Modular Augmented Arthroplasty System to Manage Larger Bone Defects in the Ankle: A Case Series

Category: Ankle Arthritis; Ankle Introduction/Purpose: Large bone defects such as those encountered after failed total ankle replacement have previously been a relative contraindication to revision ankle replacement due to inadequate bone stock. We describe our early experience and patient reported outcomes with a modular ankle replacement system with tibial and talar augments. Methods: This is a retrospective case series analysis of patients who underwent a total ankle replacement using the INVISION system across two centres between 2016 and 2022. Local approvals were granted. Patients completed f the Manchester-Oxford Foot Questionnaire (MOXFQ), Ankle Osteoarthritis Scale (AOS) and EQ-5D pre-operatively and then post-operatively at 6 months, 1 year, 2 years, 3 years and 5 years. Medical records were reviewed for complications and re-operations. X-rays were reviewed for cysts or lucencies and alignment. Results: 17 patients were included in the study; 14 men and 3 women with an average age at the time of surgery of 67.9 years (range 56 years to 80 years). The average follow-up post operatively was 40.5 months (range 7 to 78). The indication for surgery was revision of failed TAR in 16 and revision of failed ankle fusion in 1. An augmented tibia was used in 13, augmented talus in 13, and both augmented tibia and talus in 9 cases. There were no early surgical complications. One patient required debridement and implant retention for late deep infection. No implants have been revised. The average MOXFQ score improved by 19.3 points at most recent follow up. The average AOS score improved by 25.2 points. Conclusion: The early results of a modular augmented ankle arthroplasty system have shown satisfactory patient outcomes with a low complication and re-operation rate, however, this study is confined to two centres, has a small patient number and relatively short follow up period. Further research with longer follow up periods will be beneficial in the future to support revision ankle replacement systems as another option for patients with larger bone defects.