two hip bones

To understanding the fractures of the pelvis first you should know the anatomy of the pelvic girdle

Anatomy of the pelvis

The pelvis is made up of

innominate (hip) bones •  the sacrum•  the coccyx
These bones are bound to one another by strong ligaments

The hip bone or innominatum :This consists of three fused bones which are

• ilium• pubis• ischium

hip bone


• Anterosuperiorly is a broad, thin blade for muscle attachment and visceral protection
• Posteroinferiorly is a thick, weight-transmitting bar with an articular surface at each end laterally for the head of the femur; medially for the sacrum
• Iliac crest runs superiorly between the anterior and
posterior superior iliac spines; below each of these lies the corresponding inferior iliac spine.
• Posterior border of ilium curves inferiorly between the sacroiliac joint and the ischial spine, forming the greater sciatic notch.
• The glutei and tensor fascia lata muscles attach to the outer aspect of the blade of the ilium, producing well-defined ridges
• The three-layered abdominal wall muscles attach
to the anterior two- thirds of the crest
Latissimus dorsi and erector spinae attach posteriorly to tile crest
• The inguinal ligament attaches laterally to the anterior superior iliac spine


• Shaped like a rotated L
• Comprises a body and superior and inferior pubic
• Superior ramus connects the acetabulum and symphyseal articular surfaces of the pubis
• The inferior ramus extends downwards from the tubercle to its point of fusion with the ischium
• The inguinal ligament attaches to the pubic tubercle
• The adductors, perineal muscles and perineal membrane attach to the inferior ramus


• J-shaped bone with a massive body posteriorly bearing the ischial component of the acetabulum
• Inferiorly is the ischial tuberosity, which bears the weight of the sitting trunk
• Anteriorly is the ramus uniting with the pubis
• The posterior border of the body bears the ischial spine separating the greater sciatic notch superiorly from the lesser sciatic notch inferiorly
• The hamstrings and short hip rotators (except piri­formis) attach to the outer aspect of the tuberosity and the lower body
• The ischium and pubis together form the circum­ference of the obturator foramen

• All three bones fuse together at the acetabulum and form a socket for the femoral head. The acetabulum consists of about one-fifth pubis and two-fifths each of ilium and ischium.

• Made up of five fused vertebrae and is roughly triangular in shape.

• Anterior border of upper part forms the sacral promontory

• The anterior aspect comprise a central mass  and a row of four anterior sacral foramina on each side (transmitting the upper four sacral anterior primary rami) and the lateral masses of the sacrum.
• The superior aspect of the lateral mass on each side forms the ala.
• Posteriorly lies the sacral canal (the continuation of the vertebral canal),surrounded by short pedicles. strong laminae, and small spinous processus.
• Extending from the sacral canal is a row of four
posterior sacral foramina on each side.
• Inferiorly, the vertebral canal terminates in the sacra hiatus, which transmits the fifth sacral nerve.

• On either side of the hiatus lies the sacral cornu.

• On the lateral aspect of the sacrum is a large facet

for articulation with the corresponding surface the ilium

• Occasionally the fifth lumbar vertebra fuses the sacrum.

• The dural sheath terminates distally at the second piece of the sacrum.

• Beyond this the sacral canal contains the extra­ dural space, the cauda equina, and the filum terminale.


• Made up of three to five fused vertebrae, which

articulate With the sacrum.


Symphysis pubis

• like all symphyses it lies in the median plane and comprises a disc of fibrocartilage firmly fixed between two articular surfaces of hyaline cartilage.
• Surrounded and strengthened by fibrous ligaments.
• A non-synovial cavity often appears in the disc of fibrocartilage in adult life.

Sacra-iliac joints

• large and very stable joints connecting the girdle proper with the axial skeleton.
• Joints change in character with age
• in the very young they are synovial, with
almost plane surfaces
• in the elderly they are almost entirely fibrous, with irregular surfaces

• Stability of the sacroiliac joints dependent on powerful ligaments

• posterior sacroiliac ligaments, which oppose the tendency for downward and backward displacement of the sacrum between the hip bones
• the iliolumbar ligaments attaching to the transverse processes of lumber 5(L5 )and the iliac crest
• The sacrotuberous and sacrospinous ligaments attach the sacrum to the ischium and oppose downward rotation of the sacrum in the sagittal plane.
• The sacrotuberous ligament passes from the ischial tuberosity to the side of the sacrum and coccyx.
• The sacrospinous ligament passes from the ischial spine to the side of the sacrum and coccyx
• The sacrospinous and sacrotuberous ligaments define two important exits from the pelvis:
• the greater sciatic foramen; formed by the sacrospinous ligament and the greater sciatic notch
• the lesser sciatic foramen; formed by the sacrotuberous ligament and the lesser sciatic notch.

• Major anatomical relations include
• sacroiliac joints: the internal iliac vessels pass anteriorly
symphysis pubis : urethra and deep dorsal vein of the penis pass inferiorly

Causes of pelvic fractures

High energy life threatening injuries as Motor vehicle accidents and fall from height are the major causes of pelvic fractures common in young adult males or low energy injuries in elderly osteoporotic patients
fractures pelvis are commonly associated with high incidence of other injuries which may be fatal this due to high energy
injuries which associated with it is fractures

The pelvic ring comprises the sacrum and two innominate bones. They are joined by liga­ments that resist vertical shear, separation, and rotation at the S1 joints and pubic symph­ysis. With high-enery injuries, it is unusual to disrupt the pelvic ring in just one place. Just as in the forearm and lower leg, injuries to a bony ring come in pairs

Classification of pelvic fractures

Pelvic injuries may be classified according to their mechanism of injury, or according to the stability of the pelvic ring as follow

Mechanism of injury - Young and Burgess classification

lateral compression(LC) : lateral force causes internal rotation of the hemi-pelvis, causing disruption of some sacral 1( S1) ligaments or compression fractures of the sacrum. Internal rotation closes down the pelvic volume and bleeding is reduced. Lateral compression injuries may be associated with abdominal and chest injuries

Anteroposterior compression (APC) or open book injury: causes external rotation of the hemipelvis (open-book injury). This
increases the pelvic volume and thus the space for potential blood loss

Vertical shear(VS) : vertical force causes complete disruption of the posterior arch on one side and the hemispelvis is displaced superiorly. Bleeding may be significant. There is often injury to the lumbosacral plexus

And combined mechanical injury CMI

This classification is simpler to use and is a useful guide to treatment Lateral compression injuries are a result of a side impact to pelvis (car passengers, pedestrians). They are often associated with visceral injury and chest and head trauma. APC injuries are usually associated with severe pelvic haemorrhage due increase in pelvic volume. urethral and bladder injuries are common.

Vertical shear fractures (VS) are high-energy injuries with anterior and posterior pelvic disruption. There is high a incidence of associated neurological injury, in addition to viscera trauma and haemorrhage. CMIs are a combination of the above patterns

Stability of posterior arch (ilium, S1 joints and sacrum) - Tile-AO classification

Type A: stable injuries (eg avulsion fractures, transverse fractures of the sacrum or low energy pubic rami or iliac wing fractures

Type B: rotationally unstable injuries, partial disruption of the posterior arch (eg open-book injury B1 or lateral compression injury B2 or combination of these two type B3

Type C: rotationally and vertically unstable injuries, complete disruption of the posterior arch eg vertical shear injury they may be unilateral C1 combined with a rotionally unstable contralateral injury C2 or have a bilateral vertical unstable pattern C3

Clinical  features and assessment

As many of these patients have multiple injuries, a careful,assessment based on Advanced Trauma Life Support ATLS lines is required. Clinical evaluation of the pelvis is
detect associated injuries .

The perineum must be carefully examined - occasionnally open wounds in this region communicate with the pelvic fractures Signs of urethral disruption (blood at the urinary meatus perineal or scrotal haematoma and high-riding prostate on rectal examination) indicate the need for imaging of the urethra and bladder

Rectal examination is essential to detect a high-riding prostate or rectal perforation, an absolute indication for faecal diversion Vaginal examination is necessary in female patients

A neurological evaluation of the lower limbs is important

although an accurate assessment is often difficult in patients with multiple injuries.


The plain anteroposterior (AP) radiograph of the pelvis will demonstrate most bony injuries. but sacral fracture may be difficult to detect. The inlet view is superior to the AP view for demonstrating subtle degrees of true posterior displacement of the hemipelvis . The outlet view will show vertical displacement of the hemipelvis, and gives a superior view of the sacral foramina . If the patient is stable. a CT scan is the most useful additional diagnostic investigation .
This allows rapid evaluation of the head, chest. abdomen and
pelvis, and is the most accurate method of identifying associated injuries and sacral fractures.

Abdominal ultrasound is a useful alternative for evaluating the abdomen. This is non-invasive, rapid to perform, does not require patient transfer and can be repeated at short intervals. Diagnostic peritoneal lavage is sensitive but non- specific. It should be performed above the umbilicus to minimise the risk of a false positive result. For patients with signs of urethral rupture, imaging of the lower urinary tract is advisable prior to urethral catheter­isation. A retrograde urethrogram and cystogram will confirm whether urethral rupture or a bladder injury is present. An urgent urological opinion is necessary in these circumstances. Suprapubic urinary drainage is usually required.


Stable fractures

The most common stable fracture is a low-energy pubic ramus fracture in an elderly patient. These can be treated non­ operatively with a period of bed rest. Fractures of the blade of the ileum with no disruption of the ring can also be treated non­ operatively. Avulsion fractures usually involve the anterior superior or inferior iliac spine. These occasionally require operative treatment if displaced.

Unstable fractures

The goals of early treatment are

control of hypotension

• management of associated injuries

stabilisation of the pelvic fracture

Initial management

Patients who are haemodynaimcally stable or who respond to fluid resuscitation can be carefully investigated to define associated injuries. Treatment incorporating pelvic stabilisation and management of associated injuries can then be planned. In patients who remain hypotensive despite fluid resuscitation, urgent intervention is required. For fractures with an increase in pelvic volume (APC, VS and CMI), application of an external fixaror will provide stability and a reduction in pelvic volume-with tamponade of the expanding pelvic haematoma,

In patients who require a laparotomy, it is preferable to apply the external fixator out with no pelvic stabilisation, rapid expansion of the pelvic retroperitoneal haematoma occurs. and it may be difficult or impossible to close the abdomen at the completion of surgery.

Patients with open pelvic fractures require faecal diversion with a colostomy to minimise the risk of fatal sepsis. The location of the stoma should be in left upper quadrant to avoid proximity to external fixator pins or surgical incisions. Internal fixation is generally contraindicated in these cases.

Patients who remain hypotensive despite the above measures can be considered for pelvic angiography with embolisation of bleeding arteries . In patients with severe refractory hypotension, there may not be time for angiography and exploration of the pelvic haematoma with packing  is recommended. The prognosis for this group of patient, poor and the mortalirv rate is high. 

Definitive orthopaedic management

Non-operative treatment of unstable pelvic fractures is as with a high incidence of pelvic malunion, gait disturbanc seating problems and disabling pelvic and lumbar back pain. the use of external fixation has been associated with a reduced mortality, but it is not sufficiently rigid to maintain reduc the more unstable patterns of injury. Internal fixator or combined internal and external fixation has therefore more common in the treatment of unstable fractures.

Laterel compression fractures

Most lateral compression fractures are inherently stable as the intrapelvic ligaments (sacrospinous and sacrotuberou­s have merely shortened and the posterior ligaments are intact 

fixation needs to be considered only if there is marked pelvic
distortion. if rami fractures are displaced and protruding  into the perineum or vagina. or in the occasional instance of a locked symphysis.

Anteroposterior compression (APC) injuries

APC injuries are usually associated with diastasis of the pubic symphysis. If the gap at the symphysis is greater than 2.5 cm the injury can be considered unstable and fixation is recommended As the posterior ligaments are intact, anterior plating result in satisfactory restoration of pelvic stability. Access is via the lower half of a midline laparotomy or a Pfannenstiel incision the patient should be catheterised prior to surgery to minimise
 risk of bladder injury. Two plates (one superior and one anterior) provide stable fixation. Postoperatively, patients can be mobilised with crutches for the first 6 weeks. 

Vertical shear injuries

External fixation of vertical shear injuries is associated with malunion in more than 90% of cases. Internal fixation is therefore preferred . The anterior lesion is usually a diastasis or
some configuration of pubic ramus fractures. Symphyseal
disruption can be plated. If the anterior lesion is complex multiple rami fractures) and affects both sides, then there is a
role for external fixation if a very extensive exposure for internal fixation is to be avoided.

The posterior disruption is usually a sacroiliac joint dislocation
or sacral fracture. Access to the posterior disruption may be
achieved anteriorly via the ilioinguinal approach or by a direct
Posterior plating

posterior approach to the sacrum via a longitudinal incision.
Posterior approaches have been associated with a high rate of
wound complications, as the skin in this area is often degloved or badly contused. The choice of fixation for the posterior disruption depends on whether there is a sacral fracture or a dislocation.

Surgical options include anterior or posterior plating techniques. iliosacral screws or transiliac bars. Each option has advantages and disadvantages . in situations in which facilities are limited, or the patient is unable to tolerate major surgery, external fixation augmented by skeletal traction is a safe alternative

 Summary of Management of pelvic fractures

Stable fractures

• Treat with bed rest

• Mobilise within limits of pain

Unstable fractures

• Control hypotension

• Manage associated injuries

• Stabilise the pelvic fracture

Laparotomy in the presence of a pelvic fracture

• Stabilise the pelvic fracture with on externol fixator first

• Prepare for major blood loss

• Defunctioning colostomy may be required

• The mortality is high

Results and functional outcome

Mortality rates following pelvic fractures vary widely with severity of injury, 
Head injury and uncontrolled haemorrhage are the main causes of early mortality .
 Functional outcome after major pelvic disruption is often poor. This is partly due to the severity of associated injuries
 Early stabilisation with external fixation has been associated with a reduction in mortality and a reduction of late pelvic pain
 Internal fixation  reduce the rate of malunion
 reduction in vertical shear injuries can be difficult and even with modern techniques, malunion rates is high
Persistent pelvic pain is a common problem
Patients with symphyseal disruption as a component of their injury often have anterior pain. whereas patients with vertical shear injury tend to have disabling posterior pain


Unstable pelvic fractures have a high mortality and morbidity. Careful clinical evaluation and plain radiographs are
essential and a CT scan should he performed if possible.

Identification of fracture pattern helps to predict instability and the most likely associated injuries and helps plan treat­ment.

External fixation is the main way of emergency orthopaedic treat­ment for hypotensive patients with increased pelvic volume. Angiography and pelvic exploration and packing have a role in patients with uncontrolled hypotension unresponsive to other methods,

Internal fixation is the most effective treatment to obtain and maintain anatomic reduction in open-book and vertical shear injuries. Late morbidity is significant, but patients with anatomic reductions have improved functional


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