Doctors at the Mercy Hospital Orthopedic Institute in Miami, Florida noticed the same thing. They did a study to find out if the difference is linked to insurance. What they found was insurance coverage is important, but not as important as race or ethnic background.

By the time blacks and Hispanics come in for a hip replacement, they have more severe disease. They are also in poorer health in general compared to whites. Poor health status may be linked to race/ethnicity. It's not clear if this is a factor of cultural beliefs, language barriers, or genetic differences.

It could be minorities delay seeking help until their arthritis is severe. It could be arthritis is milder in patients of black or Hispanic background. More study is needed to answer these questions.