A bone fixation system for implanting in bone, the system comprising a plurality of bone fastener assemblies that attach to bone, a pair of elongate members that attach to the plurality of bone fastener assemblies, a connector member that contacts the pair of elongate members, and a plurality of locking caps that secure the connector member and the elongate members to the plurality of bone fastener assemblies, wherein at least one of the plurality of locking caps comprises a cap portion and a hook portion, where the cap portion is adapted to rotate while the hook portion is stationary.