A comparison of outcomes in morbidly obese, obese and non-obese patients undergoing primary total knee and total hip arthroplasty

Background: Obesity is a growing public health issue with the prevalence of morbid obesity, (Body Mass Index (BMI) >= 40 kg/m(2)) increasing. There is some evidence these patients have more peri- and post-operative complications and poorer outcomes when undergoing arthroplasty procedures. This audit aimed to determine and compare the outcomes of non obese, obese and morbidly obese patients undergoing arthroplasty at our institution. Method: This was a retrospective audit of patients from our institution who had undergone total knee (TKA) or total hip arthroplasty (THA) in 2009. Data collected were: age, gender, BMI, length of stay (LOS), Oxford knee or hip score (OKS/OHS), satisfaction and complications up to two years post operation. Patients were divided into three groups: BMI < 30, BMI 30-40 and BMI > 40. Outcomes for each BMI group were compared. Results: 1014 TKA and 906 THA operations were included. When compared to obese and non-obese patients, morbidly obese patients undergoing TKA had a mean LOS one day longer, a mean OKS four points lower and higher rates of postoperative problems, 37% vs. 21%. For THA patients there was no difference in LOS, OHS score was two points lower for each increasing BMI category and postoperative problems increase from 25% for non-obese to 31% for obese and 38% for morbidly obese patients. Conclusion: These results will be useful in informing obese patients of their potential outcomes following TKA or THA. These patients can then make a more informed choice before proceeding with arthroplasty. (C) 2016 Royal College of Surgeons of Edinburgh (Scottish charity number SC005317) and Royal College of Surgeons in Ireland. Published by Elsevier Ltd. All rights reserved.