Ankle Arthrodesis Using Ring External Fixation - Orthofix.com

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Special Focus: Ankle Arthrodesis Using Ring External Fixation FIGURE 1. A and B, Ankle arthrodesis using external fixation should be considered in septic ankle arthritis. status. Relative contraindications to external fixation for ankle arthrodesis are patients with total joint arthroplasties (pin tract infections may lead to infection of the joint replacement) and neuropathy of the contralateral leg (external fixator may inflict wounds in the contralateral lower extremity without the patient recognizing it). | PREOPERATIVE PLANNING History, clinical evaluation, and routine ankle radiographs establish the diagnosis of symptomatic tibiotalar arthritis. Weight-bearing radiographs of the ankle usually confirm the diagnosis. The soft tissue envelope about the ankle and the vascular status must be evaluated. Poor soft tissues about the ankle (affected by trauma and/or prior surgery) typically necessitate a less invasive exposure for joint preparation. Compromised perfusion of the extremity should prompt vascular consultation to optimize the chance for union and proper soft tissue healing. Routine weight-bearing ankle radiographs generally suffice, but if there is any suspicion on clinical evaluation for limb malalignment or foot pathology, then mechanical axis, hip and knee, and foot radiographs should also be evaluated. Computed tomography (CT) and magnetic resonance imaging (MRI) are not routinely required. In select cases, CT may help identify hindfoot arthritis/deformity if plain radiographs of the foot and ankle fail to adequately reveal these clinical findings. MRI should be considered if avascular necrosis of either the tibial plafond or talus is suggested by the radiographs; this may dictate how much bone resection is required at the arthrodesis site to access vascular surfaces for fusion. Simply placing a tibiotalar arthrodesis in neutral plantarflexion/dorsiflexion, slight hindfoot valgus, and slight external rotation will typically create a functional, plantigrade foot. However, disregard for whole limb and foot alignment may lead to a poor functional outcome, despite successful ankle fusion. Limb malalignment may need to be addressed before or simultaneous to ankle arthrodesis. An advantage with external fixation is that simultaneous combined procedures can be performed, such as proximal tibial corticotomy with lengthening/ realignment and ankle arthrodesis or concomitant ankle and foot procedures. When arthrodesis is planned in the face of infection, preoperative evaluation includes complete blood cell FIGURE 2. A support under the calf facilitates positioning of the external fixator. The surgeon must ensure that when the support is removed, the proximal ring does not impinge on the calf. Volume 5, Issue 3 151 Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
FIGURE 3. External fixation alone does not create fusion; proper joint preparation is necessary. count with differential and blood cultures. Consideration may be given to a MRI or a combination technetium bone scan/indium-labeled white blood cells scan to confirm/ evaluate the extent of infection, keeping in mind that peripheral vascular disease and antibiotics will interfere with the effectiveness of these studies. To obtain useful intraoperative cultures, antibiotics should be stopped at least 3 days before surgery. Planning should include the potential for a staged procedure. Irrigation and debridement, hardware removal, and possible antibiotic bead placement should be planned as the first stage. If the ankle is determined to be unstable at that time, the external fixator should be placed for support. In a second stage, the antibiotic beads can be removed, the ankle again debrided, and compression may be applied through the ankle if there is no evidence of persistent infection. Alternatively, the FIGURE 4. Ideal position for arthrodesis: neutral sagittal plane (plantigrade foot), slight hindfoot valgus, tibial shaft axis aligned with the second metatarsal, and no anterior talar translation within the ankle mortise. This is particularly important if a prebuilt frame is applied. 152 Special Focus: Easley et al plan can be for a single-stage procedure if the surgeon is satisfied that all of the infected tissue has been removed. | TECHNIQUE Techniques in Foot and Ankle Surgery A proximal regional anesthetic typically suffices for ankle arthrodesis using external fixation. Tourniquet use is generally limited to the approach for tibiotalar joint preparation. External fixation in itself cannot create a fusion; proper joint preparation is essential. Therefore, if there is any concern for the perfusion of either the tibial plafond or (more likely) the talar dome, then the tourniquet must be released before wound closure to confirm bleeding at the arthrodesis site. There is no need for tourniquet use during application of the external fixator. The patient is positioned supine, often with a support under the hip of the operated leg. The goal is to orient the lower leg directly perpendicular to the operating room table/floor to facilitate proper placement of the external fixator. A sterile proximal calf support (Bbump^) (Fig.2) should be created to suspend the lower leg during external fixator placement. FIGURE 5. A and B, Intraoperative fluoroscopy in 2 planes confirms proper alignment. In this case, provisional pin fixation was used. Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Page 1: Techniques in Foot and Ankle Surger
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Page 7 and 8: FIGURE 15. A and B, A supplemental
Page 9 and 10: FIGURE 20. Patient weight-bearing w
Page 11 and 12: contaminating the surgical wound. M
Page 13 and 14: performed with Ilizarov external fi

Ankle Arthrodesis Using Ring External Fixation - Orthofix.com

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