Peri-prosthetic bone cysts after total ankle replacement. A systematic review and meta-analysis

Background: Periprosthetic cystic osteolysis is a well-known complication of total ankle replacement. Several theories have been proposed for its aetiology, based on individual biomechanical, radiological, histopathology and outcome studies. Methods: Studies that met predefined inclusion/exclusion criteria were analysed to identify literature describing the presence of peri-prosthetic ankle cystic osteolysis. Quantitative data from the selected articles were combined and statistically tested in order to analyse possible relations between ankle periprosthetic bone cysts and specific implant characteristics. Results: Twenty-one articles were elected, totalizing 2430 total ankle replacements, where 430 developed peri-prosthetic cystic osteolysis. A statistically significant association (P < .001) was found between the presence of bone cysts and nonanatomic implant configuration, hydroxyapatite-coating, mobile-bearing and non tibial-stemmed implants. No significant association existed between the type of constraining and the presence of cysts (P > .05). Conclusions: Non-anatomic, mobile-bearing, hydroxyapatite-coated and non tibial-stemmed total ankle replacements are positively associated with more periprosthetic bone cysts. (C) 2017 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.