5 Year Follow Up Evaluation of a Third Generation Fixed Bearing Total Ankle Arthroplasty with an Intramedullary Tibial Component and a Central Sulcus Talus

Abstract

Category: Ankle Arthritis, Ankle Introduction/Purpose: Total ankle arthroplasty (TAA) has been shown to be a viable option in the treatment of end stage ankle arthritis (ESAA). Early reports demonstrated good results with intramedullary fixation implants. Third generation implants of this kind added a central sulcus to the talar component. This is a report of clinical follow up data from a prospectively collected database at a single US institution using a Third generation fixed bearing total ankle arthroplasty implant with a stemmed tibial component and a talar component with a central sulcus. To our knowledge, this is the first report of 5 year follow up data for this implant. Methods: Patients undergoing primary TAA at a single institution by one of four fellowship trained orthopedic foot and ankle surgeons with a Third generation fixed bearing implant consisting of an intramedullary stemmed tibial component and a sulcus talus that were at least 5 years postoperative were reviewed from a prospectively collected database. These patients were followed at regular intervals with history, physical examination and radiographs. All ankles were classified using the Canadian Orthopedic Foot and Ankle Society (COFAS) End-Stage Ankle Arthritis Classification System. The primary outcome was implant survivability. Secondary outcomes included pre- and postoperative coronal plane radiographic alignment, evaluation for osteolysis, and failure mode when applicable. All reoperation events were recorded using the COFAS Reoperations Coding System (CROCS). Results: 126 TAA with this implant were performed in 124 patients between 2010 and 2013; 74 met inclusion criteria for our study. The mean age at surgery was 61.6 +- 10.0 years (range 38.7-84.3). Four patients died with their initial implants in place. The mean duration of follow up for living patients that retained both initial components at final follow-up was 6.2 +- .9 years (range 4.7-8.1 years). 35% (26 of 74) of ankles had a preoperative coronal plane deformity of at least 10 degrees. 11% (8 of 74) of the ankles had a preoperative coronal plane deformity of at least 20 degrees. There were 6 (8%) implant failures that occurred at a mean 2.0 +- 1.4 years postoperative. Two failures were due to deep infection. One failure was related to talar component subsidence. All failures occurred in patients with =preoperative coronal plane deformity of less than 5 degrees. 81% (60 of 74) of TAA had no reoperation events in the follow up period. Conclusion: This cohort of TAA patients with minimum 5 year follow up using a third generation fixed bearing implant demonstrates acceptable implant survival, improved reoperation rates, and maintenance of coronal plane alignment. These data also suggest tolerance of a larger preoperative deformity with improved implant design. Continued follow up and reporting is needed to ensure that these favorable outcomes are maintained. Additionally, further investigation on acceptable coronal plane alignment correction with TAA is needed to determine the possible limitations of this procedure.