Obesity is Associated with Early Total Hip Revision for Aseptic Loosening

Abstract Backgrounds Obesity affects over half a billion people worldwide, including one-third of men and women in the United States. Obesity is associated with higher postoperative complication rates after total hip arthroplasty (THA). It remains unknown whether obese patients progress to revision THA faster than non-obese patients. Methods 257 consecutive primary THAs referred to an academic tertiary care center for revision THA were retrospectively stratified according to body mass index (BMI), reason for revision THA, and time from primary to revision THA. Results When examining primary THAs referred for revision THA, increasing BMI adversely affected the mean time to revision THA. The percent of a primary THAs revised at 5 years was 25% for a BMI of 18-25, 38% for a BMI of 25-30, 56% for a BMI of 30-35, 73% for a BMI of 35-40, and 75% for a BMI of over 40 (p < 0.001). The percent of a primary THAs revised at 15 years was 70%, 82%, 87%, 94% and 100%, respectively (p < 0.001). A significant increase in early revision THA for aseptic loosening/osteolysis in obese patients (56%, 23/41) when compared to the non-obese patients (12%, 10/83, p < 0.001, relative risk ratio = 4.7). Conclusions Pre-operative BMI influences the time of failure of primary THAs referred to an academic tertiary care for revision THA as well as the mechanism of failure. Specifically, obesity increased in the relative risk of early revision THA due to aseptic loosening/osteolysis by 4.7-fold.