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2. Trauma MCQs

Practice Set 94 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 1861

Topic: Pelvic & Acetabular Trauma
A 22-year-old male presents with a Young-Burgess APC II pelvic fracture. He is hemodynamically stable. The pubic symphysis diastasis is 3.0 cm. The posterior sacroiliac ligaments are intact. Which of the following statements best describes the stability of this fracture pattern?
. Rotationally and vertically unstable.
. Rotationally stable and vertically stable.
. Rotationally unstable but vertically stable.
. Vertically unstable but rotationally stable.
. Stable to all forces due to intact posterior arch.

Correct Answer & Explanation

. Rotationally unstable but vertically stable.

Explanation

A Young-Burgess Anteroposterior Compression Type II (APC II) injury is characterized by pubic symphysis diastasis greater than 2.5 cm and disruption of the anterior sacroiliac ligaments, but with intact posterior sacroiliac ligaments. This pattern makes the pelvic ring rotationally unstable (often described as an 'open book' injury) but vertically stable because the strong posterior ligaments remain intact, preventing vertical displacement.

Question 1862

Topic: 2. Trauma

A 50-year-old male with a complex pelvic fracture is undergoing definitive posterior fixation. The surgeon plans to use percutaneous iliosacral screws. To ensure accurate placement and avoid neurovascular injury, which combination of fluoroscopic views is essential for verifying guide wire and screw trajectory?

. AP pelvis and lateral hip views.
. Inlet, outlet, and lateral sacral views.
. Judet views (iliac oblique and obturator oblique).
. Frog-leg lateral and cross-table lateral views.
. CT scan with 3D reconstruction only.

Correct Answer & Explanation

. Inlet, outlet, and lateral sacral views.

Explanation

Correct Answer: BThe case study explicitly states that percutaneous iliosacral screw placement is performed under fluoroscopic guidance using 'inlet, outlet, lateral sacral views, +/- Judet views for SI joint'. These three views (inlet, outlet, and lateral sacral) are crucial for confirming the correct trajectory of the guide wire and screw, ensuring it remains within the safe corridor of the sacral ala and body, avoiding the sacral foramina and neurovascular structures. The inlet view assesses anterior-posterior displacement and sacral kyphosis, the outlet view assesses vertical displacement and sacral lordosis, and the lateral sacral view confirms the depth and trajectory within the sacral body.Option A (AP pelvis and lateral hip views)is incorrect. While an AP pelvis is a standard initial view, a lateral hip view is not specific for iliosacral screw placement. The image provided is an outlet view, which is one of the critical views.Option C (Judet views (iliac oblique and obturator oblique))is incorrect. Judet views are primarily used for acetabular fractures and are not the primary views for iliosacral screw placement, although they can be helpful for assessing the SI joint itself.Option D (Frog-leg lateral and cross-table lateral views)is incorrect. These are typically hip views and are not used for iliosacral screw placement.Option E (CT scan with 3D reconstruction only)is incorrect. While a pre-operative CT scan with 3D reconstruction is invaluable for planning, intra-operative fluoroscopy is essential for real-time guidance during screw insertion. Relying solely on a pre-operative CT without intra-operative imaging is unsafe.

Question 1863

Topic: 2. Trauma

A 38-year-old male undergoes definitive internal fixation for a Tile Type C pelvic fracture. Post-operatively, he develops severe pain, swelling, and tenderness in the gluteal region, accompanied by neurological deficits in the sciatic nerve distribution. His intracompartmental pressures are elevated. Which of the following early complications is most likely occurring?

. Deep venous thrombosis (DVT).
. Heterotopic ossification (HO).
. Pin site infection.
. Compartment syndrome.
. Malunion.

Correct Answer & Explanation

. Compartment syndrome.

Explanation

Correct Answer: DThe patient's symptoms of severe pain, swelling, tenderness, neurological deficits (sciatic nerve distribution), and elevated intracompartmental pressures in the gluteal region are classic signs of compartment syndrome. While rare in the gluteal compartment, it can occur after high-energy pelvic trauma, especially with high-volume fluid resuscitation and prolonged immobilization. Urgent fasciotomy is indicated for this life-threatening condition.Option A (Deep venous thrombosis (DVT))is incorrect. While DVT is a common complication of pelvic fractures, its symptoms typically include leg swelling, pain, and tenderness, but not elevated intracompartmental pressures or acute neurological deficits in the sciatic nerve distribution.Option B (Heterotopic ossification (HO))is incorrect. HO is a late complication involving ectopic bone formation in soft tissues, usually presenting weeks to months after injury with stiffness and pain, not acute compartment syndrome.Option C (Pin site infection)is incorrect. Pin site infections are associated with external fixation and present with localized redness, warmth, drainage, and pain around the pins, not diffuse gluteal swelling, neurological deficits, and elevated intracompartmental pressures.Option E (Malunion)is incorrect. Malunion is a late complication where the fracture heals in an unacceptable position, leading to chronic pain and dysfunction, not an acute post-operative emergency like compartment syndrome.

Question 1864

Topic: 2. Trauma
A 45-year-old male is brought to the trauma bay following a high-speed motorcycle collision. He is hemodynamically unstable despite receiving 2 units of uncrossmatched blood. A pelvic binder is applied, and an AP pelvis radiograph demonstrates an anteroposterior compression (APC) type III pelvic ring injury. If an arterial source of hemorrhage is present, which of the following vessels is most commonly injured in this specific fracture pattern?
. Superior gluteal artery
. Internal pudendal artery
. Inferior epigastric artery
. External iliac artery
. Iliolumbar artery

Correct Answer & Explanation

. Internal pudendal artery

Explanation

Anteroposterior compression (APC) injuries typically cause tearing of the anterior branches of the internal iliac artery system, most notably the internal pudendal and obturator arteries. In contrast, lateral compression injuries are more frequently associated with bleeding from posterior branches like the superior gluteal artery.

Question 1865

Topic: 2. Trauma
A 28-year-old male sustains an unstable sacral fracture with extension into the central sacral canal (Denis Zone III). Which of the following neurologic deficits is most specifically associated with fractures involving this zone?
. Weakness in ankle dorsiflexion
. Weakness in hip flexion
. Loss of knee extension
. Bowel and bladder dysfunction
. Decreased sensation over the anterior thigh

Correct Answer & Explanation

. Bowel and bladder dysfunction

Explanation

Denis Zone III sacral fractures involve the central sacral canal and have the highest rate of neurologic injury (up to 57%). These injuries frequently disrupt the sacral nerve roots governing sphincter control, leading to bowel, bladder, and sexual dysfunction.

Question 1866

Topic: 2. Trauma
A 35-year-old female sustains a closed lateral compression type II (LC-II) pelvic ring injury. Physical examination reveals a fluctuant, ballotable soft-tissue swelling overlying her left greater trochanter. If open reduction and internal fixation is planned directly through this area, what is the most significant anticipated complication?
. Heterotopic ossification
. Massive intraoperative hemorrhage
. Postoperative deep infection
. Iatrogenic sciatic nerve injury
. Compartment syndrome of the thigh

Correct Answer & Explanation

. Postoperative deep infection

Explanation

The patient has a Morel-Lavallée lesion, a closed degloving injury separating the subcutaneous tissue from the underlying fascia. Surgical incisions made directly through this compromised, necrotic tissue carry a notoriously high risk of deep postoperative infection.

Question 1867

Topic: Pelvic & Acetabular Trauma

During the acute resuscitation of a patient with a mechanically unstable pelvic ring injury, the trauma team decides to place a circumferential pelvic binder. To optimally reduce pelvic volume and provide biomechanical stability, the binder must be centered over which anatomic landmark?

. The iliac crests
. The greater trochanters
. The anterior superior iliac spines (ASIS)
. The umbilicus
. The lesser trochanters

Correct Answer & Explanation

. The greater trochanters

Explanation

Pelvic binders must be centered over the greater trochanters to effectively compress the pubic symphysis and reduce the pelvic volume. Placement higher up over the iliac crests is ineffective and can actually cause paradoxical widening of the true pelvis.

Question 1868

Topic: 2. Trauma

A 50-year-old male undergoes percutaneous iliosacral screw fixation for a completely displaced sacroiliac joint disruption. Preoperative pelvic radiographs reveal L5 transverse processes that articulate with the ilium and non-circular upper sacral neural foramina. These radiographic findings indicate an increased risk of which of the following during screw placement?

. Screw cut-out due to severe osteoporosis
. Extraosseous screw placement due to sacral dysmorphism
. Vascular injury to the superior gluteal artery
. Inadequate thread purchase in the S1 body
. Iatrogenic fracture of the sacral ala

Correct Answer & Explanation

. Extraosseous screw placement due to sacral dysmorphism

Explanation

The findings describe a dysmorphic sacrum, which features an acute alar slope, residual S1/S2 disc space, and articulating L5 transverse processes. The 'safe zone' for S1 iliosacral screws in a dysmorphic sacrum is dramatically reduced and obliquely oriented, significantly increasing the risk of extraosseous screw placement.

Question 1869

Topic: 2. Trauma

A 32-year-old male falls from a height of 30 feet, landing directly on his feet. Imaging confirms a U-shaped sacral fracture with severe displacement. Neurologic examination reveals profound bilateral lower extremity weakness and saddle anesthesia. Which of the following surgical constructs is most appropriate to restore pelvic stability and allow mobilization?

. Bilateral percutaneous iliosacral screws at S1 and S2
. Anterior symphyseal plating alone
. Lumbopelvic fixation utilizing L4/L5 pedicle screws connected to iliac screws
. Tension band wiring of the posterior superior iliac spines
. Application of an anterior supra-acetabular external fixator

Correct Answer & Explanation

. Lumbopelvic fixation utilizing L4/L5 pedicle screws connected to iliac screws

Explanation

A U-shaped sacral fracture represents spinopelvic dissociation, meaning the axial skeleton is disconnected from the pelvic ring. Bilateral lumbopelvic fixation is the construct of choice to bridge the dissociation, stabilize the spine to the pelvis, and permit early mobilization.

Question 1870

Topic: Pelvic & Acetabular Trauma

Which of the following pelvic radiograph views is most appropriate to evaluate for subtle cranial (vertical) displacement of the left hemipelvis in a suspected vertical shear injury?

. AP Pelvis
. Inlet view
. Outlet view
. Judet obturator oblique view
. Judet iliac oblique view

Correct Answer & Explanation

. Outlet view

Explanation

The pelvic outlet view (directed 45 degrees cephalad) projects the sacrum en face and is the optimal view for assessing vertical displacement (cranial/caudal translation) of a hemipelvis.

Question 1871

Topic: 2. Trauma

A 24-year-old male sustains an open book pelvic fracture (APC II). On secondary survey, there is blood at the urethral meatus and the prostate is high-riding on digital rectal exam. Which of the following is the most appropriate next step in the management of his genitourinary system?

. Immediate insertion of an 18F Foley catheter
. CT cystogram
. Retrograde urethrogram
. Flexible cystoscopy
. Percutaneous nephrostomy

Correct Answer & Explanation

. Retrograde urethrogram

Explanation

Blood at the urethral meatus and a high-riding prostate are classic signs of a posterior urethral injury. A retrograde urethrogram (RUG) must be performed prior to any catheter insertion to avoid converting a partial urethral tear into a complete transection.

Question 1872

Topic: 2. Trauma
A patient with an APC III pelvic ring injury undergoes successful open reduction and internal fixation of the pubic symphysis and percutaneous posterior fixation. Assuming no contraindications, what is the most appropriate timeline for initiating pharmacologic venous thromboembolism (VTE) prophylaxis?
. Within 24 hours postoperatively
. After 72 hours postoperatively
. On postoperative day 7
. At the time of hospital discharge
. Prophylaxis is only indicated if DVT is detected on screening ultrasound

Correct Answer & Explanation

. Within 24 hours postoperatively

Explanation

Current guidelines emphasize that patients with major pelvic fractures are at exceptionally high risk for VTE. Pharmacologic prophylaxis (e.g., LMWH) should be initiated within 24 hours of surgical stabilization, provided there is no active bleeding or coagulopathy.

Question 1873

Topic: Pelvic & Acetabular Trauma

A 41-year-old female complains of persistent dyspareunia and pelvic pain one year after undergoing anterior symphyseal plating and bilateral SI joint screw fixation for an APC II injury. Radiographs show a healed pelvic ring with intact hardware. What is the most likely cause of her dyspareunia?

. Hardware failure of the SI screws
. Nonunion of the pubic symphysis
. Residual pelvic floor dysfunction and local nerve injury
. Late-onset osteomyelitis of the pubic rami
. Intrapelvic protrusion of the symphyseal plate

Correct Answer & Explanation

. Residual pelvic floor dysfunction and local nerve injury

Explanation

Sexual dysfunction, including dyspareunia in females and erectile dysfunction in males, is a very common complication following major anterior pelvic ring disruptions. It is typically attributed to local nerve injury (pudendal nerve branches), soft-tissue scarring, and pelvic floor dysfunction rather than hardware complications.

Question 1874

Topic: 2. Trauma

A 75-year-old female sustains a fragility fracture of the pelvis (FFP) following a ground-level fall. Imaging reveals an undisplaced unilateral sacral alar fracture and an ipsilateral superior pubic ramus fracture (Lateral Compression type I equivalent). She experiences intractable pain and cannot mobilize out of bed after 4 days of optimal medical management. What is the most appropriate next step in management?

. Strict bed rest for an additional 4 weeks
. Application of a halo-femoral traction frame
. Minimally invasive percutaneous iliosacral screw fixation
. Open reduction and internal fixation of the pubic ramus with a reconstructive plate
. Referral to a pain management clinic for epidural steroid injections

Correct Answer & Explanation

. Minimally invasive percutaneous iliosacral screw fixation

Explanation

While LC-I fragility fractures are minimally displaced, intractable pain preventing mobilization carries significant morbidity and mortality in the elderly. Minimally invasive posterior fixation (e.g., percutaneous IS screws) provides stability, significantly relieves pain, and allows for early mobilization.

Question 1875

Topic: Pelvic & Acetabular Trauma
A crescent fracture of the ilium is most classically associated with which type of pelvic ring injury pattern in the Young-Burgess classification?
. Anteroposterior Compression II (APC-II)
. Lateral Compression II (LC-II)
. Lateral Compression III (LC-III)
. Vertical Shear (VS)
. Anteroposterior Compression III (APC-III)

Correct Answer & Explanation

. Lateral Compression II (LC-II)

Explanation

A crescent fracture involves a fracture of the posterior iliac wing extending into the sacroiliac joint, leaving the posterior sacroiliac ligaments intact. This is the hallmark posterior lesion of a Lateral Compression Type II (LC-II) injury.

Question 1876

Topic: 2. Trauma



The image represents a high-energy pelvic ring disruption. In the acute trauma setting, the finding of Destot's sign is highly suggestive of this class of injury. What is Destot's sign?

. Asymmetric palpable pulses in the bilateral lower extremities
. A palpable defect in the pubic symphysis
. Superficial hematoma above the inguinal ligament or in the scrotum/labia
. Severe pain elicited by simultaneous compression of the iliac crests
. Loss of the anal wink reflex

Correct Answer & Explanation

. Superficial hematoma above the inguinal ligament or in the scrotum/labia

Explanation

Destot's sign is characterized by a superficial hematoma above the inguinal ligament, within the scrotum, or in the proximal thigh. It indicates retroperitoneal bleeding that has tracked along fascial planes, strongly suggesting a major pelvic fracture.

Question 1877

Topic: Pelvic & Acetabular Trauma

Which of the following ligaments is considered the primary static stabilizer of the pelvic ring, providing the greatest resistance against vertical shear forces?

. Anterior sacroiliac ligament
. Sacrospinous ligament
. Sacrotuberous ligament
. Interosseous sacroiliac ligament
. Iliolumbar ligament

Correct Answer & Explanation

. Interosseous sacroiliac ligament

Explanation

The posterior sacroiliac complex, specifically the interosseous sacroiliac ligament, is the strongest ligament in the body and serves as the primary static stabilizer of the pelvic ring, primarily resisting vertical shear and distraction forces.

Question 1878

Topic: 2. Trauma

A 29-year-old male presents with an open pelvic fracture involving a severe perineal laceration. Examination reveals gross fecal contamination of the pelvic fracture site and absent anal sphincter tone. Immediate management, alongside aggressive debridement and skeletal stabilization, must include which of the following?

. Primary layered closure of the perineal wound
. Placement of a rectal tube for fecal diversion
. Creation of a diverting colostomy
. Local advancement flap coverage
. Continuous normal saline wound irrigation for 72 hours

Correct Answer & Explanation

. Creation of a diverting colostomy

Explanation

Open pelvic fractures complicated by fecal contamination and sphincter injury carry a massive risk for overwhelming pelvic sepsis. Immediate mechanical bowel diversion via a colostomy is mandatory, in addition to aggressive debridement and pelvic stabilization.

Question 1879

Topic: Pelvic & Acetabular Trauma
A 38-year-old male sustains a severe pelvic crush injury resulting in an LC-III fracture pattern (windswept pelvis). This injury pattern is characterized by which of the following combinations of forces?
. Bilateral anterior-posterior compression forces
. Lateral compression on one side and an anteroposterior compression (external rotation) injury on the contralateral side
. Unilateral vertical shear with contralateral lateral compression
. Bilateral vertical shear forces
. Pure internal rotation forces on both hemipelves

Correct Answer & Explanation

. Lateral compression on one side and an anteroposterior compression (external rotation) injury on the contralateral side

Explanation

An LC-III or 'windswept' pelvis occurs when a severe lateral compression force continues across the pelvic ring, causing an internal rotation injury on the impacted side and an external rotation (open book) injury on the contralateral side.

Question 1880

Topic: Pelvic & Acetabular Trauma
A 35-year-old male sustains a high-energy pelvic ring injury. AP radiograph demonstrates 4 cm of pubic symphyseal widening and widening of the left sacroiliac joint. He is hemodynamically stable. An MRI is obtained which confirms disruption of the anterior sacroiliac, sacrotuberous, and sacrospinous ligaments. Which of the following ligamentous structures remains intact in an Anteroposterior Compression Type II (APC-II) injury but is disrupted in an APC-III injury?
. Anterior sacroiliac ligament
. Sacrospinous ligament
. Sacrotuberous ligament
. Posterior sacroiliac ligament
. Iliolumbar ligament

Correct Answer & Explanation

. Sacrotuberous ligament

Explanation

APC-II injuries involve disruption of the symphysis, anterior sacroiliac ligaments, and the sacrotuberous/sacrospinous ligaments, but the strong posterior sacroiliac ligaments remain intact. APC-III injuries involve complete disruption of both anterior and posterior sacroiliac complexes, causing complete spinopelvic instability.

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