If it seems as though everyone’s getting a knee replaced these days, well, yes, they are.

Research published Wednesday in the Journal of the American Medical Association (JAMA) looked at Medicare records for more than 3.2 million people from 1991 to 2010, tracking the number of primary arthroplasty procedures (initial total knee replacement surgeries) and subsequent replacements, or revisions, of those artificial joints.

The number of initial knee replacements rose from 93,230 procedures in 1991 to 243,802 in 2010 (a 161.5-percent increase). And the number of revision surgeries increased from 9,650 to 19,871 in that time (nearly a 106-percent jump).

The authors determined that the increase wasn’t simply due to people’s turning 65 and becoming eligible for Medicare in droves. Rather, it seems more people have elected to undergo arthroplasty over the years; the study found per-capita use of the procedure jumped by nearly 60 percent over the 20 years it analyzed.

The study further found that as the amount of time patients remained in the hospital for primary knee-replacement surgery shortened from an average of almost eight days to 3.5 days, 30-day readmission rates after primary surgery grew from 4.2 percent to 5 percent. Rates of infection related to revision surgeries rose from 1.4 percent to 3 percent.

Knee replacement is typically undertaken as a means of relieving pain and increasing mobility and quality of life for people with osteoarthritis of the knee. The prevalence of that condition has increased in recent decades as obesity has become more common; being obese increases the risk of developing osteoarthritis of the knee. In the study, prevalence of obesity rose from 4 percent to 11.5 percent between 1991 and 2010.

Are you among the many who've had a knee replaced? How'd that go for you?