The present disclosure provides an intramedullary nail assembly comprising an intramedullary nail and an insert sleeve. The intramedullary nail has a nail longitudinal axis and comprises a cavity being accessible from a nail proximal end, the cavity being confined by a nail inner wall, the cavity having a cavity longitudinal axis. The nail inner wall is provided with a predominantly longitudinal groove and a predominantly transverse groove, the transverse groove and the longitudinal groove communicating with each other at a junction. The insert sleeve is configured to be received within the cavity and comprises a cam radially protruding from the insert sleeve and sized to mate with each of the longitudinal and transverse grooves such that the cam is displaceable within the longitudinal groove from a longitudinal groove proximal end to the junction and is further displaceable towards a terminal end of the transverse groove.
