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2. Trauma MCQs

Practice Set 99 of 640

This practice set contains high-yield board review questions covering key concepts in 2. Trauma. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 1961

Topic: 2. Trauma

When performing lumbopelvic fixation for spinopelvic dissociation (U-type sacral fracture), what biomechanical principle is primarily being utilized to restore stability?

. Tension band construct across the symphysis pubis
. Direct compression of the sacral foramina
. Bypassing the fractured sacrum by connecting the lumbar spine directly to the ilium
. Rigid anterior pelvic ring neutralization
. Dynamic distraction of the sacroiliac joints

Correct Answer & Explanation

. Bypassing the fractured sacrum by connecting the lumbar spine directly to the ilium

Explanation

Lumbopelvic fixation utilizes pedicle screws in the lower lumbar spine connected to iliac or S2-alar-iliac screws. This construct completely bypasses the fractured, dissociated sacrum, transferring loads directly from the lumbar spine to the pelvis.

Question 1962

Topic: 2. Trauma
A 35-year-old male sustains a severe pelvic crush injury. CT imaging reveals a sacral fracture extending medial to the sacral foramina into the central spinal canal. According to the Denis classification, what is the approximate rate of neurological deficit associated with this specific fracture zone?
. Less than 10%
. 15-20%
. 25-30%
. 40-45%
. Greater than 50%

Correct Answer & Explanation

. Greater than 50%

Explanation

Denis Zone III fractures involve the central sacral canal and carry the highest rate of neurological deficit, approximately 57%. These injuries frequently result in bowel, bladder, and sexual dysfunction.

Question 1963

Topic: 2. Trauma

A 40-year-old male is involved in a motorcycle accident and sustains a U-shaped sacral fracture. Clinical examination demonstrates saddle anesthesia and loss of rectal tone. Which of the following is the most appropriate definitive surgical management?

. Percutaneous iliosacral screw fixation of S1 and S2
. Anterior plating of the symphysis pubis only
. Lumbopelvic fixation (pedicle screws from L4/L5 to the ilium)
. Nonoperative management with prolonged bed rest
. Trans-sacral trans-iliac screw fixation alone

Correct Answer & Explanation

. Lumbopelvic fixation (pedicle screws from L4/L5 to the ilium)

Explanation

A U-type sacral fracture represents spinopelvic dissociation, separating the axial spine from the pelvic ring. Given the severe instability and neurological deficit, lumbopelvic fixation is the standard of care to restore stability and allow early mobilization.

Question 1964

Topic: Pelvic & Acetabular Trauma



A 45-year-old male sustains a pelvic ring injury necessitating operative fixation. When evaluating the pelvis for percutaneous iliosacral screw placement, the surgeon notes sacral dysmorphism. Which of the following radiographic features is indicative of a dysmorphic sacrum?

. Recessed sacral alae relative to the anterior sacral body
. An acute alar slope on the outlet view
. The upper sacral segment articulating completely below the iliac crests
. A collinear S1 neural foramen
. Absence of mammillary processes at the SI joint

Correct Answer & Explanation

. An acute alar slope on the outlet view

Explanation

Features of sacral dysmorphism include an acute alar slope, non-recessed (collinear) anterior sacral alae, prominent mammillary processes, and an upper sacral segment located above the iliac crests. These variations significantly narrow the safe corridor for iliosacral screw placement.

Question 1965

Topic: 2. Trauma
The Denis classification of sacral fractures categorizes injuries based on their anatomic location. What anatomical landmark is used to separate the sacrum into three distinct zones in this classification system?
. The sacroiliac joint
. The sacral promontory
. The sacral neuroforamina
. The sacral hiatus
. The ala of the sacrum

Correct Answer & Explanation

. The sacral neuroforamina

Explanation

The Denis classification divides sacral fractures into three zones based on their relationship to the sacral neuroforamina. Zone I is lateral to the foramina (alar), Zone II involves the foramina, and Zone III is medial to the foramina (central canal).

Question 1966

Topic: 2. Trauma

A 28-year-old female presents after a fall from a height with a Denis Zone I sacral fracture. During physical examination, she demonstrates new-onset weakness in great toe extension and decreased sensation over the dorsal aspect of her foot. Which nerve root is most likely injured?

. L4
. L5
. S1
. S2
. S3

Correct Answer & Explanation

. L5

Explanation

Denis Zone I (alar) fractures are lateral to the neuroforamina. When a neurologic deficit occurs in Zone I, it most commonly involves the L5 nerve root as it courses over the sacral ala.

Question 1967

Topic: 2. Trauma

A 45-year-old construction worker falls from a roof, landing squarely on his buttocks. Imaging reveals a transverse fracture through the S1-S2 bodies that communicates with bilateral longitudinal fractures through the sacral foramina. What is the most appropriate definitive surgical management for this injury?

. Bilateral percutaneous iliosacral screws alone
. Anterior plate fixation of the symphysis pubis
. Lumbopelvic fixation
. Sacral laminectomy without stabilization
. Closed reduction and spica casting

Correct Answer & Explanation

. Lumbopelvic fixation

Explanation

This describes a U-type sacral fracture (spino-pelvic dissociation). Lumbopelvic fixation is the treatment of choice to restore the connection between the axial skeleton and the pelvic ring, allowing for early mobilization.

Question 1968

Topic: 2. Trauma

A 40-year-old trauma patient has a vertically unstable pelvic ring injury with a sacral fracture. Which specific plain radiograph is most critical for assessing the vertical translation of the hemipelvis and evaluating the shape of the sacral foramina?

. Anteroposterior (AP) pelvis
. Pelvic Inlet view
. Pelvic Outlet view
. Judet Iliac oblique view
. Judet Obturator oblique view

Correct Answer & Explanation

. Pelvic Outlet view

Explanation

The Pelvic Outlet view is shot with a cephalad tilt and best evaluates vertical translation (superior migration) of the hemipelvis. It also clearly profiles the sacral neuroforamina.

Question 1969

Topic: 2. Trauma

A 25-year-old male sustains a sacral fracture following a motor vehicle collision.

Imaging confirms the fracture passes completely through the sacral neuroforamina but does not involve the central canal. Which of the following is the most likely clinical presentation of a neurologic deficit in this patient?

. Loss of voluntary anal sphincter tone
. Saddle anesthesia
. Unilateral sciatica or radiculopathy
. Complete paraplegia
. Upper extremity hyperreflexia

Correct Answer & Explanation

. Unilateral sciatica or radiculopathy

Explanation

A fracture passing through the sacral neuroforamina is a Denis Zone II fracture. Neurologic injuries in this zone typically present as unilateral radiculopathy or sciatica due to localized trauma to the exiting nerve roots.

Question 1970

Topic: Pelvic & Acetabular Trauma
Which radiographic view provides the best assessment of the anterior-posterior translation of the sacrum and is critical for evaluating the AP diameter of the sacral canal in suspected Denis Zone III fractures?
. Anteroposterior (AP) pelvis
. Pelvic Inlet view
. Pelvic Outlet view
. Judet Iliac oblique view
. Judet Obturator oblique view

Correct Answer & Explanation

. Pelvic Inlet view

Explanation

The Pelvic Inlet view is obtained with a caudad tilt of the x-ray beam. It looks down into the pelvic ring, providing the best view of anterior-posterior displacement of the sacrum and the pelvic brim.

Question 1971

Topic: 2. Trauma



A 28-year-old male sustains a sacral fracture following a fall. Assuming the image depicts a transforaminal fracture, what is the reported incidence of associated neurological injury according to the Denis classification?

. Less than 5%
. Approximately 10%
. Approximately 28%
. Approximately 57%
. Greater than 80%

Correct Answer & Explanation

. Approximately 28%

Explanation

Denis Zone II fractures involve the neural foramina. They are associated with a 28% rate of neurological deficit, often presenting as unilateral sciatica or an S1 radiculopathy.

Question 1972

Topic: 2. Trauma

A 35-year-old construction worker falls from a height of 20 feet. Imaging reveals a transverse fracture through the upper sacral segments communicating with bilateral transforaminal vertical fractures. What is the classic radiographic sign seen on an AP pelvis radiograph for this injury?

. The teardrop sign
. The paradoxical inlet view of the sacrum
. The crescent sign
. The spur sign
. The double-line sign

Correct Answer & Explanation

. The paradoxical inlet view of the sacrum

Explanation

A U-type sacral fracture causes spinopelvic dissociation. Kyphosis at the transverse sacral fracture site results in the upper sacrum appearing as an 'inlet' view on a standard AP pelvis radiograph, known as a paradoxical inlet view.

Question 1973

Topic: 2. Trauma

During percutaneous placement of an iliosacral screw for a sacral fracture, intraoperative fluoroscopy is utilized. Which fluoroscopic view is most critical for assessing the anteroposterior position of the screw within the sacral body to avoid injury to the iliac vessels?

. AP Pelvis
. Pelvic Outlet
. Pelvic Inlet
. Judet Obturator Oblique
. Judet Iliac Oblique

Correct Answer & Explanation

. Pelvic Inlet

Explanation

The pelvic inlet view provides visualization of the anterior and posterior cortices of the sacral alar safe zone, ensuring the screw does not breach anteriorly (endangering vessels) or posteriorly (endangering the spinal canal).

Question 1974

Topic: 2. Trauma

Which of the following sacral fracture patterns is the strongest indication for triangular osteosynthesis (lumbopelvic fixation combined with iliosacral screws) rather than isolated iliosacral screw fixation?

. Non-displaced Zone I fracture
. Unilateral Zone II fracture with 5mm displacement
. U-type sacral fracture with spinopelvic dissociation
. Anterior compression fracture of the sacrum
. Transverse fracture below the level of S4

Correct Answer & Explanation

. U-type sacral fracture with spinopelvic dissociation

Explanation

Spinopelvic dissociation (U-type or H-type fractures) disrupts the connection between the axial skeleton and the pelvis. Triangular osteosynthesis bypasses the comminuted sacrum, transferring weight-bearing forces from the lumbar spine directly to the ilium.

Question 1975

Topic: 2. Trauma

A 28-year-old female slips and falls on her buttocks. Radiographs and CT show an isolated transverse fracture of the sacrum at the level of S4. Neurological examination reveals intact bowel and bladder function. What is the most appropriate management?

. Immediate lumbopelvic fixation
. Percutaneous iliosacral screw fixation
. Open reduction and internal fixation with a tension band
. Non-operative management with symptomatic care and mobilization
. Sacral laminectomy

Correct Answer & Explanation

. Non-operative management with symptomatic care and mobilization

Explanation

Isolated transverse sacral fractures below the sacroiliac joint (S4 and below) without neurological deficits are generally stable and are best treated non-operatively with analgesia and progressive weight-bearing.

Question 1976

Topic: 2. Trauma
A patient presents with a Denis Zone III sacral fracture and a new-onset loss of anal sphincter tone and saddle anesthesia. Decompression of the sacral nerve roots is being considered. Which of the following is true regarding sacral neurologic deficits in this setting?
. Early surgical decompression guarantees full recovery of bowel/bladder function
. Bowel and bladder dysfunction are rarely associated with Zone III injuries
. Bowel and bladder recovery is generally poor despite surgical decompression
. Neurologic deficit is typically caused by L5 nerve root avulsion
. Ligation of the internal iliac artery is a routine part of the decompression

Correct Answer & Explanation

. Bowel and bladder recovery is generally poor despite surgical decompression

Explanation

Bowel, bladder, and sexual dysfunction resulting from central sacral fractures (Zone III) have a poor prognosis for full recovery, even with prompt surgical decompression.

Question 1977

Topic: 2. Trauma

A 40-year-old male sustains a severely displaced sacral fracture and a subarachnoid hemorrhage following a motorcycle collision. Regarding VTE prophylaxis for this patient on hospital day 1, which of the following is the most appropriate management?

. Immediate initiation of LMWH
. Immediate initiation of Aspirin 81mg
. Prophylactic placement of an IVC filter
. Sequential compression devices (SCDs) only until cleared by neurosurgery
. Intravenous heparin infusion

Correct Answer & Explanation

. Sequential compression devices (SCDs) only until cleared by neurosurgery

Explanation

Pharmacologic VTE prophylaxis is contraindicated in the setting of acute intracranial hemorrhage. Mechanical prophylaxis (SCDs) should be used until the traumatic brain injury has stabilized and neurosurgery clears the patient.

Question 1978

Topic: 2. Trauma

Which of the following statements is most accurate regarding Denis Zone I sacral fractures?

. They involve the central sacral canal
. They typically present with bilateral S1 radiculopathies
. They are located lateral to the neural foramina
. They carry the highest rate of bowel and bladder dysfunction
. They mandate immediate lumbopelvic stabilization regardless of displacement

Correct Answer & Explanation

. They are located lateral to the neural foramina

Explanation

Denis Zone I fractures are alar fractures located lateral to the sacral neural foramina. They have the lowest rate of neurologic deficit (around 6%), which most commonly affects the L5 nerve root.

Question 1979

Topic: Pelvic & Acetabular Trauma

A 25-year-old male with a severe Denis Zone 2 sacral fracture and an anterior-posterior compression (APC) pelvic ring injury presents in hemorrhagic shock. A pelvic binder is applied. What is the primary source of life-threatening bleeding in this specific injury pattern?

. Internal pudendal artery
. Venous plexus and cancellous bone bleeding
. Superior mesenteric artery
. Femoral artery
. External iliac vein

Correct Answer & Explanation

. Venous plexus and cancellous bone bleeding

Explanation

In the vast majority (80-90%) of pelvic ring disruptions, life-threatening hemorrhage originates from the presacral venous plexus and bleeding from the fractured cancellous bone surfaces, which is initially managed by reducing pelvic volume.

Question 1980

Topic: 2. Trauma

A 78-year-old female with a history of bilateral total hip arthroplasty and osteoporosis presents after a low-energy torsional injury. Initial radiographs, similar to the one shown, reveal a comminuted, spiral fracture of the right femoral shaft extending from the distal aspect of a cemented stem. The stem appears well-fixed with an intact cement mantle and no gross subsidence. Based on this initial assessment, what is the most appropriate provisional Vancouver Classification for this periprosthetic fracture?

. Vancouver Type A
. Vancouver Type B1
. Vancouver Type B2
. Vancouver Type B3
. Vancouver Type C

Correct Answer & Explanation

. Vancouver Type B1

Explanation

Correct Answer: Vancouver Type B1The Vancouver Classification system is the gold standard for periprosthetic femoral fractures, guiding prognosis and surgical strategy based on fracture location, implant stability, and bone stock. The case describes a fracture occurring around the stem, specifically extending from its distal aspect. This immediately places it into the Type B category. The critical distinction within Type B is the stability of the implant and the quality of the bone stock. The vignette explicitly states that the stem appears well-fixed with an intact cement mantle and no gross subsidence. This combination of a fracture around the stem and a stable implant is the definition of a Vancouver Type B1 fracture.Vancouver Type Afractures involve the trochanteric region (AG for greater trochanter, AL for lesser trochanter). This is incorrect as the fracture is in the femoral shaft, distal to the trochanters.Vancouver Type B2fractures occur around a loose stem with adequate bone stock. While the fracture is around the stem, the stem is described as stable, making B2 incorrect.Vancouver Type B3fractures occur around a loose stem with poor bone stock. Again, the stem is described as stable, making B3 incorrect.Vancouver Type Cfractures occur well distal to the tip of the prosthesis. The fracture is described as extending from the distal aspect of the stem, not well distal to it, making C incorrect.Therefore, based on the initial radiographic assessment and description of implant stability, Vancouver Type B1 is the most appropriate provisional classification.

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