Patient Reported Outcomes Improve Significantly and then Plateau at Six Months Following Total Ankle Arthroplasty

Abstract

Category: Ankle Arthritis; Ankle Introduction/Purpose: The time at which patients cease to feel improvement in pain and physical function following total ankle arthroplasty (TAA) is not well defined. Understanding this information will help surgeons guide patients toward informed surgical decisions and help set expectations for the postoperative period. Single-center patient registries for total ankle arthroplasty (TAA) are a robust and validated method of data collection and analysis. However, such registries may be numerically limited by patient follow-up and surgical volume. The current standard for outcomes-based research focused on TAA dictates that a minimum follow-up period of 2 years is necessary for publication of data. However, short-term patient-reported outcomes have not been shown to be less demonstrative than medium or long-term patient reported outcomes (PROs). Methods: Patients who underwent total ankle arthroplasty within a single institution’s PRO registry were screened for inclusion. Patients who completed preoperative and 12-month post-operative PROMIS Physical Function (PF), Pain Interference (PI), and/or Foot and Ankle Single Assessment Numeric Evaluation (FA SANE) were included in this analysis. Patients within this group that also completed PROs at 3-, 6-, and 24-months postoperatively had these timepoints included for analysis. After matching the cohort with scores at preoperative date and 12-month post-operative, differences between these PROs were determined parametrically with t-tests. Differences between preoperative and all other timepoints were determined non-parametrically with Kruskal-Wallis one-way ANOVA followed by Tukey’s test of post-hoc analysis. A p-value < 0.05 was considered statistically significant. Results: Our registry included 135 TAAs with completed baseline PROs. After excluding those that were non-compliant at the 12-month postoperative timepoint, analysis included 75, 73, and 66 unique patients with both preoperative and 12-month postoperative scores in PROMIS PF, PI, and FA SANE. Average baseline scores in PF, PI, and FA SANE were 39.3 ± 6.17, 63.3 ± 6.30, and 28.3 ± 20.9, respectively. Significant improvements were observed from baseline and every timepoint in PI and FA SANE. Improvements in PF were not significant between baseline and 3-months postoperatively but showed significant improvements at all following timepoints compared to baseline. No patient groups demonstrated significant improvement in each respective PRO between 6-months and any later postoperative timepoint (Figure 1). Conclusion: Patient-reported outcomes following TAA reached a plateau at 6-months following surgery and did not have significant improvements between 6 and 24 months. Therefore, the 6-month follow-up may be a good surrogate for final postoperative PRO score. Validation of 6-month follow-up as a strong marker of postoperative PRO may benefit TAA research by allowing for lower shorter average follow-up and allow for valuable studies regarding clinical outcomes in TAA. Shorter follow-up requirements in publications centered around PROs in TAA may lead to publications answering meaningful early outcome questions even prior to the 2-year post-op mark.