343.Joint Arthroplasty
每天朗读一段医学影像学英语文章
Clinical Presentation
A 73-year-old woman presents with persistent pain in her left hip 18 months after total hip arthroplasty.
Radiologic Findings：
Left anterior oblique (LAO) radiograph (Fig. 130A) of the pelvis shows a lucent rim around the acetabular component at the cement–bone interface。
Diagnosis：
Loosened acetabular component secondary to infection with an indolent organism.
Differential Diagnosis：
Sterile loosening
Histiocytic response
Discussion：
·The vast majority of arthroplasties are performed on the hip for chronic degenerative joint disease. Arthroplasty for smaller joints is more commonly performed to treat inflammatory arthropathies unresponsive to the best medical management and when function is severely limited.
·The most common arthroplasties are of the hip, and it is with these that the greatest experience has been accrued. A wide variety of different types of hip arthroplasty devices have been developed over the past several decades, and these are in constant evolution, with new types being introduced every year.
·Metal, plastic, and ceramic are used in varying combinations and designs. The exact appearance and orientation of the arthroplasties varies from one design to the next; therefore, only certain broad generalizations can be made.
·The acetabular component is normally anteverted, although some varieties are held in neutral position. The degree of anteversion requires measurement from a true lateral film. The femoral component is normally seated centrally within the medullary cavity of the proximal femur, although slight valgus orientation is frequently noted and considered acceptable.
·Both acetabular and femoral components may be cemented or uncemented. Occasionally, one component may be cemented and the other uncemented. Uncemented components normally have a slightly corrugated surface due to the presence of numerous tiny beads adherent to the surface to promote bone ingrowth for long-term fixation.
·A small amount of radiolucency between the bone and cement is a common finding, typically measuring 1 to 2 mm in width. In the long term, a thin radiodense line or neocortex between the cement and inner cortex may form, which should not be misinterpreted as loosening.
·A small amount of resorption of bone at the medial calcar region, where the femoral stem rests against the medial cortex, is also common. This is due to a relatively reduced stress load on the cortex at this site, referred to as stress shielding (Figs. 130B–130E).
Notes:
1. arthroplasty /ˌɑ:θrəu'plæsti/ n. 关节形成术
2. oblique /ə'blik/ adj. n. vi. 斜的
3. lucent /'lʊsnt/ adj. 透明的，光亮的
4. acetabular /ˌæsə'tæbjulə/ 髋臼的
5. cement /sə'mɛnt/ n. 水泥,接合剂
6. indolent /'ɪndələnt/ adj. 懒惰的, 懒散的, 不活跃的
7. accrue /ə'kru/ vi. 自然增长或利益增加；产生 vt. 积累；获得
8. ceramic /sə'ræmɪk/ adj. 陶器的；陶瓷的；制陶艺术的 n. 陶瓷制品；陶瓷
9. acetabular /ˌæsə'tæbjulə/ 髋臼的
10. anteversion /ˌæntɪ'vɜːʃən/ n. 子宫前倾
11. femoral /ˈfɛmərəl/ adj. 股骨的,大腿骨的,大腿的 n. 股动脉
12. medullary /'medələri/ adj. 髓质的,骨髓的,脊髓的
13. valgus /ˈvælɡəs/ n. 外翻足的人；外翻足 adj. 外翻的
14. corrugate /'kɔrə,get/ vt. (使某物)起皱褶,起皱纹,起波纹 n. 皱 车辙 畦,沟
15. radiolucency /ˌreidiəu'lju:sənsi/ n. 射线可透性,射线透射性
16. neocortex /ˌnioˈkɔrˌtɛks/ n. 新皮层
17. calcar /'kæl,kɑr/ n. 氧化炉,熔炉,距
来源：每天朗读一段医学影像学英语文章
圈主
深圳市人民医院放射科副主任医师杨敏洁