Do Morbidly Obese (BMI >40) Patients Have Increased Healing Complications Post Orthopedic Total Knee Replacement (TKA)?:A Narrative Review of Recent Literature

Abstract

Introduction: Faced with the looming obesity epidemic, orthopedic surgeons are finding an increase in demand and popularity of joint replacement surgeries, particularly those of the knee. Equally alarming is the younger age and higher BMI at which patients are electing to have the procedure performed, despite attempts at weight management and other interventions. Along with the innumerable comorbidities associated with obesity it is proving to be a challenge for orthopedic surgeons especially in terms of postoperative complications for patients at an elevated BMI.

Objective: Our aim is to investigate retrospective analyses within the last ten years and analyze those within the preoperatively morbidly obese class and observe the general increase in complications specifically post-total knee arthroplasties.

Methods: Studies were selected based on publication within the last ten years having a focus on the outcomes and complications of primary total knee arthroplasty comparing both non-obese and obese patients.

Report: Morbidly obese patients had an increase in post-operative infections, wound dehiscence, and genitourinary-related complications. Additionally, morbid obesity had a statistically significant independent risk factor for implant failures, revisions, hospital readmission, and postoperative morbidity. Conversely, patients with BMI > 40 were found to have shorter hospital stays and lower transfusion rates.

Discussion: An overwhelming majority of the studies cited within this article and those within the general literature concluded that there are increased complications with obesity and TKA. Additionally, infection was a common complication after TKA in those that were considered morbidly obese. Lastly, morbid obesity was also found to be an independent risk factor for complications in patients who underwent TKA.

Conclusion: A BMI > 40 appeared to independently increase the risk for a variety of in hospital, short term, and long-term complications following a total knee arthroplasty (TKA), even after consideration of comorbid and other related variables. However, morbid obesity seems to only be a moderate independent risk factor and did not pose systemic complications. Further research with less potential for confounding bias is necessary to further determine the impact of morbid obesity on the outcomes of TKA, as well as to establish a standardized BMI at which negative outcomes are less associated.