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Ankle Spanning External Fixator Application

McAndrew, Christopher M. MD, MSc*; Ricci, William M. MD; Miller, Anna N. MD*; Avery, Matthew C. MD*

Author Information
Journal of Orthopaedic Trauma: August 2018 - Volume 32 - Issue - p S40-S41
doi: 10.1097/BOT.0000000000001210

Abstract

BACKGROUND

Early reports of open reduction and internal fixation of tibial pilon fractures depicted an injury for which operative treatment was fraught with complications.1–3 A 2-stage approach was proposed, demonstrating much improved results regarding short and intermediate term soft-tissue complications.4,5 Since these reports, the 2-stage approach with initial reduction and external fixation, followed by delayed open reduction and internal fixation on resolution of soft-tissue swelling, has become a conventional norm for treatment of high-energy tibial pilon fractures. Optimal soft-tissue rest is accomplished with anatomic alignment of the hind foot in relation to the tibia shaft proximal to the fracture: a “plumb line” from the central tibia shaft bisects the talar body in the sagittal and coronal planes. Maintaining this alignment is achieved with strategic placement of half- and full-pins in described safe zones.6,7 In addition, evaluation of deforming forces and placement of Schantz pins in vectors that allow a “push” or “pull” to correct deformity and resist the injury forces can allow for fine-tuning of the reduction in the first stage of treatment and lead to ease of reduction at stage 2. Finally, to be performed safely, the external fixation should be outside the zone of trauma and the eventual area of definitive fixation to avoid infectious complications (see Video, Supplemental Digital Content 1, http://links.lww.com/JOT/A385). 8

VIDEO/OPERATIVE TECHNIQUE

A 23-year-old man presents with a painful and deformed left ankle after a high-speed motor vehicle crash. There is diffuse leg, ankle, and hind foot ecchymosis and swelling. He has normal toe capillary refill, sensation of light touch over the dorsal and plantar foot, as well as the medial and lateral heel, and is able to dorsiflex and plantarflex the toes, albeit painfully. The apparent deformity is inversion through the hind foot and varus through the ankle. The initial ankle radiographs demonstrate an impacted and comminuted medial tibial plafond with a vertical medial malleolus fracture, a minimally displaced short oblique fibula fracture, a comminuted talar body fracture, and a subtalar joint dislocation. Computed tomography of the ankle and hind foot delineates the injuries above and was obtained before external fixation because of persistent subtalar dislocation and to further evaluate the skeletal injury to identify portions of the injury that may be definitively fixed at the initial operating room stage. Based on the soft-tissue swelling, a staged approach with manipulative reduction and temporary ankle spanning external fixation was chosen.

The patient is positioned in the supine position on a radiolucent table with a bump under the ipsilateral hip and the leg positioned on a foam ramp. The skin is cleansed and then prepared with sterilizing solution before draping. Once draped, the proximal fracture extent and zone of soft-tissue trauma are evaluated and lines drawn to estimate definitive fixation position and anatomic landmarks. The heel is elevated on a narrow towel bump, and a line perpendicular to the sagittal plane of the foot is estimated. The safe zone for calcaneal transfixion is visualized fluoroscopically, and a 1-cm incision is made over this area on the medial heel. The centrally threaded pin is inserted orthogonal to the calcaneus and passed through a counter incision on the lateral heel. The proximal tibial pin is placed through an incision just medial to the tibial crest. The pin is inserted perpendicular to the coronal plane of the leg to allow space for bars both on the medial and lateral sides of the ankle to pass without coming in contact with the skin. The lateral bar is connected to the pin-to-bar clamp further away from the leg on the Schantz pin to allow extra space for the bar to pass safely over the antero-lateral ankle. Traction with manipulation in the coronal plane is performed. The pin-to-bar clamps are tightened before assessing the radiographic alignment. Selective lengthening along either the medial or lateral bar can make further angular corrections in the coronal plane. Sagittal plane deformity can be controlled with strategic placement of towel bumps in some cases. Sagittal plane alignment is evaluated fluoroscopically, and the final Schantz pin placement is planned based on residual fracture deformity, as needed. Planning for placement of the Schantz pin through a pin-to-bar connector off the medial (most common) or lateral (uncommon) bars or off an additional cross-connecting bar is based on an evaluation of the residual fracture deformity and the ability to use the pin to push or pull in a vector to correct the deformity in both the sagittal and coronal planes. The described uniplanar external fixator commonly provides sufficient stability to maintain fracture reduction and allow for soft-tissue rest. The addition of a midfoot pin (in our example, a pin into the cuneiforms from medial to lateral) adds additional rotational control and allows for some control of the posture of the ankle and foot in the sagittal plane.

REFERENCES

1. Kellam JF, Waddell JP. Fractures of the distal tibial metaphysis with intra-articular extension–the distal tibial explosion fracture. J Trauma. 1979;19:593–601.
2. Teeny SM, Wiss DA. Open reduction and internal fixation of tibial plafond fractures. Variables contributing to poor results and complications. Clin Orthop Relat Res. 1993:108–117.
3. Wyrsch B, McFerran MA, McAndrew M, et al. Operative treatment of fractures of the tibial plafond. A randomized, prospective study. J Bone Joint Surg Am. 1996;78:1646–1657.
4. Patterson MJ, Cole JD. Two-staged delayed open reduction and internal fixation of severe pilon fractures. J Orthop Trauma. 1999;13:85–91.
5. Sirkin M, Sanders R, DiPasquale T, et al. A staged protocol for soft tissue management in the treatment of complex pilon fractures. J Orthop Trauma. 1999;13:78–84.
6. Casey D, McConnell T, Parekh S, et al. Percutaneous pin placement in the medial calcaneus: is anywhere safe? J Orthop Trauma .2004;18:S39–S42.
7. Rozbruch SR, Ilizarov S. Limb Lengthening and Reconstructive Surgery. New York, NY: Informa Healthcare; 2007.
8. Shah CM, Babb PE, McAndrew CM, et al. Definitive plates overlapping provisional external fixator pin sites: is the infection risk increased? J Orthop Trauma. 2014;28:518–522.
Keywords:

pilon; plafond; external fixation

Supplemental Digital Content

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