A spinal implant assembly for replacing intervertebral elements between a first spinal vertebra and an adjacent second spinal vertebra includes an intervertebral implant for inserting between the first and second spinal vertebrae and a first kinematic retaining plate. The intervertebral implant comprises a body having a top surface, a bottom surface, and a first appendage extending from the top surface of the intervertebral implant. The first appendage is adapted to fit within and form a tongue and groove attachment with a first opening formed in the first spinal vertebra. The first kinematic retaining plate is attached to the first spinal vertebra so that it secures the first appendage in the first opening. The intervertebral implant further comprises a second appendage extending from the bottom surface and the second appendage is adapted to fit within and form a tongue and groove attachment with a second opening formed in the second spinal vertebra. A second kinematic retaining plate is attached to the second spinal vertebra so that it secures the second appendage in the second opening.