单纯性骨囊肿多发于长管状骨,髌骨则少见,现报告一例如下:患者男,24岁。主诉:于79军4月跌伤后,右膝关节疼痛,逐渐加重半余年,走路发软,时有响声,经治疗无效,以后发现膝部有指头大小之肿块,质硬逐渐肿大,故来我院诊治。既往患太骨节病10今年。查体:患者一般情况良好,表浅淋巴结不大,心脏正常,肝脾未扪及,四肢短小,关节膨大,活动尚可,右髌骨 Simple bone cysts mostly occur in long tubular bones, but the sacrum is rare. One case is reported as follows: The patient is male, 24 years old. Chief Complaint: After the fall of the 79th Army in April, the right knee joint pain gradually increased for more than half a year. It was soft and often sounded. After treatment was invalid, it was discovered that there was a finger-sized lump on the knee, and the hard mass was gradually enlarged. Come to our hospital for treatment. Previously suffering from osteosarcoma 10 this year. Physical examination: The patient is generally in good condition, with superficial lymph nodes, normal heart, undifferentiated liver and spleen, short limbs, joint expansion, acceptable activity, right humerus