Factors Affecting the Outcomes of Uncomplicated Primary Open Ankle Arthrodesis.

BACKGROUND

The objective of this study was to identify factors influencing operative outcomes in straightforward, uncomplicated open ankle fusions.

METHODS

We reviewed all primary open ankle fusions conducted at 1 institution over an 11-year period to identify straightforward, uncomplicated open ankle fusions. Inclusion required a minimum of 6 months follow-up. Patients were excluded for neuropathic arthropathy, insensate limb, failed total ankle replacement, simultaneous arthrodesis of the subtalar joint, or fusions performed within 1 year of injury to salvage failed fixation and painful function due to (1) open fractures, (2) segmental bone loss greater than 1 cm, (3) infection, or (4) talar body fractures. The primary outcome variable was radiographic union at 6 months. Other operative complications were analyzed as secondary outcomes. Five hundred twenty-eight ankle fusion surgeries were performed on 440 patients at 1 institution during the study period. Two hundred fifteen surgeries met inclusion/exclusion eligibility criteria for uncomplicated open ankle fusions.

RESULTS

The overall union rate was 91%. In this cohort of uncomplicated open ankle fusions, bivariate analysis over a broad range of potential factors and further focused multivariate analysis found that nonunion was more than 3 times more likely to occur after previous subtalar fusion, and 2 times more likely to occur in patients with preoperative varus ankle alignment. The rate of reoperation was 19%, with nonunion revision as the leading reason, followed by hardware removal and incision and drainage for presumed infection. Diabetes was not a significant risk factor of either deep or superficial infection.

CONCLUSION

Open ankle fusion failed in 9% of uncomplicated ankles with arthritis. Patients who had an open ankle fusion done after previous subtalar joint fusion, as well as those who had preoperative varus ankle alignment, had a significantly higher rate of nonunion.

LEVEL OF EVIDENCE: Level III, retrospective comparative study.