3D Printed Cage in Patients with Tibiotalocalcaneal Arthrodesis Using a Retrograde Intramedullary Nail: Early Outcomes

CATEGORY: Diabetes, Hindfoot, Trauma, salvage procedure INTRODUCTION/PURPOSE: Segmental bone loss in the hindfoot hinders the chance of successful outcomes. Tibiotalocalcaneal arthrodesis is a reliable option; however, the risk of nonunion is high. Structural graft is needed to fill the gap, but the use of bone grafts are limited by the availability, risk of collapse, and disease transmission. Three-dimensional (3D) printed titanium implants offer a strong scaffold that can be customized and present similar healing rates. The purpose of the study was to describe the clinical outcomes and the radiologic union rate of a case series of patients with hindfoot arthrodesis, using a retrograde intramedullary nail associated to a 3D printed titanium cage. METHODS: After obtaining approval from our institution review board, a retrospective chart review was performed on seven patients undergoing hindfoot arthrodesis, using a retrograde intramedullary nail associated to a custom 3D printed titanium cage from March 2015 to December 2017. Demographic and clinical data were collected. Functional outcomes were assessed using The American Orthopedic Foot and Ankle Score (AOFAS) and the Visual Analog Scale (VAS) for pain. Hindfoot alignment was evaluated using preoperative and postoperative weightbearing radiographs that included anteroposterior, lateral and Saltzman views. Radiographic union was assessed using computed tomography scan at 6 and 12 months postoperatively. RESULTS: All patients had ankle arthritis and six of them (85%) had prior surgery in the compromised hindfoot. The average age at TTC fusion was 57 (range, 29 to 71) years. The mean follow-up time was 21 (range, 12 to 32) months. Six patients had a healed fusion and one patient underwent below knee amputation due to recurrence of chronic osteomyelitis in the ankle. Two additional patients had minor complications. The average AOFAS at pre-op was 35 (range, 20 to 42) points as compared to 68 (range, 53 to 78) points at final follow-up; P=0.004. Preoperative VAS pain was 80.4 (range, 70 to 85) points as compared to 26.8 (range, 6 to 60) points; P=0.002. CONCLUSION: Tibiotalocalcaneal arthrodesis using customized titanium cages for patients with large bone defects has shown a high rate of union in those at high risk of nonunion. Further research is needed to monitor the development of late complications.