The present invention provides an intervertebral implant for replacing intervertebral disc material and controlling relative motion between adjacent vertebral bodies. The intervertebral implant may have at least one end plate and an intermediate component which slides into engagement with the end plate. The intermediate component may be engageable with the end plate from an anterior approach, or a right or left lateral approach. The intermediate component can be a set of bearing surfaces which articulate to provide relative motion between two vertebral bodies, an elastic insert which deforms to provide motion between two vertebral bodies, or a rigid insert which prevents relative motion between two vertebral bodies. The intermediate component is replaceable with a different intermediate component which provides a different function. The present invention also provides one or more retaining members which snap into engagement with the end plate and secure the intermediate component to the end plate.