Contemporary modern total ankle arthroplasty (TAA): A systematic review and meta-analysis of indications, survivorship and complication rates

Background: This study evaluates the clinical outcomes of contemporary total ankle arthroplasty (TAAs) to primarily establish the current benefits and risks to facilitate informed decision making to secondarily establish if improvements are seen between subsequent generations of implants, bearing philosophy, and associated surgical technique. Methods: A systematic review and meta-analysis of published data from January 2000 to January 2020 was conducted following PRISMA guidelines. Inclusion criteria: English language papers, adult population, >= 20 ankles with a minimum follow up >= 24 months, pre- and post-operative functional scores available. Ankle implants were characterised by generations, which were determined from the original studies and confirmed based on literature set definitions. Results: A total of 4642 TAAs in 4487 patients from 51 studies were included. The mean age was 61.9-years and follow up 57.8-months. Overall, 10-year survivorship rates were 77.63 %, with mobile bearing designs showing a small but significant advantage. Improved survivorship favoured the most modern implants at both two (p < 0.05), and 10-years (p < 0.01). The relative risk of a complication occurring improved with the evolution of implants e.g., nerve injury, and postoperative complications such as fracture, wound complications (e.g., dehiscence or heamatoma) and radiological abnormalities (e.g., radiolucencies, heterotopic bone formation and aseptic loosening). However, surgical site infection, and intra-operative fracture rates remain implant independent. Conclusions: Modern TAA offers improved survivorship, even with a trend to lower mean implantation age, similar complexity and ever changing indications. It would appear that implant evolution has reduced risks, especially those associated with revision, without affecting functional outcomes.