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Pelvic & Acetabular Trauma MCQs

Practice Set 12 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 221

Topic: Pelvic & Acetabular Trauma
According to the Young-Burgess classification, which injured ligamentous structure differentiates an Anteroposterior Compression Type III (APC-III) pelvic ring injury from an APC-II injury?
. Anterior sacroiliac ligaments
. Sacrotuberous ligament
. Sacrospinous ligament
. Symphyseal ligaments
. Posterior sacroiliac ligaments

Correct Answer & Explanation

. Posterior sacroiliac ligaments

Explanation

In the Young-Burgess classification, an APC-II injury involves disruption of the pubic symphysis, anterior sacroiliac ligaments, sacrospinous, and sacrotuberous ligaments, causing an 'open book' pelvis with rotational instability but preserved vertical stability. An APC-III injury includes all the above plus disruption of the strong posterior sacroiliac ligaments, resulting in both rotational and complete vertical instability.

Question 222

Topic: Pelvic & Acetabular Trauma

During a Bernese periacetabular osteotomy (PAO) for symptomatic developmental dysplasia of the hip, the posterior column of the pelvis is deliberately preserved to maintain pelvic stability and allow for early mobilization. Which of the following osteotomy cuts is NOT performed during a standard PAO?

. Incomplete osteotomy of the ischium
. Complete osteotomy of the superior pubic ramus
. Complete transverse osteotomy of the ilium
. Complete osteotomy of the posterior column of the ischium
. Osteotomy of the anterior aspect of the acetabulum

Correct Answer & Explanation

. Complete osteotomy of the posterior column of the ischium

Explanation

The Bernese periacetabular osteotomy (PAO) reorients the acetabulum while preserving the mechanical integrity of the pelvic ring. This is achieved by keeping the posterior column of the hemipelvis intact. Therefore, a complete osteotomy of the posterior column is NOT performed. The cuts include an incomplete ischial osteotomy (stopping short of the posterior column), a complete pubic root osteotomy, and an incomplete iliac osteotomy that joins the ischial cut, freeing the acetabular fragment while maintaining posterior pelvic continuity.

Question 223

Topic: Pelvic & Acetabular Trauma

A 25-year-old man is brought in hypotensive after a motorcycle crash. Pelvic radiographs reveal a 4 cm diastasis of the pubic symphysis and disruption of the anterior sacroiliac joints, but intact posterior sacroiliac ligaments. What is the most appropriate initial management for his hemodynamic instability?

. Immediate open reduction and internal fixation of the symphysis
. Application of a pelvic binder centered over the iliac crests
. Application of a pelvic binder centered over the greater trochanters
. Bilateral internal iliac artery embolization
. External fixation using iliac crest pins

Correct Answer & Explanation

. Application of a pelvic binder centered over the greater trochanters

Explanation

This is an anteroposterior compression (APC) Type II injury resulting in an open-book pelvis and increased pelvic volume. A pelvic binder should be applied immediately and centered over the greater trochanters to effectively close the pelvic ring and aid in hemorrhage control.

Question 224

Topic: Pelvic & Acetabular Trauma
A hemodynamically unstable 35-year-old male sustains an anteroposterior compression type III (APC-III) pelvic ring injury. A circumferential pelvic binder is applied in the trauma bay. To optimally reduce the pelvic volume and stabilize the fracture, the binder should be centered over which anatomic landmark?
. Anterior superior iliac spines
. Iliac crests
. Greater trochanters
. Pubic symphysis
. Ischial tuberosities

Correct Answer & Explanation

. Greater trochanters

Explanation

A pelvic binder must be centered directly over the greater trochanters to effectively close the pelvic ring and reduce pelvic volume. Placement over the iliac crests or ASIS can paradoxically open the pelvis further and exacerbate hemorrhage.

Question 225

Topic: Pelvic & Acetabular Trauma

Figure 36 shows the hip arthrogram of a newborn. Which of the following structures is enclosed by the circle?

Anatomy 2005 Practice Questions: Set 3 (Solved) - Figure 18

. Limbus
. Pulvinar
. Ligamentum teres
. Transverse acetabular ligament
. Acetabular labrum

Correct Answer & Explanation

. Acetabular labrum

Explanation

The structure enclosed by the circle is the acetabular labrum. It is visible as the white point of tissue outlined by the darkly radiopaque contrast. The appearance of the contrast surrounding the sharp white point of a normal labrum is called the "rose thorn sign." The limbus is the term reserved for a rounded, infolded labrum seen with arthrography. The pulvinar is the fatty tissue seen in the empty acetabulum when the hip is dislocated. The ligamentum teres is seen as a white stripe outlined by contrast coursing from the central acetabulum to the dislocated femoral head. The transverse acetabular ligament courses across the inferior portion of the acetabulum and is not clearly seen with arthrography. Herring JA: Tachdjian's Pediatric Orthopaedics, ed 3. Philadelphia, PA, WB Saunders, 2002, vol 1, pp 532-533.

Question 226

Topic: Pelvic & Acetabular Trauma

In the treatment of acetabular dysplasia, what type of pelvic osteotomy leaves the "teardrop" in its original position and redirects the acetabulum?

Hip 2004 Practice Questions: Set 1 (Solved) - Figure 26

. Steel
. Chiari
. Ganz periacetabular
. Dial or spherical
. Salter innominate

Correct Answer & Explanation

. Dial or spherical

Explanation

The dial or spherical osteotomy leaves the medial wall or teardrop in its original position and, as a result, is intra-articular. The other pelvic osteotomies (except Chiari) redirect the acetabulum, including the medial wall. The Chiari osteotomy improves coverage without redirecting the acetabulum within the pelvis, and it leaves the teardrop in the same place. Lack W, Windhager R, Kutschera HP, Engel A: Chiari pelvic osteotomy for osteoarthritis secondary to hip dysplasia: Indications and long-term results. J Bone Joint Surg Br 1991;73:229-234. Ganz R, Klaue K, Vinh TS, Mast JW: A new periacetabular osteotomy for the treatment of hip dysplasias: Technique and preliminary results. Clin Orthop 1988;232:26-36.

Question 227

Topic: Pelvic & Acetabular Trauma
Figure 2a shows the radiograph of a 48-year-old man who was involved in a motorcycle accident. A CT scan is shown in Figure 2b. The patient underwent pelvic angiography for persistent hypotension despite resuscitation. What vessel is most likely to be injured?
. Internal iliac
. External iliac
. Pudendal
. Superior rectal
. Superior gluteal

Correct Answer & Explanation

. Superior gluteal

Explanation

The pelvic injury is a severe anterior-posterior compression III or Tile C injury. The vessel most likely injured is the superior gluteal artery, but several arterial bleeding sources are likely. Vertical shear injuries can also injure this vessel, but it is much less common.

Question 228

Topic: Pelvic & Acetabular Trauma

Figures 28a through 28c show the MRI scans of a 30-year-old woman who weighs 290 lb and has low back and left leg pain. She also reports frequent urinary dribbling, which her gynecologist has advised her may be related to obesity. Examination will most likely reveal

. ipsilateral weakness of the tibialis anterior.
. ipsilateral weakness of the peroneus longus and brevis.
. ipsilateral weakness of the extensor hallucis longus.
. a positive Beevor's sign.
. a positive ipsilateral Gaenslen's sign.

Correct Answer & Explanation

. ipsilateral weakness of the tibialis anterior.

Explanation

The patient will most likely exhibit ipsilateral weakness of the tibialis anterior. Gaenslen's test is designed to detect sacroiliac inflammation as a source of low back pain. Beevor's sign tests the innervation of the rectus abdominus and paraspinal musculature (L1 innervation). The extensor hallucis longus is predominantly innervated by L5. The peroneals are predominantly innervated by S1. Hoppenfeld S: Physical Examination of the Spine and Extremities. Appleton, WI, Century-Crofts, 1976.

Question 229

Topic: Pelvic & Acetabular Trauma

Which of the following conditions is associated with palmoplantar pustulosis?

Upper Extremity Board Review 2008: High-Yield MCQs (Set 2) - Figure 6

. Condensing osteitis
. Sternoclavicular hyperostosis
. Friedreich's disease
. Scleroderma
. Reiter syndrome

Correct Answer & Explanation

. Sternoclavicular hyperostosis

Explanation

Sternoclavicular hyperotosis is a seronegative and HLA-B27 negative rheumatic disease. In this condition, hyperostosis may appear in the spine, long bones, sacroiliac joints, and the sternoclavicular region. This entity is also associated with palmoplantar pustulosis. Wirth MA, Rockwood CA: Disorders of the sternoclavicular joint, in Rockwood CA, Matsen FA, Wirth MA, et al (eds): The Shoulder. Philadelphia, PA, WB Saunders, 2004, vol 2, pp 608-609.

Question 230

Topic: Pelvic & Acetabular Trauma

A patient with severe rheumatoid arthritis reports progressive hip pain. Serial hip radiographs will most likely show which of the following findings?

. Asymmetric joint space narrowing
. Sacroiliac joint ankylosis
. Progressive superior and lateral migration of the femoral head
. Periarticular osteopenia
. Hip synovitis

Correct Answer & Explanation

. Progressive superior and lateral migration of the femoral head

Explanation

Radiographic findings in patients with rheumatoid arthritis include symmetric joint space narrowing, periacetabular and femoral head erosions, and diffuse periarticular osteopenia. In advanced stages, protrusio acetabuli is a common finding. Ranawat and associates have shown a rate of superior femoral head migration of 4.5 mm per year and medial (axial) migration of 2.5 mm per year. Asymmetric joint space narrowing is a classic radiographic finding of degenerative arthrosis. Sacroiliac joint ankylosis commonly occurs in ankylosing spondylitis. Hip synovitis is a pathologic diagnosis, not a radiographic finding. Lachiewicz PF: Rheumatoid arthritis of the hip. J Am Acad Orthop Surg 1997;5:332-338.

Question 231

Topic: Pelvic & Acetabular Trauma

A 30-year-old male is involved in a motorcycle collision. Radiographs demonstrate a displaced symphysis pubis (3.5 cm) and widening of the left sacroiliac joint. He remains hypotensive despite 2 liters of crystalloid and 2 units of packed RBCs. A pelvic binder was properly placed in the field. What is the most appropriate next step in management?

. CT scan of the abdomen and pelvis
. Open reduction and internal fixation of the symphysis pubis
. Pre-peritoneal pelvic packing and/or angioembolization
. Application of an external fixator
. Exploratory laparotomy

Correct Answer & Explanation

. Pre-peritoneal pelvic packing and/or angioembolization

Explanation

In a hemodynamically unstable patient with a pelvic ring injury, despite initial resuscitation and mechanical stabilization (pelvic binder), the immediate priority is hemorrhage control. This is best achieved via pre-peritoneal pelvic packing or angioembolization, depending on institutional protocol. CT is contraindicated in hemodynamically unstable patients.

Question 232

Topic: Pelvic & Acetabular Trauma
A 45-year-old male presents after a high-speed crush injury to the pelvis. Imaging demonstrates an Anteroposterior Compression Type III (APC-III) pelvic ring disruption with severe pubic symphysis diastasis and bilateral sacroiliac joint disruption. Severe hemodynamic instability in this specific fracture pattern is most frequently due to disruption of which of the following structures?
. Superior gluteal artery
. Internal pudendal artery
. External iliac artery
. Posterior venous plexus
. Corona mortis

Correct Answer & Explanation

. Posterior venous plexus

Explanation

The vast majority (80-90%) of major hemorrhage in pelvic ring injuries is venous in origin, particularly from the pre-sacral (posterior) venous plexus. If an arterial source is present, Anteroposterior Compression (APC) patterns classically injure branches of the anterior division of the internal iliac artery (such as the pudendal or obturator arteries), whereas Lateral Compression (LC) injuries more commonly injure the posterior division branches, specifically the superior gluteal artery.

Question 233

Topic: Pelvic & Acetabular Trauma
An 18-year-old pedestrian is struck by a motor vehicle and sustains a severe pelvic ring injury. AP, inlet, and outlet radiographs suggest an anteroposterior compression (APC) mechanism. According to the Young-Burgess classification system, an APC Type III injury is fundamentally distinguished from an APC Type II injury by the complete disruption of which of the following specific structures?
. Symphysis pubis
. Anterior sacroiliac ligaments
. Posterior sacroiliac ligaments
. Sacrotuberous ligament
. Sacrospinous ligament

Correct Answer & Explanation

. Posterior sacroiliac ligaments

Explanation

In the Young-Burgess classification, anteroposterior compression (APC) injuries follow a progressive pattern of ligamentous disruption. APC I features symphyseal widening <2.5 cm with intact posterior ligaments. APC II features symphyseal widening >2.5 cm, complete disruption of the anterior sacroiliac, sacrospinous, and sacrotuberous ligaments, but crucially, the strong posterior sacroiliac ligaments remain intact, allowing the hemipelvis to open like a book (rotationally unstable but vertically stable). APC III involves complete disruption of both the anterior and posterior sacroiliac ligaments, completely dissociating the hemipelvis from the sacrum (both rotationally and vertically unstable).

Question 234

Topic: Pelvic & Acetabular Trauma
In the Young-Burgess classification, an anteroposterior compression Type II (APC-II) pelvic ring injury is characterized by a symphyseal diastasis or longitudinal rami fractures and widening of the sacroiliac joint. Which of the following best describes the status of the posterior pelvic ligaments in an APC-II injury?
. Both anterior and posterior sacroiliac ligaments are ruptured
. Anterior sacroiliac ligaments are ruptured, while the posterior sacroiliac ligaments remain intact
. Both anterior and posterior sacroiliac ligaments are intact
. Sacrospinous ligaments are intact, but sacrotuberous ligaments are ruptured
. Posterior sacroiliac ligaments are ruptured, while the anterior sacroiliac ligaments remain intact

Correct Answer & Explanation

. Anterior sacroiliac ligaments are ruptured, while the posterior sacroiliac ligaments remain intact

Explanation

An APC-II injury involves disruption of the symphysis pubis (or vertical rami fractures) along with widening of the anterior sacroiliac joint. This anterior widening signifies rupture of the anterior sacroiliac ligaments and the sacrotuberous/sacrospinous ligaments, but the posterior sacroiliac ligaments remain intact. Because the strong posterior SI ligaments are intact, the pelvis is rotationally unstable but vertically stable. An APC-III injury occurs when the posterior SI ligaments also rupture, leading to global instability.

Question 235

Topic: Pelvic & Acetabular Trauma
A 45-year-old female presents in hemorrhagic shock after a severe crush injury. Pelvic radiographs show an APC-III pelvic ring injury (diastasis of the symphysis pubis and bilateral SI joint disruption). A pelvic binder is applied and fluid resuscitation initiated, but she remains hemodynamically unstable. In this clinical scenario, what is the most statistically likely source of her pelvic hemorrhage?
. Superior gluteal artery
. Obturator artery
. Internal pudendal artery
. Presacral venous plexus
. External iliac artery

Correct Answer & Explanation

. Presacral venous plexus

Explanation

Venous bleeding accounts for 80-90% of all pelvic hemorrhage in pelvic ring injuries. The presacral venous plexus and prevesical veins are the most common sources. While arterial bleeding (from the superior gluteal, pudendal, or obturator arteries) can be severe, brisk, and often requires angioembolization, the venous plexus is overwhelmingly the most likely overall source of bleeding.

Question 236

Topic: Pelvic & Acetabular Trauma
A 45-year-old female pedestrian is struck by a bus and presents hemodynamically unstable in the trauma bay. A pelvic radiograph shows a severely displaced anterior-posterior compression (APC-III) pelvic ring injury with a widened pubic symphysis. A pelvic binder is immediately applied to reduce pelvic volume. To maximize biomechanical efficacy and achieve optimal reduction of the symphysis, the binder should be centered exactly over which anatomic landmark?
. The iliac crests
. The anterior superior iliac spines (ASIS)
. The greater trochanters
. The pubic symphysis
. The umbilicus

Correct Answer & Explanation

. The greater trochanters

Explanation

In the emergent management of open-book pelvic fractures (APC injuries), a pelvic binder or sheet must be centered directly over the greater trochanters of the femur. This placement efficiently translates compressive forces across the pelvic ring, closing the pubic symphysis and reducing pelvic volume to help tamponade venous and cancellous bone bleeding. Placing the binder too high (over the iliac crests) can paradoxically widen the pelvic outlet or fail to compress the true pelvis.

Question 237

Topic: Pelvic & Acetabular Trauma

A 25-year-old male is brought to the emergency department after a high-speed motorcycle collision. He is hemodynamically unstable. A pelvic binder is appropriately placed. Radiographs reveal a rotationally unstable but vertically stable pelvic ring injury with symphyseal widening greater than 2.5 cm (APC-II pattern).

Which of the following ligaments is predominantly disrupted at the sacroiliac joint in this specific injury pattern?

. Anterior sacroiliac ligament
. Posterior sacroiliac ligament
. Sacrotuberous ligament
. Sacrospinous ligament
. Iliofemoral ligament

Correct Answer & Explanation

. Anterior sacroiliac ligament

Explanation

An Anteroposterior Compression Type II (APC-II) injury involves diastasis of the pubic symphysis > 2.5 cm, with disruption of the anterior sacroiliac, sacrotuberous, and sacrospinous ligaments. The posterior sacroiliac ligaments remain intact, maintaining vertical stability. Thus, at the sacroiliac joint, the anterior sacroiliac ligament is the one disrupted.

Question 238

Topic: Pelvic & Acetabular Trauma
A 35-year-old male sustains a severe crushing injury to his pelvis. Examination reveals a large, fluctuant swelling over the greater trochanter with ecchymosis. Aspiration of the lesion yields serosanguinous fluid with fat globules. Which of the following is the most appropriate definitive management for a large, chronic lesion of this type?
. Immediate open debridement and primary closure
. Percutaneous aspiration
. Open debridement and delayed closure or secondary intention
. Observation
. Sclerotherapy

Correct Answer & Explanation

. Open debridement and delayed closure or secondary intention

Explanation

A Morel-Lavallรฉe lesion is a closed degloving injury. Chronic lesions with a mature capsule often require open debridement, capsulectomy, and either delayed closure, use of dead-space management, or secondary intention, as simple aspiration has a high recurrence rate.

Question 239

Topic: Pelvic & Acetabular Trauma



A 32-year-old male is brought to the trauma bay following a high-speed motorcycle collision. He is hemodynamically unstable. An anteroposterior radiograph of the pelvis demonstrates a 'symphysis pubis diastasis of 4 cm and disruption of the anterior sacroiliac ligaments with intact posterior ligaments' (an APC II injury). During surgical exploration to control hemorrhage, brisk arterial bleeding is encountered posterior to the superior pubic ramus. This vessel is most likely an anastomosis between which two vascular distributions?

. Internal pudendal and superior gluteal arteries
. Inferior epigastric (or external iliac) and obturator arteries
. Superior mesenteric and inferior mesenteric arteries
. Internal iliac and median sacral arteries
. Femoral and superficial circumflex iliac arteries

Correct Answer & Explanation

. Inferior epigastric (or external iliac) and obturator arteries

Explanation

The vessel described is the 'corona mortis' (crown of death). It is an anatomic variant anastomosis between the external iliac or inferior epigastric system and the obturator artery (internal iliac system). It traverses over the superior pubic ramus at an average distance of 4 to 5 cm from the pubic symphysis. Disruption of this vascular connection during high-energy pelvic trauma, particularly anterior ring injuries, can lead to severe, life-threatening hemorrhage.

Question 240

Topic: Pelvic & Acetabular Trauma
According to the Young-Burgess classification, an Antero-Posterior Compression (APC) Type II pelvic ring injury is characterized by:
. Symphysis widening < 2.5 cm with intact posterior ligaments
. Symphysis widening > 2.5 cm with disruption of anterior sacroiliac and sacrotuberous ligaments but intact posterior sacroiliac ligaments
. Disruption of both anterior and posterior sacroiliac ligaments resulting in global instability
. Vertical translation of the hemipelvis
. A transforaminal sacral fracture on the affected side

Correct Answer & Explanation

. Symphysis widening > 2.5 cm with disruption of anterior sacroiliac and sacrotuberous ligaments but intact posterior sacroiliac ligaments

Explanation

In the Young-Burgess classification, APC I involves symphyseal diastasis < 2.5 cm with intact posterior elements. APC II involves diastasis > 2.5 cm with disruption of the anterior sacroiliac, sacrotuberous, and sacrospinous ligaments, but the posterior sacroiliac ligaments remain intact, causing rotational but not vertical instability. APC III involves complete disruption of both anterior and posterior sacroiliac ligaments, leading to complete spinopelvic dissociation.

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