The rate at which seniors get their achy knees replaced has doubled over the past 20 years with rising obesity rates being one of the major factors driving the change, a new study in the Journal of the American Medical Association says.
Seniors getting knee replacements went from 31.2 procedures per 10,000 Medicare beneficiaries in 1991 to 62.1 procedures per 10,000 in 2010. There are now about 600,000 knee replacement operations costing $9 billion a year at the nation’s hospitals.
“This growth is likely driven by a combination of factors including an expansion in the types of patients considered likely to benefit from total knee arthroplasty, an aging population, and an increasing prevalence of certain conditions that predispose patients to osteoarthritis, most notably obesity,” wrote Peter Cram of the University of Iowa and his co-authors.
There has also been a sharp uptick in the rate of revisions – where an artificial knee fails and needs to be replaced. Total revisions increased from 9,650 or 3.2 procedures per 10,000 Medicare enrollees in 1991 to 19,871 or 5.1 procedures per 10,000 enrollees in 2010, the study found. The authors reviewed more than 3.2 million total knee replacement operations over the past two decades.
“All-cause” hospital readmission rates also jumped over the two decades, suggesting either declining competence among orthopedic surgeons performing the operations or declining health status for people undergoing the operations. Thirty-day readmission rates jumped from 4.2 percent in the 1991-1994 period to 5.0 percent in the 2007-2010 period, the study said.