An implant system for use in orthopedic surgery for fixation of bone includes an intramedullary nail and a coupling unit. The intramedullary nail has a medial side, a lateral side and a proximal portion defining a longitudinal axis. The proximal portion includes a bore defining a first axis substantially parallel to the longitudinal axis of the proximal portion and a transverse bore configured to receive a bone fastener. The coupling unit is movably arranged within the bore of the proximal portion and includes one or more bone fastener engagement members at one or both of the lateral side and the medial side of the intramedullary nail.