Bone implants, assemblies, and methods thereof. The implants may include non-threaded triangular implants configured to promote fixation and fusion of the sacroiliac joint. The implants may have a triangular body configured to prevent or minimize rotational motion of the implant. The implants may include an inner core or an outer shell, which provides structural support for a lattice structure. The structural geometry may be generated through topology optimization software, such as finite element analysis, based on anatomical loading conditions for the implant.