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Pelvic & Acetabular Trauma MCQs

Practice Set 19 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 361

Topic: Pelvic & Acetabular Trauma

A 35-year-old male is brought to the ED after a motorcycle crash. His blood pressure is 80/40 mmHg and heart rate is 120 bpm. Primary survey reveals an unstable pelvis. A pelvic binder is applied. Which of the following is the most appropriate anatomical landmark for the correct placement of a pelvic binder to optimize reduction and control hemorrhage?

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

Correct Answer & Explanation

. Greater trochanters

Explanation

Pelvic binders should be placed centered over the greater trochanters to effectively close the pelvic volume and stabilize the pelvic ring. Placement over the iliac crests is a common error and fails to adequately close the symphysis.

Question 362

Topic: Pelvic & Acetabular Trauma
A hemodynamically unstable trauma patient presents with an anterior-posterior compression (APC) type III pelvic ring injury. The trauma team decides to apply a noninvasive pelvic binder. What is the correct anatomical landmark for placing the center of the binder to optimally reduce pelvic volume?
. Anterior superior iliac spines (ASIS)
. Iliac crests
. Greater trochanters
. Pubic symphysis
. Femoral neck

Correct Answer & Explanation

. Greater trochanters

Explanation

A pelvic binder should be centered over the greater trochanters to effectively compress the pelvic ring and reduce volume in open-book injuries. Placement over the iliac crests is incorrect as it can paradoxically widen the pubic symphysis.

Question 363

Topic: Pelvic & Acetabular Trauma
A hemodynamically unstable patient with an anterior-posterior compression (APC) type III pelvic ring injury transiently responds to fluid resuscitation. A pelvic binder has been appropriately placed, but the patient's blood pressure begins to drop again. FAST exam is negative. What is the most appropriate next step in management?
. Emergent exploratory laparotomy
. Preperitoneal pelvic packing and/or pelvic angioembolization
. CT scan of the abdomen and pelvis
. Removal of the pelvic binder and application of an external fixator
. Diagnostic peritoneal lavage (DPL)

Correct Answer & Explanation

. Preperitoneal pelvic packing and/or pelvic angioembolization

Explanation

In a hemodynamically unstable pelvic fracture patient with a negative FAST exam (ruling out massive intra-abdominal hemorrhage), the bleeding is likely retroperitoneal. Preperitoneal pelvic packing or angioembolization is the standard of care to achieve hemostasis.

Question 364

Topic: Pelvic & Acetabular Trauma

A 45-year-old male presents in hemorrhagic shock following a motorcycle collision. An anteroposterior pelvic radiograph demonstrates a symphyseal diastasis of 4 cm. What is the most appropriate anatomic landmark for the placement of a circumferential pelvic sheet or commercial binder to ensure optimal mechanical reduction?

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

Correct Answer & Explanation

. Greater trochanters

Explanation

Pelvic binders should be centered over the greater trochanters to effectively close an anterior ring disruption. Placement over the iliac crests is less mechanically efficient and can inadvertently worsen the displacement.

Question 365

Topic: Pelvic & Acetabular Trauma

During an anterior intrapelvic (modified Stoppa) approach to the acetabulum, the obturator nerve is visualized before it exits the pelvis. In relation to the deep pelvic musculature, what is the expected path of the obturator nerve as it heads toward the obturator canal?

. Superficial to the obturator internus fascia
. Between the obturator internus and levator ani
. Above the superior gemellus
. Inferior to the piriformis
. Piercing directly through the obturator externus

Correct Answer & Explanation

. Superficial to the obturator internus fascia

Explanation

Within the true pelvis, the obturator nerve courses along the lateral pelvic wall, running superficial to the obturator internus fascia, before exiting the pelvis via the obturator canal to enter the medial thigh.

Question 366

Topic: Pelvic & Acetabular Trauma

A 5-year-old girl with residual hip dysplasia following previous closed reduction requires a redirectional pelvic osteotomy. The surgeon opts for an osteotomy that hinges at the symphysis pubis to improve anterolateral coverage. Which of the following osteotomies is planned?

. Pemberton osteotomy
. Dega osteotomy
. Salter innominate osteotomy
. Chiari osteotomy
. Shelf arthroplasty

Correct Answer & Explanation

. Salter innominate osteotomy

Explanation

The Salter innominate osteotomy is a complete transiliac cut that hinges at the pubic symphysis to provide anterolateral coverage. In contrast, the Pemberton osteotomy hinges at the triradiate cartilage.

Question 367

Topic: Pelvic & Acetabular Trauma

A 5-year-old girl with persistent acetabular dysplasia following successful closed reduction of DDH at age 1 is planned for pelvic osteotomy. The surgeon opts for a Pemberton osteotomy over a Salter osteotomy. Which of the following is the primary biomechanical difference between a Pemberton and a Salter osteotomy?

. Pemberton is a complete cut through the innominate bone relying on the pubic symphysis as a hinge
. Pemberton decreases acetabular volume by hinging through the triradiate cartilage
. Salter hinges through the sacroiliac joint to provide anterior coverage
. Salter requires an intact triradiate cartilage to achieve mobility
. Pemberton provides only lateral coverage without improving anterior coverage

Correct Answer & Explanation

. Pemberton decreases acetabular volume by hinging through the triradiate cartilage

Explanation

The Pemberton osteotomy is an incomplete pericapsular cut that hinges on the flexible triradiate cartilage, altering the shape and decreasing the volume of the acetabulum. The Salter osteotomy is a complete cut through the ilium that redirects the entire acetabulum, hinging at the pubic symphysis without changing acetabular volume.

Question 368

Topic: Pelvic & Acetabular Trauma

A 4-year-old girl requires a pelvic osteotomy for residual acetabular dysplasia following prior closed reduction. The planned procedure aims to change the acetabular volume by hinging through the flexible triradiate cartilage. Which osteotomy fits this description?

. Salter osteotomy
. Pemberton osteotomy
. Steel triple osteotomy
. Chiari osteotomy
. Ganz periacetabular osteotomy

Correct Answer & Explanation

. Pemberton osteotomy

Explanation

The Pemberton osteotomy is an incomplete, pericapsular osteotomy that hinges on the triradiate cartilage, reducing acetabular volume and improving anterolateral coverage. In contrast, the Salter osteotomy is a complete innominate osteotomy that hinges at the pubic symphysis.

Question 369

Topic: Pelvic & Acetabular Trauma

A 5-year-old girl with an untreated developmental dysplasia of the left hip requires an open reduction and pelvic osteotomy. The surgeon plans a redirectional osteotomy that hinges at the pubic symphysis to improve anterolateral coverage. Which of the following osteotomies is being described?

. Pemberton osteotomy
. Dega osteotomy
. Salter osteotomy
. Chiari osteotomy
. Shelf osteotomy

Correct Answer & Explanation

. Salter osteotomy

Explanation

The Salter innominate osteotomy is a redirectional osteotomy that hinges at the pubic symphysis, primarily providing anterior and lateral coverage. The Pemberton and Dega are incomplete, reshaping osteotomies that hinge at the flexible triradiate cartilage.

Question 370

Topic: Pelvic & Acetabular Trauma

A 4-year-old girl with residual DDH requires an open reduction and pelvic osteotomy. The surgeon plans a Salter innominate osteotomy. This osteotomy relies on a hinge at which of the following structures to provide anterolateral coverage?

. Triradiate cartilage
. Sacroiliac joint
. Pubic symphysis
. Ischial spine
. Obturator foramen

Correct Answer & Explanation

. Pubic symphysis

Explanation

The Salter osteotomy is a complete, redirectional transiliac osteotomy that redirects the entire acetabulum to improve anterolateral coverage. It hinges symmetrically on the pubic symphysis to achieve its corrective rotation.

Question 371

Topic: Pelvic & Acetabular Trauma

When evaluating a 4-week-old infant's hip using Graf's ultrasound method, an alpha angle of 45 degrees is noted. What does this angle primarily measure?

. Cartilaginous roof coverage
. Bony roof acetabular depth
. Femoral head sphericity
. Labral version
. Capsular laxity

Correct Answer & Explanation

. Cartilaginous roof coverage

Explanation

The alpha angle reflects the bony concavity (roof) of the acetabulum, with a normal angle being greater than 60 degrees. An alpha angle of 45 degrees indicates significant bony dysplasia. The beta angle measures the cartilaginous roof coverage.

Question 372

Topic: Pelvic & Acetabular Trauma

A 4-year-old girl with untreated DDH is scheduled for open reduction and an innominate osteotomy. The planned procedure involves a complete transiliac osteotomy that redirects the entire acetabulum by hinging on the pubic symphysis. Which osteotomy is being described?

. Pemberton osteotomy
. Dega osteotomy
. Salter osteotomy
. Chiari osteotomy
. Shelf procedure

Correct Answer & Explanation

. Salter osteotomy

Explanation

The Salter osteotomy is a complete transiliac osteotomy that redirects the acetabulum to improve anterolateral coverage, hinging at the pubic symphysis. Pemberton and Dega are incomplete osteotomies that hinge on the triradiate cartilage.

Question 373

Topic: Pelvic & Acetabular Trauma

On an anteroposterior (AP) pelvis radiograph of a normal 6-month-old infant, the femoral head ossific nucleus should be located in the inferomedial quadrant formed by the intersection of which two radiographic lines?

. Shenton's and Perkin's lines
. Hilgenreiner's and Perkin's lines
. Klein's and Shenton's lines
. Wiberg's angle and Hilgenreiner's line
. Southwick's and Perkin's lines

Correct Answer & Explanation

. Hilgenreiner's and Perkin's lines

Explanation

Hilgenreiner's line (horizontal through triradiate cartilages) and Perkin's line (vertical from the lateral margin of the acetabulum) divide the hip into quadrants. In a normal hip, the ossific nucleus sits in the inferomedial quadrant.

Question 374

Topic: Pelvic & Acetabular Trauma

A 4-year-old girl presents with a persistently subluxated right hip following previous treatment for DDH. A pelvic osteotomy is planned to improve anterolateral acetabular coverage. Which of the following osteotomies hinges at the triradiate cartilage and decreases the volume of the acetabulum?

. Salter osteotomy
. Pemberton osteotomy
. Steel triple osteotomy
. Chiari osteotomy
. Ganz (PAO) osteotomy

Correct Answer & Explanation

. Pemberton osteotomy

Explanation

The Pemberton osteotomy hinges at the flexible triradiate cartilage, allowing the acetabular roof to be hinged down, thus decreasing acetabular volume and improving anterolateral coverage. The Salter osteotomy hinges at the pubic symphysis and does not change acetabular volume.

Question 375

Topic: Pelvic & Acetabular Trauma

An 18-month-old girl undergoes an open reduction for a chronically dislocated developmental dysplasia of the hip (DDH). Intraoperatively, there is significant acetabular dysplasia with a steep, shallow acetabulum. Which pelvic osteotomy is most appropriate to provide anterolateral coverage by redirecting the acetabulum without reducing its volume?

. Pemberton osteotomy
. Dega osteotomy
. Salter innominate osteotomy
. Chiari osteotomy
. Ganz periacetabular osteotomy

Correct Answer & Explanation

. Salter innominate osteotomy

Explanation

The Salter osteotomy is a complete, redirectional innominate osteotomy that hinges on the pubic symphysis, improving anterolateral coverage without changing the volume or shape of the acetabulum itself. Pemberton and Dega are incomplete, volume-reducing osteotomies.

Question 376

Topic: Pelvic & Acetabular Trauma

A 4-year-old girl with residual acetabular dysplasia requires a pelvic osteotomy. The surgeon plans an incomplete transiliac osteotomy that hinges on the triradiate cartilage to decrease the volume and change the shape of the acetabulum. Which procedure is being described?

. Salter osteotomy
. Pemberton osteotomy
. Steel triple osteotomy
. Chiari osteotomy
. Bernese periacetabular osteotomy (PAO)

Correct Answer & Explanation

. Pemberton osteotomy

Explanation

The Pemberton osteotomy hinges on the open triradiate cartilage, allowing the surgeon to reshape the acetabulum and reduce its volume. In contrast, the Salter osteotomy hinges on the pubic symphysis and redirects the entire acetabular segment without altering its shape.

Question 377

Topic: Pelvic & Acetabular Trauma

A 45-year-old man is brought to the emergency department after a high-speed motor vehicle collision. He is hypotensive with a blood pressure of 80/40 mm Hg. A pelvic radiograph shows a severely displaced 'open-book' pelvic ring injury. A commercial pelvic binder is ordered. To be most effective, the binder should be centered over which of the following anatomic landmarks?

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

Correct Answer & Explanation

. Greater trochanters

Explanation

Pelvic binders should be centered over the greater trochanters to effectively reduce pelvic volume and control hemorrhage. Placement over the iliac crests or ASIS is less effective and can paradoxically widen the pelvic ring.

Question 378

Topic: Pelvic & Acetabular Trauma

A 45-year-old man is brought to the trauma bay in hemorrhagic shock following a motorcycle crash. A pelvic radiograph demonstrates an open-book pelvic ring injury.

What is the most appropriate anatomical landmark for the optimal placement of a circumferential pelvic sheet or binder?

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

Correct Answer & Explanation

. Greater trochanters

Explanation

A pelvic binder should be centered directly over the greater trochanters to effectively close the pelvic ring and reduce intrapelvic volume. Placement over the iliac crests is a common error that can fail to reduce the diastasis or paradoxically widen the pelvis.

Question 379

Topic: Pelvic & Acetabular Trauma

A 22-year-old construction worker falls from a height and sustains a vertical shear pelvic fracture. Radiographs show superior displacement of the right hemipelvis and avulsion of the right L5 transverse process. Which of the following ligamentous complexes are completely disrupted in this injury pattern?

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

Correct Answer & Explanation

. Anterior and posterior sacroiliac, sacrotuberous, and sacrospinous ligaments

Explanation

A vertical shear fracture pattern involves global instability of the hemipelvis. It necessitates the complete disruption of the anterior and posterior pelvic ring, including both the anterior and posterior sacroiliac ligaments, as well as the pelvic floor (sacrotuberous and sacrospinous ligaments).

Question 380

Topic: Pelvic & Acetabular Trauma

An anteroposterior (AP) radiograph of the pelvis is obtained for a 60-year-old woman who fell from a ladder. The film demonstrates an isolated disruption of the iliopectineal line with a completely intact ilioischial line. Which acetabular structure is fractured?

. Anterior column
. Posterior column
. Anterior wall
. Posterior wall

Correct Answer & Explanation

. Anterior column

Explanation

On an AP radiograph of the pelvis, the iliopectineal line correlates anatomically with the anterior column of the acetabulum, while the ilioischial line correlates with the posterior column.

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