A comparison of coronal plane and rotational alignments of the knees between rheumatoid arthritis and osteoarthritis: A retrospective cohort study.

Summary: When people get knee replacements, doctors need to know exactly how the knee bones line up to make sure the new joint works perfectly. Usually, doctors study the knees of people with "wear-and-tear" arthritis (osteoarthritis). But what about knees with rheumatoid arthritis, which is caused by the immune system?

In this study, doctors looked at X-rays and 3D scans of 433 patients. They found that knees with rheumatoid arthritis have a different shape, angle, and twist compared to knees with osteoarthritis. Because of these hidden differences, surgeons need to be extra careful when putting in new knee joints for patients with rheumatoid arthritis to avoid pain and future complications.