Learmonth I D
University Department of Orthopaedic Surgery, Bristol Royal Infirmary, Bristol, UK.
Surgeon. 2003 Feb;1(1):1-8. doi: 10.1016/s1479-666x(03)80002-1.
The insertion of any implant or prosthesis into bone usually changes the biomechanical environment and, thus, alters the stresses and strains applied to the bone. Both bone overload and excessive stress protection can result in bone resorption. The material and geometry of any implant should be designed to avoid excessive flexural mismatch. Incompatibility of materials may result in interface and mechanical failure, with the consequent generation of particulate debris, subsequent osteolysis and implant failure. Particulate debris can be generated from articulating surfaces and from any other modular or fixation interface. Larger particles are associated with a foreign body giant cell reaction. Polyethylene particles in the size range of 0.5 to 10 microm excite a cytochemical reaction that culminates in osteolysis. The precise pathogenesis of osteolysis has not been characterised, but it is probable that different pathogenetic mechanisms are involved in the different radiological types of osteolysis. A large number of very small metallic particles are released from metal-on-metal couples. These may cause mutagenic damage (chromatid breaks, chromosome translocations, aneuploidy, etc.). In defining implant biocompatibility it is essential to consider the biological response both to an altered mechanical environment and to the liberation of particulate debris.
将任何植入物或假体植入骨骼通常会改变生物力学环境，从而改变施加于骨骼的应力和应变。骨骼过载和过度的应力保护都可能导致骨吸收。任何植入物的材料和几何形状都应设计成避免过度的弯曲不匹配。材料的不相容性可能导致界面和机械故障，随之产生颗粒碎片，继而发生骨溶解和植入物失效。颗粒碎片可产生于关节表面以及任何其他模块化或固定界面。较大颗粒与异物巨细胞反应有关。大小在0.5至10微米范围内的聚乙烯颗粒会引发一种细胞化学反应，最终导致骨溶解。骨溶解的确切发病机制尚未明确，但不同类型的骨溶解在放射学上可能涉及不同的发病机制。金属对金属关节会释放大量非常小的金属颗粒。这些颗粒可能会造成致突变损伤（染色单体断裂、染色体易位、非整倍体等）。在定义植入物生物相容性时，必须考虑对改变的机械环境以及颗粒碎片释放的生物学反应。
