The Vantage Total Ankle System is a fourth-generation low-profile fixed-bearing implant that has been available since 2016. We aimed to describe our early experience with this implant. This is a single-centre retrospective review of patients who underwent primary total ankle arthroplasty (TAA) with a Vantage implant between November 2017 and February 2020, with a minimum of two years’ follow-up. Four surgeons contributed patients. The primary outcome was reoperation and revision rate of the Vantage implant at two years. Secondary outcomes included radiological alignment, peri-implant complications, and pre- and postoperative patient-reported outcomes.Aims
Methods
Proper ligament engagement is an important topic of discussion for total knee arthroplasty; however, its importance to total ankle arthroplasty (TAA) is uncertain. Ligaments are often lengthened or repaired in order to achieve balance in TAA without an understanding of changes in clinical outcomes. Unconstrained designs increase ankle laxity,1 but little is known about ligament changes with constrained designs or throughout functional activity. To better understand the importance of ligament engagement, we first investigated the changes in distance between ligament insertions throughout stance with different TAA designs. We hypothesize that the distance between ligaments spanning the ankle joint would increase in specimens following TAA throughout stance. A validated method of measuring individual bone kinematics was performed on pilot specimens pre- and post-TAA using a six-degree-of-freedom robotic simulator with extrinsic muscle actuators and motion capture cameras (Figure 1).2 Reflective markers attached to surgical pins and radiopaque beads were rigidly fixed to the tibia, fibula, talus, calcaneus, and navicular for each specimen. TAAs were performed by a fellowship-trained foot and ankle surgeon on two specimens with separate designs implanted (Cadence & Salto Talaris; Integra LifeSciences; Plainsboro, NJ). Each specimen was CT-scanned after robotic simulations of stance pre- and post-TAA. Specimens were then dissected before a 3D-coordinate measuring device was used to digitize the ligament insertions and beads. Ligament insertions were registered onto the bone geometries within CT images using the digitized beads. Individual bone kinematics measured from motion capture were then used to record the point-to-point distance between centers of the ligament insertions throughout stance.INTRODUCTION
METHODS
A logical, objective and reproducible grading system for the pivot shift test is proposed. The rationale is based on performing the examination in varying positions of rotation of the tibia, allowing the type and degree of the different laxities to be defined and quantified. The system has been assessed against a new "unblocked" test for anterior subluxation and against radiographic measurements, operative findings and results. This grading system can be valuable in pre-operative assessment and planning and its use in postoperative evaluation would enable results from different centres and different procedures to be compared more accurately.
