An implant configured to fix at least a first mandibular bone part relative to a second mandibular bone part that is separated from the first mandibular bone part by a bone gap, the implant comprising: a plate member including a pre-operatively bent body having a shape corresponding to a post-operative shape of a mandible when aligned with the mandible, the plate member including a first surface configured to face at least one of the first and second mandibular bone parts (418, 422), a second surface opposite the first surface, the plate member defining a plate fixation aperture that extends through the pre-operatively bent body from the first surface to the second surface along a central aperture axis, and is configured to receive a bone fixation element so as to secure the plate member to the mandible, the plate member further including an upper surface and a lower surface, the upper surface extends between the first and second surfaces, and the lower surface is opposite the upper surface and extends between the first and second surfaces; and at least one guide (434; 574) defining a guide fixation aperture (524; 592), the at least one guide (434; 574) configured to be coupled to the plate member such that: 1) the at least one guide (434; 574) abuts each of the second surface, the upper surface, and the lower surface, 2) the guide fixation aperture (434; 592) is aligned with the plate fixation aperture, and 3) the central aperture axis does not intersect the at least one guide (434; 574), the at least one guide (434; 574) pre-operatively configured to align the plate member with the mandible when the implant is positioned against the mandible after the mandible has been separated so as to define the bone gap. a plate member including a pre-operatively bent body having a shape corresponding to a post-operative shape of a mandible when aligned with the mandible, the plate member including a first surface configured to face at least one of the first and second mandibular bone parts (418, 422), a second surface opposite the first surface, the plate member defining a plate fixation aperture that extends through the pre-operatively bent body from the first surface to the second surface along a central aperture axis, and is configured to receive a bone fixation element so as to secure the plate member to the mandible, the plate member further including an upper surface and a lower surface, the upper surface extends between the first and second surfaces, and the lower surface is opposite the upper surface and extends between the first and second surfaces; and at least one guide (434; 574) defining a guide fixation aperture (524; 592), the at least one guide (434; 574) configured to be coupled to the plate member such that: 1) the at least one guide (434; 574) abuts each of the second surface, the upper surface, and the lower surface, 2) the guide fixation aperture (434; 592) is aligned with the plate fixation aperture, and 3) the central aperture axis does not intersect the at least one guide (434; 574), the at least one guide (434; 574) pre-operatively configured to align the plate member with the mandible when the implant is positioned against the mandible after the mandible has been separated so as to define the bone gap.