A method for preparing a sacroiliac joint for stabilization which may include approaching a posterior aspect of the sacroiliac joint inferior to a PSIS with a defect-creating tool assembly, creating a defect in the sacrum and the ilium defined by at least one noncircular cross-sectional shape, delivering an implant having a body with a length extending between proximal and distal ends, the body including at least one cylindrical body with a longitudinal axis and an opening at the proximal end aligned with the longitudinal axis of the cylindrical body, a pattern of openings spaced along the cylindrical body and a planar member coupled with and extending along the cylindrical body. The implant may be implanted with the length generally following a plane of the sacroiliac joint such that it is advanced from a generally posterior to anterior approach while the body of the implant bridges the joint.