Salvage of Failed Total Ankle Arthroplasty with Fusion Using Structural Allograft and Internal Fixation

Background: The current study presents our experience with conversion of failed TAA to fusion. Materials and Methods: A retrospective review of all failed total ankles converted to fusion from 1999 to 2009 was performed at our institution. Results: Twelve total ankles were converted to isolated ankle fusions (Group I) and 12 converted to ankle-hindfoot fusions (Group H). All isolated ankle fusions were stabilized with anterior plate and screws with one nonunion. Structural bone graft was used in ten of 12. Mean outcome scores using the AOFAS-Ankle/Hindfoot score and Maryland Foot Score improved from preoperative values of 43 +/- 13 and 56.7 +/- 14 to 67 +/- 12 and 71.2 +/- 16 postoperatively, respectively (p < 0.05). All Group II ankle-hindfoot fusion patients were fixed using either anterior plate and screws, intramedullary nail, or a combination nail:plate construct. All received structural allografts. Five patients developed nonunion including four subtalar nonunions Preoperative scores on the AOFAS-AHS and MFS were 48.8 +/- 14 and 58.3 +/- 14. Postoperative scores were 51.2 +/- 17 for the AOFAS and 64.5 +/- 14 for the MFS. These changes were not statistically significant. However, the difference in nonunions was significant, p < 0.05. Conclusion: Failed total ankles can be successfully converted to fusion using structural bone graft and internal fixation. The primary risk appears to be nonunion of the subtalar joint when ankle-hindfoot fusion is required. We believe this risk can be decreased by using a separate approach for preparation of the subtalar joint.