The invention relates to an implant assembly for bone fixation, and particularly for stabilizing the vertebral column, including a plate (P) provided with at least two openings and at least two anchoring means (V) that can be positioned in said openings and be attached to the bone portions to be stabilized, and blocking means for preventing said anchoring means (V) from being accidentally released from said openings. Said blocking means include a shoulder (7) arranged on each anchoring means (V), and a non-return lip (L) which is arranged inside each opening, is integral with said plate (P), and can be deformed so as to be cleared by said shoulder (7) during the positioning of the anchoring means (V), and then prevent the extraction of the anchoring means (V) by forming an abutment against said shoulder (7).
