A modular proximal interphalangeal joint implant assembly including a first stem component, a second stem component, and an articulation assembly. The first stem component includes a first locking device and is operable to be implanted in a proximal phalanx bone. The second stem component includes a second locking device and is operable to be implanted in a middle phalanx bone. The articulation assembly includes a first articulation component operable to be removably attached to the first locking device and a second articulation component operable to be removably attached to the second locking device. The articulation assembly can include a semi-constrained articulation assembly or a constrained articulation assembly.
