Sagittal Tibiotalar Alignment May Not Affect Functional Outcomes in Fixed-Bearing Total Ankle Replacement: A Retrospective Cohort Study
- 10 Downloads
In total ankle replacement (TAR), correct positioning of the implant is crucial. Malposition of the components may increase contact pressures and diminish prosthesis survival. The effect of sagittal tibiotalar alignment on functional outcomes after fixed-bearing TAR remains unclear, however, and no studies have compared fixed-bearing implants with respect to the anteroposterior (AP) position of the talar component.
The purposes of this study were (1) to evaluate the effect of sagittal tibiotalar alignment on functional outcomes in fixed-bearing TAR and (2) to compare post-operative sagittal tibiotalar alignment in two types of fixed-bearing implants.
In a retrospective analysis of 71 primary TARs performed at a single center, we studied the INBONE™ II Total Ankle System and the Salto Talaris® Ankle. Radiographic measurements of the tibial axis–talus (T-T) ratio and the AP offset ratio were performed before and after surgery, respectively, and we evaluated Foot and Ankle Outcome Scores (FAOSs) and the 12-item Short Form Health Survey (SF-12) mental component summary (MCS) and physical component summary (PCS) scales pre-operatively and at 2 years after surgery. The Pearson correlation and independent-samples t test were used to evaluate differences in FAOSs, SF-12 MCS scores, and SF-12 PCS scores regarding post-operative sagittal alignment.
Post-operative sagittal tibiotalar alignment was neutral in 39 ankles and anterior in 32 ankles. We observed no significant between-group differences in clinical outcome scores. Patients with a Salto Talaris Ankle prosthesis had a greater AP offset ratio (0.12) than patients with an INBONE II implant (0.05). However, the greater translation did not correlate with outcome scores.
At the 2-year follow-up, no correlation between the post-operative AP offset ratio and functional outcome scores was observed between the two fixed-bearing-implant groups. Further studies with longer follow-up are needed to determine whether the difference in sagittal alignment has an effect on functional outcomes in the long term.
Keywordstotal ankle arthroplasty component alignment ankle replacement radiologic analysis ankle arthritis
Compliance with Ethical Standards
Conflict of Interest
Natalie M. Nielsen, MD, Austin E. Sanders, BA, and Carolyn M. Sofka, MD, declare that they have no conflicts of interest. Guilherme H. Saito, MD, reports fees as a consultant from Wright Medical Technology, outside the submitted work. Scott J. Ellis, MD, reports fees as a consultant from Wright Medical Technology. Constantine A. Demetracopoulos, MD, reports fees as a consultant from Integra LifeSciences and Wright Medical Technology.
All procedures followed were in accordance with the ethical standards of the responsible committee on human experimentation (institutional and national) and with the Helsinki Declaration of 1975, as revised in 2013.
Informed consent was waived from all patients for being included in this study.
Required Author Forms
Disclosure forms provided by the authors are available with the online version of this article.
- 1.Barg A, Elsner A, Anderson AE, Hintermann B. The effect of three-component total ankle replacement malalignment on clinical outcome: pain relief and functional outcome in 317 consecutive patients. J Bone Joint Surg Am. 2011;93(21):1969–1978. https://doi.org/10.2106/JBJS.J.01415.CrossRefPubMedGoogle Scholar