Tantalum Spacer Augmentation of Large Bony Defects in Hindfoot Arthrodesis

Category: Ankle Arthritis; Hindfoot Introduction/Purpose: Tibiotalocalcaneal (TTC) arthrodesis is a common surgical technique used in the treatment of various hindfoot pathologies. Large osseus defects are particularly challenging with a high rate of graft collapse and nonunion when using autograft or allograft. Porous tantalum has emerged as a favorable osteoconductive material to address sizeable hindfoot defects. The purpose of this study was to review the radiographic outcomes and complications associated with tantalum spacer augmentation in hindfoot arthrodesis. Methods: A retrospective review was performed of all patients who underwent a hindfoot arthrodesis augmented with a metal spacer (Trabecular MetalTM) from 2012 to 2020 at a single institution. Patients [endif]–>18 years of age who had a large, hindfoot osseus defect were included in the study. Surgeries were performed by two fellowship-trained foot and ankle orthopaedic surgeons. The primary outcomes assessed were presence of radiographic union, post-operative complications, and return to the operating room. Results: Fourteen patients were identified who underwent hindfoot arthrodesis with the use of a Trabecular MetalTM augment. Two of the 14 patients were lost to follow-up resulting in a total of 12 patients with an average age of 59 years (range, 42 - 74). The average length of follow-up was 26 months (range, 4 - 56). Four patients had plain radiographs at final follow-up compared to 7 patients who had CT scans performed. Nine patients underwent TTC fusion with a retrograde intramedullary nail (MedShape DynaNail) and three patients underwent isolated subtalar (ST) fusion. Ten of 12 fusions were augmented using reamer irrigator aspirator (RIA) autograft and two patients received autograft from either the tibia or fibula. Of the 12 patients, 10 achieved radiographic evidence of union for a union rate of 83%. There were three patients who required reoperations: one hypertrophic nonunion, one surgical site infection, and one symptomatic hardware. Conclusion: Tantalum provides a great structural option for patients undergoing TTC or ST fusion in the setting of large hindfoot bony defects. This method combined with the use of autograft and adequate biomechanical stabilization can produce reliable results. Functional outcomes are needed to capture the utility of this technique in attaining longterm clinical results.