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Pelvic & Acetabular Trauma MCQs

Practice Set 22 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 421

Topic: Pelvic & Acetabular Trauma

A 35-year-old male is brought to the ED after a motorcycle crash. He is tachycardic (130 bpm) and hypotensive (80/40 mmHg). A pelvic radiograph (similar to

) shows an AP compression type III (APC-III) pelvic ring injury. After massive transfusion protocol is initiated, his blood pressure remains 85/45 mmHg. A pelvic binder is correctly applied. Extended FAST is negative. What is the most appropriate next step?

. CT abdomen and pelvis
. Definitive anterior and posterior pelvic ring fixation
. Preperitoneal pelvic packing and/or angioembolization
. Application of an external fixator in the ED
. Exploratory laparotomy

Correct Answer & Explanation

. CT abdomen and pelvis

Explanation

In a hemodynamically unstable patient with a mechanically unstable pelvic ring injury and negative FAST, retroperitoneal hemorrhage is the likely source. Interventions such as preperitoneal pelvic packing and/or pelvic angiography with embolization are critical to control venous and arterial bleeding.

Question 422

Topic: Pelvic & Acetabular Trauma

A 35-year-old man presents with a hemodynamically unstable anteroposterior compression (APC-III) pelvic ring injury. A non-invasive pelvic binder is applied in the trauma bay. Over which anatomical landmarks should the binder be centered for optimal reduction and hemorrhage control?

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

Correct Answer & Explanation

. Anterior superior iliac spines

Explanation

Pelvic binders must be centered directly over the greater trochanters to effectively close the pelvic ring and reduce intrapelvic volume. Placement over the ASIS or iliac crests is biomechanically less effective and can paradoxically open the pelvis in certain fracture patterns.

Question 423

Topic: Pelvic & Acetabular Trauma

A 40-year-old man arrives at the trauma center after falling from a 3-story building. He is tachycardic (120 bpm) and hypotensive (80/40 mmHg). Pelvic radiograph shows an anteroposterior compression (APC) III injury. A pelvic binder is applied. To optimize mechanical stability and reduction of pelvic volume, where should the pelvic binder be centered?

. Iliac crests
. Greater trochanters
. Anterior superior iliac spines
. Pubic symphysis directly
. Proximal femurs

Correct Answer & Explanation

. Iliac crests

Explanation

A pelvic binder should be centered precisely over the greater trochanters to effectively close the pelvic ring and reduce intrapelvic volume. Placement over the iliac crests or ASIS can cause a flaring effect, worsening the displacement.

Question 424

Topic: Pelvic & Acetabular Trauma

A 35-year-old male is brought to the emergency department after a motorcycle crash. His blood pressure is 80/40 mm Hg and heart rate is 130 beats/min. An AP pelvis radiograph demonstrates an open book pelvic ring injury (APC III). A pelvic binder is ordered. What is the most appropriate anatomical landmark for the optimal placement of the pelvic binder?

. Iliac crests
. Greater trochanters
. Anterior superior iliac spines
. Pubic symphysis
. Subtrochanteric femur

Correct Answer & Explanation

. Iliac crests

Explanation

The most effective level for placing a pelvic binder to reduce pelvic volume and control hemorrhage in an anterior posterior compression (APC) injury is at the level of the greater trochanters. Placement over the iliac crests is less effective and may paradoxically open the pelvis further.

Question 425

Topic: Pelvic & Acetabular Trauma

A 40-year-old female presents in hemorrhagic shock following an anteroposterior compression (APC) Type III pelvic ring injury. To effectively reduce the pelvic volume and stabilize the fracture, over which specific anatomic landmark should a pelvic binder be centered?

. Iliac crests
. Anterior superior iliac spines
. Greater trochanters
. Pubic symphysis
. Subtrochanteric femur

Correct Answer & Explanation

. Iliac crests

Explanation

A pelvic binder must be centered directly over the greater trochanters to effectively compress the pelvic ring and reduce volume. Placement over the iliac crests is biomechanically incorrect and can paradoxically open the pelvis further.

Question 426

Topic: Pelvic & Acetabular Trauma

A 50-year-old male sustains a posterior wall acetabular fracture with a concomitant posterior hip dislocation. To optimally visualize the posterior wall and the anterior column of the acetabulum preoperatively, which specific radiographic view is required?

. AP Pelvis view
. Iliac oblique view
. Obturator oblique view
. Pelvic inlet view
. Pelvic outlet view

Correct Answer & Explanation

. AP Pelvis view

Explanation

The Judet obturator oblique view (the pelvis rotated 45 degrees away from the affected hip) profiles the anterior column and the posterior wall of the acetabulum. The iliac oblique view profiles the posterior column and anterior wall.

Question 427

Topic: Pelvic & Acetabular Trauma

A 45-year-old hypotensive male presents after a motorcycle crash. Pelvic radiographs demonstrate a symphyseal diastasis of 4 cm and widening of both sacroiliac joints. A pelvic binder was applied in the field. He remains hemodynamically unstable despite 2 units of uncrossmatched blood. FAST exam is negative. What is the most appropriate next intervention?

. Retrograde urethrogram
. Pre-peritoneal pelvic packing and/or angioembolization
. Definitive open reduction internal fixation of the pelvis
. Exploratory laparotomy
. Administration of tranexamic acid and observation

Correct Answer & Explanation

. Retrograde urethrogram

Explanation

In a hemodynamically unstable patient with a pelvic ring injury and a negative FAST, the source of bleeding is primarily the presacral venous plexus or internal iliac arterial branches. Pre-peritoneal pelvic packing and/or angiography with embolization are the required emergent interventions.

Question 428

Topic: Pelvic & Acetabular Trauma

A 45-year-old male is brought to the trauma bay after a motorcycle crash. He is hypotensive and tachycardic. A pelvic radiograph reveals an APC-III (open-book) pelvic ring injury. What is the correct anatomical landmark for the application of a circumferential pelvic sheet or binder?

. Iliac crests
. Anterior superior iliac spines (ASIS)
. Greater trochanters
. Symphysis pubis
. Ischial tuberosities

Correct Answer & Explanation

. Iliac crests

Explanation

Circumferential pelvic binders should be centered directly over the greater trochanters to effectively reduce pelvic volume in open-book pelvic ring injuries. Placement higher over the iliac crests is biomechanically less effective and restricts abdominal access.

Question 429

Topic: Pelvic & Acetabular Trauma

A hemodynamically unstable patient arrives with an anterior-posterior compression (APC-III) pelvic ring injury. A pelvic binder is ordered to reduce pelvic volume. Over which anatomic landmark must the binder be centered to effectively achieve mechanical stabilization?

. Iliac crests
. Anterior superior iliac spines (ASIS)
. Greater trochanters
. Symphysis pubis
. Subtrochanteric femoral diaphysis

Correct Answer & Explanation

. Iliac crests

Explanation

To effectively reduce pelvic volume and stabilize the pelvic ring, a pelvic binder must be centered over the greater trochanters. Placement over the iliac crests is incorrect and can worsen the rotational displacement of an open-book fracture.

Question 430

Topic: Pelvic & Acetabular Trauma

The sacroiliac joint is a strong, weight-bearing joint stabilized by numerous ligaments. Which of the following ligaments is considered the strongest and most important for stabilizing the sacroiliac joint, restricting anterior and inferior rotation of the sacrum?

. Sacrospinous ligament
. Sacrotuberous ligament
. Iliolumbar ligament
. Interosseous sacroiliac ligament
. Posterior sacroiliac ligament

Correct Answer & Explanation

. Sacrospinous ligament

Explanation

The sacroiliac (SI) joint is stabilized by an intricate complex of ligaments. The interosseous sacroiliac ligament is considered the strongest and most important ligament for SI joint stability. It consists of multiple short, strong fibers that fill the irregular space between the sacral and iliac tuberosities, connecting them firmly. It effectively resists anterior and inferior rotation of the sacrum relative to the ilium. The posterior sacroiliac ligaments reinforce the posterior aspect, the iliolumbar ligament connects L5 to the ilium, and the sacrospinous and sacrotuberous ligaments are extrinsic ligaments of the pelvis, providing less direct SI joint stability.

Question 431

Topic: Pelvic & Acetabular Trauma

During an anterior intrapelvic (modified Stoppa) approach for the fixation of an acetabular fracture, the surgeon must identify and protect or ligate the 'corona mortis' to prevent life-threatening hemorrhage. This structure typically represents a vascular anastomosis between which of the following systems?

. Internal pudendal and external pudendal arteries
. Superior gluteal and inferior gluteal arteries
. Obturator and external iliac (or inferior epigastric) vessels
. Iliolumbar and deep circumflex iliac vessels
. Medial femoral circumflex and obturator arteries

Correct Answer & Explanation

. Internal pudendal and external pudendal arteries

Explanation

The corona mortis ('crown of death') is a recognized vascular anastomosis between the obturator vessels (internal iliac system) and the inferior epigastric or external iliac vessels. It is located on the posterior aspect of the superior pubic ramus, on average 5-6 cm from the pubic symphysis. Iatrogenic injury during approaches to the acetabulum or anterior pelvic ring can cause rapid, severe hemorrhage that is difficult to control.

Question 432

Topic: Pelvic & Acetabular Trauma

During an ilioinguinal approach for an anterior column acetabular fracture, a vascular anastomosis connecting the obturator and external iliac (or inferior epigastric) vessels is encountered coursing over the superior pubic ramus. Injury to this "corona mortis" causes significant hemorrhage. At what average distance from the pubic symphysis does this structure typically lie?

. 1 to 2 cm
. 5 to 7 cm
. 9 to 11 cm
. 12 to 14 cm
. 15 to 17 cm

Correct Answer & Explanation

. 1 to 2 cm

Explanation

The corona mortis is a vascular connection between the obturator and external iliac or inferior epigastric vessels. It crosses the superior pubic ramus at an average distance of 5 to 7 cm (typically about 6 cm) lateral to the pubic symphysis. It must be carefully identified and ligated during anterior approaches to the pelvis and acetabulum to prevent massive, life-threatening bleeding.

Question 433

Topic: Pelvic & Acetabular Trauma

An orthopedic trauma surgeon is stabilizing an anteroposterior compression type III (APC-III) pelvic ring injury. Complete disruption of the posterior sacroiliac complex is noted. Which specific ligamentous structure in this complex is primarily responsible for resisting vertical shear/translation of the hemipelvis?

. Sacrospinous ligament
. Sacrotuberous ligament
. Anterior sacroiliac ligament
. Interosseous sacroiliac ligament
. Iliolumbar ligament

Correct Answer & Explanation

. Sacrospinous ligament

Explanation

The posterior sacroiliac complex is the strongest ligamentous complex in the body. The robust interosseous sacroiliac ligaments are the primary stabilizers against vertical translation (shear) of the hemipelvis. The anterior sacroiliac ligaments resist external rotation, while the sacrotuberous and sacrospinous ligaments also primarily limit external rotation and secondary vertical translation.

Question 434

Topic: Pelvic & Acetabular Trauma
A 24-year-old female presents with symptomatic developmental dysplasia of the hip (DDH) characterized by a lateral center-edge angle of 15 degrees and a Tรถnnis angle of 18 degrees. She is scheduled to undergo a Bernese periacetabular osteotomy (PAO). Which of the following represents a primary biomechanical or structural advantage of the Bernese PAO compared to the Salter innominate osteotomy?
. It requires a complete division of the posterior column to maximize correction.
. It maintains an intact posterior column, preserving pelvic ring stability.
. It alters the true pelvic dimensions, expanding the birth canal.
. It achieves correction through a purely extra-articular sub-gluteal approach.
. It primarily relies on a single hinge point at the pubic symphysis.

Correct Answer & Explanation

. It maintains an intact posterior column, preserving pelvic ring stability.

Explanation

The Bernese periacetabular osteotomy (PAO) involves a series of osteotomies (ischial, pubic, and iliac) that completely free the acetabulum while leaving the posterior column of the hemipelvis intact. This is a major advantage because it preserves intrinsic pelvic stability, allowing for earlier mobilization without the need for prolonged casting. Furthermore, because the posterior column is intact, it does not alter the shape or dimensions of the true pelvis, making it advantageous for women of childbearing age regarding future vaginal deliveries.

Question 435

Topic: Pelvic & Acetabular Trauma
A 35-year-old male is brought to the emergency department after a high-speed motorcycle collision. His blood pressure is 70/40 mm Hg and heart rate is 135 bpm. A FAST exam is negative. An anteroposterior pelvic radiograph shows a widened pubic symphysis of 4 cm and widened bilateral sacroiliac joints. A pelvic binder is placed, and he receives 2 units of uncrossmatched packed red blood cells. His blood pressure improves transiently to 85/50 mm Hg. What is the next most appropriate step in management?
. Transfer to the CT scanner to evaluate for retroperitoneal hemorrhage
. Immediate application of an anterior external fixator
. Preperitoneal pelvic packing or pelvic angioembolization
. Exploratory laparotomy
. Retrograde urethrogram

Correct Answer & Explanation

. Preperitoneal pelvic packing or pelvic angioembolization

Explanation

This patient has a hemodynamically unstable pelvic ring injury (APC-III equivalent). The initial step is stabilization with a pelvic binder and resuscitation. With a negative FAST exam, the abdomen is less likely to be the source of major hemorrhage, pointing toward retroperitoneal bleeding from the pelvis. If the patient remains unstable or transiently responds, definitive hemorrhage control via preperitoneal pelvic packing or angiography with embolization is the standard of care. CT scanning is contraindicated in a hemodynamically unstable patient. Exploratory laparotomy is not indicated for isolated retroperitoneal pelvic bleeding and releases the tamponade effect.

Question 436

Topic: Pelvic & Acetabular Trauma
A 45-year-old man is brought to the emergency department after a high-speed motorcycle collision. He is hemodynamically unstable with a blood pressure of 80/40 mm Hg and a heart rate of 125 beats/min. A FAST examination is negative. The anteroposterior pelvic radiograph reveals an Anteroposterior Compression Type III (APC-III) pelvic ring injury. A pelvic binder is ordered to assist with hemodynamic stabilization. What is the most appropriate anatomical landmark for the optimal placement of the pelvic binder to effectively reduce the pelvic volume?
. Centered over the iliac crests
. Centered over the greater trochanters
. Centered over the anterior superior iliac spines
. Centered over the symphysis pubis and the sacrum
. Midway between the iliac crests and the greater trochanters

Correct Answer & Explanation

. Centered over the greater trochanters

Explanation

Pelvic binders are most effective in reducing pelvic volume and controlling venous hemorrhage when placed centered over the greater trochanters. Placement over the iliac crests is a common error and is less effective; in certain fracture patterns (such as some lateral compression injuries), high placement can paradoxically exacerbate the deformity or internal bleeding.

Question 437

Topic: Pelvic & Acetabular Trauma
A 45-year-old man is brought to the trauma bay after a high-speed motorcycle collision. He has a heart rate of 130 bpm and a blood pressure of 80/50 mm Hg. A pelvic radiograph demonstrates an anteroposterior compression type III (APC-III) pelvic ring injury. A pelvic binder is applied, but his blood pressure remains 85/50 mm Hg after initial fluid resuscitation. A Focused Assessment with Sonography for Trauma (FAST) examination is negative. What is the next best step in management?
. Immediate CT scan of the abdomen and pelvis
. Emergent exploratory laparotomy
. Preperitoneal pelvic packing and/or pelvic angiography with embolization
. Application of an anterior external fixator and immediate symphyseal plating
. Administration of tranexamic acid (TXA) and continued observation in the ICU

Correct Answer & Explanation

. Preperitoneal pelvic packing and/or pelvic angiography with embolization

Explanation

In a hemodynamically unstable patient with a pelvic ring injury and a negative FAST exam (which rules out massive intra-abdominal hemorrhage), the source of bleeding is presumed to be the pelvis (venous plexus or arterial injury). Management dictates immediate mechanical stabilization (e.g., pelvic binder), followed by interventions to control the hemorrhage directly, such as preperitoneal pelvic packing or angioembolization. A CT scan is contraindicated in a hemodynamically unstable patient.

Question 438

Topic: Pelvic & Acetabular Trauma
A 28-year-old male presents with a hemodynamically unstable APC III pelvic ring injury following a high-speed motorcycle collision. Despite application of a pelvic binder and initiation of a massive transfusion protocol, he remains hypotensive. A Focused Assessment with Sonography for Trauma (FAST) exam is negative. He is taken emergently to the operating room for preperitoneal pelvic packing. Which of the following is the most likely anatomic source of his hemorrhage?
. Superior gluteal artery
. Internal pudendal artery
. Presacral venous plexus
. Obturator artery
. External iliac vein

Correct Answer & Explanation

. Presacral venous plexus

Explanation

Up to 80-85% of massive bleeding in severe pelvic ring injuries is venous in origin, most commonly arising from the presacral venous plexus and prevesical veins. Arterial bleeding (such as from the superior gluteal or internal pudendal arteries) accounts for only 10-15% of cases. Preperitoneal pelvic packing is specifically highly effective in tamponading this diffuse venous bleeding.

Question 439

Topic: Pelvic & Acetabular Trauma

A 35-year-old male is brought to the ED after a motorcycle collision. He is hypotensive with a systolic BP of 70 mmHg. Primary survey reveals an unstable pelvis. Radiographs show a widened pubic symphysis of 4 cm and disruption of the anterior and posterior sacroiliac ligaments. A pelvic binder is to be applied to temporarily stabilize the pelvis. To achieve optimal reduction of pelvic volume and mechanical stability, where should the pelvic binder be centered?

. Over the iliac crests
. Over the greater trochanters
. Over the anterior superior iliac spines
. Over the lumbar spine
. Directly over the pubic symphysis

Correct Answer & Explanation

. Over the greater trochanters

Explanation

To optimally reduce pelvic volume and control hemorrhage in anterior-posterior compression (APC) pelvic ring injuries, a pelvic binder or sheet must be centered directly over the greater trochanters. Placement over the iliac crests is a common error and can paradoxically increase the pelvic volume by pushing the iliac wings inward at the top and outward at the bottom, worsening bleeding.

Question 440

Topic: Pelvic & Acetabular Trauma
A 35-year-old male is brought to the emergency department after a high-speed motor vehicle collision. He is hypotensive with a blood pressure of 75/40 mmHg. A pelvic binder is immediately applied. The FAST exam is negative. An anteroposterior pelvic radiograph shows an anteroposterior compression (APC) type III injury with a widened pubic symphysis (>3 cm) and disrupted sacroiliac joints. Despite ongoing fluid and blood resuscitation, the patient remains hemodynamically unstable. What is the most appropriate next step in management?
. CT scan of the abdomen and pelvis with intravenous contrast
. Exploratory laparotomy with retroperitoneal packing
. Immediate open reduction and internal fixation of the anterior pelvic ring
. Preperitoneal pelvic packing and/or pelvic angiography
. Removal of the pelvic binder and application of a supra-acetabular external fixator

Correct Answer & Explanation

. Preperitoneal pelvic packing and/or pelvic angiography

Explanation

In a hemodynamically unstable patient with an unstable pelvic ring injury and a negative FAST exam, the source of bleeding is predominantly retroperitoneal, typically from the venous plexus or arterial branches of the internal iliac system. Once a pelvic binder has been applied to reduce pelvic volume, if the patient remains hemodynamically unstable, ATLS and AAOS guidelines recommend either preperitoneal pelvic packing or pelvic angiography with embolization. A CT scan is contraindicated in a hemodynamically unstable patient.

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