FRI0063 EFFECTS OF MALALIGNMENT AND DISEASE ACTIVITY ON SECONDARY OSTEOARTHRITIS PROGRESSION IN KNEES OF RHEUMATOID ARTHRITIS PATIENTS

Background: Recent advancements in treatment of rheumatoid arthritis (RA) with disease-modifying anti-rheumatic drugs (DMARDs) have been remarkable, with disease symptoms nearly disappearing due to their strong anti-inflammatory action and many patients achieving remission. As a result, the need for RA-related surgery has shown a yearly decreasing trend, especially knee surgery and synovectomy procedures [1]. On the other hand, cases of secondary osteoarthritis (OA) in knee joints as a symptom associated with RA following a total knee arthroplasty (TKA) are increasing. Objectives: We investigated the morphology of osteophytes by quantitatively evaluating their size using images obtained prior to performing a TKA. Additionally, the relationships of osteophyte size with patient background, disease activity, and degree of inflammation were examined. Methods: Radiographs of 35 consecutive knees in 30 RA patients (26 females, 4 males; mean age 63.0 years; median disease duration 15 years) who underwent TKA, including preoperative standing AP view radiographs of the knee joint, were retrospectively analyzed. Using the Image-J software package, osteophyte size in the medial femur (MF), medial tibia (MT), lateral femur (LF), and lateral tibia (LT) regions was determined. Written informed consent for data collection was obtained from all patients in accordance with the Declaration of Helsinki. Results: Preoperative Larsen grade was 2, 3, 4, and 5 in 1, 12, 18, and 2 patients, respectively, while the mean range of motion of the knee joint was 118° for flexion and -10° for extension. The mean femorotibial angle (FTA) was 178±13.6°, with varus (FTA >180°, n=14) more frequently observed as compared to valgus (FTA Conclusion: Our results suggest that secondary OA is a more prominent symptom in RA patients in whom inflammation is controlled, while disease activity has effects on osteophyte size. Reference: [1] Momohara S, Ikari K, Mochizuki T, et al: Declining use of synovectomy surgery for patients with rheumatoid arthritis in Japan. Ann Rheum Dis 2009;68:291-2. Disclosure of Interests: None declared