人工关节磨损微粒在界面中的分布及运动

目的 :观察人工关节置换中的磨损微粒在动物体内的分布及运动。　方法 :取成年新西兰兔 32只 ,在兔的股骨远端沿股骨轴线钻孔 ,植入直径 4mm ,长 15mm的圆柱形钛合金棒作为模拟假体。按膝关节内注入微粒的不同随机分为四组 ,即注入超高分子聚乙烯微粒、钛合金微粒、骨水泥微粒和等渗盐水组。在第 16周处死动物 ,取股骨远端及膝关节囊 ,观察磨损微粒在界面中的分布及运动情况。　结果 :各实验组假体隧道边缘产生一层纤维结缔组织界膜 ,其中含有大量的巨噬细胞和异物巨细胞。在这层界膜组织下可见明显的骨吸收和骨破坏现象。聚乙烯组、钛合金组、骨水泥组假体隧道边缘的组织细胞含量明显高于对照组 (P <0 .0 5 )。隧道一区的组织细胞含量明显高于二区 (P <0 .0 5 )。　结论 :人工关节磨损微粒的沉积具有一定的区域性 ,限制微粒在假体骨界面之间的移动可能会减少假体松动的发生。

Distribution and migration of wear debris in prosthesis

Objectives:To observe the distribution and migration of wear debris in animals in vivo . Methods:A plug of titanium alloy was inserted in a cavity that had been drilled in the distal end of the femur in thirty two adult rabbits. The plug was 15mm in length and 4 mm in diameter. These rabbits were randomly divided into 4 groups. The wear debris of polyethylene, titanium alloy, bone cement and normal saline were injected into the knee joints in group A, B,C and D respectively. On the 16th postoperative week, all of the rabbits were killed to obtain the femur and joint capsules for histological examinations.The distribution and migration of wear debris in animals in vivo were then observed. Results:There was a layer of fibrous tissue between the bone and the titanium alloy plug in group A, B and C. Underneath the interface there was a large number of macrophages and foreign body giant cells with obvious bone resorption and destruction. The infiltration of histocytes in group A, B and C were higher than that in group D( P <0.05). At the same time, a more significant infiltration of histocytes was found in area one than in area two( P < 0.05 ). Conclusions:The histological responses to wear debris has a tendency in different response areas. The inhibit of the migration of wear debris may prevent aseptic loosening of prosthesis.