Pelvic Ring Fractures

Introduction

The pelvic ring is uniquely positioned in orthopedic trauma as both a structural component of the skeleton — transmitting load between the spine and the lower extremities — and as the container of substantial vascular structures and pelvic viscera. Disruption of the pelvic ring carries an immediate concern for hemorrhage that frequently dictates the early management course, alongside the orthopedic concern for structural integrity, articular function, and the long-term consequences of malreduction. The lethality of the unstable pelvic ring fracture — with mortality rates of 10 to 50 percent in high-energy series, driven principally by hemorrhage and associated injuries — has made the multidisciplinary approach to pelvic trauma a model of trauma system design, with the trauma surgeon, orthopedic surgeon, interventional radiologist, and (in many centers) urologist working in coordinated sequence. This chapter, drawing principally on Rockwood and Green’s Fractures in Adults, AO Principles of Fracture Management, Apley & Solomon’s, and Miller’s Review of Orthopaedics, addresses the contemporary management of pelvic ring injury.

Surgical Anatomy

The pelvic ring is formed by the two innominate bones (each comprising the fused ilium, ischium, and pubis) and the sacrum, connected anteriorly at the pubic symphysis and posteriorly at the two sacroiliac (SI) joints. The structural integrity of the ring depends not on the bony anatomy alone but on the ligamentous complex that holds the ring together. The principal ligaments are: The posterior SI ligaments (interosseous and short posterior), which are the strongest ligaments in the body and are the principal restraint to vertical translation of the hemipelvis. Disruption of these ligaments produces vertically unstable injuries. The anterior SI ligaments, which restrain external rotation of the hemipelvis but are weaker than the posterior complex. The sacrospinous ligament (sacrum to ischial spine), which resists external rotation. The sacrotuberous ligament (sacrum to ischial tuberosity), which resists vertical and rotational displacement. The pubic symphysis with its fibrocartilaginous disc, restraining anterior diastasis. The pelvic floor ligaments (anterior and posterior ligaments of the pubic symphysis and the sacral plexus). The vascular supply of the pelvis includes the iliac vessels (common, internal, external) with their many branches; the superior gluteal artery (a branch of the internal iliac that emerges through the greater sciatic notch); the internal pudendal artery (emerging through the lesser sciatic notch); and the presacral venous plexus posteriorly, which is a major source of hemorrhage in pelvic ring disruption because of the difficulty of controlling venous bleeding in this region. The lumbosacral plexus lies anterior to the sacrum, with

the L5 nerve root descending across the sacral ala — vulnerable to traction in vertical shear injuries — and the S1-S4 roots exiting the anterior sacral foramina. The principal anatomical lines on radiographs that the surgeon must interpret are the iliopectineal line (the anterior column of the acetabulum), the ilioischial line (the posterior column), Shenton’s line (the smooth arc from the femoral neck to the obturator foramen), and the anterior and posterior rim of the acetabulum seen on the obturator and iliac oblique (Judet) views.

Classification

Two principal classification systems are in widespread use, each with its own clinical utility. The Young-Burgess Classification (1986) The Young and Burgess classification organizes pelvic ring injuries by mechanism of injury, with mechanism being predictive of associated vascular injury patterns and hemorrhage risk. The system has four major categories: Lateral compression (LC) — Direct lateral force on the pelvis. Subtypes: LC-I (oblique or transverse rami fracture with ipsilateral anterior sacral compression fracture; stable), LC-II (“crescent fracture” with rami fracture plus posterior iliac wing fracture or SI joint disruption), LC-III (“windswept pelvis” — LC-II on one side plus open-book injury on the other side, from continued lateral force). Anteroposterior compression (APC) — Direct anteroposterior force or external rotation of the hemipelvis (“open book”). Subtypes: APC-I (pubic diastasis less than 2.5 cm; anterior SI ligaments intact; stable), APC-II (pubic diastasis greater than 2.5 cm; anterior SI ligaments disrupted but posterior ligaments intact — “open book”; rotationally unstable but vertically stable), APC-III (complete disruption of all SI ligaments; both rotationally and vertically unstable). Vertical shear (VS) — Vertical displacement of the hemipelvis. Disruption of all ligamentous restraints with vertical displacement of the hemipelvis. Completely unstable in all planes. Combined mechanism (CM) — Mixed patterns not fitting clearly into the other categories. The Tile / AO Classification The Tile classification (Marvin Tile, 1980) structures injuries by stability, which is the property most directly relevant to operative decision-making: Type A — Stable. Includes fractures of the iliac wing, pubic rami fractures not disrupting the ring, and isolated avulsion fractures. The pelvic ring remains intact. Type B — Rotationally unstable, vertically stable. Includes the open-book injury (B1) and the lateral compression injury with posterior compression but intact posterior ligaments

(B2 ipsilateral, B3 contralateral or “bucket-handle”). The pelvic floor and posterior tension band remain intact, preventing vertical displacement. Type C — Rotationally and vertically unstable. The posterior tension band is completely disrupted; both rotational and vertical instability are present. Subtypes: C1 unilateral, C2 bilateral, C3 with associated acetabular fracture. The AO/OTA classification (region 61) substantially mirrors Tile with additional subtype detail.

Clinical Assessment

The patient with pelvic ring injury typically presents after high-energy trauma — motor vehicle accident, motorcycle accident, fall from height, crush injury, or pedestrian struck. The initial evaluation follows ATLS principles with attention to airway, breathing, circulation, disability, and exposure. Recognition of pelvic injury as a source of hemorrhage is critical and should be specifically considered in the patient with shock unexplained by other identified sources. Clinical examination of the pelvis is performed by gentle compression and distraction maneuvers — palpation of the iliac crests with gentle bilateral compression and bilateral distraction, with assessment for mobility, crepitus, or pain. Vigorous manipulation of an unstable pelvis can dislodge formed clot and worsen hemorrhage and is contraindicated. Inspection identifies wound and bruising patterns — perineal hematoma, scrotal or labial swelling, Destot’s sign (hematoma above the inguinal ligament), and Roux’s sign (asymmetric leg length suggesting vertical displacement). Urological evaluation includes the rectal examination (for evidence of high-riding prostate or rectal injury), inspection of the urethral meatus for blood (suggesting urethral injury), and consideration of a retrograde urethrogram before bladder catheterization in male patients with suspicious findings. Imaging in the acute setting includes: The AP pelvis radiograph as part of the ATLS primary survey. The standard images, in stable patients, additionally include the inlet view (40-degree caudal beam projection — visualizes anteroposterior translation, opening of the ring) and the outlet view (40-degree cephalic beam — visualizes vertical translation). For acetabular involvement, the Judet views (obturator oblique and iliac oblique) are added. CT scan is the modern standard for definitive pelvic imaging, providing detailed three- dimensional assessment of the ring, the SI joints, and any associated acetabular involvement. CT is the basis for operative planning and is now obtained routinely in any patient with significant pelvic injury who is stable enough for transport to the scanner.

Hemorrhage Control — The Acute Resuscitation

The unstable pelvis with hemorrhage represents one of the most pressing emergencies in orthopedic trauma. The hemorrhage may arise from the fractured cancellous bone surfaces (typically the dominant source in lower-grade injuries), the presacral venous

plexus (a frequent and difficult-to-control source), the branches of the internal iliac artery (sometimes the dominant source, particularly the superior gluteal and obturator arteries; identifiable on CT angiography or angiogram), and occasionally the iliac vessels themselves (uncommon but lethal). The acute resuscitation proceeds along three parallel axes: Mechanical Stabilization The pelvic binder — a circumferential constraining device positioned at the level of the greater trochanters (not the iliac crests) — applies compression to the pelvic ring and reduces the pelvic volume. The binder is the appropriate first-line mechanical stabilization in any patient with suspected unstable pelvic injury, applied at the scene or in the trauma bay. The binder is typically a commercial device (T-POD, SAM Pelvic Sling) but can be improvised with a sheet folded tightly. Application is at the level of the greater trochanters; positioning over the iliac crests is ineffective and can worsen injuries. For more definitive mechanical stabilization, the anterior external fixator (with pins in the iliac crests or supra-acetabular bone) provides a rigid construct that can be applied in the operating room or, in some centers, in the trauma bay. The pelvic C-clamp (Ganz / Browner clamp) is a more aggressive stabilization device with pins placed posteriorly in the iliac bone just posterior to the SI joints, providing direct posterior compression — useful for the unstable C-type injury with posterior disruption. The C-clamp is less commonly used in modern practice as resuscitative options have expanded. Resuscitative Surgery and Angiographic Embolization For the patient with continuing hemorrhage despite mechanical stabilization, two principal options exist: Preperitoneal pelvic packing — surgical opening of the preperitoneal space through a midline lower abdominal incision and packing of laparotomy pads around the pelvis to tamponade venous and cancellous bleeding. The technique, popularized particularly in European trauma systems, provides rapid hemorrhage control in the operating room and is particularly useful when angiography is not immediately available or when the patient is too unstable for transport. The packs are typically removed at 24 to 48 hours when the patient has been resuscitated. Angiographic embolization — interventional radiological identification and embolization of bleeding arterial branches (commonly internal iliac, superior gluteal, or obturator). The technique is highly effective for arterial sources but does not address venous or cancellous bleeding directly. In centers with rapid interventional radiology availability, angiographic embolization is often the first definitive intervention after mechanical stabilization. The REBOA (resuscitative endovascular balloon occlusion of the aorta) technique, where a balloon catheter is placed in the descending aorta to occlude inflow to the pelvis temporarily, has gained traction in the most extreme cases but remains a bridge to definitive treatment rather than definitive itself.

Blood Product Resuscitation Massive transfusion protocols with 1:1:1 ratio of packed red cells, fresh frozen plasma, and platelets are activated for patients with pelvic injury and hemodynamic instability, accompanied by tranexamic acid (1 g IV at presentation, 1 g over 8 hours) within 3 hours of injury per the CRASH-2 trial evidence (see Topic Trauma-6 for the broader trauma resuscitation framework). The WSES (World Society of Emergency Surgery) classification integrates anatomy with hemodynamics and provides treatment algorithms accordingly. The trauma surgeon, orthopedic surgeon, and interventional radiologist must work in coordinated sequence — typically with mechanical stabilization first, then operative pelvic packing or angiographic embolization based on clinical trajectory.

Treatment of Specific Patterns — Anterior Ring

Pubic Symphysis Disruption Pubic symphysis diastasis greater than 2.5 cm (the standard threshold) represents disruption of the anterior pelvic ligamentous complex and indicates an unstable APC or VS injury. Operative fixation is by open reduction and plate fixation through a Pfannenstiel approach, with a curved 4- or 6-hole plate spanning the symphysis. The construct is generally augmented by posterior fixation in C-type injuries. Pubic Rami Fractures Isolated pubic rami fractures in elderly osteoporotic patients are extremely common, generally low-energy, and managed non-operatively with progressive mobilization. The historical concept that these represent ring injuries that should be assumed to have occult posterior involvement has been largely replaced by the recognition that most are truly minor isolated injuries. CT may identify an associated posterior injury that would change management. Pubic rami fractures with significant posterior involvement are addressed surgically. The standard technique is open reduction with anterior plating, but more recent percutaneous techniques using anterior subcutaneous internal fixation (“INFIX”) with pedicle screws and a connecting rod tunneled subcutaneously have gained popularity for selected anterior ring injuries.

Treatment of Specific Patterns — Posterior Ring

Sacroiliac Joint Disruption Pure SI joint disruption is managed by percutaneous iliosacral (IS) screws — cannulated screws placed under fluoroscopic guidance through the iliac bone, across the SI joint, and into the sacral body. The technique requires precise imaging and understanding of sacral anatomy because the screws pass close to the L5 nerve root anteriorly and the S1 foramen distally. Sacral dysmorphism — anatomical variation in the upper sacrum found in approximately 40 percent of the population, with mammillary bodies, transitional vertebra,

or other features — must be recognized because it changes the safe corridor for screw placement. Sacral Fractures Sacral fractures are classified by the Denis classification (Denis et al., 1988) into three zones: Zone I: Lateral to the sacral foramina. Lower risk of neurological injury (approximately 6 percent). Zone II: Through the sacral foramina. Higher neurological injury risk (approximately 28 percent), with sensory and motor deficits in the L5-S2 distribution. Zone III: Medial to the sacral foramina (sacral body involvement). Highest neurological injury risk (approximately 57 percent), with potential for cauda equina syndrome requiring urgent decompression. The U-shaped or H-shaped sacral fracture (longitudinal fractures bilaterally with a transverse component, the so-called “spinopelvic dissociation”) represents a severe injury with frequent neurological involvement and is often managed by lumbopelvic fixation with iliac screws connected by rods to lumbar pedicle screws, creating a triangular construct that bridges the disruption. The treatment of standard sacral fractures parallels the SI joint approach — percutaneous iliosacral screws for fractures with adequate bone purchase. The classical “transiliac transsacral” screw passes through both ilia and across the entire sacrum, providing maximum stability.

Iliac Wing Fractures Iliac wing fractures may be treated non-operatively if they do not disrupt the pelvic ring; significantly displaced iliac wing fractures with ring involvement require open reduction and plate fixation, typically through a lateral or posterior approach.

Operative Strategy by Injury Type

The operative strategy follows the injury type: APC-II (“open book”) is typically treated by anterior plate fixation of the symphysis, with the posterior ligaments intact providing posterior stability. Vertical instability of either hemipelvis indicates underlying APC-III or C-type pattern and requires posterior fixation. APC-III requires both anterior and posterior fixation — symphyseal plate with posterior iliosacral screws. LC-I is generally stable and managed non-operatively, although unstable LC-I patterns or those with significant displacement may benefit from fixation.

LC-II (“crescent”) typically requires posterior fixation of the iliac wing component, often with anterior fixation as well. LC-III (“windswept”) is severely unstable and requires comprehensive fixation of both sides. VS (Tile C) requires both anterior and posterior fixation, typically with restoration of vertical reduction by traction or in operative reduction followed by posterior screw or plate fixation. The timing of definitive fixation in the polytrauma patient incorporates the damage-control orthopedics principles discussed in Topic Trauma-6 — temporary stabilization with binder, external fixator, or C-clamp in the unstable patient, with definitive fixation delayed until physiological stabilization (typically 3 to 14 days).

Special Considerations

Open Pelvic Fractures The open pelvic fracture — pelvic ring injury with communication of the fracture to the environment, typically through perineal, rectal, or vaginal wounds — carries a substantially worse prognosis than the closed counterpart, with mortality rates of 30 to 50 percent. Management requires aggressive surgical debridement of the wound, broad- spectrum antibiotic coverage, diverting colostomy for perineal or rectal wounds to prevent ongoing fecal contamination, and definitive orthopedic fixation when the patient is stable. Genitourinary Injuries Pelvic ring injury is associated with urethral injury in approximately 10 percent of male patients and bladder injury in approximately 5 to 10 percent of all patients. Retrograde urethrogram should be performed before bladder catheterization in male patients with suggestive signs (high-riding prostate, blood at meatus, perineal hematoma). Bladder rupture is classified as intraperitoneal (requiring operative repair) or extraperitoneal (typically managed by catheter drainage alone if not severe). The orthopedic surgeon must consider the planned approach to pelvic fixation in patients with significant urological injury; anterior symphyseal plating can be challenging in the patient with bladder injury or in whom suprapubic catheter has been placed. Pediatric Pelvic Ring Injuries Pediatric pelvic ring injuries are uncommon and have a substantially different presentation from the adult — the elastic ligaments of the child allow more displacement before fracture, and the open growth plates of the iliac wing and acetabulum may show Salter- Harris-like patterns. Many pediatric pelvic injuries that would require operative fixation in an adult can be managed non-operatively because of the remarkable remodeling potential of the immature skeleton.

Postoperative Considerations and Complications The complications of operative pelvic ring fixation include infection (1 to 5 percent, higher with open fractures), neurological injury (typically L5 or S1 traction-related; iatrogenic injury from misplaced screws should be specifically considered), fixation failure with malunion or loss of reduction, chronic pain at the SI joints or symphysis, and sexual or urological dysfunction. Long-term outcomes correlate with the quality of reduction — patients with malreduction (residual asymmetry, leg-length discrepancy from vertical malreduction) have worse functional outcomes and higher rates of chronic pain. VTE prophylaxis (see Topic Trauma-7) is particularly important in pelvic ring injuries because of the very high baseline VTE risk; mechanical and pharmacological prophylaxis are typically begun within 24 hours of injury or surgery as discussed.

Summary and Take-Home Points

The pelvic ring injury combines structural orthopedic concerns with the acute hemorrhage emergency, requiring multidisciplinary management coordinated between trauma, orthopedic, and interventional radiology services. The Young-Burgess classification by mechanism (LC, APC, VS, CM) is predictive of associated hemorrhage patterns; the Tile classification by stability (A stable, B rotationally unstable, C completely unstable) directs operative management. The acute hemorrhage management follows the sequence of mechanical stabilization (pelvic binder at the trochanters, anterior external fixator, C-clamp for posterior compression in selected cases) plus blood product resuscitation with massive transfusion protocol and tranexamic acid, followed by definitive hemorrhage control with either preperitoneal pelvic packing (operative tamponade) or angiographic embolization (radiological control of arterial bleeders). The choice between packing and embolization depends on patient stability and institutional resources; in many centers both are used in coordination. Definitive fixation strategies follow the injury pattern: anterior symphyseal plating for APC- II, posterior iliosacral screws for SI joint disruption and sacral fractures, combined anterior and posterior fixation for APC-III and Tile C patterns, and lumbopelvic fixation with triangular constructs for severe spinopelvic dissociation. The Denis zoning of sacral fractures (I lateral, II through foramina, III medial) predicts neurological injury risk. Open pelvic fractures with perineal or rectal wounds carry substantially higher mortality and require diverting colostomy in addition to orthopedic fixation. Urethral and bladder injuries are common associated injuries that influence both immediate management and the approach to definitive orthopedic fixation. The chapter that follows turns to the acetabulum and the hip — the next set of pelvic- region injuries — where the acetabular fractures of Letournel structure the operative approach and the choice of column and combined fixation.