A device of performing osteosynthesis includes an osteosynthesis element, e.g., a bone plate, having an upper face, a lower face and an opening with a central axis linking the upper and lower faces. The opening receives a multi-axial pivotable insert for a longitudinal bone fixing element, such as a bone screw. The insert has a central passage with a longitudinal axis for housing the bone fixing element. The insert may be configured as a helical spring with an external sheath surface and an internal sheath surface that defines the central passage. When placed in the through hole, the insert is rotationally fixed relative to its longitudinal axis, but remains pivotally adjustable within the through hole relative to the osteosynthesis element.