Pelvic and acetabular fractures — Young-Burgess and Letournel classification, haemodynamic control, ORIF

Overview

Pelvic ring injuries range from stable, minimally displaced fractures to life-threatening disruptions with massive haemorrhage and multisystem injury. The Young-Burgess (YB) classification is the dominant mechanistic system in trauma settings because it predicts associated injuries, transfusion requirements, and guides immediate resuscitation decisions. Mortality with non-operative management of unstable pelvic ring injuries historically approached 18%; contemporary multidisciplinary protocols incorporating binders, pelvic packing, angioembolisation, and REBOA have substantially improved survival. A single classification is insufficient for complete management decisions: the YB system (mechanism-based) and the Tile/AO-OTA system (stability-based) are complementary, with no clinically relevant difference in predictive value for mortality or transfusion requirements between the two.

Anatomy and Biomechanics

Osseoligamentous Ring

The pelvis is a true ring structure: disruption at one point mandates injury at a second point before displacement can occur. The posterior ring, sacrum, sacroiliac joints (SIJ), and posterior SIJ ligamentous complex, carries the dominant load and is the primary determinant of stability. The anterior ring (pubic symphysis, superior and inferior rami) contributes rotational stiffness.

Key Ligaments

Haemorrhagic Anatomy

The majority (~85%) of pelvic haemorrhage originates from disrupted cancellous bone surfaces and the presacral/iliac venous plexuses; arterial injury accounts for ~15% but causes the most dramatic haemodynamic deterioration. The superior gluteal artery (internal iliac branch) is the most commonly injured vessel. The retroperitoneal space accommodates 3-4 litres before tamponade arrests venous bleeding; this tamponade is lost in open-book injuries because pelvic volume is increased. Closing the pelvis with a binder or external fixation restores tamponade potential.

Young-Burgess Classification

Conceptual Basis

The YB system categorises pelvic ring injuries by the direction of the causative force, expanding upon Pennal's earlier mechanistic classification. It correlates mechanism with anatomical disruption, predicts associated organ injuries, and guides haemorrhage risk stratification. Four groups are described: anteroposterior compression (APC), lateral compression (LC), vertical shear (VS), and combined mechanism (CM).

Classification

Haemorrhage Correlation

• APC-III has a circulatory shock rate of approximately 67% at presentation
• APC patterns require substantially higher transfusion volumes than LC patterns: APC first-day blood utilisation ~28.4 units versus ~5.8 units for LC
• APC-III: 62% of patients require a mean of ~12.6 units packed red cells; LC-III: 60% require a mean of ~4.0 units
• APC and VS patterns most frequently require haemorrhage control intervention (confirmed in AAST multi-institutional prospective data)
• LC-I is the most common pelvic fracture pattern overall and carries low haemorrhage risk
• Unstable patterns (LC-II/III, APC-II/III, VS, CM) correlate with higher AIS scores, greater transfusion requirements, and higher mortality in both the YB and Tile classifications, the key prognostic difference is that the YB system, when dichotomised into partially stable versus unstable, more clearly discriminates mortality

Associated Injury Predictions by Pattern

Tile / AO-OTA Classification (Complementary System)

Type A → non-operative; Type B → operative vs. non-operative depending on displacement and functional status; Type C → operative fixation almost always required. Type C injuries have the worst outcomes, predominantly due to associated neurological injuries.

Denis Classification of Sacral Fractures (Adjunct)

Zone III fractures are by definition the most neurologically significant. U-shaped (spinopelvic dissociation) and H-shaped sacral fractures involve bilateral Zone II/III and require lumbopelvic fixation.

Clinical Assessment

History

• Mechanism: high-speed MVC, pedestrian vs. vehicle, fall from height, crush, equestrian accident
• Bimodal age distribution: high-energy injuries in the young; low-energy falls in elderly osteoporotic patients (side impact is a major mortality risk factor even in modern vehicles)
• Haemodynamic status at scene; pre-hospital fluid volumes

Primary Survey

ATLS-based. Haemodynamic instability: SBP < 90 mmHg despite initial resuscitation, or persistent HR > 120 bpm. The pelvis must be identified as the haemorrhage source by systematic exclusion of chest, abdomen, and long bone bleeding.

Examination

• Inspection: asymmetry, leg length discrepancy, rotation, perineal/scrotal bruising, Morel-Lavallée lesion (closed internal degloving of the flank/thigh)
• Palpation: manual compression/distraction performed once only, repeated examination dislodges forming clot
• Perineal: open fracture wound, blood at urethral meatus, vaginal laceration, scrotal haematoma
• Neurological: sacral root deficit (S2-S4), perianal sensation, bulbocavernosus reflex, bladder/bowel function
• Flamingo/push-pull testing: subacute setting only, contraindicated in haemodynamic instability and in Denis Zone II/III sacral fractures (neurological risk)

Investigations

Management of Haemodynamic Instability

Damage Control Resuscitation Principles

• Permissive hypotension: target SBP 80-90 mmHg until surgical haemorrhage control is achieved
• Massive transfusion protocol (MTP): balanced blood product resuscitation, pRBC : FFP : platelets at 1:1:1
• Tranexamic acid (TXA): administer within 3 hours of injury
• Avoid the lethal triad: hypothermia, acidosis, coagulopathy

Step 1, Pelvic Binder / Sheet Wrap

Applied at the level of the greater trochanters (not the iliac crests). Reduces pelvic volume in open-book/APC injuries, promotes tamponade, allows autotransfusion from lower limbs. A simple sheet wrap is as effective as a commercial binder acutely.

• Indications: APC-II/III patterns; any haemodynamically unstable pelvic fracture
• Caution in LC patterns: the internal rotation force of the binder may worsen LC displacement, apply clinical judgement

Step 2, External Pelvic Fixation

Achieves ring stability and augments volume reduction. Two principal damage-control options:

External fixation is a bridging/damage-control measure. Definitive posterior ring stabilisation (percutaneous iliosacral screws or ORIF) follows physiological optimisation.

Step 3, Preperitoneal Pelvic Packing (PPP)

Rationale: ~85% of pelvic haemorrhage is venous/cancellous in origin and responds to mechanical tamponade. Angioembolisation addresses arterial bleeding only; PPP targets the dominant venous source.

Technique: midline infraumbilical incision, extraperitoneal dissection into the space of Retzius and bilateral paravesical spaces, placement of 3 laparotomy packs on each side directed toward the sacrum. The peritoneum is not entered. Planned re-look with pack removal at 24-48 hours.

Evidence: institutional series demonstrate significant reduction in transfusion requirements and mortality when PPP is combined with external fixation. PPP and angioembolisation are complementary; many centres now use a combined protocol (PPP first, then angioembolisation for persistent arterial haemorrhage).

Complication of note: PPP carries a higher risk of venous thromboembolism compared with angioembolisation alone, early and aggressive VTE prophylaxis is essential once haemostasis is secured.

Step 4, Angioembolisation

Indications:

• CT evidence of active arterial extravasation
• Haemodynamic instability persisting after binder, external fixation, and/or PPP
• APC-II/III and VS patterns with suspected arterial injury

Technique: selective catheterisation of the internal iliac artery; super-selective embolisation preferred to minimise ischaemic complications (gluteal necrosis, sexual dysfunction, bladder ischaemia). Bilateral internal iliac embolisation performed when source is unlocalised.

Limitation: does not address venous/cancellous haemorrhage; availability is not universal around-the-clock.

REBOA (Resuscitative Endovascular Balloon Occlusion of the Aorta)

Mechanism: an endovascular catheter with a compliant balloon is introduced via femoral arterial access and inflated within the aorta to partially or completely occlude flow, thereby reducing distal haemorrhage, augmenting proximal (cardiac, cerebral) perfusion pressure, and bridging the patient to definitive haemorrhage control.

Aortic Zone Deployment

Zone III is the preferred deployment zone for pelvic haemorrhage because it reduces distal pelvic flow while preserving visceral and renal perfusion to a greater degree than Zone I.

Indications in pelvic fracture:

• SBP < 90 mmHg not responding to resuscitation
• Bridge to PPP, angioembolisation, or damage control surgery
• Temporising measure in lieu of resuscitative thoracotomy for non-compressible torso haemorrhage

Complications:

• Limb ischaemia and amputation (most commonly reported)
• Access site haematoma and pseudoaneurysm
• Visceral ischaemia-reperfusion injury (especially Zone I, prolonged inflation)
• Balloon rupture, catheter migration

Current evidence and limitations: systematic review data show no significant difference in health-related quality of life between REBOA and resuscitative thoracotomy. Reported complications include amputations, haematomas, and pseudoaneurysm. A clear population-wide indication for REBOA has not been established; it functions as a powerful adjunct within a multidisciplinary haemorrhage control algorithm. Dedicated training and around-the-clock endovascular capability are prerequisites.

Institutional Protocol Framework

Haemodynamically unstable pelvic fracture
 ↓
Activate MTP + TXA (within 3 hours)
 ↓
Pelvic binder at greater trochanter level
 ↓
FAST: intraperitoneal haemorrhage?
 YES → emergency laparotomy (± REBOA Zone I bridge)
 NO → continue pelvic haemorrhage algorithm
 ↓
CT angiography if haemodynamically permitting
 Arterial blush → angioembolisation
 ↓
External fixation ± REBOA Zone III if persistent instability
 ↓
Preperitoneal pelvic packing (PPP)
 ↓
Angioembolisation (if not already performed / persistent arterial bleed)
 ↓
ICU stabilisation → definitive fixation (48-72 hours)

Operative Management, Definitive Fixation

Anterior Ring

Posterior Ring

Timing

• Damage control external fixation: immediately when haemodynamically unstable
• Definitive internal fixation: delayed 48-72 hours once physiologically resuscitated (pH > 7.35, temperature > 36 °C, coagulopathy corrected, lactate normalising)

Complications

Outcomes and Prognosis

• Mortality in haemodynamically unstable pelvic fractures: 10-40% depending on injury severity, associated injuries, and speed of haemorrhage control
• APC injuries carry approximately 2-3× the mortality of LC injuries
• Unstable patterns (YB: LC-II/III, APC-II/III, VS, CM; Tile: B and C) are independently associated with higher transfusion requirements and mortality
• Functional outcomes correlate with posterior ring displacement; > 1 cm residual displacement associates with chronic pain, leg length discrepancy, and gait disturbance
• Pelvic asymmetry > 1.1 cm at follow-up (including paediatric patients) correlates with inferior functional outcomes and does not predictably remodel
• Validated outcome measures: SF-36, MAJEED Pelvic Score, Iowa Pelvic Score
• Neurological injury is the dominant long-term morbidity driver in Type C / VS injuries

Paediatric Considerations

• Pelvic fractures in children are rare due to greater skeletal elasticity and cartilaginous ring components
• YB classification is applicable to paediatric injuries; the Torode and Zieg classification is specific to children and complements YB
• Children < 10 years with minimal pelvic asymmetry generally tolerate non-operative management with satisfactory outcomes
• Pelvic asymmetry does not predictably remodel; > 1.1 cm at follow-up is associated with inferior functional scores
• Indications for operative fixation mirror adult principles for significantly displaced, unstable patterns
• Growth plate considerations affect IS screw trajectory planning in the skeletally immature

Key Examination Points (Viva Focus)

• The YB system is mechanistic (direction of force); Tile/AO-OTA is stability-based, both are complementary; neither is superior for predicting all outcomes, but YB better discriminates mortality when dichotomised into stable vs. unstable
• Highest haemorrhage risk: APC-III and VS patterns; APC-III has ~67% circulatory shock rate at presentation
• Pelvic binder must be placed at the greater trochanters, not the iliac crests
• PPP addresses venous/cancellous haemorrhage (dominant ~85%); angioembolisation addresses arterial bleeding (~15%)
• PPP carries higher VTE risk than angioembolisation alone
• REBOA Zone III is preferred for pelvic haemorrhage; Zone I for near-arrest/torrential haemorrhage
• No significant difference in health-related QoL between REBOA and resuscitative thoracotomy in systematic review data; no clear population-wide indication established
• Most common REBOA complication: limb ischaemia / amputation
• Definitive posterior ring fixation is delayed until physiological resuscitation is complete (pH > 7.35, normothermia, corrected coagulopathy)
• The Denis classification guides neurological risk stratification of sacral fractures: Zone III carries ~57% nerve injury rate; U-/H-shaped fractures require lumbopelvic fixation

Sources

• AOA (Australian Orthopaedic Association) position statements
• AAOS guidelines (American Academy of Orthopaedic Surgeons)
• Cochrane Library reviews