Should Obese Patients Undergo Bariatric Surgery before TJA?
Dr. Alexander McLawhorn answers questions from ICJR about the potential benefits of referring joint replacement patients with an elevated BMI for weight management that may include bariatric surgery.
ICJR: Is there a point – for example, a BMI level – at which you will recommend to patients with obesity that they undergo bariatric surgery before having a joint replacement procedure?
Alexander S. McLawhorn, MD, MBA: Let me start by summarizing what we know about bariatric surgery, or surgical weight management. It should be noted that bariatric surgery includes several different procedures, such as gastric bypass, gastric banding, and sleeve gastrectomy. Each procedure has slightly different effects on weight loss and a patient’s metabolism after surgery.
- Bariatric surgery procedures are safe, with complication rates and mortality rates similar to those of total joint replacement surgery. 
- The procedure is indicated for any patient with a BMI of 40 or more and for patients with a BMI of 35 or more plus an obesity-related comorbidity, such as diabetes, hypertension, or osteoarthritis. 
- Bariatric surgery is more effective than non-surgical methods for weight loss in terms of the amount of weight lost and the durability of the weight loss. 
- The procedure is effective at reducing comorbidity burdens, improving quality of life, and increasing life expectancy in morbidly obese patients. [3,4]
- Bariatric surgery creates a catabolic state. The impact of catabolism on outcomes after total joint replacement is unknown.
- The procedure can create a chronic malnourished state;  again, the impact on outcomes after total joint replacement is unknown.
- Osteopenia/osteoporosis and anemia are common after some bariatric procedures.
I use this information and my patient assessment to make an individualized decision about referring a patient to a weight management clinic for counseling about surgical and non-surgical options for weight loss. There is, however, little evidence to support any algorithm for referral for weight management. The following are my current practices for referral to a weight management program.
BMI of 50 or more: These patients are typically referred to a weight management program. Total joint replacement would be very technically demanding in patients at this BMI level, and the likelihood of a complication – which would be exceedingly challenging from both surgical and medical management perspectives – would be quite high. In patients whose BMI exceeds 55 or 60, body habitus may preclude performing safe total joint replacement procedure. Referral to a weight management program is a necessity.
BMI between 40 and 50: Although I counsel these patients about weight loss, I don’t automatically delay total joint replacement surgery, particularly in patients who have clinically and radiographically severe hip or knee arthritis and are becoming wheelchair-bound or homebound. I discuss with them the risks of surgery in the context of elevated BMI.
I also make implant choices (such as use of stems in total knees) and other intraoperative management decisions (such as weight-based dosing of antibiotics, use of betadine lavage, use of extra skin prep, and use of superficial drains) that are intended to minimize operative complications. In addition, I send these patients for a pre-anesthesia consult with our anesthesiologists as part of the preoperative screening and optimization process.
Patients with a BMI at this level but only mild to moderate osteoarthritis based on clinical examination and/or radiographic evidence are referred to a weight management program before I offer surgery. In my mind, these patients still have “tread on the tires,” and weight loss could improve their overall health and reduce joint pain. It may be possible to significantly delay or even prevent total joint replacement in these patients if they lose enough weight. 
BMI between 30 and 40: I usually do not refer these patients to a weight management program, but I will counsel them on weight loss.
Body habitus and the distribution of fat is also a consideration for joint replacement surgery:
- I do not offer anterior approach total hip replacement to morbidly obese patients because an abdominal pannus is typically present and is a risk factor for surgical site infection (SSI).
- With the posterior approach to the hip, the depth of fat overlying the greater trochanter directly impacts the difficulty of the procedure, surgical time, and risk for complications including SSI and implant malposition.
- In total knee patients, a large amount of fat overlying the medial thigh forces the knees into varus alignment and places a large adduction moment on the knee, which I think is a risk factor for mechanical failure after the procedure.
Patients with end-stage hip and knee arthritis who have failed bariatric surgery and/or remain morbidly obese after bariatric surgery present a challenging dilemma, as they probably represent a very high-risk population for complications after hip and knee replacement secondary to body habitus, co-morbid conditions, and chronic malnutrition.
ICJR: Is there evidence in the literature that bariatric surgery is of value in these patients, such as reducing complications or improving outcomes of the joint replacement surgery?
Dr. McLawhorn: There is literature for and against bariatric surgery prior to total joint arthroplasty, but the quality and quantity are limited and the level of evidence is generally low. Several clinical studies support the benefits of bariatric surgery, [7-10] while an equal number of clinical studies question its benefit in this regard. [11-14] A computer-based model that I published with colleagues suggests that bariatric surgery before total knee replacement is probably a cost-effective recommendation from a societal perspective. 
The principal issue with most of the existing clinical literature is that the groups that were compared were too dissimilar. For example, selection bias affects studies in which morbidly obese patients who underwent bariatric surgery are compared with those that did not. Patients who have bariatric surgery tend to have higher BMIs and more comorbidities than those who do not have the surgery. Fair and relevant comparisons should involve matching the cohorts of morbidly obese patients based on their pre-bariatric condition.
My colleagues and I presented such a study at the American Association of Hip and Knee Surgeons’ meeting involving a cohort of patients from New York state.  In our analysis, patients with morbid obesity who underwent bariatric surgery before total joint replacement had a reduction in comorbidities and in-hospital complications after both total hip and total knee replacement. Prior bariatric surgery in our cohort reduced the risk for 90-day postoperative complications after total knee replacement but not after total hip replacement. In addition, bariatric surgery did not reduce the risk for revision surgery or the risk for postoperative dislocation after total hip replacement surgery. 
I think it’s important to note that in our study, arthroplasty outcomes were not worse in patients who had prior bariatric surgery,  contrary to what had been speculated in past research. It is my opinion that orthopedic surgeons can recommend bariatric surgery to morbidly obese patients with hip and knee osteoarthritis and have a fair amount of confidence that it will reduce weight, improve quality of life, and lessen the comorbidity burden without compromising joint replacement outcomes.
Keep in mind, however, that the optimal timing for bariatric surgery, optimal type of bariatric surgery, evidence-based targets for weight loss, and markers indicating optimal nutritional status for joint replacement after bariatric surgery have not been established.
Further, it is important to ensure that patients with hip and knee osteoarthritis who are referred for weight management do not feel abandoned by their orthopedic providers. Clinical care pathways and clinical care coordinators may be helpful to patients in this regard.
- Colquitt JL, Pickett K, Loveman E, Frampton GK. Surgery for weight loss in adults. Cochrane Database Syst Rev. 2014 Aug 8;8:CD003641.
- SAGES Guidelines Committee. SAGES guideline for clinical application of laparoscopic bariatric surgery. Surg Obes Relat Dis. 2009 May-Jun;5(3):387-405. Epub 2009 Feb 23.
- Puzziferri N, Roshek TB 3rd, Mayo HG, Gallagher R, Belle SH, Livingston EH. Long-term follow-up after bariatric surgery: a systematic review. JAMA. 2014 Sep 3;312(9):934-42.
- Kim J, Eisenberg D, Azagury D, Rogers A, Campos GM. American Society for Metabolic and Bariatric Surgery position statement on long-term survival benefit after metabolic and bariatric surgery. Surg Obes Relat Dis. 2016 Mar-Apr;12(3):453-9. Epub 2015 Nov 27.
- Blume CA, Boni CC, Casagrande DS, Rizzolli J, Padoin AV, Mottin CC. Nutritional profile of patients before and after Roux-en-Y gastric bypass: 3-year follow-up. Obes Surg. 2012 Nov;22(11):1676-85.
- Springer BD, Carter JT, McLawhorn AS, Scharf K, Roslin M, Kallies KJ, Morton JM, Kothari SN. Obesity and the role of bariatric surgery in the surgical management of osteoarthritis of the hip and knee: a review of the literature. Surg Obes Relat Dis. 2017 Jan;13(1):111-118. doi: 10.1016/j.soard.2016.09.011. Epub 2016 Sep 14.
- Parvizi J, Trousdale RT, Sarr MG. Total joint arthroplasty in patients surgically treated for morbid obesity. J Arthroplasty. 2000 Dec;15(8):1003-8.
- Kulkarni A, Jameson SS, James P, Woodcock S, Muller S, Reed MR. Does bariatric surgery prior to lower limb joint replacement reduce complications? Surgeon. 2011 Feb;9(1):18-21. Epub 2010 Sep 27.
- Werner BC, Kurkis GM, Gwathmey FW, Browne JA. Bariatric Surgery Prior to Total Knee Arthroplasty is Associated With Fewer Postoperative Complications. J Arthroplasty. 2015 Sep;30(9 Suppl):81-5. Epub 2015 Jun 3.
- Watts C, Martin JR, Houdek M, Abdel M, Lewallen D, Taunton M. Prior bariatric surgery may decrease the rate of re-operation and revision following total hip arthroplasty. Bone Joint J. 2016 Sep;98-B(9):1180-4
- Severson EP, Singh JA, Browne JA, Trousdale RT, Sarr MG, Lewallen DG. Total knee arthroplasty in morbidly obese patients treated with bariatric surgery: a comparative study. J Arthroplasty. 2012 Oct;27(9):1696-700.
- Inacio MC, Paxton EW, Fisher D, Li RA, Barber TC, Singh JA. Bariatric surgery prior to total joint arthroplasty may not provide dramatic improvements in post-arthroplasty surgical outcomes. J Arthroplasty. 2014 Jul;29(7):1359-64. Epub 2014 Feb 26.
- Nickel BT, Klement MR, Penrose CT, Green CL, Seyler TM, Bolognesi MP. Lingering Risk: Bariatric Surgery Before Total Knee Arthroplasty. J Arthroplasty. 2016 Sep;31(9 Suppl):207-11. Epub 2016 Mar 15.
- Martin JR, Watts CD, Taunton MJ. Bariatric surgery does not improve outcomes in patients undergoing primary total knee arthroplasty. Bone Joint J. 2015 Nov;97-B(11):1501-5.
- McLawhorn AS, Southren D, Wang YC, Marx RG, Dodwell ER. Cost-Effectiveness of Bariatric Surgery Prior to Total Knee Arthroplasty in the Morbidly Obese: A Computer Model-Based Evaluation. J Bone Joint Surg Am. 2016 Jan 20;98(2):e6.
- McLawhorn AS, Levack AE, Lee YY, Ge M, Do H, Lyman S, Dodwell ER. Bariatric Surgery Improves Outcomes after Lower Extremity Arthroplasty in the Morbidly Obese: A Propensity Score-Matched Study. AAHKS 26th Annual Meeting. http://meeting.aahks.net/wp-content/uploads/2016/10/16_paper-44-levack.pdf. Accessed 25 July 2017.
About the Expert
Alexander S. McLawhorn, MD, MBA, is Assistant Attending Orthopedic Surgeon, Adult Reconstruction & Joint Replacement, at Hospital for Special Surgery, New York, New York.
Dr. McLawhorn has disclosed that he is a paid consultant for Ethicon US, LLC, and Intellijoint Surgical Inc.