An implant for in—vivo implantation which comprises an assembly of two or more constructive elements (3,4) which are movable relative to each other. Each constructive element (3,4) is partly or completely porous and comprises a porous part (5,6) with a matrix (7,8) of open cells (51,61). A first matrix (7) of the first element (3) comprises a first overlapping part (50) with a form—closed connection to a second overlapping part (60) of a second matrix (8) of the second of the constructive elements (4) through which the first overlapping part extends. The overlapping parts (50,60) are movable relative to each other to change a combined shape of the overlapping parts.