Menu

Pelvic & Acetabular Trauma MCQs

Practice Set 5 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 81

Topic: Pelvic & Acetabular Trauma
A 45-year-old hemodynamically unstable male presents after a motorcycle accident with an APC-III pelvic ring injury. A pelvic binder is applied, and he receives 2 units of packed RBCs, but his systolic blood pressure remains 70 mmHg. A FAST exam is negative. What is the most appropriate next step in management?
. Immediate exploratory laparotomy
. Bilateral internal iliac artery embolization
. Application of an external fixator and immediate retrograde urethrogram
. Preperitoneal pelvic packing and/or pelvic angiography
. Observation and continued massive transfusion protocol

Correct Answer & Explanation

. Preperitoneal pelvic packing and/or pelvic angiography

Explanation

In a hemodynamically unstable patient with a pelvic ring injury and a negative FAST, the source of bleeding is presumed to be the pelvis. Preperitoneal packing or angiography (depending on institutional protocol and immediate availability) is the next definitive step to control hemorrhage.

Question 82

Topic: Pelvic & Acetabular Trauma
A 35-year-old male involved in a high-speed MVC presents with a hemodynamically unstable APC-III pelvic ring injury. Following pelvic binder application and initial fluid resuscitation, his blood pressure remains 70/40 mmHg. The FAST exam is negative. What is the next best step in management?
. Emergent CT abdomen and pelvis
. Exploratory laparotomy
. Preperitoneal pelvic packing and/or angioembolization
. Definitive anterior and posterior pelvic ring fixation
. REBOA placement at Zone I

Correct Answer & Explanation

. Preperitoneal pelvic packing and/or angioembolization

Explanation

For a hemodynamically unstable pelvic fracture with a negative FAST exam (ruling out major intra-abdominal hemorrhage), preperitoneal pelvic packing and/or angiography with embolization is the appropriate emergent intervention.

Question 83

Topic: Pelvic & Acetabular Trauma

In the evaluation of a patient with a complex acetabular fracture, an obturator oblique radiograph is obtained. Which two primary structures of the acetabulum are best visualized in profile on this specific radiographic view?

. Anterior column and posterior wall
. Posterior column and anterior wall
. Iliac wing and posterior column
. Ischial spine and anterior wall
. Quadrilateral plate and anterior column

Correct Answer & Explanation

. Anterior column and posterior wall

Explanation

Judet-Letournel radiographic evaluation of the acetabulum includes orthogonal views. The obturator oblique view best profiles the anterior column and the posterior lip/wall of the acetabulum.

Question 84

Topic: Pelvic & Acetabular Trauma

On an anteroposterior (AP) radiograph of the pelvis, which underlying anatomic structure is defined by the iliopectineal line?

. Anterior column
. Posterior column
. Anterior wall
. Posterior wall
. Quadrilateral surface

Correct Answer & Explanation

. Anterior column

Explanation

The iliopectineal line represents the anterior column of the acetabulum on an AP pelvic radiograph. Disruption of this line indicates a fracture involving the anterior column.

Question 85

Topic: Pelvic & Acetabular Trauma

When evaluating Judet views for a suspected acetabular fracture, the obturator oblique view provides the optimal assessment for which specific combination of anatomical structures?

. Anterior wall and posterior column
. Anterior column and posterior wall
. Iliac wing and sacral ala
. Ischial spine and superior pubic ramus
. Quadrilateral plate and symphysis pubis

Correct Answer & Explanation

. Anterior column and posterior wall

Explanation

The obturator oblique view is obtained by rotating the patient 45 degrees away from the affected side. It profiles the anterior column and posterior wall of the acetabulum, as well as the pelvic inlet.

Question 86

Topic: Pelvic & Acetabular Trauma

A 30-year-old male is brought in after a motorcycle collision with a heart rate of 130 bpm and blood pressure of 80/50 mmHg. Radiographs show a widened pubic symphysis (4 cm) and completely displaced bilateral sacroiliac joints. Where is the most anatomically correct location to place a pelvic circumferential compression device?

. Over the iliac crests
. Centered over the greater trochanters
. Inferior to the pubic symphysis
. At the level of the umbilicus
. Over the proximal femurs

Correct Answer & Explanation

. Centered over the greater trochanters

Explanation

A pelvic binder should be centered directly over the greater trochanters to effectively close the pelvic ring and reduce pelvic volume. Placement over the iliac crests is less effective and can paradoxically widen the pelvis in certain fracture patterns.

Question 87

Topic: Pelvic & Acetabular Trauma
A 40-year-old male is involved in a high-speed motorcycle collision and is hemodynamically unstable. Pelvic radiographs show an anteroposterior compression (APC) type III injury with total disruption of the anterior and posterior sacroiliac ligaments. What is the most appropriate first step in emergent orthopedic management?
. Angiography and embolization
. Placement of a pelvic binder at the level of the greater trochanters
. Application of a supra-acetabular external fixator
. Open reduction internal fixation of the pubic symphysis
. Retroperitoneal packing

Correct Answer & Explanation

. Placement of a pelvic binder at the level of the greater trochanters

Explanation

In a hemodynamically unstable patient with an open-book pelvic fracture, the immediate first step is mechanical stabilization of the pelvic volume. This is most rapidly and effectively achieved with a pelvic binder placed at the level of the greater trochanters.

Question 88

Topic: Pelvic & Acetabular Trauma
A 28-year-old male is brought to the trauma bay with a heart rate of 120 bpm and blood pressure of 85/50 mmHg. Pelvic radiographs show an anteroposterior compression (APC-III) injury. To be maximally effective, a pelvic binder should be centered over which anatomic landmark?
. Anterior superior iliac spines (ASIS)
. Iliac crests
. Greater trochanters
. Symphysis pubis
. Umbilicus

Correct Answer & Explanation

. Greater trochanters

Explanation

Pelvic binders provide the most effective reduction of pelvic volume and bleeding control when placed directly over the greater trochanters. Placement higher over the iliac crests is less effective and can paradoxically open the pelvic ring further.

Question 89

Topic: Pelvic & Acetabular Trauma

A supra-acetabular external fixator is placed for a pelvic ring injury. To optimally decrease the stresses at the pin-bone interface and minimize the risk of pin loosening, which biomechanical adjustment is best?

. Decreasing the pin diameter
. Increasing the distance between the connecting rod and the skin
. Using a single connecting rod instead of two stacked rods
. Increasing the diameter of the Schanz pins
. Placing the pins perfectly parallel to the joint surface

Correct Answer & Explanation

. Increasing the diameter of the Schanz pins

Explanation

Pin loosening is primarily caused by excessive stress at the pin-bone interface. Increasing the diameter of the Schanz pins exponentially increases their bending stiffness (proportional to r^4), drastically reducing micromotion and stress at the bone interface.

Question 90

Topic: Pelvic & Acetabular Trauma

A 25-year-old female sustains a high-energy pelvic injury. Initial AP pelvis radiographs show significant widening of the pubic symphysis and a subtle widening of the left sacroiliac joint. Inlet and outlet views are difficult to interpret due to patient guarding. A CT scan with 3D reconstructions is performed. Which of the following posterior ligamentous structures is considered the primary stabilizer preventing distraction of the SI joint and is most critical for resisting vertical shear forces?

. Anterior Sacroiliac Ligaments
. Sacrospinous Ligaments
. Iliolumbar Ligaments
. Interosseous Sacroiliac Ligaments
. Long Posterior Sacroiliac Ligaments

Correct Answer & Explanation

. Interosseous Sacroiliac Ligaments

Explanation

Correct Answer: DThe case content, under 'Anatomy of the Pelvic Ring' and 'Posterior Pelvic Ring,' explicitly states: 'The interosseous ligaments are the primary stabilizers, preventing distraction of the SI joint.' It further elaborates that the posterior SI ligaments (which include the interosseous) are 'extremely strong' and 'predominantly resisted by the posterior SI ligaments and the mechanical interlock of the sacrum within the iliac wings' for shear stability.Option A (Anterior Sacroiliac Ligaments)is incorrect. The case states these are 'thinner' and 'less critical for stability than posterior ligaments.'Option B (Sacrospinous Ligaments)is incorrect. While they 'resist external rotation and vertical shear forces,' they are not described as the 'primary stabilizers preventing distraction of the SI joint' in the same way the interosseous ligaments are.Option C (Iliolumbar Ligaments)is incorrect. These ligaments 'connect the transverse processes of L4 and L5 to the iliac crest' and 'contribute to lumbopelvic stability and transfer lumbar forces to the pelvis,' but they are not the primary stabilizers of the SI joint itself against distraction or vertical shear.Option E (Long Posterior Sacroiliac Ligaments)is incorrect. While they are part of the strong posterior ligamentous complex and 'resist external rotation and vertical sheer forces,' the text specifically identifies the 'interosseous ligaments' as the 'primary stabilizers, preventing distraction of the SI joint.'

Question 91

Topic: Pelvic & Acetabular Trauma

A 42-year-old male presents with chronic left-sided pelvic pain and instability following a motor vehicle collision 1 year prior. Initial radiographs were interpreted as a stable lateral compression injury, but his symptoms have worsened. Current AP pelvis radiographs show subtle widening of the left SI joint. A follow-up CT scan reveals an avulsion of the iliac cortical rim adjacent to the SI joint. This specific radiographic finding is pathognomonic for which of the following?

. Anterior sacroiliac ligamentous injury.
. Sacrotuberous ligament avulsion.
. Severe posterior ligamentous injury.
. Iliolumbar ligamentous sprain.
. Pubic symphysis instability.

Correct Answer & Explanation

. Severe posterior ligamentous injury.

Explanation

Correct Answer: CThe case content, under 'Biomechanics of Pelvic Stability' and 'Radiographic insights,' explicitly states: 'The "crescent sign" (avulsion of the iliac cortical rim) is pathognomonic for severe posterior ligamentous injury.' This sign indicates a significant disruption of the strong posterior ligamentous complex, which is crucial for pelvic stability.Option A (Anterior sacroiliac ligamentous injury)is incorrect. While anterior SI ligaments can be injured, the crescent sign specifically points to the posterior complex due to the strong attachments to the iliac rim.Option B (Sacrotuberous ligament avulsion)is incorrect. The sacrotuberous ligament connects the sacrum/PSIS to the ischial tuberosity. While its avulsion indicates significant injury, the 'crescent sign' specifically refers to the iliac cortical rim avulsion, which is more directly associated with the posterior SI ligaments.Option D (Iliolumbar ligamentous sprain)is incorrect. Iliolumbar ligaments connect the lumbar spine to the iliac crest and are not directly associated with the 'crescent sign' at the SI joint.Option E (Pubic symphysis instability)is incorrect. Pubic symphysis instability is an anterior ring injury and would manifest as symphyseal widening, not an iliac cortical rim avulsion.

Question 92

Topic: Pelvic & Acetabular Trauma

A 55-year-old male presents with persistent pain and difficulty ambulating 9 months after sustaining a pelvic ring injury. His initial injury was characterized by a widely diastased pubic symphysis and partial disruption of the posterior sacroiliac ligaments, without significant vertical displacement. According to the Tile classification, this initial injury pattern is best described as:

. Type A: Stable
. Type B: Rotationally unstable, vertically stable
. Type C: Rotationally and vertically unstable
. Young & Burgess Vertical Shear
. AO/OTA Type 61-C3

Correct Answer & Explanation

. Type B: Rotationally unstable, vertically stable

Explanation

Correct Answer: BThe case content, under 'Summary of Key Literature / Guidelines' and 'Tile Classification,' describes: 'Type B: Rotationally unstable, vertically stable (e.g., "open book," lateral compression). Disruption of anterior and partial posterior ligaments.' The patient's initial injury, with a 'widely diastased pubic symphysis' (anterior disruption) and 'partial disruption of the posterior sacroiliac ligaments, without significant vertical displacement,' perfectly matches the description of a Tile Type B injury.Option A (Type A: Stable)is incorrect. Type A injuries are stable and involve minimal disruption, such as isolated rami fractures or avulsions. This patient's injury involves significant anterior and partial posterior disruption, making it unstable.Option C (Type C: Rotationally and vertically unstable)is incorrect. Type C injuries involve complete disruption of both anterior and posterior ligaments, leading to vertical instability. The patient's injury explicitly states 'without significant vertical displacement,' ruling out Type C.Option D (Young & Burgess Vertical Shear)is incorrect. While Young & Burgess is a valid classification, the question specifically asks for the Tile classification. A Vertical Shear injury would correspond to a Tile Type C due to its vertical instability.Option E (AO/OTA Type 61-C3)is incorrect. While AO/OTA is a comprehensive classification, the question specifically asks for the Tile classification. Furthermore, a C3 injury in AO/OTA would imply a highly unstable, complex injury, likely with vertical instability, which is not described for this patient's initial injury.

Question 93

Topic: Pelvic & Acetabular Trauma

A 60-year-old female, 18 months post-pelvic ring injury, presents with chronic, severe, and activity-limiting pain in her right SI joint region. She has a significant waddling gait, requires a walker for ambulation, and reports difficulty with all activities of daily living. Radiographs show a persistent 1.2 cm diastasis of the right SI joint and a 0.8 cm vertical migration of the right hemipelvis, which has progressed from 0.5 cm at 6 months post-op. She has undergone extensive physical therapy and multiple SI joint injections without sustained relief. Which of the following is the most compelling indication for surgical intervention in this patient?

. Persistent pain refractory to conservative management.
. Progressive deformity and vertical migration.
. Significant functional impairment and gait disturbance.
. Risk of future degenerative changes.
. All of the above.

Correct Answer & Explanation

. All of the above.

Explanation

Correct Answer: EThe case content, under 'Indications for Intervention,' lists several operative indications. This patient presents with multiple, clear indications:Persistent Pain:'Unremitting or activity-limiting pain localized to the pelvis or lumbosacral region, not responsive to conservative management.' The patient has 'chronic, severe, and activity-limiting pain' refractory to 'extensive physical therapy and multiple SI joint injections.'Progressive Deformity:'Radiographic evidence of ongoing displacement, widening of the pubic symphysis, or vertical migration of the hemipelvis (e.g., >1 cm displacement).' The patient has 'persistent 1.2 cm diastasis of the right SI joint and a 0.8 cm vertical migration of the right hemipelvis, which has progressed from 0.5 cm.'Functional Impairment:'Significant gait disturbance (e.g., waddling gait, limb length discrepancy), difficulty with weight-bearing, or inability to perform activities of daily living due to instability.' The patient has a 'significant waddling gait, requires a walker for ambulation, and reports difficulty with all activities of daily living.'While 'Risk of future degenerative changes' is a valid long-term concern for untreated instability, the immediate and most compelling reasons for surgery are the severe pain, functional impairment, and progressive radiographic deformity. Since all listed options (A, B, C) are strong, independent indications for surgery, and the patient exhibits all of them, 'All of the above' is the most accurate answer.

Question 94

Topic: Pelvic & Acetabular Trauma

A 55-year-old female sustains a pelvic fracture after a fall from a height. She is hemodynamically stable. Initial radiographs reveal a Young-Burgess Vertical Shear (VS) injury. Which of the following statements regarding this fracture pattern is most accurate?

. It is typically managed non-operatively with bed rest and pain control.
. It is characterized by pubic symphysis diastasis less than 2.5 cm with intact posterior ligaments.
. It results from a high-energy axial load and involves complete disruption of both anterior and posterior pelvic rings with vertical displacement.
. It is a rotationally unstable but vertically stable injury, often referred to as an 'open book' fracture.
. The primary source of hemorrhage is usually arterial, originating from the superior gluteal artery.

Correct Answer & Explanation

. It results from a high-energy axial load and involves complete disruption of both anterior and posterior pelvic rings with vertical displacement.

Explanation

Correct Answer: CA Young-Burgess Vertical Shear (VS) injury is a high-energy injury resulting from an axial load (e.g., fall from height landing on feet). It is characterized by complete disruption of both the anterior and posterior pelvic rings, leading to significant vertical displacement. This pattern is highly unstable, both rotationally and vertically, and carries a very high morbidity and mortality.Option A (It is typically managed non-operatively with bed rest and pain control)is incorrect. VS injuries are inherently unstable and always require operative stabilization due to complete disruption of both anterior and posterior rings.Option B (It is characterized by pubic symphysis diastasis less than 2.5 cm with intact posterior ligaments)is incorrect. This description aligns with a Young-Burgess Anteroposterior Compression Type I (APC I) injury, which is rotationally stable.Option D (It is a rotationally unstable but vertically stable injury, often referred to as an 'open book' fracture)is incorrect. This describes a Young-Burgess Anteroposterior Compression Type II (APC II) injury. VS injuries are both rotationally and vertically unstable.Option E (The primary source of hemorrhage is usually arterial, originating from the superior gluteal artery)is incorrect. While arterial bleeding (e.g., from the superior gluteal artery) can occur, the vast majority (80-90%) of significant pelvic hemorrhage, especially in high-energy unstable fractures like VS, is venous in origin, primarily from the presacral venous plexus and internal iliac veins.

Question 95

Topic: Pelvic & Acetabular Trauma

A 35-year-old male presents with a complex pelvic fracture. As part of the initial imaging workup, the following radiographs are obtained:

Based on the provided image, which view is depicted, and what specific information does it primarily provide regarding pelvic fracture assessment?

. AP Pelvis view; assesses overall ring integrity and symphysis diastasis.
. Inlet view; assesses sacral kyphosis/angulation and anterior-posterior displacement of the posterior ring.
. Outlet view; assesses vertical migration of the hemipelvis and sacral lordosis/angulation.
. Judet view (Obturator Oblique); assesses the anterior column and posterior wall of the acetabulum.
. Judet view (Iliac Oblique); assesses the posterior column and anterior wall of the acetabulum.

Correct Answer & Explanation

. Outlet view; assesses vertical migration of the hemipelvis and sacral lordosis/angulation.

Explanation

Correct Answer: CThe image provided is anOutlet viewof the pelvis. This view is characterized by the projection of the pubic symphysis over the sacrum, allowing for clear visualization of the vertical alignment of the hemipelvis. It is primarily used to assess for superior or inferior vertical migration (displacement) of the hemipelvis and to evaluate the sacral lordosis or angulation.Option A (AP Pelvis view)is incorrect. An AP pelvis view shows the entire pelvic ring, symphysis, and SI joints without significant superimposition, but it is not the view shown. It is the initial mandatory view.Option B (Inlet view)is incorrect. An inlet view projects the posterior structures (sacrum, SI joints) without superimposition, useful for assessing sacral kyphosis/angulation and anterior-posterior displacement of the posterior ring. The image does not show the characteristic appearance of an inlet view where the pelvic brim is clearly visualized.Option D (Judet view (Obturator Oblique))is incorrect. Judet views are specific for acetabular fractures. The obturator oblique view visualizes the anterior column and posterior wall of the acetabulum. The image is a pelvic ring view, not an acetabular view.Option E (Judet view (Iliac Oblique))is incorrect. The iliac oblique view visualizes the posterior column and anterior wall of the acetabulum. Again, the image is a pelvic ring view.

Question 96

Topic: Pelvic & Acetabular Trauma
A 22-year-old male presents with a Young-Burgess APC II pelvic fracture. He is hemodynamically stable. The pubic symphysis diastasis is 3.0 cm. The posterior sacroiliac ligaments are intact. Which of the following statements best describes the stability of this fracture pattern?
. Rotationally and vertically unstable.
. Rotationally stable and vertically stable.
. Rotationally unstable but vertically stable.
. Vertically unstable but rotationally stable.
. Stable to all forces due to intact posterior arch.

Correct Answer & Explanation

. Rotationally unstable but vertically stable.

Explanation

A Young-Burgess Anteroposterior Compression Type II (APC II) injury is characterized by pubic symphysis diastasis greater than 2.5 cm and disruption of the anterior sacroiliac ligaments, but with intact posterior sacroiliac ligaments. This pattern makes the pelvic ring rotationally unstable (often described as an 'open book' injury) but vertically stable because the strong posterior ligaments remain intact, preventing vertical displacement.

Question 97

Topic: Pelvic & Acetabular Trauma

During the acute resuscitation of a patient with a mechanically unstable pelvic ring injury, the trauma team decides to place a circumferential pelvic binder. To optimally reduce pelvic volume and provide biomechanical stability, the binder must be centered over which anatomic landmark?

. The iliac crests
. The greater trochanters
. The anterior superior iliac spines (ASIS)
. The umbilicus
. The lesser trochanters

Correct Answer & Explanation

. The greater trochanters

Explanation

Pelvic binders must be centered over the greater trochanters to effectively compress the pubic symphysis and reduce the pelvic volume. Placement higher up over the iliac crests is ineffective and can actually cause paradoxical widening of the true pelvis.

Question 98

Topic: Pelvic & Acetabular Trauma

Which of the following pelvic radiograph views is most appropriate to evaluate for subtle cranial (vertical) displacement of the left hemipelvis in a suspected vertical shear injury?

. AP Pelvis
. Inlet view
. Outlet view
. Judet obturator oblique view
. Judet iliac oblique view

Correct Answer & Explanation

. Outlet view

Explanation

The pelvic outlet view (directed 45 degrees cephalad) projects the sacrum en face and is the optimal view for assessing vertical displacement (cranial/caudal translation) of a hemipelvis.

Question 99

Topic: Pelvic & Acetabular Trauma

A 41-year-old female complains of persistent dyspareunia and pelvic pain one year after undergoing anterior symphyseal plating and bilateral SI joint screw fixation for an APC II injury. Radiographs show a healed pelvic ring with intact hardware. What is the most likely cause of her dyspareunia?

. Hardware failure of the SI screws
. Nonunion of the pubic symphysis
. Residual pelvic floor dysfunction and local nerve injury
. Late-onset osteomyelitis of the pubic rami
. Intrapelvic protrusion of the symphyseal plate

Correct Answer & Explanation

. Residual pelvic floor dysfunction and local nerve injury

Explanation

Sexual dysfunction, including dyspareunia in females and erectile dysfunction in males, is a very common complication following major anterior pelvic ring disruptions. It is typically attributed to local nerve injury (pudendal nerve branches), soft-tissue scarring, and pelvic floor dysfunction rather than hardware complications.

Question 100

Topic: Pelvic & Acetabular Trauma
A crescent fracture of the ilium is most classically associated with which type of pelvic ring injury pattern in the Young-Burgess classification?
. Anteroposterior Compression II (APC-II)
. Lateral Compression II (LC-II)
. Lateral Compression III (LC-III)
. Vertical Shear (VS)
. Anteroposterior Compression III (APC-III)

Correct Answer & Explanation

. Lateral Compression II (LC-II)

Explanation

A crescent fracture involves a fracture of the posterior iliac wing extending into the sacroiliac joint, leaving the posterior sacroiliac ligaments intact. This is the hallmark posterior lesion of a Lateral Compression Type II (LC-II) injury.

Test Yourself

Switch to an interactive, timed exam simulation to truly master this topic.

On this Page