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Pelvic fracture

A pelvic fracture is a disruption in the continuity of one or more bones forming the pelvic ring, which consists of the , , and paired hip bones (ilium, , and pubis) that connect the to the lower and protect vital pelvic organs. These injuries represent approximately 3% of all adult skeletal fractures and occur at an incidence of about 37 per 100,000 individuals annually , with recent studies showing an increasing global incidence, including approximately 4.5 million new cases in 2021, particularly among older adults due to fragility fractures. Pelvic fractures are broadly classified into stable and unstable types based on the integrity of the pelvic ring and ligamentous structures. Stable fractures, such as isolated iliac wing or pubic ramus breaks, involve a single disruption with minimal displacement and typically heal without surgery. In contrast, unstable fractures—often categorized using the Young-Burgess classification into anteroposterior compression (APC), lateral compression, or vertical shear patterns—involve multiple breaks or ligamentous injuries that compromise pelvic stability and are associated with higher risks of complications. High-energy mechanisms, such as motor vehicle collisions or falls from significant heights, account for most unstable fractures, particularly in younger males aged 15 to 28, while low-energy trauma from minor falls predominates in older adults with osteoporosis, especially women over 35. Symptoms of pelvic fractures include severe pain in the , , or lower back that worsens with , along with visible bruising, swelling, and difficulty bearing weight or ambulating. Due to the pelvis's proximity to major blood vessels, nerves, and organs like the and intestines, these injuries frequently present with life-threatening complications such as internal hemorrhage, , or associated to the , chest, or in up to 90% of high-energy cases. Diagnosis typically begins with anteroposterior pelvic radiographs and to assess stability and neurological function, followed by computed (CT) scans for detailed fracture and of sources. Treatment strategies vary by fracture stability and patient condition, emphasizing rapid stabilization to control bleeding and prevent further injury. Stable fractures are managed nonoperatively with control, , and assistive devices like crutches for 6 to 12 weeks, while unstable fractures often require urgent interventions such as pelvic binders for temporary external stabilization, angiographic for arterial bleeding, or surgical fixation using plates, screws, and external frames. Recovery involves multidisciplinary care, including to restore mobility and strength, with full weight-bearing usually achievable by three months in uncomplicated cases; however, long-term outcomes may include , (affecting up to 61% of men and 56% of women), and reduced .

Anatomy and Pathophysiology

Bony and Soft Tissue Structures

The pelvis is composed of a bony ring formed by the two innominate bones (each consisting of the ilium, , and pubis), the , and the , creating a stable structure that encircles and protects the pelvic viscera. The ilium forms the broad, superior flared portion; the constitutes the posterior-inferior part with its tuberosity for sitting; and the pubis forms the anterior aspect, including the superior and inferior rami that meet at the . The , a triangular wedged between the ilia, articulates posteriorly via the sacroiliac joints, while the attaches inferiorly to the , providing attachment points for ligaments and muscles. The , a deep cup-shaped socket on the lateral aspect of each innominate , is formed by contributions from the ilium (superior two-fifths), (posterior two-fifths), and pubis (anterior one-fifth), serving as the articulation for the and facilitating weight transfer from the trunk to the lower limbs. Key ligaments reinforce the pelvic ring's integrity and enable efficient load transmission. The sacroiliac ligaments, comprising anterior, posterior, and interosseous components, connect the to the ilium and are the strongest in the body, primarily resisting shear forces and transmitting axial loads from the to the lower extremities with minimal motion. The pubis ligaments, including the superior and arcuate pubic ligaments, bind the pubic bones anteriorly at the fibrocartilaginous , distributing compressive forces across the anterior and allowing slight , particularly in females during . The sacrospinous ligament, a triangular band extending from the and to the (approximately 38-46 mm in length), and the , a fan-shaped structure from the to the (64-70 mm), stabilize the posterior , convert the into the lesser notch, and resist rotational forces while aiding in posterior load transfer to the femurs. Surrounding the bony pelvis are critical soft tissues that contribute to support, mobility, and protection. Muscles include the gluteal group (e.g., , medius, and minimus), which originate from the ilium and insert on the or , providing hip extension, abduction, and stabilization during weight-bearing; the pelvic floor muscles, such as the (pubococcygeus, iliococcygeus, puborectalis) and coccygeus, form a muscular spanning the to support viscera and maintain continence. Neurovascular structures traverse the pelvis, with the iliac vessels (common, internal, and external iliac arteries and veins) supplying blood to the lower limbs and pelvic organs via branches like the ; the , formed from L4-S4 roots, provides motor and sensory innervation to the lower extremities and via nerves such as the pudendal (S2-S4) and sciatic. Organs at risk within the true pelvis include the (anteriorly), (posteriorly), and reproductive structures (/ in females or in males, centrally), all suspended and protected by the and endopelvic fascia. Functionally, the divides into the false (greater) pelvis superiorly, which forms part of the and supports the weight of abdominal contents by bounding the iliac fossae, and the true (lesser) pelvis inferiorly, a bony housing the pelvic viscera, narrower in males for and wider in females to accommodate , both contributing to overall load distribution from the trunk to the legs. Disruption of these interconnected bony and elements can compromise pelvic stability, though specific mechanisms are detailed elsewhere.

Injury Mechanisms and Stability

Pelvic fractures typically arise from high-energy , such as accidents or falls from significant heights, which impart specific force vectors to the pelvic ring. These mechanisms include anteroposterior (APC), where frontal impacts cause the pelvis to splay open, disrupting the and sacroiliac ligaments; severe APC injuries (type III) result in complete posterior sacroiliac disruption and substantial external rotation of the hemipelvis. Lateral (LC) occurs from side-loading forces, often in collisions, producing ipsilateral sacral or iliac wing fractures with a characteristic "bucket-handle" overlap of the anterior ring. Vertical (VS) injuries stem from axial loads, as in falls onto extended lower limbs, leading to superior and posterior displacement of one hemipelvis relative to the other through disruption of the anterior and posterior ligaments. Combined mechanisms, blending elements of these patterns, frequently complicate high-energy events and heighten the risk of instability. In contrast, low-energy mechanisms predominate in elderly patients with , where ground-level falls or even minor trauma precipitate insufficiency fractures of the , ilium, or pubic rami due to weakened unable to withstand normal stresses. These fractures often involve the posterior and occur without high-impact forces, reflecting underlying bone fragility rather than acute overload. Biomechanically, pelvic ring stability relies on the interplay of anterior and posterior structures functioning as tension and compression bands to resist rotational, translational, and vertical forces. The posterior sacroiliac complex, including the interosseous and posterior sacroiliac ligaments, provides the primary resistance to and , while the ligaments (sacrospinous and sacrotuberous) counter external and vertical displacement. Stable fractures maintain the integrity of this posterior complex, with symphyseal diastasis less than 2.5 cm and vertical displacement less than 1 cm, allowing physiologic load transfer without . Unstable fractures, by contrast, involve disruption of posterior ligaments, resulting in rotational (e.g., open-book in APC II) or vertical instability that compromises overall ring integrity. These injury patterns can provoke significant pathophysiological consequences, including hemorrhage from shearing of the presacral venous plexus and disruption of arterial branches like the superior gluteal artery, potentially leading to loss of 15-20% of total and subsequent .

Clinical Presentation

Signs and Symptoms

Patients with pelvic fractures often experience severe pain localized to the , groin, or lower back, which intensifies with any movement, such as walking, hip , or log-rolling during clinical . This pain arises from disruption of the pelvic ring and surrounding soft tissues, limiting mobility and prompting patients to maintain a flexed position at the and to alleviate discomfort. Physical examination typically reveals bruising and swelling around the , including ecchymosis over the iliac wings, pubis, or perineal area; the Grey-Turner sign, characterized by flank discoloration, signals retroperitoneal hemorrhage. Deformities such as leg length discrepancy or external rotation of the lower limbs may be evident due to pelvic displacement, further complicating weight-bearing. Systemic manifestations include and from , especially in fractures with substantial blood loss, alongside or indicating or urethral involvement. Neurological symptoms, such as perineal numbness or impaired bowel and function, stem from sacral compression or injury. The presentation varies by fracture stability: low-energy stable fractures cause milder, localized with preserved hemodynamic status, whereas high-energy unstable fractures provoke intense , profound instability, and life-threatening , potentially leading to if unrecognized.

Complications and Associated Injuries

Pelvic fractures frequently lead to hemorrhagic complications, primarily due to disruption of the pelvic venous plexus, resulting in retroperitoneal hematomas that can cause significant blood loss and hemodynamic instability. Arterial injuries, such as those involving the and its branches, occur in a subset of cases and exacerbate , particularly in high-energy . In unstable pelvic fractures, these hemorrhagic events contribute to mortality risks approaching 20%, often from despite interventions like or . Urogenital injuries are common associates of pelvic fractures, with bladder ruptures occurring in up to 10% of cases and classified as extraperitoneal or intraperitoneal based on . Extraperitoneal ruptures, typically linked to anterior pelvic ring disruptions, involve the wall near the pubic bone and are often managed conservatively with drainage, whereas intraperitoneal ruptures require surgical repair to prevent . Urethral injuries accompany about 10% of pelvic fractures, presenting with or inability to void. Vaginal lacerations affect 2-4% of female patients, often from bone fragments penetrating the vaginal wall, while rectal lacerations occur in 1-2% and increase contamination risk. Thromboembolic events, including deep vein (DVT) and (PE), arise from venous injury, pelvic stasis, and prolonged immobility post-fracture, with incidences reaching 40-60% in untreated patients. These complications stem from the hypercoagulable state induced by and can manifest as lower extremity swelling or respiratory distress, necessitating prophylactic anticoagulation. Infections complicate open pelvic fractures or surgical interventions, with rates of surgical site infections around 5-10% following fixation. Open fractures heighten contamination risk from perineal wounds, potentially leading to through bacterial seeding into bone fragments. Chronic complications include and , affecting approximately 5% of pelvic fractures and resulting from inadequate initial stabilization, causing persistent pain, leg length discrepancies, and abnormalities. Sexual and reproductive impacts are notable, with and reported in approximately 50-60% of female survivors due to scar tissue or disruption, and occurring in up to 30-50% of males from neurovascular injury. These long-term issues often require multidisciplinary management, including therapy.

Diagnosis

Clinical Evaluation

The clinical evaluation of a suspected pelvic fracture begins with a detailed history to identify the injury mechanism, patient comorbidities, and associated symptoms, which guide the urgency and approach to management. The mechanism is typically high-energy , such as collisions or falls from height in younger patients, or low-energy mechanisms like ground-level falls in older adults with . Comorbidities, including anticoagulation use (e.g., or direct oral anticoagulants), low , , and prior , increase the risk of fracture and associated hemorrhage, necessitating careful assessment of bleeding potential. Symptoms often include severe pelvic or lower that may radiate to the , back, or thighs; inability to bear weight; and signs of urogenital involvement such as , incontinence, or . Physical examination follows (ATLS) principles, prioritizing the ABCs (airway, breathing, circulation) before secondary survey to address life-threatening issues. Inspection reveals ecchymosis (e.g., Destot's sign over the , , or ), swelling, or open wounds indicating potential open fractures. should be gentle to avoid exacerbating instability or bleeding, focusing on tenderness over the pelvic ring, sacroiliac joints, or ; aggressive manipulation is contraindicated in suspected unstable fractures. Stability is assessed via the pelvic compression or rocking test, where gentle anterior-posterior compression of the iliac crests or anterior distraction evaluates ring integrity—instability suggests disruption and higher hemorrhage risk, but these tests have limited specificity and should be performed only once. The (FAST) exam is integrated early to detect intra-abdominal bleeding, complementing the circulation assessment. Special tests include digital rectal and vaginal examinations to identify open fractures, bony fragments protruding into the pelvis, or injuries to the rectum, vagina, or urethra (e.g., high-riding prostate or blood at the meatus). Neurological assessment evaluates sacral roots S2-S4 for sensory deficits, perianal sensation, anal tone, and lower extremity motor function, as sacral fractures carry a 5-56% risk of nerve injury depending on the zone involved. Red flags signaling severe injury include hemodynamic instability (e.g., systolic <90 mmHg, heart rate >120 , or signs of hypoperfusion), which indicates major pelvic hemorrhage with mortality up to 45% in open fractures and mandates immediate and stabilization. These findings prompt urgent intervention, with imaging reserved for confirmation once the patient is stabilized.

Imaging and Classification

Imaging of pelvic fractures begins with plain radiography, which serves as the initial screening tool in settings. An anteroposterior () view of the is routinely obtained to identify gross disruptions such as symphysis pubis diastasis greater than 2.5 cm or widening, which suggest . However, plain radiographs have significant limitations, including a of only 10.5% for detecting sacral fractures in elderly patients with blunt pelvic , potentially missing 20-38% of sacral insufficiency fractures overall. To better assess rotational and vertical displacement, supplementary inlet and outlet views are recommended; the inlet view (caudad projection) evaluates anterior-posterior displacement and pelvic ring narrowing, while the outlet view (cephalad projection) assesses superior-inferior displacement of the hemipelvis and sacral fractures. Computed tomography (CT) is the gold standard for detailed evaluation of pelvic fractures, providing high-resolution multiplanar reconstructions (sagittal, coronal, and 3D) to precisely delineate fracture morphology, sacroiliac joint involvement, and associated soft-tissue injuries such as hematomas. Contrast-enhanced CT protocols are optimized to detect vascular injuries, with sensitivity ranging from 71-90% for posterior ring fractures, though it may miss up to 54% of additional occult fractures identified by MRI. Magnetic resonance imaging (MRI) is particularly valuable for assessing soft-tissue structures, including ligaments and the sacral plexus, and for diagnosing occult fractures in osteoporotic patients, offering 96-100% sensitivity without ionizing radiation. In cases of suspected arterial hemorrhage, angiography is indicated to identify and treat vascular injuries through embolization, especially in hemodynamically unstable patients with pelvic fractures. Classification systems for pelvic fractures are essential for predicting mechanical stability and informing treatment planning, with the Tile and Young-Burgess systems being the most widely adopted. The classification, originally described in 1980 and based on the integrity of the posterior sacroiliac , categorizes injuries into three types according to rotational and vertical stability.
TypeDescriptionStability
APosterior arch intact (e.g., avulsion injuries, iliac wing fractures, transverse sacrococcygeal fractures)Rotationally and vertically stable
BIncomplete posterior arch disruption (e.g., open-book external rotation injuries, lateral compression internal rotation injuries, bilateral variants)Rotationally unstable but vertically stable
CComplete posterior arch disruption (e.g., unilateral or bilateral sacroiliac fracture-dislocations, sacral fractures)Rotationally and vertically unstable
The Young-Burgess classification, introduced in 1986, complements Tile by incorporating injury mechanisms (anteroposterior compression [APC], lateral compression [LC], vertical shear [VS], and combined mechanisms [CM]) to predict ligamentous damage and hemorrhage risk.
MechanismSubtypes and Key Features
APC IStable; symphysis widening <2.5 cm
APC IIRotationally unstable; symphysis widening >2.5 cm, anterior SI joint diastasis, intact posterior ligaments (open-book injury)
APC IIIFully unstable; complete anterior and posterior SI joint disruption
LC IStable; oblique/transverse ramus fracture with ipsilateral sacral ala compression
LC IIRotationally unstable; ramus fracture with iliac wing (crescent) fracture
LC IIIUnstable (windswept); ipsilateral LC II with contralateral APC
VSUnstable; vertical hemipelvis displacement through pubic symphysis and SI joint
CMVariable stability; complex patterns combining above mechanisms
These systems guide surgical decision-making by identifying unstable patterns requiring fixation; for instance, II and III injuries often necessitate anterior stabilization (e.g., external fixator) and posterior repair to close the pelvic ring, while Type C or injuries demand comprehensive to restore vertical stability. Modern imaging, particularly and MRI, has enhanced the accuracy of these classifications beyond pre- era reliance on radiographs alone.

Management

Initial Stabilization

Initial stabilization of pelvic fractures prioritizes hemorrhage control and hemodynamic support in the prehospital and settings, following (ATLS) protocols to address life-threatening instability. In the prehospital phase, circumferential using a pelvic binder or wrapped sheet is applied to suspected unstable pelvic injuries to reduce pelvic volume by approximately 10% and venous bleeding, which accounts for the majority of intra-pelvic hemorrhage. Binders should be positioned at the level of the greater trochanters to optimize , and log-rolling the patient must be avoided to prevent exacerbating instability or spinal injury. These devices serve as temporary measures until definitive care in the operating room. Upon arrival in the emergency department, two large-bore (16-gauge) intravenous lines are established immediately for fluid resuscitation, targeting permissive hypotension with a systolic blood pressure of 80-90 mmHg in hemodynamically unstable patients to maintain end-organ perfusion while minimizing clot disruption. Initial fluid administration includes at least 2 liters of crystalloid over the first few minutes, followed by activation of massive transfusion protocols using a 1:1:1 ratio of packed red blood cells, fresh frozen plasma, and platelets if ongoing hemorrhage is suspected. Pelvic binders are indicated for systolic blood pressure below 90 mmHg and should be continued or initiated if not already applied prehospital. For damage control in open-book pelvic fractures, or a is employed to provide anterior-posterior and reduce pelvic space, facilitating temporary alignment of fragments and decreasing the need for blood products. These interventions align with post-2020 trauma guidelines emphasizing rapid mechanical stabilization to improve survival rates in scenarios. Serial clinical examinations, including and assessment of , are performed alongside of and levels, which serve as sensitive indicators of traumatic-hemorrhagic severity and response to . Normalization of these parameters guides ongoing management and helps identify persistent hypoperfusion.

Definitive Treatment

Definitive treatment of pelvic fractures aims to achieve anatomic and fixation to restore pelvic , with options varying based on fracture stability and patient condition. For fractures classified as Tile A, which involve no disruption of the posterior pelvic , non-surgical is typically indicated. This approach includes initial to minimize risk, followed by progressive mobilization with partial weight-bearing as tolerated, along with serial radiographic imaging to monitor healing and detect any progression to instability. prophylaxis, such as , is essential during this period to mitigate the high risk of venous in immobilized patients with pelvic fractures. Surgical intervention is required for unstable fractures (Tile B and C) to address rotational or vertical instability and prevent long-term complications like . Open reduction and (ORIF) using plates and screws is commonly employed for anterior ramus or iliac wing fractures, providing rigid stabilization. serves primarily for temporary stability in the acute phase but can be used definitively in select cases with anterior ring disruption. For sacroiliac () joint injuries, percutaneous iliosacral screws offer posterior fixation with minimal soft tissue disruption. Specific techniques include anterior plating for greater than 2.5 cm via a Pfannenstiel or modified Stoppa approach, and posterior iliosacral screws inserted under fluoroscopic guidance for sacral fractures. Minimally invasive methods, such as percutaneous screw fixation or the anterior (INFIX), reduce operative time and blood loss while achieving comparable stability. The timing of definitive balances physiological stability with fracture urgency, guided by damage control orthopedics principles in patients. Early fixation within 36 hours is preferred for hemodynamically stable patients to reduce complications like and multi-organ failure, while delayed fixation (after 4-5 days) is recommended for those with borderline to avoid a "second hit" inflammatory response. In unstable patients, temporary measures like precede definitive ORIF once is complete. Recent advancements include robotic-assisted surgery for precise screw placement in pelvic fractures, improving accuracy and reducing radiation exposure compared to traditional . Systems like the RAFR enable closed reduction and fixation, particularly beneficial in complex sacral or acetabular involvement. For nonunions, biologics such as morphogenetic proteins (BMPs), including and BMP-7, promote osteogenesis when used as adjuncts to revision surgery, accelerating healing in persistent pelvic ring disruptions.70008-1/pdf)

Rehabilitation

Rehabilitation following a pelvic fracture focuses on restoring functional mobility, minimizing complications, and promoting long-term independence through structured, phased protocols. These programs typically involve a multidisciplinary including physiotherapists, physicians, and specialists to address , psychological impacts, and any associated injuries. Evidence-based guidelines emphasize early intervention to optimize outcomes, with protocols tailored to fracture stability and comorbidities. The acute phase prioritizes pain control and prevention of secondary issues such as deep vein thrombosis (DVT), often using (LMWH) for thromboprophylaxis in immobilized patients. Non-weight-bearing exercises and passive mobilization begin shortly after stabilization, typically within 1-2 days post-surgery or 15 days for , to prevent contractures and pressure ulcers. Goals include achieving partial independence in transfers and basic activities within 2-6 weeks. In the subacute phase, partial is introduced progressively, starting at 6-12 weeks, with increases of about 25% body weight weekly under supervision. incorporates training using assistive devices, strengthening exercises such as pelvic tilts and bridges to target core and , and balance activities to improve stability. Cardiovascular conditioning, like stationary or walking, supports endurance recovery. The chronic phase aims for full weight-bearing and return to activities by 3-6 months, with continued emphasis on strength and flexibility to achieve pre-injury mobility levels. Functional outcomes are often assessed using metrics like the Harris Hip Score, which evaluates pain, function, and , showing good to excellent results in 70-90% of cases with comprehensive . Multidisciplinary care integrates through medications and modalities like or electrical , alongside psychological to address trauma-related anxiety or common in high-energy injuries. For patients with urogenital injuries requiring ostomy, specialized focuses on wound care, appliance management, and reintegration into daily activities to prevent infections and quality of life. Special considerations apply to elderly patients, who experience slower healing due to and reduced bone density, necessitating individualized progression and strategies such as home modifications and balance training to sustain mobility and reduce re-injury .

Outcomes and Epidemiology

Prognosis

The prognosis of pelvic fractures varies widely depending on fracture , patient age, injury mechanism, and associated comorbidities, with overall mortality rates ranging from 5% to 50%, particularly elevated in high-energy and elderly patients. In elderly individuals over 65 years, mortality can approach 40%, driven by factors such as increased frailty and concomitant injuries, while high-energy fractures in younger patients carry a mortality of approximately 8-16%. Key predictors of mortality include advanced age greater than 65 years, an (ISS) exceeding 25, and , which collectively heighten the through hemodynamic instability and multi-organ failure. Morbidity remains significant, with 30-50% of survivors experiencing and approximately 20% facing long-term , often manifesting as reduced or persistent pelvic . Surgical intervention achieves bony union rates of 85-95% in appropriately selected cases, though outcomes are influenced by fracture pattern and timely fixation. Prognostic outcomes differ markedly by fracture type: stable fractures generally yield excellent recovery with minimal long-term sequelae, whereas unstable fractures are associated with poorer prognosis and up to 40% complication rates, including and . In the long term, quality of life is impacted, with patients showing lower physical component scores (e.g., 47.7 versus population norms of 50) particularly in vertical shear injuries due to residual displacement and limb discrepancies. Recent 2020s data highlight improved survival and reduced transfusion needs through angioembolization for hemodynamically unstable cases, with mortality declining by up to 0.43% annually post-2017 via multidisciplinary protocols incorporating this technique.

Incidence and Prevention

Pelvic fractures occur at an incidence of approximately 20 to 40 per individuals annually, representing approximately 3 percent of all skeletal injuries. Recent studies indicate an increasing trend, particularly for fragility fractures in the elderly, with rates rising from 15.8 to 37.6 per in some populations between 1988 and 2018. The distribution exhibits a bimodal , with peaks among young adults due to high-energy and among the elderly from low-energy falls. Demographically, high-energy pelvic fractures show a predominance with a 2:1 ratio, primarily affecting younger individuals involved in accidents. In contrast, low-energy fractures are more common in females over 70 years, often linked to , with incidence rates rising to 92 per 100,000 in those over 65. Key risk factors include high-speed motor vehicle collisions, which account for a significant proportion of cases, alongside that predisposes individuals to fragility fractures. (DEXA) screening is recommended for at-risk populations to detect low early. and substance use further elevate risk by impairing coordination and judgment, contributing to falls and accidents. Prevention strategies emphasize vehicle safety measures, where seatbelts and airbags combined reduce the risk of major injuries, including pelvic fractures, by up to 67 percent. For the elderly, includes hip protectors, which can reduce risk by nearly threefold when worn during falls, particularly in institutional settings. Home modifications such as installing grab bars, improving lighting, and removing tripping hazards also lower fall incidence. Maintaining bone health through adequate calcium and intake, along with bisphosphonates for those with , decreases fracture risk by preserving bone density. On a level, organized systems have demonstrably improved outcomes for pelvic fracture patients by enhancing prehospital care and timely intervention, as evidenced by reduced mortality in dedicated centers.