A targeting device (1) for guiding a drill arrangement (11, 12) for forming an arc-shaped bore in an assembly of adjacent bones or bone fragments, comprises a support frame (2 5 7), a pivoting device (8) mounted to the support frame (2 5 7) and arranged to receive the drill arrangement (11 12) and to allow a pivoting movement of the drill arrangement (11 12) along an arc-shaped path having a predetermined radius of curvature rc around a pivot axis (9). The support frame (2 5 7) is provided with at least three fixation devices (3 4 6) each configured to fix one of the bones (14 15 16) or fragments of the bone assembly to define a fixed position in space of the bone assembly (14 15 16) with respect to the pivoting device (8) when the bone assembly is installed to the support frame (2 5 7).
