Should There Be Strict BMI Cutoffs for TKA and THA?
Recently we posted a blog about candidacy for and outcomes of Total Knee Arthroplasty (TKA) and Total Hip Arthroplasty (THA) in morbidly obese patients who underwent pre-operative weight loss. Operating on obese patients for TKA and THA continues to be a hot button topic of risk versus reward.
Two well-respected orthopedic authorities, recently faced off to have a deeper conversation about whether or not orthopedic surgeons should have strict BMI cutoffs for performing primary TKA or THA. Benjamin F. Ricciardi, MD engaged Thomas K. Fehring, MD, from OrthoCarolina and Nicholas Giori, MD and PhD, a Stanford University professor, to face off. Highlights are summarized below.
Q: To what degree does the evidence support a strict BMI cutoff to determine eligibility for primary TKA and THA?
Dr. Fehring noted many Americans (35%) are obese and the association between patients with a BMI above 40 and surgical complications/infection is irrefutable. He recommends looking at big data such as Medicare or Veterans Affairs, meta-analysis, and position statements by specialty medical societies. All findings to date underscore the need to have a strict cutoff, but Dr. Fehring noted it’s important to develop weight loss strategies for patients prior to arthroplasty.
Dr. Giori agreed that obesity is undeniably related to complications, but BMI is a weak risk factor compared to others that are commonly accepted (such as heart and metabolic disorders).
Q: Given the expansion of strict BMI cutoffs at the administrative level, how should safety (non-maleficence) be balanced against access to care?
Dr. Giori said that while BMI cutoffs are well-intended, the ones currently used have the effect of arbitrarily rationing care without medical justification. Also, he feels it disproportionately affects minorities, women and patients in low socio-economic classes. In his opinion, the decision should be based on joint decision making between the doctor and the patient. Risk adjustments in payment models (for doctors’ compensation) would help in the future.
Dr. Fehring agreed with many of the points, but at a certain point the risk outweighs the benefit, and attempting to operate on all patients regardless of BMI becomes dangerous. Keeping his “do no harm” obligation in mind, Dr. Fehring stated a BMI cutoff of 40 as a reasonable goal for patient safety.
Q: If a patient with morbid obesity is to undergo arthroplasty, what steps should be taken before surgery to make hip or knee arthroplasty safer?
Dr. Fehring recommended the patient be in the best possible health they can be prior to elective surgery to avoid complications. An optimization program, factoring in body weight, blood glucose control, serum albumin, and smoking status are part of his clinic’s protocol; patients get tools to meet and stick to set goals before getting surgery. It’s not just about treating the knee or hip; it’s about treating the whole patient as well, he said.
Dr. Giori recognized that optimization programs can help and his clinic also offers one, but the best that can be done regarding obesity is encouragement and education, and referring the patient to a structured weight-reduction program. On the flipside, the patient should do his or her best to lose weight to get below a given BMI threshold. From there, doctor and patient can create a shared decision-making plan that may or may not involve surgery.
If you’d like to discuss weight concerns prior to your total knee or hip, please contact our office. We’ll help you return to your healthy, pain-free lifestyle.