Tibial Component Micromotion: Spikes, Arcs, and Keels, Oh My!

by Vince Vacketta, DPM

Aseptic loosening due to implant micromotion and poor osseointegration remains a major challenge for minimal resection, resurfacing total ankle arthroplasty designs. Recent research led by Johnson and Cesar de Cesar Netto has evaluated the impact of three common fixation designs – spikes (Stryker Infinity), arcs (P28 Apex 3D), and keels (Salto Talaris) – using a finite element model. 

Building on their previous research, the authors modeled these implants without sidewall interference. Their earlier findings showed that the absence of sidewall interference led to increased micromotion. In this study, the arc design exhibited the most micromotion, followed by the spike and keel models. The stability of the spike and arc models depended heavily on stable sidewall interference, whereas the keel design offered more inherent stability even without sidewall support. 

Takeaway

Maintaining and managing sidewall stability is likely the most critical in implant stability. Among the designs, the arc configuration appears to be the least stable across all models.