Intraarticular rheumatoid nodule detection in the knee joint using ultrasonography.

Rheumatoid nodules represent a classic diagnostic sign of rheumatoid arthritis. They can be found in 20-25% of patients and are localized to the extensor surface of the proximal ulna and other friction areas such as the back of the head, the sacrum, the digits and the Achilles tendon. They can also develop in some internal organs such as the lungs, kidneys and the heart. Rheumatoid nodules are a characteristic extra-articular feature of RA. Intraarticular rheumatoid nodules are rare and their detection is a diagnostic challenge. There are few reports in the medical literature on their ultrasonographic detection. We report our results from a retrospective study on 9 patients (5 with gait problems and 4 - asymptomatic) with intraarticular rheumatoid nodules in the knee joint. Ultrasonography was most important in their detection. The diagnosis was confirmed histologically in two of our patients following surgical removal of the nodules.