Background Studies examining national trends in total ankle arthroplasty (TAA) in the U.S. are lacking.

Objectives To assess the time-trends in utilization, clinical characteristics and outcomes of patients undergoing total ankle arthroplasty (TAA) in the U.S.

Methods We used the Nationwide Inpatient Sample (NIS) data from 1998 to 2010 to examine time-trends in the utilization rates of TAA. We used the Cochran Armitage test for trend to assess time-trends across the years and the analysis of variance (ANOVA), Wilcoxon test or chi-squared test (as appropriate) to compare the first (1998-2000) and the last time periods (2009-10).

Results TAA utilization rate increased significant from 1998 to 2010: 0.13 to 0.84 per 100,000 overall, 0.14 to 0.88 per 100,000 in females and from 0.11 to 0.81 per 100,000 in males (p<0.0001 for each comparison for time-trends). Compared to the 1998-2000, those undergoing TAA in 2009-10: were older (41% fewer patients <50 years, p<0.0001); less likely to have RA as the underlying diagnosis (55% fewer patients, p=0.0001); more likely to have Deyo-Charlson index of two or more (197% more, p=0.0010); and had a shorter length of stay at 2.5 days (17% reduction, p<0.0001). Mortality was rare, ranging 0 to 0.6% and discharge to inpatient facility ranged 12.6-14.1%; we noted no significant time-trends in either (p>0.05).

Conclusions The utilization rate of TAA increased rapidly in the U.S. from 1998 to 2010, but post-arthroplasty mortality rate was stable. Underlying diagnosis and medical comorbidity changed over time and both can impact outcomes after TAA. Further studies should examine how the outcomes and complications of TAA have evolved over time.

Disclosure of Interest J. Singh Grant/research support from: takeda, savient, Consultant for: Takeda, Savient, Allergan, Regeneron, R. Ramachandran: None declared