with diabetes, rocker-bottom Charcot neuroarthropathy with midfoot collapse, and midfoot osteomyelitis due to chronic ulcerations treated from the summer of 2022 through January 2024.
We presented the patients with proposed procedures of wound debridement, midfoot wedge resection, and external fixation application as an alternative to a proximal amputation in an attempt at limb salvage. After a full informed consent discussion, all patients underwent the operative procedures (technique described below) with modifications appropriate to their deformity and with the same attending surgeon. Following external fixation removal, all patients transitioned to a custom foot and ankle orthosis. All patients underwent adequate targeted antibiotic therapy with the aid of our infectious disease colleagues, as well routine postoperative follow-up.
Describing the Surgical Technique
Initial Positioning and Preparation. It is important to have the entire lower extremity in appropriate alignment and rotation. One may achieve this by placing an ipsilateral hip bump. Next, one should create a platform which allows the leg to be in the same plane and level as the thigh. This allows the operative extremity to be in a higher plane than the contralateral extremity, providing a greater working area. Utilization of a proximal thigh tourniquet is most appropriate, in our experience. Sterile preparation proximal to the knee is prudent, as this will allow for visualization of the knee in relation to the rotation of the extremity. In the event there is an open wound, we find one may consider chlorhexidine proximal to the ankle and betadine preparation distal to the level of the ankle.
Component Preparation. Having all the components in place prior to application allows for a more efficient process of applying the static frame. Prior to entering the OR, it is important to have the pre-built static circular frame. One may consider having 2 size options. As the OR table is being set, one may request the scrub tech to set up a Mayo stand so components of the circular frame are readily accessible. This may include smooth wires, olive wires, bolts, nuts, wrenches, angled-socket wrenches, tensioners, mallet, and 4 saline-moistened X-ray detectable gauze sponges.
Debridement and Joint Preparation. At this point, one may direct attention to the midfoot Charcot deformity to perform the necessary debridements with wedge resection and preparation of joints if appropriate. After performing wedge resections, we fixate the forefoot and midfoot to the hindfoot with wires. We recommend wires advanced from the first ray and second ray to the talus and those for the lateral column advanced into the calcaneus.
Frame Application. Prepare a stack of blue towels stacked longitudinally under the extremity. Then slide the frame over the extremity. It is important to align the central bar along the long axis of the tibia and parallel with the knee.
Wire Placement. Many surgeons differ as to where to place the initial wires. Developing a standardized approach will allow for ease of application, efficiency, and repeatability. We recommend beginning with locking the calcaneus in place and then working proximally. This will ultimately allow the frame to be locked in place and then one may manipulate the distal foot to allow for appropriate reduction of the deformity.
Additionally, while advancing the wires, we recommend the wire be held to allow for further stabilization with a saline-moistened X-ray detectable gauze sponge. This will prevent the wire from bending and will cool the wire to prevent thermal bone necrosis. The assistant may then use the wrench to help direct the wire once it penetrates out of the skin. First, one should throw the calcaneal wires in the inferior posterior quadrant of the calcaneus where the first wire is above the foot plate and the second is below.
Locking the Tibial Block. Attention should then be directed proximally. A rule of thumb we use is that each tibial block ring should have one wire placed in a transverse manner and the other placed in an oblique manner. We recommend that the wire placed from lateral-to-medial be thrown in a transverse manner and the wire placed from medial-to-lateral be thrown in an oblique manner. This in essence will allow the surgeon to avoid the danger zones while also avoiding the wires from penetrating through the OR table and breaking sterility.
Locking the Frame in Place. Once placing the tibial block wires and the calcaneal wires, one may put on the bolts and nuts to lock the wires into the frame. At this point, one may standardize the approach by deciding to tighten the medial aspect of all the wires above the rings and tensioning the lateral side. After, one may switch the approach of the wires under the rings and tighten all the lateral wires while tensioning the medial wires. We recommend tensioning the calcaneal wires to 90kg and tibial wires to 120kg. Once locking the frame into place, one can remove the longitudinal stack of blue towels.
Additional Adjustment and Corrections. During this step, one may utilize additional wires to manipulate the forefoot and midfoot to make additional correction to the midfoot Charcot deformity. One may utilize smooth wires to allow for manipulation in order to realign Meary’s and Kite’s angle and create a medial arch if permissible. At this point, the external fixation application should be completed and the tourniquet should be deflated.
Results and Observations
Review of the patients’ radiographs reveal that all 3 feet developed a bony/fibrous union of their osteotomy. Most cultures grew methicillin-resistant Staphylococcus aureus, but yeast was also found. Per infectious disease recommendations and culture results, vancomycin was the most commonly used antibiotic for intravenous therapy postoperatively. Other antibiotics used included piperacillin/tazobactam, fluconazole, and ampicillin/sulbactam. Pathologic specimens were consistent with ulcer-related inflammation in all cases for which samples were sent, also revealing definitive evidence of osteomyelitis. Having started with a rocker-bottom midfoot, all patients at the conclusion of the study had a plantigrade foot with no signs of acute infection. All patients at 12 months out from surgery have been able to successfully ambulate with a patient-specific custom foot and ankle orthosis.
Discussion and Final Thoughts
Complications of the diabetic foot stand as the leading cause for nontraumatic amputations in the lower limb, posing a significant burden on health-related quality of life for patients with diabetes. The fear of ulceration, recurrent infection, and potential chronic disability are major concerns for these patients. Among the complications, chronic diabetic foot ulcers secondary to diabetic neuropathy and Charcot breakdown are prevalent and challenging to manage.3,4 Charcot neuropathy causes a multitude of sensorimotor and psychosocial symptoms, contributing to elevated rates of lower limb amputation and mortality.5 Midfoot Charcot breakdown causes increased central plantar pressure, precipitating skin breakdown and plantar ulceration, with neuropathy often cited as the primary culprit.6 Early recognition and prevention is key for managing high-risk patients; however, failure or delay in intervention can result in malformation, midfoot breakdown, ulceration, and osteomyelitis, presenting patients with the choice between proximal amputation or attempted limb salvage.
Addressing osteomyelitis in this context necessitates more than only infection resolution; it entails a multifaceted approach encompassing surgical infection management, medical treatment, and surgical reconstruction to restore foot balance and offload uneven pressure distributions, thus preventing recurrence. External fixation has been employed with varying success in lower extremity Charcot deformity. A systematic review by Ramanujam and colleagues in 2020, comprising 13 selected studies involving 114 diabetic patients, of whom 56 underwent surgical treatment for midfoot Charcot neuroarthropathy with osteomyelitis, underscored the relatively high success rates associated with surgical intervention in this cohort. Various fixation methods, including debridement combined with simple exostectomy, soft tissue reconstruction, and external fixator application, have shown promise.7
The surgical method described in this article presents a potentially promising approach to treatment, offering patients a functional foot while preventing the need for amputation. Furthermore, specimens obtained during the operative procedure facilitated culture-directed antibiotic therapy, while the external fixator afforded easy access to and surveillance of the wound and surrounding skin. Importantly, no adverse effects on overall outcomes were observed due to fibrous or bony union. This comprehensive approach, we feel, yields favorable outcomes in terms of ulcer resolution and prevention of future ulceration.
Charcot neuroarthropathy poses one of the most formidable challenges faced by foot and ankle surgeons today. Unfortunately, a significant number of patients either fail early conservative treatments or present at a later stage of Charcot breakdown, necessitating surgical reconstruction and infection management. This article presents a detailed, step-by-step guide outlining a novel multi-team approach for effectively treating midfoot Charcot neuroarthropathy breakdown complicated by osteomyelitis. By following this comprehensive approach, the patients presented achieved a functioning, wound-free, plantigrade foot within 12 months of the initial surgery.
While the technique presented in the paper is technically demanding, we feel it offers a method to work to achieve a plantigrade foot free of ulceration and abnormal pressure points, enabling patients to walk again. Our aim is not only to share this innovative technique, but also to provide surgeons with a unique and practical tool for managing midfoot Charcot neuropathy complicated by osteomyelitis. To enhance the validity of this approach, a larger sample size of patients should be considered in future studies, ensuring a more robust evaluation of its effectiveness and reproducibility in the clinical setting.
Dr. Stallings and Rhoton are current chief residents at Yale New Haven Hospital.
Dr. Cheung is a current reconstructive foot and ankle surgical fellow at Silicon Valley Comprehensive Foot and Ankle Surgical Fellowship.
Dr. Korwek is a current reconstructive foot and ankle surgical fellow at North Jersey Reconstructive Foot and Ankle Surgical Fellowship.
Dr. Fasihuddin is a podiatric surgeon at Barnes-Jewish Hospital.
Dr. Rashid is an Associate of the American College of Foot and Ankle Surgeons and an attending physician at New Haven Foot Surgeons.
Dr. Blume is a Fellow of the American College of Foot and Ankle Surgeons and an attending physician, Medical Director of Ambulatory Services, and Co-director of the HVC/CLI/Limb Preservation program at Yale New Haven Hospital.
References
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