A lumbar disc prosthesis is provided including a first member with a vertebral disc contact surface and a recessed portion on an opposing surface thereof a second member with a vertebral disc contact surface and a protruding portion on an opposing surface thereof. The protruding portion of the second member engages with the recessed portion of the first member in use. A facet joint prosthesis is provided, including a first member for attachment to a first posterior lumbar disc in use and a second member for attachment to a second posterior lumbar disc in use, where at least a part of the first member is telescopically mounted in at least a part of the second member in use.
