An intervertebral implant comprises a first member for engaging a first vertebral body and a second member for engaging a second vertebral body. The first member has a first surface with a first curve, and the second member has a second surface with a second curve. The first member is translatable with respect to the second member and the second curve is positioned within the first curve to bias the first and second curved surfaces towards central alignment along a longitudinal axis passing through the first and second vertebral bodies.