SAT0480 Bone Marrow Lesion in Advanced Osteoarthritis of The Knees. Correlation Study between Histopathological Findings and Structural Damage

Background Osteoarthritis, the most common form of arthritis, is the leading cause of mobility-related disability in elderly persons. With the aging of the population, the prevalence of osteoarthritis is increasing. Loss of hyaline articular cartilage is a central pathologic event in osteoarthritis, but the pathogenesis of cartilage loss is poorly understood. Specifically, there is a paucity of information about what factors identify joints at high risk for progression. Identification of such factors might permit better understanding of the disease process. Objectives To correlate histopathology of a bone marrow lesion (BML) pattern with severity and structural damage in osteoarthritic knees. Methods Twenty consecutive patients (age range, 59–66 years; mean, 65 years) referred for total knee replacements were examined with sagittal short inversion time inversion-recovery (STIR) and T1- and T2-weighted MRI one week prior to surgery before surgery. Different structural abnormalities on MRI were compared with those on histologic maps. Results The histopathology of BML in cases of OA revealed that 6 biopsies of cases showing bone marrow fibrosis (30%), 4 of them grade 1 (20%) and 2 of them grade 2 (10%). 18 biopsies showing cyst (90%), 9 biopsies showing abnormal trabeculae (45%), 2 of them with grade 1 (10%), 4 of them grade 2 (20%) and 3 of them grade 3 (15%). 5 biopsies showing lymphocyte (25%), 40% of them had ++CD3, while 60% of them had ++CD20. 5 biopsies showing fatty marrow (25%), 9 biopsies showing haemosidrotic marrow (45%), 6 biopsies showing blood vessels (30%), 5 of them with grade 2 (25%) and 1 with grade 3 (5%). The MRI findings of OA patients had been revealed that there were 6 patients with BML of grade 1 (30%), 10 patients of grade 2 (50%) and 4 patients of grade 3 (20%). Conclusions –BML has a strong correlation with radiographic everity measurements of osteoarthritis of the knee and pain. –In patients with knee osteoarthritis, BML in bone underneath cartilage markedly increase risk for structural progression in the knee. –Hyperemia and hematopoietic marrow were possible reasons for appearance of BML as high signal- intensity on STIR images. –BMLs are a cornerstone in progression of osteoarthritis. Acknowledgement My deepest gratitude to prof. Dr. Hassan Bassiouni, for offering me the idea of the research. I would like to thank Prof. Dr. Ibrahim Hassan for his great effort in examination of slides which is the fundamental of our study. My deepest thanks to Ass. Prof. Dr. Sami Abd El-Hakem for his cooperation and continous guidence. My deepest thanks to Ass. Prof. Dr, Abdellah Nazeer who tought me the first steps in MRI which is a fundamental brick in my work. I would like to thank Dr. Ahmed Ali Abdel Aziz for his unlimited support in reviewing the manuscript. Disclosure of Interest None declared