Fusion remains the primary technique to salvage the failed total ankle. Fusions present a daunting challenge because of the large bone defect left by the explanted arthroplasty components and the difficulty obtaining stable fixation. Limiting the fusion to the tibiotalar joint preserves the essential motion of the hindfoot. However, because of loss of talar bone stock, it is often necessary to include the subtalar joint in a tibiotalocalcaneal fusion. This article discusses how to determine whether an isolated ankle or ankle-hindfoot fusion is indicated and presents surgical techniques for filling the bone defect and achieving stable internal fixation.