Comparing Risk of Periprosthetic Ankle Fracture in Stemmed vs Non-Stemmed Implants Following Total Ankle Replacement

Research Type: Level 3 - Retrospective cohort study, Case-control study, Meta-analysis of Level 3 studies Introduction/Purpose: Total ankle replacement (TAR) has continued to rise in popularity for treatment of end-stage ankle osteoarthritis in the United States. Newer generations of TAR implants have introduced modifications in profile and fixation designs to expand surgical indications, improve survivorship, and minimize complications. The relative strengths between TAR fixation type, such as low-profile cages versus stemmed tibial fixation, remains a topic of interest in current literature. While several studies have described overall survivorship and complications between stemmed and non-stemmed implant designs, descriptions of incidence in periprosthetic fractures between TAR designs remains limited. As such, the objective of this review was to describe and compare rates of postoperative periprosthetic fracture between stemmed and non-stemmed total ankle implants. Methods: This review queried the 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 collected articles that described postoperative outcomes and complications following primary TAR. Furthermore, only articles that included or described any incidence of periprosthetic fracture following TAR were included. Case reports, previous systematic reviews, meta-analyses, non-English articles, abstracts, and revision TAR outcome papers were excluded. Two independent reviewers carried out data extraction, with implant type (stemmed or non-stemmed implant) and complication rates as the primary metrics of interest. Finally, data analysis was carried out comparing relative rates of ankle fracture between stemmed and non-stemmed TAR implants. 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 studies met the inclusion criteria. There was a total of 443 cases and 2,982 cases in the stemmed and non-stemmed groups, respectively. Incidence of periprosthetic fracture was similar between both groups, with rate of 2.71% and 2.92% respectively in the stemmed versus non-stemmed group (p = 0.81). Stemmed implants demonstrated a significantly lower rate of hardware failure (p < 0.01), but higher rates of aseptic loosening (p = 0.04), malalignment (p = 0.03), and gutter impingement (p < 0.01). There were no significant differences in rates of revision or infection between the two groups. These results should be considered with caution, understanding that the data was aggregated from only from articles that described periprosthetic fractures in TAR. Conclusion: This systematic review summarizes the incidence of periprosthetic fractures in stemmed and non-stemmed total ankle systems described in current literature. Both modes of tibial fixation demonstrated low rates of periprosthetic fractures without significant difference. These findings suggest that the degree of tibial fixation does not necessarily augment risk for postoperative fracture, though differences in other postoperative outcomes may exist.Future research to describe location and severity of periprosthetic fractures by implant type may help further elucidate the risk factors for this complication. Table 1: Comparison of postoperative complication rates between Stemmed and Stemless TAR Implants. P values less than 0.05 were bolded and considered significant.