An orthopedic anchoring system for attaching a spinal stabilization system and concomitantly fusing a sacroiliac joint is disclosed that includes a delivery tool and an implant assembly for insertion into a joint space of a sacroiliac joint. The implant assembly may be secured using anchors inserted through bores within the implant body and into the underlying sacrum and/or ilium. The implant body may also include an attachment fitting reversibly attached to a guide to provide attachment fittings for elements of the spinal stabilization system. The implant assembly may be releasably coupled to an implant arm of the delivery tool such that the implant arm is substantially aligned with the insertion element of the implant assembly. An anchor arm used to insert the anchor may be coupled to the implant arm in a fixed and nonadjustable arrangement such that the anchor is generally aligned with a bore within the implant assembly.