Muyibat A. Adelani, MD discusses her field in Obesity and Osteoarthritis.
[MUSIC PLAYING] MUYIBAT ADELANI: Hi, my name is Muyibat Adelani. I'm an assistant professor here in orthopedic surgery at University of Chicago Medicine. And today, we're going to talk about obesity and osteoarthritis. I have no financial disclosures to make of any kind. For a long time, obesity has been linked to both the cause of osteoarthritis and its treatment. This talk will review the relationship between obesity and the etiology of osteoarthritis as well as the impact that obesity has on the way we treat osteoarthritis, particularly in the hip and knee. For the purpose of this talk, we'll define obesity as a BMI of 30 or greater. As we all know a significant portion of the American population is either overweight or obese. Obesity has been linked to both an increased prevalence of osteoarthritis as well as greater severity of disease. The risk of developing the arthritis is four times higher in obese men and five times higher in obese women than in non-obese patients. Patients with a BMI of greater than 40 are more than eight times more likely to require a total hip replacement in their lifetime than a non-obese patient. Thus, the increasing epidemic of obesity will likely lead to an increased burden of osteoarthritis, in this case, the population. The classic theory behind obesity and osteoarthritis, or the so-called intuitive biomechanical theory, suggests that increased body weight leads to increased forces around the joint. And those increased forces lead to increased articular cartilage wear and subsequent osteoarthritis. This theory is mostly studied in the knew where forces across the knee joint have been shown to be up to three times more than body weight while walking and up to six times body weight while climbing stairs. These increased forces across the knee joint may lead to changes in the density of the bone below the cartilage and subsequent articular cartilage wear. There are also receptors on the chondrocytes themselves that may sense these mechanical forces and lead to an increased secretion of cytokine, which leads to increased articular cartilage inflammation and wear and subsequent osteoarthritis. Recently, there's been an increased interest in this biomechanical response. More and more evidence is pointing to an inflammatory response as a component of the association between obesity and osteoarthritis. White adipose tissue, which is excessive in obese individuals can act as an endocrine organ which actually secrete numerous pro-inflammatory and immunomodulatory cytokines. This is supported by the fact that inflammatory markers are found to be elevated in obese individuals. Additionally, certain cytokines are produced by white adipose tissue and are found to be elevated in both the plasma and synovial fluid of obese patients. The most studied of these cytokines is leptin. Although the relationship between these cytokines and systemic inflammation is not entirely understood, it is thought that this pro-inflammatory state, which is implicated in multiple diseases including metabolic syndrome is the same as that which causes osteoarthritis. So in addition to the prevalence and severity of osteoarthritis, obesity may also be linked to the pain associated with it. Obesity has been found to be associated with numerous musculoskeletal pain syndromes including fibromyalgia as well as depression. Weight loss has been shown to drastically reduce or even eliminate hip and knee pain even in those with significant osteoarthritis. Most studies demonstrating this have been in the bariatric patient population where massive amounts of weight loss have been shown to significantly decrease pain and improve function after bariatric surgery. Obesity is also a major risk factor for complications in the surgical management of osteoarthritis. Up to 30% of obese patients undergoing total hip and knee replacement may experience some sort of complication. It is very difficult to separate obesity from the other problems that follow it such as diabetes and hypertension, but it has been well demonstrated in the literature that complication significantly increase in obese patients. These complications include venous thromboembolism, which is most likely related to decreased mobility after surgery and venous stasis, wound complications, which can be double that in non-obese patients, deep surgical site infections, which may increase three to nine-fold compared to non-obese patients, as well as surgical complications. The surgery in obese patients is very technically demanding and physically difficult. And this may result in component malposition, total hip-joint dislocation, prosthetic loosening, and even subsequent failure requiring revision surgery. Obesity may also be associated with longer operative times, longer hospitalizations, and higher medical costs. It has shown that obesity may be associated with lower functional scores following surgery, including a lower WOMAC score and lower knee society scores, although this has been inconsistent across the literature. Total joint replacement in obese patients is associated with so many negative result. Why you can consider it. Well there are many potential benefits worth considering, including pain relief and improved function. Some even suggest that total joint replacement may allow for improved exercise tolerance and subsequent weight loss after surgery. Although multiple studies have demonstrated that increase activity levels and weight loss do not typically occur after joint replacement. Nevertheless, we know that total joint replacement can be life changing in patients with debilitating osteoarthritis including those who are obese. Our American Association of Hip and Knee Surgeons has released its own consensus statement, which states the following, "The morbidly obese and super obese have complication profiles that may outweigh the functional benefits of total joint arthroplasty. These patients should be counseled regarding these risk prior to any surgical intervention. It is our consensus opinion that consideration should be given to delaying total joint arthroplasty in a patient with a BMI of greater than 40, especially when associated with other comorbid conditions, such as poorly controlled diabetes or malnutrition." So what does this really mean? To me, this means that we need to look at all patients, including those who are obese as individuals and evaluate their own risk-benefit profile. If we believe that the benefits outweigh the risk in that particular patient, then total joint replacement is worth considering. However, if we believe that this patient can be further optimized with either weight loss and or control of their other comorbid conditions, that should be initiated prior to consideration of total joint arthroplasty. So in summary, obesity creates both a biomechanical and physiologic environment that predisposes patients to osteoarthritis. Weight loss has potential to improve that, and subsequently, improve the pain associated with hip and knee arthritis in these patients. For patients in whom weight loss alone is not enough to improve symptoms or in whom weight loss is not possible, total joint replacement is a reasonable alternative. The potential benefits of surgery must therefore be balanced against the increased risk of any perioperative complication. Thank you so much for your time.
