兔髋臼后壁骨折模型建立及验证

Development and validation of rabbit models of acetabular posterior wall fractures

目的建立一种模拟人髋臼骨折的动物实验模型并进行验证，以期用于开展髋臼骨折相关疾病的在体研究。方法选取成年新西兰兔30只（60髋），麻醉后摄全髋关节伸直位x线片排除明显畸形及脱位，采用影像归档和通信系统（PACS）测量髋关节外侧中心边缘角（LCEA）及头臼指数（AHI），并与正常成人参考值对比。另取成年新西兰兔24只，按随机数字表法均分为三组：A组为正常对照组，B、C组采用重物冲击模拟高能量髋臼后壁骨折的方法，建立兔右侧髋臼后壁骨折模型，股骨头对髋臼冲击载荷通过压力感受器测量；B组髋臼骨折不予处理，c组髋臼骨折行钢板螺钉内固定。3个月后摄x线片，采用骨性关节炎（OA）半定量评分对兔右侧髋关节进行评分并比较；处死后取髋臼后壁骨块再经处理后进行组织学检测，观察臼软骨退变情况，比较各组后壁臼软骨Mankin组织学评分。结果正常成年兔髋关节LCEA为（29．9±3．6）。（95％CI29．12～30．75），AHI为（84．6±1．6）％（95％CI84．18～84．99），均在正常成人参考值范围内（成人LCEA〉25。且〈40。为正常；AHI为84％～85％）（P〉0．05）。模拟髋臼骨折中股骨头对髋臼冲击载荷约为45MPa。3个月后三组右髋关节x线片及组织学检测表现：相较于对照组，B组发生明显的创伤性关节炎合并半脱位改变，软骨面出现裂解、纤维化及周围骨赘形成；C组出现关节软骨厚度变薄，软骨细胞排列紊乱、增生肥大等早期退变表现。三组右侧髋关节x线片OA半定量评分及后壁臼软骨组织病理染色Mankin组织学评分，结果显示均为B组〉C组〉A组，且三组间差异均有统计学意义（P〈0．05）。结论兔股骨头与髋臼的相关匹配性良好，适用于模拟人髋关节疾病的动物实验研究；兔活体髋臼后壁骨折模型能真实有效地模拟人的髋臼后壁骨折，可用于开展模拟人髋臼骨折相关疾病病理生理及治疗干预的在体动物实验研究。

Objective To validate the rationality of establishing an animal model to simulate aeetabular fractures in human patients so as to develop invivo studies about conditions involving acetabular fractures. Methods Thirty mature New Zealand rabbits （60 hips） were submitted to extended non- weight-beating radiography of the hip, and obvious deformity and dislocation were excluded. Lateral center-edge angle （LCEA） and acetabular-head index （AHI） of the hip were measured by picture arehiving and communication systems （PACS）, and the results were compared with normal adults. Another 24 mature New Zealand rabbits collected were divided into three groups according to the random number table ： group A, served as normal controls and groups B and C, subjected to high-energy fractures of the acetabular posterior wall by using heavy impact method. Load between femoral head and acetabulum was measured by pressure transducer. Acetabular fractures in group C were fixed with a plate-screw system, but not in group B. After 3 months, radiography of the hip was implemented. A semi-quantitative scoring system about osteoarthritis （OA） was applied to each radiographic image. Cartilage tissues of the acetabular posterior wall were resected for histological study, and was rated using the Mankin histologic rating system. Results LCEA and AHI of the rabbit hip were （29.9±3.6） ^（95% C129.12-30.75） and （ 84.6 ± 1.6 ） % （95% C[ 84.18±84.99 ） respectively, and all were in the normal reference ranges of adult human （P 〉 0.05 ）. Contact stress delivered to the acetabulum was 45 MPa. After 3 months, radiography and histology of the hip exhibited obvious differences among the groups. Hip joint with post- traumatic osteoarthritis combined with subluxation and cartilage with irregular surface, fibrous tissue and osteophyte were seen in group B. Decreased thickness of the articular cartilage and malalignment and proliferation of cartilaginous cells on acetabulum posterior wall were seen in group C. Hip OA semi- quantitative score and Mankin score in groups B and C were better than group A, but the results were the best in group B （P 〈 0. 05）. Conclusions Rabbit hip joint presents good matching with the acetabulum and is suitable for animal studies simulating human hip conditions. The rabbit model of acetabular fractures developed in this study simulates human posterior wall acetabular fractures availably, and is suitable for animal studies about pathophysiology, treatment and intervention of human conditions involving acetabular fractures.