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 61
Topic: Pelvic & Acetabular Trauma
A hemodynamically unstable 30-year-old man is brought in after a motorcycle accident. Pelvic radiograph shows a pubic symphysis diastasis of 4 cm and widening of the sacroiliac joints. After initiating massive transfusion protocols, what is the most appropriate immediate orthopedic intervention?
Correct Answer & Explanation
. Application of a pelvic binder or sheet
Explanation
In a hemodynamically unstable patient with an anteroposterior compression (APC) pelvic ring injury, the immediate priority is closing the pelvic volume using a pelvic binder to tamponade venous bleeding.
Question 62
Topic: Pelvic & Acetabular Trauma
In the setting of a traumatic anterior pelvic ring injury (APC-III), where is the anatomically correct placement of a circumferential pelvic binder to effectively reduce pelvic volume?
Correct Answer & Explanation
. Centered over the greater trochanters
Explanation
To optimally reduce pelvic volume and stabilize the pelvic ring, a pelvic binder must be centered directly over the greater trochanters. Placement higher over the iliac crests is less effective and may worsen the deformity.
Question 63
Topic: Pelvic & Acetabular Trauma
A 40-year-old male sustains an anteroposterior compression (APC-III) pelvic ring injury. Upon arrival, he is hypotensive and tachycardic. Despite the immediate application of a pelvic binder and administration of 2 units of packed red blood cells, he remains hemodynamically unstable. What is the most appropriate next step in management?
In a hemodynamically unstable patient with a mechanically stabilized pelvic ring (via binder), the source of continued shock is likely retroperitoneal venous or arterial bleeding. Preperitoneal packing and angiography with embolization are the interventions of choice. CT is contraindicated in a hemodynamically unstable patient.
Question 64
Topic: Pelvic & Acetabular Trauma
A 35-year-old male is brought to the trauma bay after an industrial crush injury. He has an open-book pelvic ring disruption (APC-III) and remains hemodynamically unstable despite a massive transfusion protocol. What is the most appropriate next step in management?
Correct Answer & Explanation
. Application of a pelvic binder and preperitoneal pelvic packing
Explanation
In a hemodynamically unstable patient with a mechanically unstable pelvic ring, temporary mechanical stabilization (binder) combined with preperitoneal pelvic packing is the most rapid and effective initial step to control the retroperitoneal venous bleeding, which is the most common hemorrhage source.
Question 65
Topic: Pelvic & Acetabular Trauma
A 28-year-old female presents to the trauma center after a motorcycle crash. She is hypotensive (BP 75/40 mmHg) and has an obvious pelvic deformity. Radiographs demonstrate a widened symphysis pubis and disrupted anterior sacroiliac ligaments with intact posterior ligaments (APC II). A pelvic binder is immediately applied. Which of the following is the correct anatomical landmark for optimal placement of the pelvic binder?
Correct Answer & Explanation
. Centered over the greater trochanters
Explanation
For optimal mechanical advantage and maximal reduction of pelvic volume, a pelvic binder or sheet must be centered directly over the greater trochanters. Placement over the iliac crests or ASIS can exacerbate the deformity or cause inadequate reduction.
Question 66
Topic: Pelvic & Acetabular Trauma
A 42-year-old female is brought in by EMS after being struck by a motor vehicle. Her blood pressure is 80/40 mmHg, and examination reveals a mechanically unstable "open book" pelvic ring injury. To achieve the most effective reduction of pelvic volume and assist in hemorrhage control, a commercial pelvic binder should be centered directly over which anatomic landmark?
Correct Answer & Explanation
. Greater trochanters
Explanation
To optimally compress the pelvic ring and reduce pelvic volume, a pelvic binder or sheet must be centered directly over the greater trochanters. Placing it higher over the iliac crests is less effective and can paradoxically open the pelvis further in certain fracture patterns.
Question 67
Topic: Pelvic & Acetabular Trauma
A 32-year-old male is brought to the trauma bay after a motorcycle collision. Pelvic radiographs demonstrate widening of the pubic symphysis to 3.5 cm and widening of the anterior sacroiliac joints, consistent with an Anteroposterior Compression II (APC II) injury. Which of the following posterior pelvic ligaments remain intact in this injury pattern?
Correct Answer & Explanation
. Sacrospinous ligament
Explanation
An APC II pelvic ring injury involves diastasis of the pubic symphysis, disruption of the anterior sacroiliac ligaments, and tearing of the sacrotuberous and sacrospinous ligaments. The posterior sacroiliac ligaments remain intact, providing vertical stability.
Question 68
Topic: Pelvic & Acetabular Trauma
A 45-year-old male is involved in a high-speed motorcycle collision and sustains an APC-III pelvic ring injury. He is hemodynamically unstable upon arrival. Following application of a pelvic binder, his blood pressure remains 70/40 mmHg and his heart rate is 130 bpm. A FAST exam is negative. What is the most appropriate next step in management?
Correct Answer & Explanation
. Preperitoneal pelvic packing and/or angiography
Explanation
In a hemodynamically unstable patient with a pelvic ring injury and a negative FAST exam, retroperitoneal hemorrhage is the likely source. Immediate preperitoneal pelvic packing or angioembolization is indicated to control the bleeding.
Question 69
Topic: Pelvic & Acetabular Trauma
A 30-year-old male is brought to the trauma bay after a motorcycle collision. His blood pressure is 70/40 mmHg. A FAST exam is negative. Pelvic radiographs show an APC III pelvic ring injury. A pelvic binder is appropriately applied, and he receives 2 units of uncrossmatched PRBCs, but his blood pressure only improves to 75/40 mmHg. What is the most appropriate next step in management?
Correct Answer & Explanation
. Preperitoneal pelvic packing or pelvic angiography
Explanation
In a hemodynamically unstable patient with a pelvic ring injury and negative FAST, a pelvic binder is the initial step. If instability persists despite initial resuscitation and binder application, preperitoneal packing or angiography (based on institutional protocol) is indicated to control hemorrhage.
Question 70
Topic: Pelvic & Acetabular Trauma
A 35-year-old male arrives in the trauma bay in hemorrhagic shock following a pelvic crush injury. Radiographs show an anteroposterior compression (APC) type III pelvic ring injury. To achieve the most effective mechanical stabilization and volume reduction, a pelvic binder should be placed centered over which anatomic landmark?
Correct Answer & Explanation
. The greater trochanters
Explanation
Pelvic binders should be centered over the greater trochanters to effectively compress the pelvic ring and reduce pelvic volume. Placement over the iliac crests is ineffective and can paradoxically open the pelvis in certain fracture patterns.
Question 71
Topic: Pelvic & Acetabular Trauma
A 35-year-old male is brought to the trauma bay after a motorcycle crash. His pelvis radiograph reveals an anteroposterior compression type III (APC-III) pelvic ring injury. Despite the application of a pelvic binder and infusion of 2 liters of crystalloid and 2 units of packed red blood cells, he remains hemodynamically unstable. A FAST exam is negative. What is the most appropriate next step in management?
In a hemodynamically unstable patient with a mechanically unstable pelvic ring injury and a negative FAST exam, the source of bleeding is presumed to be the pelvis. The standard of care after mechanical stabilization (pelvic binder) is preperitoneal pelvic packing and/or angiography to control venous and arterial hemorrhage.
Question 72
Topic: Pelvic & Acetabular Trauma
A 40-year-old male presents in hypotensive shock after a crush injury. Pelvic radiographs show a 3 cm symphyseal diastasis and anterior widening of the sacroiliac joints (APC II). What is the primary ligamentous injury responsible for rotational instability?
Correct Answer & Explanation
. Sacrotuberous and sacrospinous ligaments
Explanation
In an APC II pelvic ring injury, the anterior sacroiliac, sacrotuberous, and sacrospinous ligaments are disrupted, causing rotational instability. The posterior sacroiliac ligaments remain intact, preserving vertical stability.
Question 73
Topic: Pelvic & Acetabular Trauma
A 35-year-old male is brought in after a high-speed motor vehicle collision. Radiographs demonstrate an anteroposterior compression (APC) pelvic ring injury. Which of the following ligaments must be disrupted to classify this as an APC III rather than an APC II injury?
Correct Answer & Explanation
. Posterior sacroiliac ligament
Explanation
An APC II injury involves disruption of the pubic symphysis, anterior SI, sacrotuberous, and sacrospinous ligaments. An APC III injury implies complete hemipelvis instability, necessitating the additional disruption of the strong posterior SI ligaments.
Question 74
Topic: Pelvic & Acetabular Trauma
A 45-year-old male presents to the emergency department after a high-energy motor vehicle accident. He has a comminuted pelvic ring injury involving the pubic symphysis and right sacroiliac joint, classified as an APC III. On initial evaluation, he is hypotensive, tachycardic, and has gross hematuria with a high-riding prostate on digital rectal examination. What is the most appropriate initial management step for his suspected urological injury after initial resuscitation?
Correct Answer & Explanation
. Perform a retrograde urethrogram (RUG) prior to any urethral instrumentation.
Explanation
The patient's presentation with a high-energy pelvic fracture, gross hematuria, and a high-riding prostate strongly suggests a posterior urethral injury. In such cases, urethral instrumentation with a Foley catheter is contraindicated until a retrograde urethrogram (RUG) has been performed to rule out or characterize the urethral injury. Attempting to insert a Foley catheter blindly can convert a partial tear into a complete tear or create a false passage, worsening the injury. If a urethral injury is confirmed and Foley insertion is not possible, a suprapubic catheter is the preferred method for bladder drainage.
Question 75
Topic: Pelvic & Acetabular Trauma
In the Young-Burgess classification of pelvic ring injuries, which type is most frequently associated with the highest volume of retroperitoneal hemorrhage and requires urgent pelvic binder placement?
Correct Answer & Explanation
. Anteroposterior Compression Type III (APC-III)
Explanation
APC-III (open book) pelvic injuries involve complete disruption of the anterior and posterior sacroiliac ligaments, leading to dramatic pelvic volume expansion. This severely compromises the presacral venous plexus, making it prone to exsanguinating hemorrhage.
Question 76
Topic: Pelvic & Acetabular Trauma
A 35-year-old male presents in hypotensive shock following a motorcycle crash. Pelvic radiographs show symphyseal diastasis of 4 cm and disruption of the anterior sacroiliac ligaments, but intact posterior sacroiliac ligaments. A pelvic binder is applied, and his hemodynamics stabilize. What is the most appropriate definitive management for his pelvic injury?
Correct Answer & Explanation
. Open reduction and internal fixation of the pubic symphysis
Explanation
This is an APC-II pelvic ring injury. Because the posterior SI ligaments are intact, the posterior ring is vertically stable, so anterior ring fixation (ORIF of the symphysis) is sufficient for definitive stabilization.
Question 77
Topic: Pelvic & Acetabular Trauma
A 45-year-old male is brought to the trauma bay after a motorcycle crash. His blood pressure is 80/50 mmHg. Radiographs show a widened pubic symphysis (4 cm) and disruption of the right sacroiliac joint. What is the most appropriate anatomic landmark for positioning a pelvic binder?
Correct Answer & Explanation
. 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 can paradoxically open the pelvic ring in certain fracture patterns.
Question 78
Topic: Pelvic & Acetabular Trauma
A 45-year-old male arrives at the trauma bay hypotensive and tachycardic following a crush injury. Radiographs show a widened pubic symphysis (>3 cm) and disrupted sacroiliac joints. A pelvic binder is applied, and 2 units of packed RBCs are given, but his blood pressure remains 75/40 mmHg. A FAST exam is negative. What is the most appropriate next step?
Correct Answer & Explanation
. Pre-peritoneal pelvic packing or angiography
Explanation
In a hemodynamically unstable patient with a pelvic ring injury, negative FAST, and no response to initial resuscitation and binder application, the source of bleeding is likely retroperitoneal. Immediate pre-peritoneal pelvic packing or angioembolization is indicated.
Question 79
Topic: Pelvic & Acetabular Trauma
In the initial trauma bay management of a hemodynamically unstable patient with an anteroposterior compression (APC-III) pelvic ring injury, where should the pelvic binder be centered for optimal mechanical advantage?
Correct Answer & Explanation
. Greater trochanters
Explanation
Pelvic binders should be centered directly over the greater trochanters to effectively close the pelvic ring and reduce pelvic volume. Placement over the iliac crests is incorrect and less mechanically effective.
Question 80
Topic: Pelvic & Acetabular Trauma
A 42-year-old male is brought to the trauma bay after a crush injury. He has an anteroposterior compression (APC) type III pelvic ring injury and remains hypotensive despite aggressive fluid resuscitation and application of a pelvic binder. What is the most common anatomical source of major hemorrhage in unstable pelvic ring injuries?
Correct Answer & Explanation
. Posterior pelvic venous plexus
Explanation
While arterial bleeding (such as from the superior gluteal artery or internal pudendal artery) can cause life-threatening hemorrhage, approximately 80-90% of bleeding in pelvic trauma originates from the pre-sacral and pre-vesical venous plexuses or the fractured cancellous bone surfaces.
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