Abstract
Research Type:
Level 1 - Randomized controlled trial (RCT), Meta-analysis of randomized trials with homogeneous results
Introduction/Purpose:
While total ankle replacement (TAR) outcomes are reported as positive across the literature, complications such as periprosthetic ankle fracture (PAF) still represent a difficult problem for orthopaedic surgeons. More recent generations of TAR have demonstrated lower rates of complications compared to older models. However, while various studies have demonstrated that the rate of PAF decreased between second- and third-generation implants, there is limited literature to suggest that this trend continued into fourth-generation implants. However, as the number of studies presenting data on fourth-generation implants has continued to increase, follow-up periods have reached acceptable lengths to adequately assess many complications, including PAF. Therefore, the objective of this systematic review was to compare the rate of PAF between third- and fourth-generation total ankle systems.
Methods:
The review encompassed Embase, MEDLINE, CINAHL, and CENTRAL databases from inception until March 2024, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Inclusion criteria pertained to articles discussing outcomes for primary TAR utilizing a specific third- or fourth-generation implant system. Further, only articles that specifically discussed PAF rates were included. Exclusion criteria pertained to case reports, previous systematic reviews or meta-analyses, non-English articles, revision TAR articles, and abstracts. Data extraction was performed by two independent readers, and implant-related information and complication rates were the primary metrics of interest. Finally, data-analysis was performed to compare the relative rates of ankle fracture for both third- and fourth-generation TAR systems. Comparison of rates was performed using a two-proportion z-test, with p-values less than 0.05 being considered statistically significant.
Results:
Out of the initially retrieved 489 articles, 23 met the inclusion criteria. A total of 2477 and 505 cases comprised the third- and fourth-generation implant groups, respectively. Follow-up durations of 82.14 and 35.75 months were reported for third- and fourth-generation groups, respectively. PAF rates were similar, with rates of 2.87% and 3.16% for third- and fourth-generation groups (p = 0.71). However, the fourth-generation group reflected lower rates of revision (p < 0.001) and hardware failure (p = 0.03) (Table 1). These results should be interpreted with caution as only articles that reported on the presence or absence of PAF were included, likely not including articles that focused primarily on other complications.
Conclusion:
In conclusion, this systematic review represents a robust comparison of PAF rates in third- and fourth-generation TAR systems. No significant difference in fracture rate was observed between both groups, suggesting that differences in implant generations is becoming less evident. While the PAF rate did increase in fourth-generation implants, both rates remain less than 4%. To understand other important metrics, such as different complication rates, long-term survivorship, and functional outcomes, future research is needed. However, this review utilizes a robust sample of nearly 3000 patients to suggest that PAF rates have remained the same as newer generation TAR has been introduced.
