Summary Pelvic ring fractures are high energy fractures of the pelvic ring which typically occur due to blunt trauma. Diagnosis is made radiographically with pelvic radiographs and further characterized with CT scan. Treatment is typically operative fixation depending on degree of pelvis instability, fracture displacement and patient activity demands. Etiology Associated injuries orthopaedics chest injury in up to 63% long bone fractures in 50% spine fractures in 25% non-orthopaedic urogenital sexual dysfunction up to 50% head and abdominal injury in 40% Pediatric pelvic ring fractures children with open triradiate cartilage have different fracture patterns than do children whose triradiate cartilage has closed if triradiate cartilage is open the iliac wing is weaker than the elastic pelvic ligaments, resulting in bone failure before pelvic ring disruption for this reason fractures usually involve the pubic rami and iliac wings and rarely require surgical treatment Anatomy Osteology ring structure made up of the sacrum and two innominate bones stability dependent on strong surrounding ligamentous structures displacement can only occur with disruption of the ring in two places neurovascular structures intimately associated with posterior pelvic ligaments high index of suspicion for injury of internal iliac vessels or lumbosacral plexus Ligaments anterior symphyseal ligaments resist external rotation pelvic floor sacrospinous ligaments resist external rotation sacrotuberous ligaments resist shear and flexion posterior sacroiliac complex (posterior tension band) strongest ligaments in the body more important than anterior structures for pelvic ring stability anterior sacroiliac ligaments resist external rotation after failure of pelvic floor and anterior structures interosseous sacroiliac resist anterior-posterior translation of pelvis posterior sacroiliac resist cephalad-caudad displacement of pelvis iliolumbar resist rotation and augment posterior SI ligaments Vascular common iliac system begins near L4 at bifurcation of abdominal aorta external iliac artery courses anteriorly along pelvic brim and emerges as the common femoral artery distal to the inguinal ligament internal iliac artery dives posteriorly near SI joint and divides in the posterior division (giving of superiior gluteal artery) and anterior division (becoming obturator artery) corona mortis is a connection between the obturator and and external iliac systems mean distance of 6.2cm from the pubic symphysis venous plexus in posterior pelvis accounts for 90% of the hemorrhage associated with pelvic ring injuries Neurologic Lumbosacral trunk crosses anterior sacral ala and SI joint L5 nerve root exits below L5 TP a courses over sacral ala 2cm medial to SI joint Classification Tile classification Tile classification A: Stable A1: fracture not involving the ring (avulsion or iliac wing fracture) A2: stable or minimally displaced fracture of the ring A3: transverse sacral fracture (Denis zone III sacral fracture) B: Rotationally unstable, vertically stable B1: open book injury (external rotation) B2: lateral compression injury (internal rotation) B2-1: with anterior ring rotation/displacement through ipsilateral rami B2-2-with anterior ring rotation/displacement through contralateral rami (bucket-handle injury) B3: bilateral C: Rotationally and vertically unstable C1: unilateral C1-1: iliac fracture C1-2: sacroiliac fracture-dislocation C1-3: sacral fracture C2: bilateral with one side type B and one side type C C3: bilateral with both sides type C Young-Burgess Classification Anterior Posterior Compression (APC) APC I Symphysis widening < 2.5 cm APC II Symphysis widening > 2.5 cm. Anterior SI joint diastasis. Posterior SI ligaments are intact. Disruption of sacrospinous and sacrotuberous ligaments. APC III Disruption of anterior and posterior SI ligaments (SI dislocation). Disruption of sacrospinous and sacrotuberous ligaments. APCIII associated with vascular injury Lateral Compression (LC) LC I Oblique or transverse ramus fracture and ipsilateral anterior sacral ala compression fracture. LC II Rami fracture and ipsilateral posterior ilium fracture dislocation (crescent fracture). LC III Ipsilateral lateral compression and contralateral APC (windswept pelvis). Common mechanism is rollover vehicle accident or pedestrian vs auto. Vertical Shear (VS) Vertical shear Posterior and superior directed force. Associated with the highest risk of hypovolemic shock (63%); mortality rate up to 25% Physical Exam Symptoms pain & inability to bear weight Physical exam inspection test stability by placing gentle rotational force on each iliac crest low sensitivity for detecting instability perform only once look for abnormal lower extremity positioning external rotation of one or both extremities limb-length discrepancy skin scrotal, labial or perineal hematoma, swelling or ecchymosis flank hematoma lacerations of perineum degloving injuries (Morel-Lavallee lesion) neurologic exam rule out lumbosacral plexus injuries (L5 and S1 are most common) rectal exam to evaluate sphincter tone and perirectal sensation up to 10-15% of patients will sustain neurologic injury urogenital exam most common finding is gross hematuria more common in males (21% in males, 8% in females) vaginal and rectal examinations mandatory to rule out occult open fracture Imaging Radiographs recommended views AP part of initial ATLS evaluation look for asymmetry, rotation or displacement of each hemipelvis evidence of anterior ring injury needs further imaging inlet xray beam angled 40° caudad (may be as little as 25 degrees) adequate image when S1 overlaps S2 body (i.e. perpendicular to S1 endplate) ideal for visualizing anterior or posterior translation of the hemipelvis internal or external rotation of the hemipelvis widening of the SI joint sacral ala impaction outlet xray beam angled ~40° cephalad (may be as much as 60 degrees) adequate image when pubic symphysis overlies S2 body ideal for visualizing vertical translation of the hemipelvis flexion/extension of the hemipelvis disruption of sacral foramina and location of sacral fractures Single-leg stance AP pelvis ("flamingo views") Patient alternates with right and left foot up while AP pelvis is obtained Used in evaluation of suspected chronic pelvic ring instability Examiner measures vertical translation of the pubic bones Serves as a means of assessing pathologic motion at the SI joint findings radiographic signs of instability > 5 mm displacement of posterior sacroiliac complex presence of posterior sacral fracture gap avulsion fractures (ischial spine, ischial tuberosity, sacrum, transverse process of 5th lumbar vertebrae) CT routine part of pelvic ring injury evaluation better characterization of posterior ring injuries helps define comminution and fragment rotation visualize position of fracture lines relative to sacral foramina radiographic signs of sacral dysmorphism: anterior up-sloping upper sacral ala irregular, non-circular, sacral nerve root tunnels residual S1 disk tongue-and-groove SI joint Studies Serum labs hgb serum lactate base excess Initial Management & Resusitation Bleeding Source intraabdominal (present in up to 40% of cases) intrathoracic retroperitoneal extremity (thigh compartments) pelvic common sources of hemorrhage venous injury (80%) shearing injury of posterior thin walled venous plexus leads to retroperitoneal hematoma (can hold up to 4L of blood) bleeding cancellous bone uncommon sources of hemorrhage arterial injury (10-20%) superior gluteal most common (posterior ring injury, APC pattern) internal pudendal (anterior ring injury, LC pattern) obturator (LC pattern) Treatment resuscitation PRBC:FFP:Platelets ideally should be transfused 1:1:1 this ratio shown to improve mortality in patients requiring massive transfusion pelvic binder/sheet indications initial management of an unstable ring injury should be centered over the greater trochanters contraindications hypothetical risk of over-rotation of hemipelvis and hollow viscus injury (bladder) in pelvic fractures with internal rotation component (LC) no clinical evidence exists of this complication occurring pitfalls binder can mask pelvic ring injuries, creating false negative radiographs and CT images stress examination under anesthesia may be indicated in patients who present to the trauma slot in a pelvic binder, hemodynamic instability, and negative pelvis radiographs/CT scan external fixation indications pelvic ring injuries with an external rotation component (APC, VS, CM) unstable ring injury with ongoing blood loss should be placed before emergent laparotomy contraindications ilium fracture that precludes safe application acetabular fracture angiography / embolization indications controversial and based on multiple variables including: protocol of institution, stability of patient, proximity of angiography suite , availability and experience of IR staff CT angiography useful for determining presence or absence of ongoing arterial hemorrhage (98-100% negative predictive value) contraindications not clearly defined technique selective embolization of identifiable bleeding sources in patients with uncontrolled bleeding after selective embolization, bilateral temporary internal iliac embolization may be effective repeat angiography if patient continues to be hypotensive after embolization recurrent hemorrhage from previously embolized artery is common complications include gluteal necrosis and impotence Definitive Treatment Overview by Classification Definitive treatment of Anterior Posterior Compression (APC) injuries APC I Non-operative. Protected weight bearing APC II Anterior symphyseal plate or external fixator +/- posterior fixation APC III Anterior symphyseal multi-hole plate or external fixator and posterior stabilization with SI screws or plate/screws Definitive treatment of Lateral Compression (LC) injuries LC I Non-operative.-Protected weight bearing (complete, comminuted sacral component.-Weight bearing as tolerated (simple, incomplete sacral fracture) LC II Open reduction and internal fixation of ilium LC III Posterior stabilization with plate or SI screws as needed. Percutaneous or open based on injury pattern and surgeon preference. Definitive treatment of Vertical Shear (VS) injuries Vertical Shear Posterior stabilization with plate or SI screws as needed. Percutaneous or open based on injury pattern and surgeon preference. Nonoperative weight bearing as tolerated indications mechanically stable pelvic ring injuries including LC1 anterior impaction fracture of sacrum and oblique ramus fractures with < 1cm of posterior ring displacement APC1 traumatic widening of symphysis < 2.5 cm with intact posterior pelvic ring isolated pubic ramus fractures parturition-induced pelvic diastasis bedrest and pelvic binder in acute setting with diastasis less than 4cm Operative ORIF indications symphysis diastasis > 2.5 cm SI joint displacement > 1 cm sacral fracture with displacement > 1 cm displacement or rotation of hemipelvis open fracture chronic pain and diastasis in parturition-induced diastasis or acute setting >4-6cm technique for open fractures aggressive debridement according to open fracture principles anterior subcutaneous pelvic fixator (INFIX) indications same indications as anterior external fixation and symphyseal plating complications heterotopic ossification, femoral nerve injury, infection diverting colostomy indications consider in open pelvic fractures especially with extensive perineal injury or rectal involvement Techniques Pelvic Binding technique centered over greater trochanters to effect indirect reduction do not place over iliac crest/abdomen ineffective and precludes assessment of abdomen may augment with internal rotation of lower extremities and taping at ankles transition to alternative fixation as soon as possible prolonged pressure from binder or sheet may cause skin necrosis working portals may be cut in sheet to place percutaneous fixation early pelvic binding and CT have been associated with underestimation of pelvic ring instability fluroscopic exam under anesthesia can be used to assess stability in these circumstances External fixation theoretically works by decreasing pelvic volume stability of bleeding bone surfaces and venous plexus in order to form clot pins inserted into ilium supra-acetabular pin insertion single pin in column of supracetabular bone from AIIS towards PSIS obturator outlet view helps to identify pin entry point iliac oblique view helps to direct pin above greater sciatic notch obturator oblique inlet view helps to ensure pin placement within inner and outer table AIIS pins can place the lateral femoral cutaneous nerve at risk pedicle screws with internal subcutaneous bar may be used superior iliac crest pin insertion multiple half pins in the superior iliac crest place in thickest portion of ilium (gluteal pillar) may be placed with minimal fluoroscopy ORIF anterior ring stabilization single superior plate apply through rectus-splitting Pfannenstiel approach may perform in conjunction with laparotomy or GU procedure posterior ring stabilization anterior SI plating risk of L4 and L5 injury with placement of anterior sacral retractors iliosacral screws (percutaneous) good for sacral fractures and SI dislocations safe zone is in S1 vertebral body outlet radiograph view best guides superior-inferior screw placement inlet radiograph view best guides anterior-posterior screw placement in sacral dysmorphism, the safe zone in S2 is larger L5 nerve root injury complication with errors in screw placement entry point best viewed on lateral sacral view and pelvic outlet views risk of loss of reduction highest in vertical sacral fracture patterns posterior SI "tension" plating can have prominent HW complications anterior and posterior ring stabilization necessary in vertically unstable injuries ipsilateral acetabular and pelvic ring fractures in general, reduction and fixation of the pelvic ring should be performed first Rehabilitation stable fractures treated nonsurgically patients may mobilize immediately with protected weight bearing after stable fracture pattern in confirmed (may require post-mobilization views to confirm stability) unstable fractures treated surgically patient mobility and weight bearing depend on the location of the posterior pelvic ring fracture mobility includes weight-of-limb weight bearing ipsilateral to the posterior pelvic injury with full weight bearing on contralateral side patients with bilateral posterior pelvic ring injuries limited to bed-to-chair transfers only when radiographic healing has occured weight bearing can be gradually advanced Complications Urogenital Injuries present in 12-20% of patients with pelvic fractures higher incidence in males (21%) includes posterior urethral tear most common urogenital injury with pelvic ring fracture bladder rupture may see extravasation around the pubic symphysis associated with mortality of 22-34% diagnosis made with retrograde urethrocystogram indications for retrograde urethrocystogram include blood at meatus high riding or excessively mobile prostate hematuria treatment suprapubic catheter placement suprapubic catheter is a relative contraindication to anterior ring plating surgical repair rupture should be repaired at the same time or prior to definitive fixation in order to minimize infection risk complications long-term complications common (up to 35%) urethral stricture - most common impotence anterior pelvic ring infection incontinence parturition sequelae (i.e. caesarean section) Neurologic injury L5 nerve root runs over sacral ala joint may be injured if SI screw is placed to anterior anterior subcutaneous pelvic fixator may give rise to LFCN injury (most common) or femoral nerve injury DVT and PE DVT in ~ 60%, PE in ~ 27%, fatal PE in 2% prophylaxis essential mechanical compression pharmacologic prevention (LMWH or Lovenox) vena caval filters (closed head injury) Chronic instability rare complication; can be seen in nonoperative cases presents with subjective instability and mechanical symptoms diagnosed with alternating single-leg-stance pelvic radiographs (flamingo views) Infection risk factors include: obesity diabetes prolonged operation time prolonged ICU stay larger amount of packed red blood cell transfusions, associated genitourinary and abdominal trauma open fractures preoperative angioembolization is controversial Prognosis High prevalence of poor functional outcome and chronic pain Poor outcome associated with SI joint incongruity of > 1 cm high degree initial displacement malunion or residual displacement leg length discrepancy > 2 cm nonunion neurologic injury urethral injury Mortality rate 1-15% for closed fractures, as much as 50% for open fractures hemorrhage is leading cause of death overall closed head injury is the most common for lateral compression injuries increased mortality associated with systolic BP <90 on presentation age >60 years increased Injury Severity Score (ISS) or Revised Trauma Score (RTS) need for transfusion > 4 units APC III injury