KITAMURA Atsushi Jikei University, Faculty of Medicine, Research Assistant, 医学部, 助手 (40234273)
MARUMO Keishi Jikei University, Faculty of Medicine, Lecturer, 医学部, 講師 (70199925)
Unlike radiographs, MRI is able to delineate articular cartilage, ligament, meniscus, and subarticular bone marrow. MRI is thought to be the most suitable modality for evaluation of anatomy and disorders of the joints. The purpose of this study was to evaluate the MRI findings of the "normal" aging knees and osteoarthritis (OA) . Materials were 48 cases of volunteer without a history of knee disorders and 67 cases of knee osteoarthritis. The anterior cruciate ligament(ACL), meniscus, articular cartilage, subarticular signal abnormalities, subchondral cysts, and osteophyte were evaluated.
There were either meniscal degeneration or horizontal tear in 75% of the volunteers older than 40-years of age. However, articular cartilage erosion, osteophyte formation, subchondral signal abnormalities, and subchondral cysts were present in limited cases, and the degree of these changes was localized and mild. No ACL abnormalities were patent in the volunteer group. On the other hand, meniscal abnormalities were present in all cases, especially medial meniscal complex tears were present in 74% of the OA cases. articular cartilage erosion, osteophyte formation, and subchondral signal abnormalities were present in much frequently, and the changes were wider and pronounce. Subchondral cysts were present in almost all cases and ACL injuries were present in 33% of OA cases.
Although age-realted changes of meniscal degeneration and horizontal tears were frequently present in patients with older than 40-years of age, there was no apparent correlation between these changes and development of OA in our volunteers. In addition to aging, complex tears of the menisci and ACL injuries were thought to be important contributing factors in development of OA.