Abstract
Background: Obesity is a major risk factor for osteoarthritis (OA) and negatively impacts both short-term and long-term outcomes following total knee arthroplasty (TKA). Bariatric surgery has been proposed as a strategy to improve surgical outcomes in obese patients; however, its effects on postoperative complications, hospital stay, healthcare costs, and revision rates remain insufficiently explored. This study investigates whether bariatric surgery before TKA is associated with improved outcomes. Methods: This retrospective cohort study utilized data from the Nationwide Inpatient Sample (NIS) from 2016 to 2019, including 2,519,099 TKA patients, of whom 56,291 had a history of bariatric surgery. Propensity score matching was applied to balance baseline characteristics between groups. Statistical analyses compared the length of hospital stay (LOS), total healthcare costs, postoperative complications, and revision rates. Results: Patients with a history of bariatric surgery exhibited significantly lower rates of sepsis, deep vein thrombosis (DVT), pulmonary embolism (PE), acute kidney injury (AKI), and ileus compared to those without. Additionally, these patients had a shorter LOS and slightly lower total hospital charges. However, the bariatric surgery group had higher rates of blood loss anemia, intraoperative fractures, and blood transfusions. Revision surgery rates were also higher in the bariatric surgery group, with mechanical loosening and prosthesis instability being more common etiologies. Conclusions: Bariatric surgery is associated with fewer early postoperative complications and shorter hospital stays in TKA patients, suggesting potential perioperative benefits. However, increased risks of blood loss anemia, intraoperative fractures, and revision surgery highlight the need for further research on long-term outcomes and alternative weight-loss strategies, such as pharmacologic interventions.