Design Rationale for Total Ankle Arthroplasty Systems

An Update

Christopher E. Gross, MD; Ariel A. Palanca, MD; James K. DeOrio, MD

Disclosures

J Am Acad Orthop Surg. 2018;26(10):353-359. 

In This Article

Abstract and Introduction

Abstract

The design of total ankle arthroplasty systems is evolving as a result of findings from longer-term studies. Our understanding of modes of failure has increased, and surgical techniques have become more refined. Currently, five total ankle arthroplasty systems are used in the United States. The landscape has changed considerably in the decade since the latest article reviewing total ankle design was published. Some implants with acceptable intermediate results had much poorer outcomes at 7- to 10-year follow-up. As more research showing mid- to long-term outcomes is published, the design rationale and current outcomes data for each of these implants must be considered.

Introduction

The design of total ankle arthroplasty (TAA) systems is evolving. With longer term follow-up, our understanding of modes of failure has increased and surgical techniques have been refined. Currently, five TAA systems are commonly used in the United States: INBONE (Wright Medical Group), INFINITY (Wright Medical Group), Salto Talaris (Integra Lifesciences), Scandinavian Total Ankle Replacement (STAR [Stryker]), and Trabecular Metal Total Ankle (Zimmer Biomet). Two systems have recently entered the US market: the VANTAGE (Exactech) and the Cadence (Integra LifeSciences). During the 10 years since the publication of the latest total ankle design review article,[1] the landscape has changed substantially; some implants with adequate intermediate results had much poorer outcomes at 7- to 10-year follow-up.[2,3] As more research regarding mid- to long-term outcomes becomes available, it is important to consider the design rationale and current outcome data for each of these implants.

First-generation ankle arthroplasty designs were associated with high rates of osteolysis, implant loosening, tibial and talar bone loss, and wound complications.[4–7] The second-generation designs improved on the first-generation devices, with porous metal-backed surfaces to improve osseous integration; replacement of the tibiotalar, talofibular, and medial-malleolar talar articulations; and/or improved stability with the fusion of the syndesmosis. However, these designs had complications related to syndesmotic nonunion, polyethylene wear, implant migration, and impingement.[8] Improvements in the design of third- and fourth-generation TAA systems include minimal bone resection, superior bony ingrowth, retention of ligamentous support, and anatomic balancing. In fact, several companies have also begun to invest in lines of revision ankle replacements. Furthermore, refined implantation instrumentation has allowed for superior repeatability and a more comprehensive surgical technique compared with earlier systems.

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