An expandable prosthetic implant for engagement between vertebrae, comprising: - an inner member (12, 400, 650) having a hollow interior portion and a threaded external portion, wherein the inner member (12, 400, 650) comprises an interior surface at least partially surrounding the hollow interior portion, wherein the interior surface has a cutout; - a first endplate (20, 300, 450) configured to engage a first vertebral body, wherein the first endplate (20, 300, 450) comprises an extension portion configured to be received within the hollow interior portion of the inner member (12, 400, 650), wherein the extension portion comprises flexible tabs configured to secure the first endplate (20, 300, 450) to the inner member (12, 400, 650); - an outer member (14, 402, 702) having a hollow interior portion configured to coaxially receive the inner member (12, 400, 650) therein, wherein the inner (12, 400, 650) and outer (14, 402, 702) members are moveable relative to each other along a longitudinal axis; - a second endplate (62, 350, 500) configured to engage a second vertebral body, wherein the second endplate (62, 350, 500) comprises flexible tabs extending from a surface of the second endplate (62, 350, 500), the flexible tabs configured to secure the second endplate (62, 350, 500) to the outer member (14, 402, 702); - a gear member positioned coaxial to the inner member (12, 400, 650) and outer member (14, 402, 702) and axially fixed to the outer member (14, 402, 702) and freely rotatable with respect to the outer member (14, 402, 702), - wherein the gear member threadedly engages the threaded portion of the inner member (12, 400, 650), - wherein the implant is configured to engage the vertebrae such that first (20, 300, 450) and second endplates (62, 350, 500) are oriented in a predetermined alignment with respect to the first and second vertebral bodies, and - wherein the gear member comprises gear teeth extending around the perimeter of the gear member, the gear teeth extending substantially from a proximal end of the gear member to a distal end of the gear member characterized in that - the extension portion has an exterior surface provided with cutouts around one or more sides of the flexible tabs and configured to allow the flexible tabs to bend radially about a bending axis substantially parallel to the longitudinal axis of the extension portion. - an inner member (12, 400, 650) having a hollow interior portion and a threaded external portion, wherein the inner member (12, 400, 650) comprises an interior surface at least partially surrounding the hollow interior portion, wherein the interior surface has a cutout; - a first endplate (20, 300, 450) configured to engage a first vertebral body, wherein the first endplate (20, 300, 450) comprises an extension portion configured to be received within the hollow interior portion of the inner member (12, 400, 650), wherein the extension portion comprises flexible tabs configured to secure the first endplate (20, 300, 450) to the inner member (12, 400, 650); - an outer member (14, 402, 702) having a hollow interior portion configured to coaxially receive the inner member (12, 400, 650) therein, wherein the inner (12, 400, 650) and outer (14, 402, 702) members are moveable relative to each other along a longitudinal axis; - a second endplate (62, 350, 500) configured to engage a second vertebral body, wherein the second endplate (62, 350, 500) comprises flexible tabs extending from a surface of the second endplate (62, 350, 500), the flexible tabs configured to secure the second endplate (62, 350, 500) to the outer member (14, 402, 702); - a gear member positioned coaxial to the inner member (12, 400, 650) and outer member (14, 402, 702) and axially fixed to the outer member (14, 402, 702) and freely rotatable with respect to the outer member (14, 402, 702), - wherein the gear member threadedly engages the threaded portion of the inner member (12, 400, 650), - wherein the implant is configured to engage the vertebrae such that first (20, 300, 450) and second endplates (62, 350, 500) are oriented in a predetermined alignment with respect to the first and second vertebral bodies, and - wherein the gear member comprises gear teeth extending around the perimeter of the gear member, the gear teeth extending substantially from a proximal end of the gear member to a distal end of the gear member characterized in that - the extension portion has an exterior surface provided with cutouts around one or more sides of the flexible tabs and configured to allow the flexible tabs to bend radially about a bending axis substantially parallel to the longitudinal axis of the extension portion.