A bone screw is provided comprising a longitudinal core member (10, 10') having a longitudinal axis (L) defining a longitudinal direction and having a surface, wherein a helical groove (15, 150, 15') is provided in a least a portion of the surface； and a helical thread body (20, 20') that is a separate part and that is provided in the groove (15, 150, 15')； wherein the groove (15, 150, 15') has a first width (wg) and the thread body (20, 20') has a second width (wt) and wherein the first width (wg) is greater than the second width (wt) such that the thread body (20, 20') can slide in the groove (15, 150, 15') in the longitudinal direction.
