髌骨倾斜导致髌骨软骨软化实验研究

An experimental study on patellar tilt induced chondromalacia patellae

为了研究髌骨倾斜是否为髌骨软骨软化（ＣＰ）的病因，髌骨软骨软化的发生与何种异常应力有关，选用２４只雌性新西兰兔，随机分４组，每组６只。右膝为实验侧，将髌外侧支持带紧缩造成髌骨外侧倾斜，左膝实施假手术为对照侧，定期处死动物，分别进行髌骨倾斜角Ｘ线测量、髌骨软骨面的接触压力测量、软骨组织切片观察以及软骨组织Ｍａｎｋｉｎ评分。结果显示：实验侧髌骨倾斜角明显大于对照侧。术后６周至１２周时，实验侧髌骨内侧软骨面接触压力明显较对照侧减低（ｐ＜０．０５）。光镜下，术后６周时髌骨内侧面软骨中层与深层轻度变性，１２周至１８周时软骨明显变性，软骨细胞坏死或Ｃｌｏｎｅ状增生，中层与深层软骨基质较多纵行裂隙以及片状苏木素深染的纤维网，表面溃疡形成，ＳａｆｒａｎｉｎＯ染色提示蛋白多糖严重丢失。软骨组织Ｍａｎｋｉｎ评分，实验侧髌骨内侧面软骨得分高于髌骨外侧面软骨（ｐ＜０．０５），说明髌骨内侧面软骨退变较外侧面明显。结论：髌骨倾斜造成髌骨内侧面应力减低导致髌骨软骨软化。

Twenty_four New Zealand rabbits were randomly divided into four groups.The right knees had the patella tilted surgically and were used as the experimental sides.Sham_operations were done over the left knees and were used as the contrlos.The animals were sacrificed at different periods after the operation.The patellar tilt angles of the X_ray film and the contact pressure of the cartilaginous surface of the patella was measured, histopathological observation and mankin scores were also performed.The results revealed that the patellar tilting angle of experiment knees was larger than that of the controls.The contact pressure of the experimental knee was significantly lower than that of the controls(p<0.05) during 6 to 12 weeks of postoperation. On the experimental sides,the degeneration of medial patellar cartilage in middle and deeper layers began at 6 weeks after operation.The most severe degeneration of cartilage,such as cell necrosis,cell proliferation as clone,longitudinal fissure,the fram_work fibril with intense homatoxylin staning,and the surface ulcer took place during 12 to 18 weeks of postoperation.The Safranin O reduced dramatically.Mankin scores of medial patellar cartilage were significantl higher than that of lateral patellar cartilage(p<0.05),but no singnificant change in the lateral patellar cartilaginous surface was found. It is suggested that patellar tilt reduced the contact pressure of madial patellar facet and caused chondromalacia patellae.