Abstract
Introduction/Purpose:
With the last decade’s surge in total ankle replacement (TAR), there is an anticipated commensurate increase in the number of revisions that orthopaedic foot and ankle surgeons will encounter. The salvage and implant options to deal with a failed primary TAR are expanding. However, the literature on survivorship and outcomes after revision TAR in the modern era is relatively limited. What’s more, little is known about the risk factors for further revision or failure of revision TAR. This study aimed to describe the timing to and survivorship after revision TAR. We hypothesized that tibial-sided failures would occur earlier after the index surgery, and secondary revisions after failure of revision TAR would occur more due to talar-sided failures than tibial-sided failures.
Methods:
This is a single-institution retrospective cohort study of TAR patients (2012-2022) with minimum 2-year follow-up. Revision TARs (defined as exchange of tibial and/or talar components) with any implant (Cadence, Inbone, Invision, Infinity, Salto, STAR, Vantage, Zimmer; or custom total talus replacement [TTR]) were included. Five surgeons contributed patients.
Demographics, primary and revision surgical data, and postoperative complications were recorded. Etiology of failure necessitating revision (tibial failure, talus failure, combined failure) and ultimate outcomes after revision (revision TAR survived, additional revisions, conversion to fusion, below-knee-amputation [BKA]) were recorded. Revisions for periprosthetic joint infection (PJI) and conversions to fusion were excluded. There were 59 ankles that underwent revision for any cause. Excluding 9 2-stage revisions for PJI and 3 conversions to ankle or tibiotalocalcaneal fusion, there were 47 ankles that underwent revision TAR that were included for analysis. Chi-square and ANOVA tests were used to compare risk factors and timing for failure.
Results:
There were 47 revision TARs, with mean age 60.6 (range: 31-77) years, mean BMI 29.5 kg/m2, 19 (40.4%) females, and mean 3.5 years follow-up. Revisions for tibial failure (n=22) occurred significantly earlier (1.3 ± 0.5 years) than those for talus failure (n=19, 2.3 ± 1.7 years) or combined tibial/talus failure (n=6, 2.9 ± 3.3 years) (P=0.048). Revisions for tibial-only failure had significantly better survivorship (95.5%) than revisions for talus or combined tibia/talus failures: 26% of talus failures and 33% of combined tibia/talus failures underwent at least one more revision (P=0.033). Of the 7 failures after revision talus, 2 ultimately underwent BKA, 2 were converted to TTR, 2 were revised to modular stemmed talus implants, and 1 was treated with explant and cement spacer for PJI.
Conclusion:
This study demonstrates that TAR tibial failures occur earlier than talus failures or combined tibial/talus failures. When patients with isolated tibial failure undergo revision of both tibial and talar components, they usually do well with good survivorship post-revision. However, revisions for talar failures and combined tibial/talar failures occur later but are more devastating: nearly 1/3 go on to a second revision. This is important given the consequences of talar implant subsidence, bone necrosis, loss of bone stock, and limited salvage options. As TAR utilization expands, it is imperative to develop implants and surgical strategies to maximize success for revision surgery.
Flowchart of failures after revision TAR.
PJI = periprosthetic joint infection. TTC = tibiotalocalcaneal. BKA = below-knee amputation. Tibial implant geometry included: Low-pro = lowprofile tibial implant. Stem = stemmed tibial implant. Keel = keeled tibial implant. Talus implant geometry included: chamfer/round and flat-cuttalus.