A modular system for total knee arthroplasty includes a modular trial implant assembly. The modular implant assembly includes an elongate shaft configured for insertion into an elongate cavity in a bone, a reamer removably coupleable to the elongate shaft via a connection that allows the reamer to rotate while the elongate shaft remains in a substantially fixed angular orientation. The reamer has an outer surface that tapers toward the distal end configured to form a tapered cavity in an end of a bone in which the reamer is inserted and rotated. The modular trial implant assembly further includes a trial implant removably coupleable to a proximal end of the reamer. A modular final implant assembly includes an elongate stem, a tapered body and an implant body, each having a size and shape that can substantially correspond to a size and shape of the elongate shaft, the reamer and the trial implant, respectively.