Introduction
P and acetabular fractures are severe musculoskeletal injuries. High-energy traumatic events such as automobile crashes continue to cause significant injuries, whereas refinements in the initial evaluation and resuscitation of trauma patients have led to increased patient survivability. With increasing longevity, a growing geriatric population is also vulnerable to lower energy pelvic fractures. The complex fracture patterns and associated injuries of the high-energy trauma patient, the poor bone quality and associated medical comorbidities of the elderly trauma patient, combined with the challenging pelvic osteology and soft tissue anatomy make the treatment of these injuries daunting for the orthopedic surgeon. Patients with operatively treated pelvic fractures have previously experienced significant morbidity, often in the form of hemorrhage or wound healing complications. The desire to avoid the morbidity of open surgery and technical and conceptual advances in obtaining and interpreting intraoperative images have driven the development of minimally invasive fixation. Percutaneous techniques have been established as biomechanically sound, safe, and effective in treating patients with a variety of pelvic ring injuries. Open reduction and stable internal fixation with a focus on anatomic restoration of the articular surface remains the gold standard in acetabular fracture care, although percutaneous treatment, either as a supplement to formal open reduction and stable internal fixation or as a stand-alone procedure with select indications has also been reported. Regardless of technique or surgical approach, safe and effective fracture fixation mandates a thorough understanding of the osteology and radiographic anatomy of the pelvis. We have come to conceptualize the opportunities for fixation about the pelvis and acetabulum as pelvic osseous fixation pathways (OFPs). These geometrically complex ‘‘bone tubes’’ are simply corticated bony cylinders of different dimensions and orientations that accommodate intraosseous implants (Fig. 1). Commonly, screws are used to fill the available OFP and thereby stabilize pelvic and acetabular fractures either percutaneously or after a formal open approach. The screw numbers, locations, diameters, and lengths selected are completely dependent on the individual patient’s osteology, assuming that an accurate fracture reduction has been achieved. The goals of this article are to review the osteology of these pathways, to provide a detailed description of the associated radiographic anatomy and requisite fluoroscopic views, and to summarize their clinical applications (Table 1).