A prosthetic intervertebral disc joint assembly for replacing at least a portion of an intervertebral disc between first and second adjacent vertebrae comprising: a first component (20, 120) for engaging a first vertebra, the first component having an intervertebral portion (20a, 120a) insertable between adjacent vertebrae and having a bone-engaging side for engaging an endplate of the first vertebra and an inner side opposite the bone-engaging side, the inner side of the intervertebral portion (20a, 120a) having an articulating surface (22, 122) comprising a generally convex surface； a second component (30, 130) for engaging a second vertebra, the second component having an intervertebral portion (30a, 130a) insertable between adjacent vertebrae and having a bone-engaging side for engaging an endplate of the second vertebra and an inner side opposite the bone-engaging side, the inner side of the intervertebral portion (30a, 130a) having an articulating surface (32, 132) comprising a generally concave surface； wherein the convex articulating surface (22, 122) of the first component is sized and shaped to pivot in the concave articulating surface (32, 132) of the second component, and wherein the first component (20, 120) further comprises a fixation portion (20b, 120b) for securing the first component to the anterior side of the first vertebra, said fixation portion (20b, 120b) extending from the trailing end of the intervertebral portion (20a, 120a) of the first component and wherein the second component (30, 130) further comprises a fixation portion (30b, 130b) for securing the second component to the anterior side of the second vertebra, said fixation portion (30b, 130b) extending from the trailing end of the intervertebral portion (30a, 130a) of the second component.
