Unit9-B.docxVIP

Text B OsteoarthritisIntroduction to osteoarthritis 骨关节炎概论Osteoarthritis is a type of arthritis that is caused by the breakdown and eventual loss of the cartilage of one or more joints. Cartilage is a protein substance that serves as a “cushion” between the bones of the joints. Osteoarthritis is also known as degenerative arthritis. Among the over 100 different types of arthritis conditions, osteoarthritis is the most common，affecting over 20 million people in the United States. Osteoarthritis occurs more frequently as we age. Before age 45, osteoarthritis occurs more frequently in males. After age 55 years, it occurs more frequently in females. In the United States, all races appear equally affected. A higher incidence of osteoarthritis exists in the Japanese population, while South African blacks, East Indians，and Southern Chinese have lower rates. 骨性关节炎是一种由一个或多个关节软骨破坏和损伤引起的关节炎。软骨是一种能在关节的骨头之间充当“缓冲”作用的蛋白质。骨性关节炎又称为退行性关节炎。在100余种不同类型的关节炎中，骨关节炎是最常见的，它影响着超过2000万的美国人。随着年龄的增长，骨关节炎的发生率增高。在45岁以前，骨关节炎在男性中更为常见。55岁以后，女性多发。在美国，所有种族都受到同样的影响。骨关节炎在日本发病率较高，南非黑人、东印度人和中国南部人群发病率较低。Osteoarthritis commonly affects the hands, feet, spine, and large weight-bearing joints, such as the hips and knees. Most cases of osteoarthritis have no known cause and are referred to as primary osteoarthritis. When the cause of the osteoarthritis is known, the condition is referred to as secondary osteoarthritis. Osteoarthritis is sometimes abbreviated OA.What causes osteoarthritis ?骨关节炎通常累及手、脚、脊柱和大的负重关节，如髋关节和膝关节。大多数骨关节炎没有明确的病因，被称为原发性骨关节炎。有明确病因的骨关节炎被称为继发性骨关节炎，有时也被简称为骨关节炎。是什么原因导致骨性关节炎？Primary osteoarthritis, osteoarthritis not resulting from injury or disease, is mostly a result of natural aging of the joint( Fig. 9-2). With aging, the water content of the cartilage increases, and the protein makeup of cartilage degenerates. Eventually，cartilage begins to degenerate by flaking or forming tiny crevasses. In advanced osteoarthritis, there is a total loss of the cartilage cushion between the bones of the join