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Saito et al.
Table 3. FAOS Preoperatively and 1 Year Postoperatively.
FAOS Subscale
Pain
Symptoms
Activities of daily living
Quality of life

Preoperative Score (Mean ± SD)

Postoperative Score (Mean ± SD)

P Value

39.0 ± 19.7
34.0 ± 18.2
52.3 ± 21.1
15.7 ± 16.6

83.3 ± 20.4
65.2 ± 21.2
87.5 ± 14.8
64.2 ± 27.3

<.0001
<.0001
<.0001
<.0001

Abbreviation: FAOS, Foot and Ankle Outcome Score.

The 3 cases of failure in this study presented a subsidence of the tibial component. Furthermore, at least 5 other
patients at latest follow-up had concerning abnormalities
regarding the tibial component: a nonprogressive subsidence, a 9-mm bone cyst formation and 3 cases of nonprogressive radiolucencies greater than 1 mm. Even though the
5 patients were asymptomatic at the last follow-up visit,
these findings raise concern regarding the long-term survivorship of the tibial implant. The rate of radiolucencies
around the tibial component (31%) observed in the present
study was similar to the reported rates of other implants5,9,27
that range from 30% to 43%. At a mean follow-up of 2.8
years, Schweitzer et al27 reported a rate of 39% of radiolucencies about the tibial component with the use of a fixedbearing TAA. Few radiographic abnormalities related to the
talar component were observed in this study, with only 2
patients (3.1%) presenting radiolucencies smaller than 0.5
mm and 1 patient (1.5%) presenting a subsidence of the
talar component.
The short-term follow-up is the main limitation of the
present study. As a consequence, only the 1-year postoperative FAOS was available for all patients. Furthermore, the
cases reported in this study were the first surgeries performed with the Infinity TAA in our hospital. Even though
the 3 surgeons had an extensive prior experience with other
TAA designs, the results could have been affected by the
learning curve associated with the use of a new implant.26
Moreover, the fact that 3 different surgeons were involved
in the procedures could have affected the results. On the
other hand, it potentially makes this study more applicable
to a larger group of surgeons. Another limitation lies in the
fact that 9 patients received an INBONE talus instead of an
Infinity talus, which could represent a confounding factor.
Finally, the comparison of results with previous reports is
hindered by the different criteria adopted in the literature to
classify complications.

Conclusion
The Infinity TAA showed a 95.3% survivorship at an average follow-up of 24.5 months, with a 21.8% rate of complications. Most of the complications were minor and not
related to the implant, and were successfully treated either
with a single reoperation procedure or nonoperatively.

Radiographic abnormalities related to the talar implant
were uncommon. Failures and radiographic abnormalities
were most commonly associated with the tibial component.
Further studies are needed to evaluate the survivorship of
the tibial implant in the long-term.
Declaration of Conflicting Interests
The author(s) declared the following potential conflicts of interest
with respect to the research, authorship, and/or publication of this
article: Constantine A. Demetracopoulos, MD, and Scott J. Ellis,
MD, report other from Wright Medical, outside the submitted
work. ICMJE forms for all authors are available online.

Funding
The author(s) received no financial support for the research,
authorship, and/or publication of this article.

ORCID iDs
Guilherme H. Saito, MD,
https://orcid.org/0000-0002-1211-9258
Cesar de Cesar Netto, MD, PhD,
https://orcid.org/0000-00016037-0685

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https://www.orcid.org/0000-0002-1211-9258 https://www.orcid.org/0000-0001-6037-0685 https://www.orcid.org/0000-0001-6037-0685

Table of Contents for the Digital Edition of Foot & Ankle International - July 2018