Revision Arthrodesis in the Foot and Ankle

Abstract

Category: Ankle Arthritis Introduction/Purpose: Arthrodesis is a common surgical procedure used to manage arthritis and deformity in the foot and ankle. Nonunion or failure of the bone to fuse, is a known possible outcome in any arthrodesis surgery and often presents as persistent pain and swelling after an arthrodesis procedure. Published rates of nonunion in the foot and ankle literature range from 0 to 47 % depending on the patient population and joint involved. Multiple factors can contribute to developing a nonunion including; arthrodesis location, fixation method, tobacco use, diabetes, infection and others. Methods: The case logs of three fellowship trained foot and ankle surgeons were reviewed from January 2007 to September 2014. ICD-9 code 733.82 (nonunion fracture), 998.89 (miscellaneous complication), and a word search for nonunion in case logs were used to identify subjects. The clinical charts were reviewed for patient factors incuding: diabetes, inflammatory arthropathy, tobacco use, history of infection, prior nonunion elsewhere in the body, neuropathy, Charcot arthropathy, post-traumatic arthritis, and prior attempt at revision arthrodesis at the same clinical site. Surgical records were reviewed to identify location of the nonunion, type of instrumention, use of structural allograft, use of cancellous autograft (CA), use of iliac crest bone marrow aspirate (ICBMA) and use of orthobiologics such as bone morphogenetic protein (BMP) during the revision arthrodesis. Successful revision was defined as radiographic union in the final x-ray taken during follow-up by the attending orthopaedic surgeon and radiologist. Results: Eighty-two cases of revision arthrodesis were identified. The overall nonunion rate during revision arthrodesis was 23%. The average length of follow up was 16 months. Univariate analysis was performed on the patient and surgical factors to determine influence on nonunion rates. Of these factors, statistical analysis identified only neuropathy and prior attempts at revision as significant risks (P< .05) for persistent nonunion. Odds ratio calculated based on previous attempts at revision arthrodesis found a 2.8 fold increase in the risk of failure for each previous attempt at revision. Charcot arthropathy approached significance at p=.051, but was limited by its small sample size (n=2). Smoking, location, use of orthobiologics and other clinical factors did not prove significant. Please see table for further details. Conclusion: Revision arthrodesis for nonunion in the foot and ankle can be highly successful (77%) under a variety of patient and surgical conditions. Neuropathy is a significant patient risk factor for persistent nonunions and is important to identify even in the non-diabetic patient. As the number of attempts at revisions increases there is a subsequent 3-fold increase in the risk of persistent nonunion.