A compression bone screw (100) comprises a shank (110), a first element (120) and a second element (130). The shank (1 10) has longitudinally opposing first and second shank portions (111,112). The first shank portion (111) is externally threaded with a first shank thread (113). The first element (120) is threadingly mounted on the first shank portion (111) by way of a first element internal thread (122) threadingly engaging the first shank thread (113). The first element (120) is externally threaded with a first element external thread (123). The second element (130) is mounted on, or integrally formed with, the second shank portion (1 12). The second element (130) is externally threaded with a second element external thread (133). The second element external thread (133) and the first element external thread (123) are like-handed. The first shank portion (111) and the first element (120) are configured to operate in a first mode of operation in which the shank (110) and the first element (120) are rotationally driven in unison and a second mode of operation in which the shank (110) is rotationally driven independent of the first element (120), such that the first element (120) moves along the first shank portion (111) towards the second element (130).
