Periprosthetic Fractures in Total Ankle Replacement: Classification System and Treatment Algorithm

Background: Despite progress in implant design and surgical technique, the reported number of periprosthetic ankle fractures following total ankle joint replacement continues to increase. A treatment-oriented classification of these fractures has not yet been reported. The purpose of this study was to evaluate the prevalence, cause, and location of periprosthetic fractures and the stability of the associated prosthetic components after total ankle replacement and to develop a method of classification. Methods: Data regarding 503 total ankle replacements with a mean follow-up of 14.7 months were reviewed. The prevalence, location, and possible cause of the fractures as well as prosthesis stability were analyzed and a systematic method of classification based on these factors was developed. Results: Twenty-one patients (4.2%) with a periprosthetic fracture were identified. The fracture was intraoperative (Type 1) in eleven patients (2.2%) and postoperative in the remaining ten (2.0%). Two of the latter fractures were traumatic (Type 2) and eight were stress fractures (Type 3). Two-thirds (fourteen) of the twenty-one fractures occurred in the medial malleolus. Conclusions: The prevalence of periprosthetic fractures following primary total ankle replacement was relatively low. We propose a classification system for these fractures that is based on more than 500 cases. We believe that this classification can facilitate therapeutic decision-making, as it allows for differential analysis of the cause and guides the choice among operative and nonoperative treatment options. Level of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.