Obesity is an epidemic, with approximately 35% of the US population affected. This rate is unlikely to decline and may increase the demand for total knee arthroplasty (TKA). Data regarding the risks, benefits, and potential complications of TKA in this patient population are conflicting. Preoperative considerations are optimization of nutritional status, safe weight loss strategies, and bariatric surgery. Intraoperative concerns unique to this population include inadequate exposure, implant alignment, and durable implant fixation; postoperative issues include tibial loosening, wound complications, cardiovascular events, and respiratory complications. A thorough understanding of the medical and surgical complications associated with TKA in the obese patient will facilitate research efforts and improve outcomes.