A new study observing the risk of total knee replacement revision or failure at a high-volume orthopedic hospital found that race and poverty were not significant factors in risk for knee replacement surgeries.
Previous studies established that black patients have a higher risk for knee replacement revision and also report more pain and worse joint function two years after the operation when compared to white patients. However, the new study published in Arthritis Care & Research found minimal trends in race as a risk factor and zero trend in poverty.
At New York’s Hospital for Special Surgery between January 2008 and February 2012, 4,062 patients had a total knee replacement. Among them, 122 (3%) required revisions at a median of five years of follow-up. The risk of knee replacement revision was 1.7 times higher in black patients compared to white patients, but researchers found that race and poverty were not driving factors, nor did they explain differences in patients with knee replacement failure.
“There was a trend toward race being a risk factor, but it was not statistically significant, and poverty had no impact: There wasn’t even a trend,” HSS rheumatology fellowship program director and lead study author Dr. Anne Bass said in prepared remarks. “We were definitely surprised by our results.”
Instead of race and poverty, the study found that factors associated with higher risk for revision included younger age, being male and the use of constrained prosthesis (a knee implant designed to provide stability). Risk factors influencing failure included treatment from a surgeon who performs a low number of knee replacement surgeries, as well as patients’ low expectations for improvement.
“Younger people and males are typically more active, putting more strain on their implants,” added HSS orthopedic surgeon and study author Dr. Mark Figgie. “Constrained prostheses are only used in patients with bigger deformities and ligament imbalances, which tend to put more strain on the implant and loosen the bone-cement interface. Our findings suggest that all patients should seek care from experienced surgeons at a high-volume hospital.”
The research team is set to begin a new study with data from about one million patients across California, New York, Florida, Arizona and Arkansas, according to a news release. The study would explore the risk factors associated with race and poverty in knee replacement revision on a larger scale and is expected to be completed later this year.
“We are asking the same questions about race and poverty, and we will be able to look at the influence of hospital choice on the risk of revision by linking to the American Hospital Association database,” Bass said. “We are also looking at differences in revisions caused by infections versus mechanical issues.”