Knee Surgeries Skyrocket with More Aging, Active Adults

Sep. 24, 2012
Stephen Kates, M.D.

Total knee arthroplasty is one of the most common and costly elective surgeries in the United States, with a volume that soared 162 percent since 1991 among those receiving Medicare benefits, according to a report today in the Journal of the American Medical Association.

Patient demand, a higher number of Medicare enrollees, and more osteoarthritis due to obesity are among the factors that drove the rapid rise in surgeries, the study said. And although the marked growth in total knee arthroplasty suggests the procedure is largely safe, successful, and extremely popular among active older adults, the JAMA report also noted the high volume could be viewed as a source of strain on the government, insurers, individuals and businesses struggling with how to contain health care spending.

The report is timely and hints at the complexities of restraining costs within a changing health care environment, said Stephen L. Kates, M.D., professor of Orthopaedics at the University of Rochester Medical Center, and a co-author on the study. Lead author was Peter Cram, M.D., M.B.A., of the University of Iowa Carver College of Medicine. Yue Li, Ph.D., a policy and outcomes researcher in the Department of Community and Preventive Medicine at URMC, also was a co-author on the study.

“We’ve identified a number of interesting trends that we hope will add to the national conversation on health and economic policies,” Kates said. “Knee replacement surgery has become one of the most expensive diagnoses in medicine today because it is growing disproportionately to the population.”

Craig Ward, a 56-year-old lifelong athlete and sanctioned bowler, is among the millions of people who have benefitted from knee replacement. In 1987 he had arthroscopic surgery on both knees. After subsequent injuries, years of cortisone injections and over-the-counter pain relievers, Ward elected to have Kates replace the left knee on June 25, 2012.

His goal was to return to work a month ahead of the usual, three-month recovery period – and he did, on Aug. 27. Ward attributes his speedy recovery to doing homework before the procedure, knowing what to expect, and pushing hard at rehabilitation. He is already bowling twice a week again, and plans to compete in the annual New York State tournament next spring.

“Having a goal in mind and being doggedly determined – I think those are the factors that allowed me to get back to what I was doing before,” said Ward, a Fairport, N.Y. resident.

The JAMA study involved observation of nearly 3.6 million patients ages 65 and older, who underwent primary and revision knee surgery during the past 20 years, to look for changes in volume, utilization, and outcome.

Per-capita utilization of primary knee surgery jumped 76 percent, and the volume of revision surgery increased 99 percent. Rates of poor outcomes remained stable, but 30-day readmission rates went up slightly (4.2 percent to 5 percent), as did the prevalence of obesity and diabetes. Another major trend, the study said, is the move toward outpatient rehabilitation and a significant decline in length-of-stays in the hospital. The latter was accompanied, however, by increasing readmission rates in recent years. Among those who had revision surgery, researchers charted a rise in hospital readmissions due to infections.

As middle-aged and older adults attempt to remain pain-free and active for as long as possible, data suggests that approximately 500,000 total knee arthroplasties (TKA) are performed annually in the U.S. – at a cost of about $15,000 per surgery or $9 billion per year.

Because of a lack of a national registry, however, researchers could not investigate whether all or most surgeries are being done appropriately, after following clinical guidelines for managing knee osteoarthritis with medications and physical therapy.  

An accompanying JAMA editorial focused on the cost issue. It suggested that payment structures may need to change, to bundle the total cost from preoperative care through the recovery period. The editorial also suggested a future system in which high-volume joint replacement centers, which have the experience and infrastructure to keep costs lower, would take the majority of cases.

“It is difficult to determine the extent to which growth in TKA utilization represents growth in appropriate use of a highly effective procedure or overuse of a highly reimbursed procedure,” the study authors said. “It is likely that both factors are at play.”

Kates receives research funding from the Agency for Healthcare Research and Quality (AHRQ), Synthes USA, American Geriatric Society, Orthopaedic Research and Education Foundation, National Institute of Arthritis and Musculoskeletal and Skin Diseases, and the AO Trauma, which recently awarded $3 million to Kates and colleagues to study drug-resistant staph infections in joint replacement and fracture repair.

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