Ankle Arthrodesis Using Ring/Multiplanar External Fixation


Indications

  • Ankle arthrodesis

    • Symptomatic end-stage ankle arthritis (posttraumatic, inflammatory, primary)

    • Failed nonoperative management

  • External fixation

    • History of sepsis/osteomyelitis at the arthrodesis site ( Fig. 55.1A–B )

      FIG. 55.1, (From Easley M, Looney C, Wellman S, Wilson J. Ankle arthrodesis using ring external fixation. Tech Foot Ankle Surg. 2006,5:1–14)

    • Compromised soft tissue envelope

    • Inadequate bone stock to support internal fixation at the arthrodesis site

    • Failed prior ankle arthrodesis using internal fixation ( Fig. 55.1C )

    • Failed total ankle arthroplasty ( Fig. 55.1D )

    • Anticipated noncompliance with non–weight-bearing status

  • The case illustrating this procedure is that of a patient with posttraumatic end-stage ankle arthritis, an inability to comply with a non–weight-bearing status (for other medical reasons), and adequate support at home to maintain adequate pin care

Indications Pitfalls

  • Patient with prior total joint arthroplasty (pin tract infection may seed joint implant)

  • Anticipated noncompliance with pin care

Examination/Imaging

Physical Examination

  • Range of motion (ROM)

    • Typically limited, painful ankle ROM

    • Preferably asymptomatic, full hindfoot ROM (following ankle fusion, greater stress experienced on the hindfoot articulations)

  • Alignment (clinical)

    • Must be assessed with the patient weight bearing

    • Assess deformity that will need to be corrected to reestablish a plantigrade foot (equinus, varus/valgus)

  • Soft tissue envelope (previous incisions) often less important with external fixation compared with internal fixation since limited exposure typically suffices to prepare the tibiotalar joint for arthrodesis

  • Vascular examination to confirm that adequate perfusion is present to allow healing

Imaging

  • Weight-bearing radiographs of the foot and ankle

    • Confirm end-stage tibiotalar arthritis

    • Assess malalignment

    • Assess associated deformity and compensatory alignment in the foot

  • If avascular necrosis of the talus is suspected, magnetic resonance imaging to predetermine how much bone will need to be resected to achieve viable tibiotalar surfaces for healing (usefulness may be limited by previously placed hardware)

Treatment Options

  • Ankle arthrodesis using internal fixation

  • Distraction arthroplasty

  • Ankle fresh/fresh frozen allograft (ankle replacement with allograft ankle)

  • Total ankle arthroplasty

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