ADVERTISEMENT

Complex Ankle and Hindfoot Arthrodesis Using Circular External Fixation

September 25, 2018 | Surgery
Andrew R. Hsu, MD
Author and Disclosure Information

Author’s Disclosure Statement: Dr. Hsu reports that he is a paid speaker for Arthrex, Inc.

Dr. Hsu is Chief, Division of Foot & Ankle Surgery and Assistant Clinical Professor of Orthopaedic Surgery, Department of Orthopaedic Surgery, University of California-Irvine, Orange, California.

Address correspondence to: Andrew R. Hsu, MD, Department of Orthopaedic Surgery, University of California-Irvine, 101 The City Drive South, Pavilion 3, Building 29A, Orange, CA 92868 (tel, 650-906-8923; fax, 714-456-7547; email, hsuar@uci.edu).

Andrew R. Hsu, MD . Complex Ankle and Hindfoot Arthrodesis Using Circular External Fixation. Am J Orthop.

September 25, 2018

 

TAKE-HOME POINTS

  • Ankle and hindfoot fusion using circular external fixation is a useful surgical technique in patients with diabetes, Charcot, osteomyelitis, deformity, and/or bone and soft tissue compromise in order to obtain solid bony fusion, stable limb alignment, and eradication of infection in cases of complex pathology.
  • Deformity correction with osteotomies and meticulous joint preparation is required in order to obtain broad, cancellous bony surfaces for fusion with neutral alignment. Autograft from the distal fibula and/or medial malleolus can be combined with bone allograft to assist with joint fusion.
  • The ankle and hindfoot are provisionally pinned into neutral coronal and sagittal alignment through the plantar surface of the foot using large K-wires prior to placement of the lower leg in the center of a circular 3-ring compression frame. Typically, 2 to 3 points of fixation are used per ring with a combination of half-pins and smooth wires.
  • Ring attachments are built up or down to the level of the half-pins and wires in order to prevent pins and wires from bending, breaking, or causing iatrogenic deformity during tensioning. Crossing olive wires are used in the midfoot and calcaneus with dual tensioning devices to ensure an even pull on both sides of the foot.
  • Dynamic or static compression struts are used to obtain 8 to 10 mm of compression across the ankle and hindfoot, followed by addition of an anterior foot ring to increase construct rigidity. Daily pin care is started 3 to 4 days after surgery and patients are kept non-weight-bearing for approximately 2 months in the frame with a total frame period of 3 to 8 months depending on bony healing on X-ray.

DISCUSSION

A key aspect of recovery after ankle and hindfoot fusion using the Ilizarov technique is balancing pin care, soft tissue swelling, and weight-bearing status. The average time patients will spend in the frame is approximately 25 to 28 weeks, but can range from 12 to 84 weeks.1,2Given the considerable variability in both soft tissue healing and bony union, patients should be extensively counseled before surgery to set expectations correctly and ensure that they have the necessary help and support to care for the frame during the treatment period. Patients should be followed closely during the first 6 weeks to ensure that pins and wires do not become infected or break, as both of these issues require immediate intervention.

In a review of 11 patients who underwent tibiocalcaneal arthrodesis using an Ilizarov external fixator for infected talar nonunions or extrusions, Rochman and colleagues8 reported an 81% rate of successful fusion with a final mean American Orthopaedic Foot and Ankle Society score of 65 (out of a maximum 86). Similar results were reported by Saltzman9 in a series of 8 patients with diffuse ankle osteomyelitis treated with resection of all infected tissue and hybrid-frame compression arthrodesis. All patients received 6 weeks of intravenous antibiotics, and frames were removed at 3 months, and walking casts were applied for 1 to 2 additional months. Ankle sepsis was eradicated in all patients, and 7/8 (87.5%) ankles successfully fused at an average of 13.5 weeks (range, 10-16 weeks). One limb required below-knee amputation at 5 weeks due to non-reconstructible vascular insufficiency. At an average of 3.4-year follow-up, none of the 7 fused ankles required further surgery.

Fragomen and colleagues1 retrospectively reviewed 101 patients who underwent complex ankle fusion using the Ilizarov technique and found that 76/91 (83.5%) patients achieved fusion at an average of 25 weeks (range, 10-65 weeks). Smoking was associated with a 54% rate of nonunion and 15/19 (79%) patients with Charcot neuroarthropathy achieved ankle fusion, but had a subsequent subtalar joint failure, thus highlighting the need for TTC arthrodesis in Charcot patients. Salem and colleagues2 reviewed 21 Ilizarov ankle fusions and reported that all patients achieved fusion at an average of 28 weeks (range, 12-84 weeks). Complications occurred in 11 patients, including 2 nonunions that healed after revision frame application and 4 pin tract infections.

CONCLUSION

Overall, the Ilizarov technique using circular external fixation is a powerful tool that can be used to treat a variety of disorders including complex foot and ankle deformity and infection. While case series generally show favorable outcomes, patients must be informed that this technique is a salvage procedure for limb preservation that requires meticulous operative technique, diligent postoperative care, and tight control of medical comorbidities, such as blood sugar levels in individuals with diabetes to achieve a successful outcome.

ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT