In normal activities such as walking, r􀀁n­ning, kneeling, climbing stairs and gettmg in and out of chairs the loa􀀗 pu􀀙 OI.the human knee joint can exceed five times the weight of the body. Nowadays large num­bers of people make ! urtrer d mands on the knee in participatmg 1_n sucli sport  as football, tennis and long distance runn􀀯ng. It is no wonder that many people go mto their later years with one knee ?r 􀀼oth knees so badly deteriorated as to cnpplmg. 
 It is now possible to. replace such a knee with a mechanical device that imitates the subtle and complex motions of which around knee is capable. 
In this article the use of a n_ew kmd 􀁉f artificial knee ( Sp hero Cen tenc Knee) is discussed. the indications and advantages of this new device which is currently have been used are encountered, but patients, surgeons and engineers have beE:n. w􀁖rr­ned that the natural human ki:1ee Jomt is a remarkable product and also  ca1;1 be im­itated with increasing success, it will 11ever be duplicated.