Background: Obesity is an epidemic, especially in developed countries. This affects the general health of these patients, especially when they are having a major surgical procedure such as total hip arthroplasty (THA). Several articles have described the effects of obesity on THA with varying conclusions. This metaanalysis aims to compare the outcomes, complications, and peri-operative parameters of THA in the obese (BMI!30 kg/m 2) vs non-obese (BMI<30 kg/m 2) population as well as a subgroup analysis of morbidly obese (BMI!40 kg/m 2) vs non-obese population. Methods: A multi-database search was performed according to PRISMA guidelines. Data from studies assessing the outcomes and complications of THA in the obese and non-obese population were extracted and analyzed. Results: Sixty-seven studies were included in this meta-analysis, consisting of 581,012 obese and 1,609,812 non-obese patients. Meta-analysis could not be performed on patient reported outcome measures due to heterogeneous reporting methods. Obese patients had a higher risk of all complications (OR ¼ 1.53, 95%CI: 1.30e1.80, P < 0.001), deep infections (OR ¼ 2.71, 95%CI: 2.08e3.53, P < 0.001), superficial infections (OR ¼ 1.99, 95%CI: 1.55e2.55, P < 0.001), dislocations (OR ¼ 1.72, 95%CI: 1.66e1.79, P < 0.001), reoperations (OR ¼ 1.61, 95%CI: 1.40e1.85, P < 0.001), revisions (OR ¼ 1.44, 95%CI: 1.32e1.57, P < 0.001), and readmissions (OR ¼ 1.37, 95%CI: 1.15e1.63, P < 0.001). When subgroup analysis of morbidly obese (BMI!40 kg/m 2) patients was performed, the risks of all these parameters were even greater. Conclusion: Obese and morbidly obese patients are at higher risks of complications post THA than nonobese patients. Surgeons should be aware of these risks in order to counsel patients and adopt prophylactic strategies to reduce these risks where applicable.
