CT-confirmed union rates following ankle and hindfoot arthrodesis with and without biological augmentation: A retrospective series.

BACKGROUND: Nonunion remains a major complication after ankle and hindfoot arthrodesis. Biologic augmentation is frequently used to mitigate this risk, but incremental benefit remains unproven. This study evaluated CT-verified union rates performed with and without bone graft and identified factors associated with nonunion.

METHODS: We retrospectively reviewed 227 consecutive adult ankle and hindfoot arthrodesis with postoperative weight-bearing CT at 12 weeks. Union was defined as ≥ 50% osseous bridging, assessed blinded to graft use. Univariable and multivariable logistic regression evaluated factors associated with nonunion.

RESULTS: Overall CT-verified union was 92.5% (210/227). Union did not differ between non-graft and graft procedures (92.4% vs 92.8%; p = 1.00). Previous adjacent hindfoot fusion was the only independent predictor of nonunion (adjusted OR 5.65; 95% CI 1.91-16.68; p = 0.0017). Graft use did not significantly increase union odds (adjusted OR 2.02; 95% CI 0.64-6.42; p = 0.233).

CONCLUSION: High CT-verified union rates are achievable without routine graft use, supporting selective rather than routine biologic augmentation.

LEVEL OF EVIDENCE: Level III - retrospective comparative cohort study.