Foot and Ankle International - 2026-04-23 - Journal Article
Association Between Obesity and Short- and Midterm Complications Following Total Ankle Replacement.
Teehan E, Shen V, Hossain MS, Fealy A, Chodos MD
Topics
Key Takeaway
Patients with BMI ≥40 undergoing total ankle replacement had 2.45× higher odds of 90-day major medical complications versus nonobese patients, while 5-year implant survival was statistically similar across BMI groups (86.4%–91.6%) but the study was underpowered to exclude clinically meaningful differences.
Summary Depth
Choose how much analysis to show on this article page.
Summary
This retrospective TriNetX database study stratified 3,533 primary TAR patients into four BMI cohorts to assess short- and midterm complications. BMI ≥40 was associated with significantly higher 90-day major medical complications (OR 2.45) and elevated periprosthetic fracture risk at 90 days for BMI ≥35 (OR 1.78–1.98); after propensity-score matching, only the 90-day medical complication risk remained significant. Five-year implant survival ranged 86.4%–91.6% across groups with no statistically significant difference, though the study was explicitly underpowered to detect clinically meaningful survivorship differences.
Key Limitation
The study is explicitly underpowered to exclude clinically meaningful differences in 5-year implant survival, particularly in the morbidly obese cohort (n=296), making the survivorship equivalence conclusion unreliable.
Original Abstract
BACKGROUND
Total ankle replacement (TAR) is increasingly used to treat end-stage ankle osteoarthritis, but the effect of obesity on complications and implant failure remains understudied. This study evaluates short- and midterm outcomes of TAR across body mass index (BMI) categories.
METHODS
This is a retrospective database cohort using TriNetX Research Database, a federated national database of deidentified electronic medical records from more than 100 health care organizations (HCOs). Patients ≥18 years who underwent primary TAR from 2014 to 2025 with minimum 2 years of follow-up were included. Patients were stratified by
BMI
<30 (nonobese), 30.0 to 34.9, 35.0 to 39.9, and ≥40. Our primary outcome was 5-year implant failure rate. Secondary outcomes included 90-day surgical site infections and major complications, as well as 1-year implant failure and 1- and 5-year periprosthetic joint infection (PJI) rates. Propensity-score matching (PSM) was performed comparing BMI <30 and BMI ≥35.
RESULTS
A total of 3533 patients (50% female; mean age across cohorts ranged 59-64 years) were analyzed, including 1511 nonobese patients, 1118 with BMI 30.0 to 34.9, 608 with BMI 35.0 to 39.9, and 296 with BMI ≥40. At 90 days postoperatively, patients with BMI ≥40 had higher rates of major medical complications vs nonobese patients (OR 2.45, 95% CI 1.28-4.68; P = .005). Also, by 90 days, periprosthetic fracture risk was also elevated in patients with BMI 35.0 to 39.9 (OR 1.78, 95% CI 1.07-2.97; P = .025) and ≥40 (OR 1.98, 95% CI 1.06-3.71; P = .030). In propensity score matching, only the risk of 90-day medical complications remained elevated in patients with BMI ≥35. With the numbers available, no significant differences were observed in 5-year implant failure, with implant survival of 90.0% in patients with BMI <30, 90.3% in BMI 30.0 to 34.9, 91.6% in BMI 35.0 to 39.9, and 86.4% in BMI ≥40. However, the study is underpowered to exclude clinically meaningful differences.
DISCUSSION
While 5-year implant survivorship appeared comparable across cohorts, patients with BMI ≥40 demonstrated a significantly higher risk of early postoperative medical complications. However, the study lacked sufficient power to definitively exclude clinically meaningful differences in long-term failure, particularly given the non-significantly lower survivorship in the morbidly obese.
LEVEL OF EVIDENCE
Level III, retrospective comparative study.