A collar (2) arranged to couple to a prosthetic component for implantation at the end of a long bone, the prosthetic component having a distal portion arranged to couple to the bone and a proximal neck portion arranged to couple to an articulation component. The collar (2) comprises a plate including a neck hole (4) to receive a neck portion, such that the collar can rotate about the neck portion. The collar (2) further comprises a plurality of attachment portions (12) for coupling the plate to bone fragments or soft tissues. The collar (2) is lockable to the neck portion to prevent further rotation. A prosthesis comprising a combination of a collar (2), a prosthetic component and an articulation component, and a surgical method of using the collar (2) are also disclosed.
