FRIDAY, May 31 , 2013 (HealthDay News) -- Although knee-replacement surgery has improved dramatically over the years -- with smaller incisions and better pain management and rehabilitation -- the procedure's success may depend on socioeconomic factors, new research finds.
Lower-income patients are more likely to be dissatisfied and have worse knee function than more affluent patients following knee replacement, according to the study, which was published online recently in the journal Clinical Orthopaedics and Related Research.
Researchers led by Dr. Robert Barrack, of the Washington University School of Medicine in St. Louis, examined more than 600 people who underwent knee-replacement surgery at one of five major total joint centers across the United States. The patients, whose average age was 54, were asked about their job, their level of education and their income. The study also took participants' gender and ethnicity into account.
The patients completed questionnaires following their surgery to determine how satisfied they were with the results of the procedure.
Patients' income levels were linked to their level of satisfaction with their knee replacement, the study revealed. Those making less than $25,000 a year were less satisfied with the procedure and had more limitations with their knee function after surgery, according to a journal news release.
Income level was the only socioeconomic factor that affected patients' satisfaction with their knee replacement, the researchers said. Women and minority patients, however, were more likely to report having functional limitations after surgery.
Inadequate postsurgical rehabilitation for patients with lower incomes could help explain their findings, the researchers said. They noted that previous studies have shown that minority patients are more likely to be treated at hospitals that do not perform as many knee-replacement procedures as high-volume specialist centers, where overall satisfaction levels are high.
The researchers said the study did not find a cause-and-effect relationship between lower income and dissatisfaction with knee-replacement surgery, but said the association was "significant."
"It is certainly possible, based on our results, that socioeconomic factors -- particularly household income -- may be strongly associated with satisfaction and functional results," they said. "Future studies should be directed to determining the causes of this association, and if further studies do, in fact, confirm this hypothesis, then studies of clinical results after total knee [replacement] should consider stratifying patients by socioeconomic status."
Visit the U.S. National Library of Medicine to learn more about knee replacement.