Pelvic ring fracture

The pelvic ring is formed by the sacrum posteriorly and the two innominate bones (ilium, ischium, pubis) anteriorly, connected at the pubic symphysis and two sacroiliac joints. Fractures range from low-energy avulsion injuries in young athletes and insufficiency fractures in osteoporotic bone, to high-energy ring disruptions from falls from height or sports collisions that cause massive hemorrhage and life-threatening instability.

Tile's AO/OTA classification categorizes pelvic fractures by stability: Type A (stable, minor injury), Type B (rotationally unstable), and Type C (rotationally and vertically unstable). Unstable patterns are orthopedic emergencies.

Low-energy fractures present with groin or pelvic pain and difficulty bearing weight. High-energy injuries present with hemodynamic instability, obvious deformity, or inability to transfer. AP pelvis X-ray is the primary screening study; inlet and outlet views add information. CT with contrast characterizes the injury pattern and detects vascular injury.

Rotationally or vertically unstable fractures require stabilization. Emergent stabilization may be needed for hemorrhage control before definitive fixation.

External patient-education references and related OSI pages for additional background:

• Britannica — Bone disease (fractures)
• Britannica — Hip (anatomy)
• AAOS OrthoInfo — patient education library
• OSI glossary — orthopedic terminology in plain language