Introduction
- The majority of pelvic fractures are the result of high-energy blunt injures
- Patients require emergent and thorough evaluation
- As compared to the extremities, the pelvis has greater soft tissue constraints, as well as vital non-musculoskeletal structures
- Treatment of pelvic fractures requires techniques different from those used in the extremities
- Treatment can be surgical or nonsurgical, but emphasize the re-establishment of a stable ring structure that allows appropriate transfer of weight from the torso to the hips and legs
Anatomy
Bony Anatomy
- Pelvis is composed of 3 bones, 1 sacrum and 2 innominate bones
- Innominate bone forms from the fusion of the immature
- Ischium (infero-posterior)
- Illium (superior)
- Pubis (infero-anterior)
- The acutabulm forms at the junction of these 3 bones
- Important bony prominences and landmarks include
- The anterior superior illiac spine (ASIS)
- The anterior inferior illiac spine (AIIS)
- Iliac crest
- Iliac fossa
- Posterior superior illiac spine (PSIS)
- Ischial spine
- Ischial tuberosity
- Inferior and superior pubic rami
- Pectineal eminence
- Pubic tubercle
- Figure to show landmarks via lateral view of inominate bone and anterior view of the pelvis

Ring stability
- The bony pelvis is stabilized primarily by
- Symphysis pubis
- Forms the anterior part of the pelvic ring
- Composed of a complex of
- Hyaline cartilage
- Fibrocartilage
- Fibrous tissues
- Sacroilliac (SI) joints
- Forms the posterior part of the pelvic ring
- Composed of both hyaline and fibro-cartilage
- Stabilized via posterior, anterior and interosseous ligaments; the latter are the strongest ligaments in the body
- Not a true synovial joint, as it does not originate from an anlage of condensed mesanchyme
- The elements of the pelvis are further stabilized relative to each other through
- Sacro-spinous ligament (anteroposterior and rotational vectors)
- Long and short sacro-tuberous ligament (vertical vector)
- From a superior view with the pubis facing down, the sacrum forms an upside down keystone (or suspension bridge) that does not have inherent stability; with loss of bony or ligamentous constraints, the sacrum tends to displace anteriorly (the bridge will fall)
- From an anterior view the sacrum forms the keystone of an arch that transfers weight from the spine to the acetabuli
Non-musculoskeletal structures
Pathogenesis
- Direct impact to the pelvis with indirect transfer of forces to anterior and posterior ring elements
- Mechanisms of Injury
- Lateral compression
- Antero-posterior compression
- Vertical shear
- Combination of the above
- Impact forces cause rotation-translation of a hemipelvis fragment relative to the sacrum in the axial plane or translation in the coronal plane
- Settings
- Most commonly motor vehicle and pedestrian-vehicle crashes
- Motorcycle crashes, fall from heights and crush injuries are less common
Natural History
- Mortality 5 - 20% (up to 42% for open fractures)
- Increasing mortality with increased age
- > 70 years old has 50% mortality
- Pedestrian injury has 50% mortality
- Pregnant cases have 33% fetal loss
- 20 - 40% of females subsequently need caesarean section
Clinical Presentation
- Comorbidities
- The risk of additional injuries approaches 40-50%
- Significant injuries to the viscera, great vessels (highest in APC-III) and head (highest in LC-II) are common with high energy mechanisms
- APCs have the highest rate of blood loss and death
- APC-III has a mortality rate as high as 37%
- Newer studies, however, have called into question these particular associations with specific fracture patterns
- Associated injured
- Arteries
- Internal pudendal : the most frequent cause of active bleeding
- Iliolumbar artery
- Superior gluteal artery
- Lateral sacral artery
- Internal iliac artery
- Neurologic
- L5, S1 are the most commonly injured spinal nerve roots
- The degree of displacement of the posterior elements rather than specific location appears to be more important determinant of injury
- GU
- GI
Imaging and Diagnostic Studies
- Patients with significant pelvic ring injuries should receive a full trauma evaluation according to American College of Surgeon's Advanced Trauma Life Support
- Evaluation includes assessment of Airway, Breathing, Circulation
Radiographic evaluation
- Initial radiographic evaluation includes
- AP view
- Provides initial assessment of the anterior and posterior portions of the ring
- May show concomitant acetabular injuries
- Inlet (40 degree caudal) view; provides information regarding
- Rotation of each hemipelvis
- Translation of the ilium relative to the sacrum
- Outlet (40 degree cephalad) view; shows
- Sagital plane rotation
- Vertical displacement
- Sacral fractures
- Judet views are not typically needed, unless
- There is a concomitant acetabular fracture
- A better view of a ramus rootlet fracture is sought
- Recommended in preparation of an anterior column screw
- Anterior ring injuries are often easily seen
- Symphysis diastasis
- Pubic rami fractures
- Posterior injuries can be more subtle
- Sacral fractures
- Sacroiliac (SI) joint injuries
- Signs of posterior injury or instability
- Irregularities of the SI joint
- Fracture of the L5 transverse process
- Inferior pubic ramus fracture
- Horizontal translation most often appears as posterior translation of ilium in SI dislocations /fracture-dislocations; also known as crescent fracture
- Vertical displacement is commonly identified as cephalad migration of ilium; complete separation and migration is called Malgaign fracture
CT Scan
- With any significant pelvic injury, a CT scan with fine cuts should be obtained
- Allows for measurement of
- "Safe zone" in the bodies of S1 or S2, if iliosacral screws are indicated
- Degree of antero-posterior sacral alar comminution
- SI gapping with hemipelvis rotation
- Sacral foraminal involvement on coronal images
- Special attention should be paid to the posterior elements, as sacral fractures can be missed on plain radiographs
Classification
Anatomic
- The Letournel system is based purely on the location of the fracture
- show Figure

Mechanism
- Penal first introduced a mechanistic classification system in 1961
- Lateral compression (LC)
- Anterior-posterior compression (APC)
- Vertical shear (VS)
- Young and Burgess (1986)
- LC fractures were subdivided into 3 types:
- Type I : pubic rami fractures with impaction of the SI joint
- Type II
- Pubic rami fractures with internal rotation, posterior disruption
- Posterior disruption can take 2 forms :
- Iliac wing fracture
- Varying degrees of anterior SI impaction and posterior SI disruption depending on location of impact on ilium
- Type III : LC fracture on one side with APC fracture on the other side
- APC fractures were divided into 3 types:
- Type I : Anterior ring widening with intact posterior elements
- Type II
- SI anterior widening
- External rotation of the ilium
- Disruption of sacro-tuberous and sacro-spinous ligaments
- Type III : Complete posterior/SI disruption
- Strength of this system is that it is predictive of associated injuries and may aid in the initial evaluation and stabilization of the patient
Stability
- Bucholtz in 1981 and Tile in 1988 created a system based on stability
- The Tile classification
- Type A, stable
- A1 : avulsion
- A2 : minimally displaced ring
- Type B, rotationally unstable
- Type C, rotationally and vertically unstable
- The OTA/AO scheme presents a variation where
- Type A is stable
- A1 : Avulsion
- A2 : Impaction
- A3 : Transverse sacral/coccygeal fracture
- Type B is partially stable
- B1 : Unilateral/partial in external or internal rotation
- B2 : Bilateral/partial
- Type C is unstable
- C1 : Unilateral/complete
- C2 : Bilateral/incomplete
- C3 : Bilateral/complete
Treatment
Resuscitation
- Fluid replacement
- Antishock garment
- Embolisation
- Direct surgical intervention
- Application of external fixator can significantly reduce venous and bony bleeding
Provisional stabilisation
- For fractures that increase pelvic volume, i.e. open book (B1) or vertical shear (C3), apply external fixator or pelvic clamp percutaneously in emergency room
- External fixator placement :
- 2 pins placed percutaneously in each Ileum
- 1 at ASIS, 1 at iliac tubercle, at 45 degrees to each other
- Complete frame as anterior rectangle
By Type
- A
- B
- B1 : no stabilization
- B2 : stabilise with external fixator or anterior plate
- B3 (bucket handle)
- If LLD < 1.5 cm : accept
- If LLD > 1.5 cm or pelvic deformity excessive : reduce with pins in the iliac crest, maintain with anterior frame
- C
- Anterior frame and skeletal traction (supracondylar femoral pin)
- Safe
- Indicated if :
- There is adequate reduction of posterior sacroiliac complex
- When posterior injury is a iliac fracture rather than an SI dislocation or a sacral fracture
- Disadvantage is traction for 8-12 weeks
- ORIF
- Risks
- Bleeding
- Loss of tamponade
- Coagulopathy
- Infection
- Wound necrosis, esp. in posterior wounds
- Nerve damage
- Indications
- Inadequate reduction of posterior injury, esp. SI dislocation
- Open posterior wound
- Associated with acetabular fracture
Indications for External Fixator
- B : to aid and maintain reduction
- C
- To produce partial stability
- Decreases bleeding
- Decreases pain
- Aids nursing
- If ORIF is to be performed, it should be delayed, but no more than 7 days, until
- Patient is stable
- All investigations completed
- Operation planned
Complications
- ORIF delayed more than 3 weeks would limit accuracy of reduction, because of callus formation
- Non-union / malunion
- High incidence in Malgaine type 90%
- Usually symptomatic
- High incidence of nerve, bladder complications at revision surgery
- Infection
- 6% incidence
- Increased incidence of infection associated with open bowel injury
- Increased incidence with ilio-inguinal approach
- Avoid operations in febrile patients
- Use prophylactic antibiotics
- Manage by draining wounds
- Nerve palsy
- 11.2% incidence
- 17.4% in posterior fractures
- Usually peroneal component of sciatic nerve
- Ectopic bone formation
- 20% incidence
- Indomethicin useful
- Radiation is also an option
- Thrombo-embolic problems
- Give anticoagulation for 6 - 8 weeks after open operation
- 3500 units heparin tds starting at 72 hours post-injury or surgery and adjusted according to APTT (aim for APTT 31-36)
- Warfarinise after one week post-injury or operation (INR 2 - 2.5)
- Urethral injury
- Occurs in 1/3 of unstable fractures (13% overall)
- Perform retrograde urethrogram prior to IDC
- Cystogram
- IVP may be indicated
- Bladder rupture is usually extra-peritoneal and may lead to vesico-colic or vesical fistulas
- Impotence 40%
- Post-traumatic osteoarthritis in 4 - 15%; depends on quality of reduction