A prefabricated movement joint system for a concrete floor slab arrangement, wherein the prefabricated movement joint system is configured to be arranged in a joint to be formed between a first concrete floor slab and a second concrete floor slab in the concrete floor slab arrangement, the prefabricated movement joint system comprising a first top edge rail of metal or other material for providing edge protection in two planes for a first upper edge of the first concrete floor slab in the joint to be formed between the first concrete floor slab and the second concrete floor slab in the concrete floor slab arrangement a second top edge rail of metal or other material for providing edge protection in two planes for a second upper edge of the second concrete floor slab in the joint to be formed between the first concrete floor slab and the second concrete floor slab in the concrete floor slab arrangement, and a divider plate of metal or other material to be arranged in the joint to be formed at least partly between the first concrete floor slab and the second concrete floor slab in the concrete floor slab arrangement and at least partly between the first top edge rail and the second top edge rail, wherein the first top edge rail of the prefabricated movement joint system comprises a first rail portion and a second rail portion, wherein the first rail portion of the first top edge rail is to be arranged essentially parallel with a top face of the first concrete floor slab, and wherein the second rail portion of the first top edge rail is to be arranged essentially parallel with a joint face facing the joint to be formed between the first concrete floor slab and the second concrete floor slab, the first rail portion is provided in an essentially right angle in relation to the second edge rail portion so that the first top edge rail has an essentially L-shaped cross section form, the first rail portion of the first top edge rail is in the form of an elongated flat sheet member having uniform thickness, the second rail portion of the first top edge rail is in the form of an elongated flat sheet member having uniform thickness, the thickness of the first rail portion of the first top edge rail corresponding to the thickness of the second rail portion of the first top edge rail, and the first top edge rail have a plurality of first anchors to be cast into concrete of the first concrete floor slab to anchor the first top edge rail in the first concrete floor slab, characterized in that at least one first anchor of said plurality of first anchors has been formed by cutting and plastically deforming material forming the second rail portion of the first top edge rail so that said at least one first anchor is an integral part of the second rail portion of the first top edge rail and consist of material that has been used forming the second rail portion of the first top edge rail, and so that the second rail portion of the first top edge rail has a first opening through the second rail portion of the first top edge rail at the location said at least one first anchor has been formed of material forming the second rail portion of the first top edge rail, and said at least one first anchor has an at least partly teethed side edge such as an at least partly saw-toothed side edge.