Midfoot Charcot Reconstruction PDF

M i d f o o t C h a rco t Reconstruction a, b,c Noman A. Siddiqui, DPM, MHA *, Guido A. LaPorta, DPM, MS KEYWORDS  Charcot joint  Midfoot Charcot  Bayonet  Intramedullary foot fixation  Diabetic complicati...

M i d f o o t C h a rco t Reconstruction a, b,c Noman A. Siddiqui, DPM, MHA *, Guido A. LaPorta, DPM, MS KEYWORDS  Charcot joint  Midfoot Charcot  Bayonet  Intramedullary foot fixation  Diabetic complications  Neuropathy KEY POINTS  Charcot joint should be identified based on stage and location.  The conservative goal is to prevent significant bony collapse; bony collapse with instability leads to soft tissue complications, which can result in amputation.  Surgical intervention is often necessary when instability between the forefoot, midfoot, and hindfoot elements exist.  Medial and lateral column stability play a large role in providing guidance to the degree of surgical intervention required.  Surgical principles should focus on respecting the soft tissues, obtaining and maintaining correction, and using orthobiologics for improved healing. INTRODUCTION Charcot neuroarthropathy can result in a disabling condition that can affect the bones and joints of the foot.1 Charcot foot most commonly results from peripheral neuropa- thy leading to loss of protective sensation, autonomic dysfunction, and increased blood flow to the foot. Even though the diabetic foot is the most common cause of Charcot neuroarthropathy, multiple other conditions have also been implicated in creating Charcot joints.2,3 Progression of a Charcot joint leads to bone loss and joint subluxations/disloca- tions, which can distort the normal architecture of the foot and ankle. Long- standing dislocation can result in soft tissue breakdown and arthritis to the neigh- boring joints.4,5 Therefore, the normal gait pattern is disrupted making it difficult to ambulate without the assistance of bracing or shoe modifications.6,7 Various surgical methods have been described for management of Charcot collapse.8–11 However, the authors believe that when approaching Charcot foot Disclosure Statement: None. a International Center for Limb Lengthening, Rubin Institute for Advanced Orthopedics, Sinai Hospital of Baltimore, 2401 West Belvedere Avenue, Baltimore, MD 21215, USA; b Geisinger CMC, 1800 Mulberry St, Scranton, PA 18510, USA; c Our Lady of Lourdes Memorial Hospital, 169 Riverside Dr, Binghamton, NY 13905, USA * Corresponding author. E-mail address: [email protected] Clin Podiatr Med Surg 35 (2018) 509–520 https://doi.org/10.1016/j.cpm.2018.07.003 podiatric.theclinics.com 0891-8422/18/ª 2018 Elsevier Inc. All rights reserved. 510 Siddiqui & LaPorta deformity, there are basic deformity planning and management principles that should be considered for conservative or operative treatment. These deformity planning and management principles are presented based on the authors’ extensive experience with midfoot Charcot foot deformity correction. DEFORMITY PLANNING/PREOPERATIVE EVALUATION Identifying the stage (Eichenholtz classification)12 and location of the deformity is a simple, primary principle that should be applied whenever managing Charcot joints. Eichenholtz12 described three stages of Charcot foot that were based on pathologic findings. They are categorized as I. Development phase II. Coalescence phase III. Healing phase Shibata and colleagues13 added an additional phase (stage 0), which precedes the developmental phase and during this phase radiographic findings are negative. The mainstays of treatment in the predevelopment and developmental phase are offload- ing of the affected extremity. During this phase, it is important to rule out any infective process that could have resulted from a previous ulceration or a past history of chronic osteomyelitis. Once the stage has been determined, it is important to note the location of the Charcot deformity. Various authors have classified the Charcot foot based on the anatomic involvement of bones and joints.2,14,15 These classifications are useful in communicating the level of Charcot; however, none have been validated as predictive of outcome. The authors believe that location still has a significant role in determination of the type and success of treatment of the Charcot foot deformity. In the clinical examination, the patient’s foot is assessed for areas of ulcerations or preulcerative lesions. These may coincide with bony prominences or locations of insta- bility, thus leading to increased pressure, and must be noted. Evaluating stability in the forefoot, midfoot, and hindfoot can provide insight as to the urgency for operative treat- ment. A complete vascular examination with particular attention to capillary refill and palpable pulses is noted. The authors recommend a vascular work-up with a vascular surgeon during conservative and/or surgical management of the patient. The foot is also assessed for stability of the bony architecture and equinus deformity. Unstable lateral column Charcot joints result in plantar-central ulcerations of the midfoot and can lead to infection of the midfoot and require surgical intervention to obtain stability. Unstable midfoot Charcot can result in loss of bony and ligamentous stability and dor- siflexion the midfoot onto the hindfoot (ie, “bayonet” effect) (Fig. 1). The biomechanical and clinical consequences of bayoneting are discussed in greater detail later in this article. It is important to stabilize the hindfoot and the midfoot when assessing maximum dorsiflexion for presence of equinus. An unstable foot gives the impression of increased dorsiflexion through the midfoot when the Silfverskiöld test is performed. INDICATIONS FOR SURGERY ON CHARCOT FOOT DEFORMITY Operating on midfoot Charcot neuropathy is difficult because the risk of complications is higher than in patients without neuropathy. Therefore, clear indications are essential to the success of surgery: 1. Unstable joints/deformity 2. Nonhealing/infected ulcer and/or osteomyelitis  Midfoot Charcot Reconstruction 511 Fig. 1. Lateral view demonstrating collapsing medial arch and “bayonetting” deformity of the forefoot/midfoot on the hindfoot. (Copyright 2018, Rubin Institute for Advanced Ortho- pedics, Sinai Hospital of Baltimore, Baltimore, MD.) 3. Equinus 4. Deformity is unable to be braced Surgical Principles Surgical management of midfoot Charcot deformity should be based on sound surgi- cal principles. Patients with diabetes are known to have poorer healing potential because of advanced glycosylated end products16 and other comorbidities that can complicate bony and soft tissue healing. Therefore, surgical intervention must take into account all aspects of healing soft tissue and bony elements that are involved in repair. Respect the soft tissue Respecting the soft tissue before, during, and after treatment is critical to limiting post- surgical complications. Infections are more common postoperatively in the diabetic population.17 During stage II or III of a Charcot joint, enough soft tissue edema and er- ythema has resolved and the clinician can assess the foot and ankle to determine a surgical plan. Taking note of any superficial or deep ulcerations and associated bony prominences assists the surgeon in determining a conservative and/or surgical plan. The overall health of the soft tissue envelope of the foot is important and is affected by chronic edema, prior surgery, and/or trophic changes caused by auto- nomic neuropathy. Depending on the degree and location of involvement, the surgeon can plan an appropriate surgical approach for correction or offloading techniques to accommodate the deformity. The goal is to maintain a closed skin envelope and pre- vent ulcerations, which are the precursor of deep infections. Obtain and maintain correction In managing Charcot foot, an important principle is to obtain correction and then main- tain correction. Conservative measures include such options as total-contact casting, diabetic shoes, and crow walkers. However, if the surgeon determines that conserva- tive measures are not able to protect the patient from violation of principle number one (protect the soft tissue), then the surgeon must use appropriate surgery to correct the deformity. 512 Siddiqui & LaPorta With this principle, the surgeon must determine the method of correction, which is acute or gradual. In the acute approach, the surgeon accomplishes the goal of obtain- ing realignment by decreasing the cubic content of bone in the midfoot. Wedge resec- tions are a powerful method and allow for acute realignment. Fixation methods are per the surgeon’s preference. However, locked plantar/medial plating and large-diameter axial screw fixation have been reported as successful methods with this technique for correction.11,18,19 Gradual correction follows a two-stage method and has been advocated to allow the patient to maintain foot length and to obtain more accurate realignment of the deformed segments.20 This method combines the use of hexapod external fixation fol- lowed by fusion of joints with internal fixation to maintain the correction.21 Regardless of the method of fixation, the correction is maintained by trying to achieve bony union or fusion.11,21 When correcting the medial or lateral column, it is vital that surgeons prepare joints to fuse joints. This basic fusion principle is critical to provide stability to the hardware or bony segments. Placing fixation across joints without preparing articular surfaces decreases the likelihood of achieving fusion/union beyond the zone of midfoot collapse. Orthobiologic supplementation Autografts have been considered the standard for grafting and supplementation in many aspects of orthopedic and foot and ankle surgery. However, donor site morbidity and quantity of graft have led to the use of allograft material. Allografts have served as an acceptable alternative for structural and inductive scaffold for sup- plementation.22 However, in specific populations, such as patients with diabetes, there is evidence that bone biology is affected at the cellular level.23,24 This can decrease the quality of bone available for fusion. Advancements in orthobiologics has allowed for the development of various prod- ucts, such as recombinant human bone morphogenetic protein (rhBMP), platelet-rich plasma, and bone marrow aspirate. Fourman and colleagues25 performed a retro- spective comparative study in 2014 on 82 patients undergoing ankle arthrodesis with external fixation with rhBMP-2. Forty patients did not receive rhBMP-2, and 42 patients received intraoperative rhBMP-2. There were no significant differences in patient demographics, body mass index, diabetes, Charcot joints, tobacco use, and history of infection between the two groups. The results demonstrated 93% union for those receiving rhBMP-2 versus 53% union in the ones who did not receive rhBMP-2. This was verified by computed tomography, which was statistically signif- icant. Additionally, patients treated with rhBMP-2 spent less time in the external fix- ation than the control (approximately 37 days). Bibbo and colleagues26 performed a prospective study that looked at the effects of platelet-rich plasma in foot and ankle surgery for 62 high-risk patients. The study found high fusion rates (>90%) of the ankle and hindfoot with the use of platelet-rich plasma. Given that patients with Char- cot joints are high risk for nonhealing, it is helpful to supplement the operative site with biologic adjuncts that enhance the environment for the bone to achieve fusion or healing. EVALUATING THE DEFORMITY When addressing the patient with midfoot Charcot, the location of the Charcot collapse is identified. After determining this, the surgeon should note whether or not there is an ulceration present. Ulcerations over bony prominences should be approached with suspicion for osteomyelitis. Appropriate diagnostic testing with ra- diographs, MRI, or nuclear imaging should be used if a bone infection is suspected.  Midfoot Charcot Reconstruction 513 Finally, based on these findings, the surgeon can address the Charcot foot with sur- gical correction. Patients with midfoot Charcot can present with or without ulcers. Those without ul- cers tend to have collapse on the medial column and may present with varying de- grees of stable Lisfranc Charcot. These deformities are seen in patients with Schon type 1A Charcot distribution, which tend disrupt the first and second metatarsals and their respective articulation. These deformities respond well to offloading of bony prominences and conservative management. The key in these deformities is to allow for bony consolidation of the dislocation and to evaluate the patient for equi- nus deformity via the Silfverskiöld test. Those who do not have an equinus contracture tend to do better than those who have an equinus contracture. Patients who have equinus tend to develop ulcers over bony prominences. In those instances, surgical intervention can focus on bony prominence resection and a tendo-Achilles lengthening. At our facility, we tend to perform a gastroc-soleus recession along with bony protuberance exostectomy. The gastroc-soleus recession is preferred over the Hoke triple-hemisection because it is better at maintaining push-off strength and decreases the risk of a calcaneus gait, which is a complication of the latter. Midfoot Charcot deformities with ulcers become more common because the Char- cot deformity progresses more proximal as seen in Schon type 2 and 3. In these types of patients, it is important to note if the ulcer is medial or lateral. Lateral ulcers are a sign of greater instability and a disruption of the lateral column, and the patient is on a path to the classic “rockerbottom” deformity. This collapse is exacerbated by the effect of the ground reaction vector that is initiated at heel strike (Fig. 2). This re- petitive act only assists in further dislocation of the lateral column. In this population, an equinus contracture further exacerbates this lateral column disruption and many patients develop an ulceration of the plantar lateral foot. The ulceration is maintained by the “bayoneting” effect of the forefoot on the hindfoot, which is commonly seen in these types of deformities (see Fig. 1). Medial ulcers occur when there is peritalar dislocation of the navicular-cuneiform joint and the talus dislocates medial and plantar. The authors believe that these deformities must be addressed surgically to create a stable foot and ankle complex. Correction is performed acutely via wedge re- sections or gradually using hexapod devices. If there is a history of ulceration or oste- omyelitis, the authors always stage the correction to minimize the risk of future infection. When undertaking a midfoot Charcot reconstruction, the authors aim is to accomplish the following:  Maintain anatomic realignment  Use minimally invasive fixation technique  Obtain formal multiple joint fusion  Achieve joint fixation/fusion beyond the level of Charcot collapse  Select rigid fixation  Preserve foot length  Combine with external fixation if necessary This is accomplished in various methods; however, the authors prefer to use the intramedullary foot fixation technique with some modifications as described next.21 SURGICAL TECHNIQUE The authors use a percutaneous technique to ensure the proper placement of intrame- dullary foot fixation. The patient is supine on a radiolucent table with a bump under the 514 Siddiqui & LaPorta Fig. 2. Ground reaction force vector starts at the level of the calcaneocuboid joint laterally to the level of T10. (Copyright 2018, Rubin Institute for Advanced Orthopedics, Sinai Hospi- tal of Baltimore, Baltimore, MD.) ipsilateral hip to obtain a foot-forward position. A thigh tourniquet is applied to the lower extremity. The extremity is prepared in an aseptic fashion to the level of the tour- niquet, providing the ability to flex the knee during the procedure. A gastroc-soleus recession is performed to resolve any equinus contracture. A limited open technique  Midfoot Charcot Reconstruction 515 for preparation is performed on joints that will be fixated along the medial and lateral column. Temporary fixation with smooth wires to obtain alignment is performed. Then a 1.8-mm Ilizarov wire is inserted from the plantar aspect of the first metatarsophalan- geal joint to the center of the first metatarsal head by maximum dorsiflexion of the first metatarsophalangeal joint (Fig. 3). A lateral fluoroscopic view ensures that the direc- tion of the wire is parallel and coincides with the lateral anatomic axis of the first meta- tarsal (see Fig. 3). The guide pin is advanced manually with a mallet to the level of the base of the first metatarsal, which ensures intramedullary placement of the guide pin. The goal of lateral column stabilization is to obtain a formal fusion of the calcaneocu- boid joint. A 1.8-mm Ilizarov wire is inserted through the interosseous structures of the third and fourth intermetatarsal bases. A stab incision is made dorsally at the insertion site of the 1.8-mm wire. Blunt dissection is carried down to the metatarsal base. A 4.8- mm cannulated drill bit is then inserted over the 1.8-mm wire and then drilled into the anterior portions of the calcaneus. The drill, along with the 1.8-mm wire, are removed and replaced with the guide pin from the 6.5/7.0/8.0-mm cannulated screw set. After confirmation of proper insertion on the anteroposterior and lateral fluoroscopic views, the three screws are inserted. Fig. 3. (A) A 1.8-mm Ilizarov wire is inserted from the plantar aspect of the first metatarso- phalangeal joint to the center of the first metatarsal head by maximum dorsiflexion of the first metatarsophalangeal joint. (B) The 1.8-mm Ilizarov wire is placed on the equator of the metatarsal head. (C) Lateral fluoroscopic view ensures that the direction of the wire is par- allel and coincides with the lateral anatomic axis of the first metatarsal. (Copyright 2018, Ru- bin Institute for Advanced Orthopedics, Sinai Hospital of Baltimore, Baltimore, MD.) 516 Siddiqui & LaPorta The head of the screws are buried into the bone. Compression occurs once the screw engages the talar and calcaneal body. However, the authors focus is to provide stability and it is not imperative to achieve compression along the medial and lateral columns. The authors have incorporated subtalar joint fusions as a part of the final construct to impart hindfoot stability to the medial and lateral columns in Charcot joints. A stan- dard medial approach is used to prepare the articular surfaces of the subtalar joint and fully threaded 6.5/7.0/8.0-mm fixation is used to achieve compression across the hindfoot. The plantar incisions are then closed with 3.0 Monocryl sutures (Ethicon Inc, Somer- ville, NJ). The patient is placed in a 90 bivalved non–weightbearing short leg cast for the initial postoperative course. The patient is seen 1 week postoperatively, and skin incisions are evaluated. The patient is then placed in a non–weightbearing short-leg cast for a total of 8 weeks, with intermittent follow-up. External fixation is used to pro- tect and offload internal fixation. It is a useful adjunct for these procedures to allow earlier load transfer for this patient population who may have difficulty with prolonged cast immobilization. The authors address the equinus component that tends to reoccur months after reconstructive surgery. We routinely check for recurrent equinus and believe if there is no residual equinus component, there is less likelihood of collapse that results in ulceration in the future. In the authors experience, even if midfoot collapse reoccurs (because of broken hardware, partial/incomplete fusion, pseudoarthrosis), as long as the foot functions as a solid unit and has adequate ankle dorsiflexion, then the pa- tient’s chances for recurrent ulceration decreases. CASE EXAMPLE Midfoot Charcot Correction with Internal and External Fixation A 72-year-old African American man presented with midfoot Charcot deformity of the left foot. He had received treatment from other physicians for many weeks for chronic gout, cellulitis, and an “ankle sprain.” Patient related no prior trauma or history of gout before this episode. A referral to the author was prompted when persistent pedal edema and signs of a preulcerative lesion were noted with no skin breakdown. Patient denied any pain to the left foot and had been ambulating in left CAM boot walker, as recommended by another physician. He was in excellent medical health but related a well-controlled past medical history of diabetes mellitus type II, hypertension, and hyperlipidemia. Clinically, he presented with an edematous foot with no erythema or signs of acute infection. The soft tissue envelope was intact; however, a sign of a preulcer- ative lesion was noted plantar centrally in the midfoot. Excellent pulses, capillary refill, and normal temperature gradient was appreciated. Loss of protective sensa- tion was noted with Semmes-Weinstein monofilament examination. He had supple range of motion in the hindfoot but gross instability was noted of the medial and lateral columns of the midfoot and forefoot. His radiographic evaluation indi- cated midfoot Lisfranc/perinavicular Charcot joints with bone loss and comminu- tion. A collapsed Meary angle and bayonetting of the forefoot to hindfoot were observed (see Fig. 1). Combining the clinical and radiographic findings allowed the foot to be classified as Eichenholtz stage 2 with radiographic characteristics of a Schon 3/4 deformity. Formal vascular studies were conducted, which were positive for excellent perfusion to the extremity. The patient consented to surgical intervention.  Midfoot Charcot Reconstruction 517 A two-stage correction was used that obtained gradual distraction and realign- ment of the midfoot deformity with hexapod external fixation (Fig. 4). Once the correction was achieved, the realignment was maintained with focused joint fu- sions (as described previously) and placement of internal and external fixation (Fig. 5). The external fixation device was used to protect the internal construct dur- ing the healing phase and a load-sharing device for the patient’s activities of daily living. The sutures were removed at 3 weeks, and he was allowed to shower and to ambulate for most activities with the assistance of a walker. He had an overall un- eventful postoperative course. If there was a concern for a pin-related infection, it was managed immediately with orally administered antibiotics. Approximately 10 weeks after surgery, the external fixation device was removed when radio- graphic signs of bony consolidation were observed. After frame removal, the foot Fig. 4. Stage 1 of the correction involved application of multiplanar hexapod external fixa- tion to obtain gradual correction of the deformity. The hindfoot was acutely corrected with tendo-Achilles lengthening and extra-articular pinning of the ankle joint. (Copyright 2018, Rubin Institute for Advanced Orthopedics, Sinai Hospital of Baltimore, Baltimore, MD.) 518 Siddiqui & LaPorta Fig. 5. Stage 2 of the correction (after gradual correction) involved formal fusion of all medial and lateral column joints with internal fixation using the intramedullary foot fixa- tion technique. (Copyright 2018, Rubin Institute for Advanced Orthopedics, Sinai Hospital of Baltimore, Baltimore, MD.) was protected in a short CAM walker boot for 8 months. The boot was converted to an Arizona brace with protective extra depth diabetic footwear. The patient had a positive outcome that has been maintained for many years after the reconstruction (Fig. 6). Fig. 6. Anteroposterior (A) and lateral (B) views of foot show solid fusion and that realign- ment was maintained of the medial and lateral columns. (Copyright 2018, Rubin Institute for Advanced Orthopedics, Sinai Hospital of Baltimore, Baltimore, MD.)  Midfoot Charcot Reconstruction 519 SUMMARY Midfoot Charcot deformity is one of the more complex pathologies encountered by foot and ankle surgeons. Nonoperative treatment with total contact casting, immobi- lization, and use of an AFO, such as a Charcot restraint orthotic walker, are reliable methods to treat this complex condition. However, in cases that involve unstable joints/deformity, nonhealing foot ulcers with or without osteomyelitis, equinus, and a nonbraceable-deformity, often it becomes necessary to intervene with operative methods to salvage a limb. There are many methods to address the condition, and the authors have demonstrated methods to correct the deformity successfully. 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