A facet joint replacement system includes an inferior implant with an inferior articular surface, a superior implant with a superior articular surface and may include a crosslink extending across a vertebral sagittal plane. The inferior implant may comprise an inferior strut, and a polyaxially adjustable, lockable mechanism which may couple the inferior articular surface with a first end of the inferior strut, and couple the inferior articular surface with the crosslink. A second end of the inferior strut may be secured to a polyaxially adjustable, lockable fixation assembly securable in a vertebra. The superior implant may be secured to a polyaxially adjustable lockable fixation assembly securable in a vertebra. The positions of the inferior articular surface and the first end of the inferior strut are independently translatable along a medial-lateral axis of the vertebra prior to lockout by the lockable mechanism. The crosslink may be placed into the lockable mechanism from a posterior approach.
