Single-Center, Early Experience with the First 3D-Printed Surface, Fixed Bearing, Total Ankle Arthroplasty: A Minimum of 2-Year Follow-Up

Abstract

Introduction/Purpose: As the fourth generation of total ankle arthroplasty (TAA) implants evolve, treatment solutions for end- stage ankle arthritis continue to improve. Technological advancements in CT guided planning and 3-D printing offers surgeons the ability to perform TAA with patient specific instrumentation and implants. 3-D printed components are designed to act as scaffold in hopes to facilitate early in-growth, to increase implant stability, to support long-term survivorship, and ultimately to improve the quality of life our patients. We present our early experience at a single academic center with a minimum of 2-year follow up data on the first 3-D printed, fixed bearing, TAA in the United States. We hypothesize that 3-D printed technology will demonstrate improved long-term survival and increased bony in-growth on the implant-bone interface. Methods: A retrospective review was performed on patients who underwent TAA with a minimum of 2-year clinical and radiographic data in which this 3-D printed TAA was utilized at our single academic center. Patient demographic, radiographic, and functional outcome scores were collected preoperatively, at 6 months, 1 year, and 2 years. The severity of ankle arthritis and associated deformities in patients were stratified using the COFAS classification. The primary outcomes of this study were implant survivorship, comparative analysis of preoperative and postoperative Patient Reported Outcomes Measurement Information System (PROMIS) physical function scores, VAS pain scores, radiographic development of linear radiolucency >2 mm, cystic radiolucency > 5mm, subsidence, and adverse events within 2 years of surgery. Results: Thirty patients were included with a median follow-up of 26 months (range, 24-36 months). Implant survival rate was 90%. One patient was revised to a stemmed TAA secondary to tibial subsidence. One patient required a TTC fusion secondary to Charcot collapse. One patient was revised to a staged ankle fusion secondary to periprosthetic joint infection. Two patients (6.7%) experienced linear radiolucency >2mm with tibial subsidence in which one patient required a revision TAA (mentioned above) and another who was asymptomatic. No significant cystic radiolucency >5 mm were identified. Five patients required re-operation from complications unrelated to the implant. VAS scores decreased significantly from 6 (IQR, 4-8) to 1 (IQR, 2-4) (P <.001; r=0.55). PROMIS Physical scores increased significantly from 43.6 (IQR, 33-47.7) to 50.8 (44.8-57.7)(P <.001; r=0.60). Conclusion: The utilization of this new 3-D printed, fixed bearing TAA demonstrated a ninety percent overall implant survival rate in our small cohort of patients. Further data will be required to determine the long term efficacy of this new 3-D printed implant on patient outcomes. Our early experience and complications presented in our study demonstrate that this 3-D printed TAA implant is safe and effective in the treatment of end-stage ankle arthritis.