NEW ORLEANS – Performing bariatric surgery prior to total knee or hip replacement instead of vice versa resulted in significantly shorter orthopedic surgical operating time and length of stay in an observational study, Emanuel E. Nearing II, MD, reported at Obesity Week 2016.

“We propose that strong consideration be given to bariatric surgery as a means of weight loss and BMI [body mass index] reduction in patients with obesity prior to total joint replacement,” he said at the meeting presented by the Obesity Society of America and the American Society for Metabolic and Bariatric Surgery.

The question of which type of surgery to perform first in patients deemed likely to benefit from both is an important and highly practical one. At present orthopedic surgeons perform 320,000 total hip arthroplasties and more than 600,000 total knee arthroplasties annually. By 2030, it’s estimated that those figures will soar by 174% and 673%, respectively, noted Dr. Nearing, a bariatric surgery fellow at the Gundersen Health System in La Crosse, Wisc.

“A common complaint of patients presenting with obesity is that their osteoarthritis has limited their mobility and that their weight gain is secondary to that reduced mobility. They believe that a new joint will help them regain their mobility and then lose weight. Interestingly, this does not appear to be the case. In fact, the majority of patients in our study actually gained weight following joint replacement. Given that, these patients need to be weight-optimized prior to total joint replacement. Bariatric surgery is a durable way to facilitate this,” he continued.

Dr. Nearing presented a retrospective observational study of 102 patients who underwent either laparoscopic Roux-en-Y gastric bypass or laparoscopic sleeve gastrectomy plus a total knee or hip replacement in the Gundersen system. Sixty-six patients had their bariatric surgery first, by a mean of 4.3 years, while the other 36 had arthroplasty a mean of 4.9 years before their bariatric surgery. The two groups were similar in terms of demographics and baseline comorbid conditions.

Patients who had their total joint replacement first had a mean preoperative BMI of 43.7 kg/m² and a mean pre–bariatric surgery BMI of 46.3 kg/m². The patients who had bariatric surgery first had a preoperative BMI of 49.6 kg/^m2 and a mean pre–orthopedic surgery BMI of 37.6 kgm². One year after joint replacement surgery, patients who had that operation first had a mean BMI of 43.9 kg/m², compared with 37.8 kg/m² for those who waited until after they underwent bariatric surgery.

Mean operative time for total joint replacement when it was the first operation was 113.5 minutes and substantially less at 71 minutes when it was done after bariatric surgery. Mean hospital length of stay for total joint replacement when it followed bariatric surgery was 2.9 days, a full day less than when joint replacement came first.

Rates of complications including skin or soft tissue infection, venous thromboembolism, hematoma, need for transfusion, and periprosthetic infection at 30 and 90 days didn’t differ between the two groups. Neither did the need for late reinterventions.

Dr. Nearing noted that a working group of the American Association of Hip and Knee Surgeons has conducted a review of the orthopedic surgery literature and concluded that all patients with a BMI of 30 kg/m² or more undergoing total knee or hip arthroplasty are at increased risk for perioperative respiratory complications, thromboembolic events, delayed wound healing, infection, and need for joint revision surgery (J Arthroplasty. 2013 May;28[5]:714-21).

He observed that a retrospective study such as his cannot shed light on the optimal time interval for total joint replacement following bariatric surgery. That key question is being addressed by the ongoing prospective SWIFT (Surgical Weight-Loss to Improve Functional Status Trajectories Following Total Knee Arthroplasty) trial. The study hypothesis is that bariatric surgery prior to the knee replacement surgery will reduce risk and improve long-term outcomes and physical function.

Several audience member commented that, based upon their experience, they would have anticipated that complication rates would have been significantly lower in total joint replacement patients when that operation followed bariatric surgery.

“We were surprised, too,” Dr. Nearing replied. “I think the explanation is that at Gundersen we have three bariatric surgeons and only a handful of orthopedic surgeons, and we use protocols and pathways. We just routinely do our operations the same way each and every time.”

John M. Morton, MD, a former American Society for Metabolic and Bariatric Surgery president, commented that the Gundersen study findings sound a call for more cross-specialty collaboration in steering obese patients with severe knee or hip osteoarthritis to bariatric surgery first in order to maximize the results of the joint replacement surgery.

“I think we’re all seeing weight loss as another form of prehabilitation for other specialties. Our orthopedic colleagues are kind of like us – surgeons – so this seems to be a great place for us to partner with them,” said Dr. Morton, chief of bariatric and minimally invasive surgery at Stanford (Calif.) University.

Dr. Nearing reported having no financial interests relevant to his study.

bjancin@frontlinemedcom.com

Bariatric surgery or total joint replacement: which first?