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 541
Topic: Pelvic & Acetabular Trauma
In a hemodynamically unstable patient with a suspected anteroposterior compression (APC) pelvic ring injury, what is the correct anatomic landmark for the optimal placement of a circumferential pelvic binder?
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 pelvic volume. Placement over the iliac crests is incorrect and can paradoxically widen the pelvic outlet.
Question 542
Topic: Pelvic & Acetabular Trauma
A trauma patient undergoes a pelvic series after a high-speed motor vehicle collision.
On an obturator oblique radiograph (Judet view) of the pelvis, which two osseous acetabular structures are best profiled?
Correct Answer & Explanation
. Anterior column and posterior wall
Explanation
The Judet views are orthogonal X-rays used to evaluate acetabular fractures. The obturator oblique view (pelvis rotated 45 degrees away from the affected side) best profiles the anterior column and the posterior wall of the acetabulum. Conversely, the iliac oblique view profiles the posterior column and the anterior wall.
Question 543
Topic: Pelvic & Acetabular Trauma
A trauma patient is evaluated with a pelvic radiograph series after a fall from a height. On an iliac oblique radiograph (Judet view), which two osseous structures of the acetabulum are best profiled?
Correct Answer & Explanation
. Anterior column and posterior wall
Explanation
The iliac oblique view is obtained with the patient rotated 45 degrees toward the uninjured side. This view best profiles the posterior column and the anterior wall of the acetabulum.
Question 544
Topic: Pelvic & Acetabular Trauma
A patient presents with a suspected anterior column acetabular fracture. Which standard radiographic view best profiles the anterior column of the acetabulum and the posterior edge of the iliac wing?
Correct Answer & Explanation
. AP Pelvis
Explanation
The Judet iliac oblique view profiles the anterior column and the posterior wall of the acetabulum. The obturator oblique view profiles the posterior column and the anterior wall.
Question 545
Topic: Pelvic & Acetabular Trauma
A 35-year-old male is brought to the ED after a high-speed motorcycle collision. He is hypotensive with a blood pressure of 80/40 mmHg and a heart rate of 125 bpm. Secondary survey reveals an unstable pelvis. A pelvic binder is to be applied. What is the correct anatomical landmark for optimal placement of the pelvic binder to effectively reduce pelvic volume?
Correct Answer & Explanation
. Greater trochanters
Explanation
Pelvic binders are most effective at reducing pelvic volume and stabilizing the fracture when placed directly over the greater trochanters. Placing the binder too high (e.g., over the ASIS or iliac crests) is mechanically less effective and may paradoxically exacerbate the deformity.
Question 546
Topic: Pelvic & Acetabular Trauma
A 45-year-old obese female sustains a severe closed crush injury to her lateral thigh. Three weeks later, she presents with a fluctuant, painless mass over the greater trochanter. Aspiration yields serosanguinous fluid. What is the most definitive surgical management for this chronic lesion if conservative measures and simple drainage fail?
Correct Answer & Explanation
. Open excision of the pseudocapsule and dead space obliteration
Explanation
The clinical presentation describes a chronic Morel-Lavallée lesion, a closed degloving injury where subcutaneous tissue separates from the underlying fascia, creating a potential space that fills with hemolymph. Over time, a pseudocapsule forms, preventing adherence of tissue layers. When conservative measures fail, definitive treatment requires open excision of the pseudocapsule (capsulectomy) and closure of the dead space, often via quilting sutures or surgical drains.
Question 547
Topic: Pelvic & Acetabular Trauma
Emergency medical services bring in a hypotensive patient with a suspected 'open book' pelvic fracture. A pelvic binder was applied in the field. To effectively reduce pelvic volume and mechanically control hemorrhage, the binder should be centered precisely over which anatomical landmark?
Correct Answer & Explanation
. The iliac crests
Explanation
To optimally close an open-book pelvic ring injury and reduce intrapelvic volume (thereby creating a tamponade effect), the compressive force must be applied directly across the greater trochanters. Placing the binder too high (over the iliac crests or ASIS) compresses the false pelvis, failing to stabilize the true pelvic ring and potentially paradoxically opening the symphysis further.
Question 548
Topic: Pelvic & Acetabular Trauma
A 28-year-old male involved in a high-speed motor vehicle collision sustains an anteroposterior compression type III (APC-III) pelvic ring injury. After successful hemodynamic resuscitation and application of a pelvic binder, what is the most appropriate definitive orthopedic management?
Correct Answer & Explanation
. Both anterior symphyseal fixation and posterior pelvic ring stabilization
Explanation
An APC-III pelvic ring injury is rotationally and vertically unstable, characterized by complete disruption of the pubic symphysis (or rami) anteriorly, and complete disruption of the anterior and posterior sacroiliac ligaments posteriorly. Definitive management necessitates stabilization of both the anterior and posterior ring to restore stability and pelvic volume.
Question 549
Topic: Pelvic & Acetabular Trauma
On the standard AP pelvis radiograph of a 40-year-old male trauma patient, the iliopectineal line is disrupted, but the ilioischial line and the posterior wall margin remain intact. According to the Letournel and Judet classification, which structural component of the acetabulum is fractured?
Correct Answer & Explanation
. Anterior column
Explanation
The radiographic lines of the acetabulum on an AP pelvis view correlate with specific anatomical structures. The iliopectineal line represents the anterior column, and the ilioischial line represents the posterior column. Disruption of the iliopectineal line with an intact ilioischial line indicates an isolated anterior column fracture.
Question 550
Topic: Pelvic & Acetabular Trauma
A 45-year-old male is brought to the ED after a high-speed MVC. He is hypotensive (BP 80/50). Pelvic radiograph shows an APC-III injury. Where is the most appropriate anatomical landmark to center a pelvic binder?
Correct Answer & Explanation
. Greater trochanters
Explanation
A pelvic binder should be centered over the greater trochanters to effectively close the pelvic ring, particularly in anteroposterior compression (APC) injuries. Placing it over the iliac crests is a common error and is less effective mechanically, as it does not adequately reduce the symphysis.
Question 551
Topic: Pelvic & Acetabular Trauma
A 28-year-old pregnant female at 32 weeks gestation sustains an unstable anteroposterior compression (APC III) pelvic ring injury following a motor vehicle collision. She is hemodynamically unstable despite initial aggressive fluid resuscitation. What is the best initial step regarding the management of her pelvic injury?
Correct Answer & Explanation
. Application of a pelvic binder at the level of the greater trochanters
Explanation
In a hemodynamically unstable pregnant patient with an open-book pelvic fracture, mechanical stabilization of the pelvis is a priority and can be safely achieved with a pelvic binder. The binder must be placed accurately at the level of the greater trochanters, which will effectively reduce the pelvic volume without directly compressing the gravid uterus.
Question 552
Topic: Pelvic & Acetabular Trauma
During the ilioinguinal approach for an anterior column acetabulum fracture, massive arterial bleeding is encountered on the posterior aspect of the superior pubic ramus. Which vascular structure is most likely injured?
Correct Answer & Explanation
. The anastomosis between the external iliac artery and the obturator artery
Explanation
Massive bleeding in this location is classic for injury to the corona mortis (crown of death). It is an arterial or venous anastomosis between the external iliac (or inferior epigastric) vessels and the obturator vessels located on the posterior aspect of the superior pubic ramus, typically about 5-6 cm from the pubic symphysis.
Question 553
Topic: Pelvic & Acetabular Trauma
Which of the following pelvic ring injury patterns is most highly associated with a massive retroperitoneal hemorrhage requiring angiographic embolization?
Correct Answer & Explanation
. Anteroposterior compression type III (APC-III)
Explanation
APC-III (open book) pelvic fractures involve complete disruption of the symphysis pubis and both the anterior and posterior sacroiliac ligaments, leading to massive pelvic volume expansion. This pattern is highly associated with severe retroperitoneal venous and arterial hemorrhage. The internal pudendal and superior gluteal arteries are frequently injured. Angiography is often required if the patient remains hemodynamically unstable despite mechanical stabilization.
Question 554
Topic: Pelvic & Acetabular Trauma
A 32-year-old male arrives in the trauma bay hemodynamically unstable following a crush injury. Radiographs show a widened pubic symphysis consistent with an APC-II (open book) pelvic ring injury. A decision is made to apply a pelvic binder. To maximize mechanical advantage and effectively reduce the pelvic volume, over which specific anatomic landmark should the binder be centered?
Correct Answer & Explanation
. Anterior superior iliac spines (ASIS)
Explanation
To effectively reduce pelvic volume and stabilize an 'open book' pelvic fracture, a pelvic binder (or sheet) must be centered directly over the greater trochanters of the femurs. Placing it higher, over the iliac crests or ASIS, can ironically act as a fulcrum to splay the pelvis further open and fails to provide adequate compression to the posterior pelvic ring.
Question 555
Topic: Pelvic & Acetabular Trauma
The primary soft-tissue stabilizer of the posterior pelvic ring, providing the strongest resistance against vertical shear forces, is the:
Correct Answer & Explanation
. Anterior sacroiliac ligament
Explanation
The interosseous sacroiliac ligament is the strongest ligament in the body. It bridges the irregular articular surfaces of the sacrum and ilium and is the primary stabilizer of the posterior pelvic ring, providing the major resistance to vertical shear forces.
Question 556
Topic: Pelvic & Acetabular Trauma
A 24-year-old hockey player presents with anterior groin pain exacerbated by hip flexion and internal rotation. Radiographs demonstrate a prominent alpha angle.
Which of the following is the most likely location of the associated labral or chondral pathology in this condition?
Correct Answer & Explanation
. Anterosuperior quadrant of the acetabulum
Explanation
Cam impingement typically causes chondral delamination and labral tears in the anterosuperior quadrant of the acetabulum (clock face 1 to 3 o'clock). The abnormal morphology of the femoral head-neck junction is forced into the joint during flexion and internal rotation.
Question 557
Topic: Pelvic & Acetabular Trauma
When applying a non-invasive pelvic binder for a hemodynamically unstable patient with a suspected pelvic ring disruption, what is the correct anatomical landmark for placement?
Correct Answer & Explanation
. Level of the iliac crests
Explanation
Pelvic binders must be centered over the greater trochanters to provide an effective inward compressive force to reduce pelvic volume. Placement over the iliac crests is ineffective and can worsen some injuries.
Question 558
Topic: Pelvic & Acetabular Trauma
A 45-year-old male presents after a motorcycle collision with hemodynamic instability. Clinical evaluation and radiographs demonstrate an open book pelvic injury (APC-III). To effectively reduce pelvic volume and control hemorrhage, where should the circumferential pelvic binder be centered?
Correct Answer & Explanation
. Over the greater trochanters
Explanation
A pelvic binder must be placed at the level of the greater trochanters to effectively close the pelvic ring and reduce volume. Placement over the iliac crests or higher is ineffective and may paradoxically worsen the open book deformity.
Question 559
Topic: Pelvic & Acetabular Trauma
A 35-year-old male is brought into the trauma bay following a high-speed motor vehicle collision. He is hemodynamically unstable with a blood pressure of 80/40 mmHg and heart rate of 120 bpm. Pelvic radiographs reveal an anteroposterior compression type III (APC-III) pelvic ring injury. A pelvic binder is immediately applied. What is the most appropriate anatomical landmark for the optimal placement of the pelvic binder?
Correct Answer & Explanation
. Greater trochanters
Explanation
Pelvic binders should be centered over the greater trochanters to effectively close the pelvic volume and stabilize the symphysis pubis. Placement over the iliac crests is a common error and can paradoxically open the pelvis further.
Question 560
Topic: Pelvic & Acetabular Trauma
A 25-year-old male presents after a motorcycle collision with a pelvic ring injury. AP radiograph shows 3 cm of pubic symphysis diastasis and widening of the anterior sacroiliac joints. The posterior SI joints are intact. What is the most appropriate definitive management?
Correct Answer & Explanation
. Spanning external fixation
Explanation
This is an APC-II injury characterized by diastasis >2.5 cm, torn anterior SI ligaments, and intact posterior SI ligaments. Definitive management is anterior stabilization, typically achieved with symphyseal plating.
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