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Pelvic & Acetabular Trauma MCQs

Practice Set 15 of 35

This practice set contains high-yield board review questions covering key concepts in Pelvic & Acetabular Trauma. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 281

Topic: Pelvic & Acetabular Trauma

A 13-year-old obese male presents with left groin pain and obligatory external rotation of the hip during flexion. Imaging confirms a severe slipped upper femoral epiphysis (SUFE). Anatomically, what is the primary mechanism of deformity in this condition?

. Anterior and superior displacement of the epiphysis
. Anterior and superior displacement of the metaphysis
. Posterior and inferior displacement of the metaphysis
. Posterior and superior displacement of the metaphysis
. Medial and inferior displacement of the epiphysis

Correct Answer & Explanation

. Anterior and superior displacement of the metaphysis

Explanation

In SUFE, the epiphysis remains relatively secured in the acetabulum by the ligamentum teres. The deformity is actually caused by the femoral neck (metaphysis) displacing anteriorly and superiorly relative to the epiphysis.

Question 282

Topic: Pelvic & Acetabular Trauma
A 35-year-old male is brought to the trauma bay following a high-speed motorcycle collision. He has a mechanically unstable APC-III pelvic ring injury. Despite application of a pelvic binder and initial fluid resuscitation, his blood pressure remains 70/40 mmHg. FAST scan is negative. What is the most appropriate next step in management?
. Exploratory laparotomy
. Removal of the pelvic binder to assess the skin
. Immediate internal fixation of the anterior ring
. Pelvic angiography with embolization or preperitoneal pelvic packing
. Application of lower extremity traction

Correct Answer & Explanation

. Pelvic angiography with embolization or preperitoneal pelvic packing

Explanation

In a hemodynamically unstable patient with a pelvic ring injury and a negative FAST scan, the source of bleeding is likely retroperitoneal. Preperitoneal pelvic packing or pelvic angiography with embolization is indicated to control hemorrhage.

Question 283

Topic: Pelvic & Acetabular Trauma
During a Trauma viva, you are presented with a hemodynamically unstable patient with an Antero-Posterior Compression (APC) Type III pelvic injury. According to BOAST guidelines, what is the most appropriate initial mechanical intervention?
. Application of a pelvic binder over the iliac crests
. Application of a pelvic binder centered over the greater trochanters
. Immediate application of an anterior external fixator
. Emergency resuscitative endovascular balloon occlusion of the aorta (REBOA)
. Urgent internal fixation with symphyseal plating

Correct Answer & Explanation

. Application of a pelvic binder centered over the greater trochanters

Explanation

A pelvic binder provides rapid, non-invasive hemorrhage control by reducing pelvic volume. It must be centered over the greater trochanters to effectively close the pelvic ring, as placement over the iliac crests can worsen the deformity.

Question 284

Topic: Pelvic & Acetabular Trauma
A 40-year-old male arrives at the trauma bay with hemodynamic instability following a crush injury to the pelvis. AP pelvis radiograph demonstrates an APC-III pelvic ring injury. An emergent pelvic binder is to be applied. At what anatomic level should the binder be centered for optimal reduction of the pelvic volume?
. Over the iliac crests
. Midway between the iliac crests and the pubic symphysis
. Centered over the greater trochanters
. Directly over the lower lumbar spine and sacrum
. Centered over the proximal femoral shafts

Correct Answer & Explanation

. Centered over the greater trochanters

Explanation

Pelvic binders must be centered over the greater trochanters to effectively close the pelvic ring and reduce pelvic volume. Placement over the iliac crests is a common error and is less effective at closing the symphysis pubis; it can even paradoxically worsen inferior ring displacement.

Question 285

Topic: Pelvic & Acetabular Trauma

In the Young-Burgess classification, an Anteroposterior Compression (APC) Type II pelvic ring injury is characterized by pubic symphysis diastasis and disruption of which of the following posterior ring structures?

. Anterior sacroiliac ligaments with intact posterior sacroiliac ligaments
. Posterior sacroiliac ligaments with intact anterior sacroiliac ligaments
. Complete disruption of both anterior and posterior sacroiliac ligaments
. Fracture of the sacral ala with intact sacroiliac ligaments
. Disruption of the iliolumbar ligament only

Correct Answer & Explanation

. Anterior sacroiliac ligaments with intact posterior sacroiliac ligaments

Explanation

An APC II injury involves widening of the pubic symphysis and rupture of the anterior sacroiliac ligaments, sacrospinous, and sacrotuberous ligaments. The strong posterior sacroiliac ligaments remain intact, which prevents vertical displacement but allows the hemipelvis to "open like a book," resulting in rotational instability.

Question 286

Topic: Pelvic & Acetabular Trauma
According to the Young and Burgess classification, which of the following pelvic ring injuries is most highly associated with massive retroperitoneal hemorrhage requiring angioembolization?
. Anterior posterior compression (APC) type I
. Anterior posterior compression (APC) type III
. Lateral compression (LC) type I
. Lateral compression (LC) type II
. Vertical shear (VS)

Correct Answer & Explanation

. Anterior posterior compression (APC) type III

Explanation

APC III pelvic ring injuries involve complete disruption of the anterior and posterior pelvic rings (symphysis, sacrospinous, sacrotuberous, and anterior/posterior sacroiliac ligaments). This massive volume expansion and disruption of the posterior venous plexus and arterial branches carry the highest risk for massive retroperitoneal hemorrhage.

Question 287

Topic: Pelvic & Acetabular Trauma
A 28-year-old hypotensive male is brought to the trauma bay following a motorcycle crash. An AP pelvis radiograph demonstrates an 'open book' (APC-III) pelvic ring injury. A pelvic binder is ordered. At what specific anatomic landmark should the binder be centered to optimally reduce the pelvic volume?
. Anterior superior iliac spines (ASIS)
. Iliac crests
. Greater trochanters
. Ischial tuberosities
. Pubic symphysis

Correct Answer & Explanation

. Greater trochanters

Explanation

To effectively reduce the pelvic volume and close a pubic diastasis in an unstable pelvic ring injury, the pelvic binder or sheet must be centered directly over the greater trochanters. Placing it higher (e.g., over the iliac crests or ASIS) is a common clinical error that can inadvertently gap the symphysis further or fail to provide adequate mechanical reduction.

Question 288

Topic: Pelvic & Acetabular Trauma
In the acute management of a hemodynamically unstable patient with an anteroposterior compression (APC) type III pelvic ring injury, what is the correct anatomical landmark for the placement of a circumferential pelvic sheet or binder?
. Over the iliac crests
. At the level of the anterior superior iliac spines
. Centered over the greater trochanters
. Over the umbilicus
. Distal to the lesser trochanters

Correct Answer & Explanation

. Centered over the greater trochanters

Explanation

A pelvic binder must be centered over the greater trochanters and the symphysis pubis to provide maximal compressive force to close the pelvic volume. Placing it too high (e.g., over the iliac crests or ASIS) is less effective and may paradoxically open the pelvis further, in addition to restricting abdominal access.

Question 289

Topic: Pelvic & Acetabular Trauma

A 34-year-old male is involved in a motorcycle collision and sustains an Anteroposterior Compression Type II (APC-II) pelvic ring injury. Based on the Young-Burgess classification, which of the following ligamentous structures is entirely disrupted in an APC-II injury but intact in an APC-I injury?

. Symphysis pubis only
. Anterior sacroiliac, sacrotuberous, and sacrospinous ligaments
. Posterior sacroiliac ligaments
. Iliolumbar ligaments
. Sacrotuberous ligaments only

Correct Answer & Explanation

. Anterior sacroiliac, sacrotuberous, and sacrospinous ligaments

Explanation

In the Young-Burgess classification, an APC-I injury involves disruption of the symphysis pubis (less than 2.5 cm diastasis) but intact anterior and posterior pelvic ligaments. An APC-II injury is characterized by a symphysis diastasis >2.5 cm and disruption of the anterior sacroiliac, sacrotuberous, and sacrospinous ligaments. The posterior sacroiliac ligaments remain intact in APC-II, providing vertical stability but leaving rotational instability.

Question 290

Topic: Pelvic & Acetabular Trauma
A 35-year-old male sustains an anteroposterior compression type III (APC-III) pelvic ring injury. He is hemodynamically unstable despite initial resuscitation and the application of a pelvic binder. A FAST scan is negative. What is the most appropriate next step in management?
. Immediate exploratory laparotomy
. Preperitoneal pelvic packing and/or angiography
. Skeletal traction of the lower extremities
. Open reduction and internal fixation of the symphysis pubis
. Sacroiliac screw fixation

Correct Answer & Explanation

. Preperitoneal pelvic packing and/or angiography

Explanation

In a patient with a mechanically unstable pelvic ring injury and persistent hemodynamic instability despite a pelvic binder, if intraperitoneal bleeding has been ruled out (negative FAST), the source of bleeding is assumed to be the pelvic retroperitoneum. The standard algorithm involves either emergent preperitoneal pelvic packing (PPP) or pelvic angiography with embolization to address venous or arterial hemorrhage, respectively.

Question 291

Topic: Pelvic & Acetabular Trauma
In the Young-Burgess classification of pelvic ring injuries, which of the following accurately describes the ligamentous disruption in an Anteroposterior Compression Type II (APC II) injury?
. Symphyseal diastasis less than 2.5 cm with intact posterior ligaments
. Symphyseal diastasis greater than 2.5 cm with disruption of both anterior and posterior sacroiliac ligaments
. Symphyseal diastasis with disruption of the anterior sacroiliac ligaments and intact posterior sacroiliac ligaments
. Vertical displacement of the hemipelvis with complete ligamentous disruption
. Internal rotation of the hemipelvis with a crush injury to the anterior sacrum

Correct Answer & Explanation

. Symphyseal diastasis with disruption of the anterior sacroiliac ligaments and intact posterior sacroiliac ligaments

Explanation

An APC II pelvic ring injury is an 'open book' injury caused by an anteroposterior force. It involves symphyseal diastasis (usually > 2.5 cm), disruption of the sacrotuberous and sacrospinous ligaments, and tearing of the anterior sacroiliac (SI) ligaments. Crucially, the strong posterior SI ligaments remain intact, providing rotational instability but vertical stability. Complete posterior disruption defines an APC III injury.

Question 292

Topic: Pelvic & Acetabular Trauma
In the Young-Burgess classification, an Anterior Posterior Compression (APC) Type II pelvic ring injury is primarily characterized by the rupture of the anterior sacroiliac ligaments along with which other ligamentous structures, leading to a rotationally unstable but vertically stable pelvis?
. Posterior sacroiliac and iliolumbar ligaments
. Sacrotuberous and sacrospinous ligaments
. Iliolumbar ligaments only
. Symphyseal ligaments only
. Sacrotuberous, sacrospinous, and posterior sacroiliac ligaments

Correct Answer & Explanation

. Sacrotuberous and sacrospinous ligaments

Explanation

An APC II injury involves disruption of the symphysis pubis (or parasymphyseal fractures) combined with tearing of the anterior sacroiliac ligaments, the sacrotuberous ligaments, and the sacrospinous ligaments. This creates an 'open book' pelvis that is rotationally unstable. Crucially, the strong posterior sacroiliac ligaments remain intact, preserving the vertical stability of the hemipelvis. If the posterior SI ligaments rupture, the injury becomes an APC III (rotationally and vertically unstable).

Question 293

Topic: Pelvic & Acetabular Trauma
A 35-year-old male arrives in the trauma bay after a motorcycle crash. His pelvis radiograph shows an anteroposterior compression type III (APC III) injury. His blood pressure is 80/40 mmHg. What is the most anatomically effective location for the application of a circumferential pelvic sheet or binder?
. Over the iliac wings
. At the level of the anterior superior iliac spines
. Centered over the greater trochanters
. Just superior to the umbilicus
. Around the proximal thighs

Correct Answer & Explanation

. Centered over the greater trochanters

Explanation

A pelvic binder must be centered over the greater trochanters to effectively close the pelvic ring and reduce pelvic volume. Placement over the iliac wings can paradoxically open the pelvic ring by acting as a fulcrum.

Question 294

Topic: Pelvic & Acetabular Trauma

The Salter innominate osteotomy is commonly used in the treatment of developmental dysplasia of the hip (DDH). Around which anatomic structure does the distal fragment rotate to improve anterolateral coverage of the femoral head?

. The sacroiliac joint
. The pubic symphysis
. The triradiate cartilage
. The ischial spine
. The greater sciatic notch

Correct Answer & Explanation

. The greater sciatic notch

Explanation

The Salter osteotomy is a single-cut innominate osteotomy that goes from the greater sciatic notch to the anterior inferior iliac spine. The distal fragment hinges and rotates on the pubic symphysis to provide improved anterolateral coverage of the femoral head.

Question 295

Topic: Pelvic & Acetabular Trauma
A 30-year-old male is involved in a severe motorcycle collision and sustains an anteroposterior compression type III (APC-III) pelvic ring injury. After the application of a pelvic binder and initial fluid resuscitation, he remains hemodynamically unstable. An emergent angiogram is performed. Which of the following vessels is most likely to be the source of arterial bleeding in this specific injury pattern?
. Superior gluteal artery
. Internal pudendal artery
. Lumbar artery
. Inferior epigastric artery
. Iliolumbar artery

Correct Answer & Explanation

. Internal pudendal artery

Explanation

Anteroposterior compression (APC) pelvic injuries cause symphyseal diastasis and disruption of the anterior pelvic structures. Hemorrhage in APC injuries is most commonly venous, but when arterial bleeding occurs, the anterior branches of the internal iliac arteryโ€”most notably the internal pudendal and obturator arteriesโ€”are most frequently injured. The superior gluteal artery is more commonly injured in posterior ring disruptions and lateral compression (LC) injuries.

Question 296

Topic: Pelvic & Acetabular Trauma
A 30-year-old male is brought to the trauma bay after a motorcycle accident with an anteroposterior compression type III (APC-III) pelvic ring injury. He is hemodynamically unstable. In this type of injury, what is the most common anatomic source of massive venous hemorrhage?
. Superior gluteal vein
. Internal pudendal vein
. Presacral venous plexus
. External iliac vein
. Obturator vein

Correct Answer & Explanation

. Presacral venous plexus

Explanation

In pelvic ring injuries with posterior disruption (such as APC-III and vertical shear injuries), the presacral venous plexus and the prevesical venous plexus are the most common sources of major venous bleeding. Venous bleeding accounts for 80-90% of pelvic hemorrhage.

Question 297

Topic: Pelvic & Acetabular Trauma

Which of the following arterial structures is most commonly injured and causes significant hemorrhage in a patient with a lateral compression (LC) pelvic ring injury with a displaced sacral fracture?

. Superior gluteal artery
. Internal pudendal artery
. Obturator artery
. Inferior epigastric artery
. Corona mortis

Correct Answer & Explanation

. Superior gluteal artery

Explanation

The superior gluteal artery exits the pelvis through the greater sciatic foramen in close proximity to the posterior sacroiliac complex and sacrum. It is the most commonly injured artery in posterior pelvic ring disruptions, particularly lateral compression injuries with displaced sacral fractures.

Question 298

Topic: Pelvic & Acetabular Trauma
A 45-year-old male is brought to the trauma bay in hemorrhagic shock after a high-speed motorcycle crash. Pelvic radiographs demonstrate an Anteroposterior Compression Type III (APC III) injury. Which of the following ligamentous complexes are completely disrupted in this specific injury pattern?
. Anterior sacroiliac, sacrotuberous, and sacrospinous ligaments only
. Anterior sacroiliac, posterior sacroiliac, sacrotuberous, and sacrospinous ligaments
. Posterior sacroiliac and iliolumbar ligaments only
. Sacrospinous and sacrotuberous ligaments only
. Anterior and posterior sacroiliac ligaments only

Correct Answer & Explanation

. Anterior sacroiliac, posterior sacroiliac, sacrotuberous, and sacrospinous ligaments

Explanation

An APC III injury (Young-Burgess classification) involves complete symphyseal disruption (diastasis) accompanied by complete rupture of the anterior sacroiliac, posterior sacroiliac, sacrotuberous, and sacrospinous ligaments. This results in a hemipelvis that is both rotationally and vertically unstable, and it carries the highest risk of massive retroperitoneal hemorrhage among APC patterns.

Question 299

Topic: Pelvic & Acetabular Trauma
In the Young-Burgess classification, an Anteroposterior Compression (APC) Type II pelvic ring injury results in the 'open book' deformity. This is characterized by diastasis of the symphysis pubis and rupture of the anterior sacroiliac, sacrotuberous, and sacrospinous ligaments. Which critical ligamentous complex remains INTACT in an APC II injury, thereby preventing vertical instability?
. Anterior sacroiliac ligaments
. Symphysis pubis ligaments
. Posterior sacroiliac ligaments
. Iliolumbar ligaments
. Sacrotuberous ligaments

Correct Answer & Explanation

. Posterior sacroiliac ligaments

Explanation

An APC II injury involves disruption of the anterior sacroiliac ligaments and pelvic floor ligaments (sacrotuberous, sacrospinous), leading to rotational instability. However, the stout posterior sacroiliac ligaments remain intact, providing vertical stability. If these tear, the injury becomes an APC III, which is both rotationally and vertically unstable.

Question 300

Topic: Pelvic & Acetabular Trauma

A 25-year-old male is brought to the emergency department after a motorcycle collision with a hemodynamically unstable suspected pelvic ring injury. A circumferential pelvic binder is to be applied. What is the correct anatomical landmark to center the binder for optimal reduction of pelvic volume?

. Anterior superior iliac spines (ASIS)
. Iliac crests
. Greater trochanters
. Pubic symphysis
. Sacral promontory

Correct Answer & Explanation

. Greater trochanters

Explanation

A pelvic binder should be centered directly over the greater trochanters of the femurs. This location most effectively closes the pelvic ring and reduces pelvic volume, particularly in 'open book' (APC) type injuries. Placing the binder too high (over the iliac crests or ASIS) may paradoxically widen the pelvis or be ineffective.

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