A facet joint replacement system includes an inferior implant with an inferior articular surface, and a superior implant with a superior articular surface. The inferior implant may comprise an inferior strut, and a polyaxially adjustable, lockable mechanism which couples the inferior articular surface with a first end of the inferior strut. A second end of the inferior strut may be secured to a polyaxially adjustable, lockable fixation assembly securable in a vertebra. The first end of the inferior strut may be post-shaped, and the second end ring-shaped, and vice versa. The superior implant may be secured to a polyaxially adjustable lockable fixation assembly securable in a vertebra. Inferior and superior implants may be implanted individually, paired on one lateral vertebral side, bi-laterally, and/or in multiple vertebral levels. A crosslink may be secured to one implant and extend across a vertebral sagittal plane to a second implant. A clip may align the articular surfaces during implantation.