TKR Incidence Data in U.S.

How prevalent is total knee replacement (TKR) in the United States? A team led by Elena Losina, of Brigham and Women’s Hospital in Boston, Massachusetts, used a computer simulation of the history of knee osteoarthritis, together with data from two national surveys to estimate the incidence of TKR among U.S. patients with end-stage knee osteoarthritis.

As reported by Liam Davenport, medwireNews reporter, they estimated that the prevalence of TKR in adults aged 50 years and over was 4.2%. Women had a higher incidence, at 4.8%, and men had a lower one, at 3.4%. Total knee replacements increased with each additional decade in age for both males and females. Doctors diagnosed symptomatic knee osteoarthritis in 11.5% of adults aged 50 years and over. Women still led, at 13.3%, with men following at 9.4%.

Using U.S. Census data, the researchers estimate that 4, 007, 400 U.S. adults have had a TKR, and 536, 100 of that number now live with a revised TKR. Nearly 1.5 million of these primary TKRs were implanted in patients who were from 50 to 59 years old.

Losina and her team estimate that 11, 059, 800 adults in the United States have symptomatic knee osteoarthritis. The percentage of these individuals who have an intact TKR implanted in their bodies is about equally divided between men at 31.6% and women at 31.3%. More women, 5.1%, have had a revised TKR than men at 4.4%.

The researchers put the lifetime risk of having a TKR at 7% from the age of 25 in men and 9.5% in women. They put the life time risk of contracting knee osteoarthritis at 13.3% for men and 18.8% in women.

Davenport , in her article, quotes the authors in the Journal of Bone and Joint Surgery as writing, "While total knee replacement is a remarkably successful treatment for individuals with end-stage knee osteoarthritis, our findings emphasize the large public health burden posed by the millions of adults in the U.S. living with total knee replacement."