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2. Trauma MCQs

Practice Set 635 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 12681

Topic: Pelvic & Acetabular Trauma

A 28-year-old motorcyclist is brought to the emergency department in hemorrhagic shock following an accident. A pelvic radiograph shows widening of the pubic symphysis by 4 cm and disruption of the anterior sacroiliac ligaments. Application of a pelvic binder is crucial to control bleeding primarily from which anatomic source?

. External iliac artery
. Presacral venous plexus
. Internal pudendal artery
. Superior gluteal artery
. Obturator artery

Correct Answer & Explanation

. Presacral venous plexus

Explanation

Antero-posterior compression (APC) pelvic fractures often cause severe retroperitoneal hemorrhage. The predominant source of hemorrhage in pelvic ring injuries is the presacral venous plexus and bleeding from cancellous bone, which is partially tamponaded by reducing the pelvic volume with a binder.

Question 12682

Topic: 2. Trauma

A 42-year-old pedestrian is struck by a car, sustaining a Schatzker type VI tibial plateau fracture. He presents with massive soft tissue swelling, fracture blisters, and diminished pedal pulses. What is the most appropriate initial orthopedic management?

. Immediate open reduction and internal fixation with dual plating
. Application of a knee spanning external fixator
. Closed reduction and long leg cast application
. Immediate intramedullary nailing of the tibia
. Fasciotomy followed by long leg splinting

Correct Answer & Explanation

. Application of a knee spanning external fixator

Explanation

High-energy tibial plateau fractures (Schatzker VI) are heavily associated with severe soft tissue compromise. The standard initial management is a knee-spanning external fixator to restore length and alignment while allowing the soft tissues to recover prior to definitive internal fixation.

Question 12683

Topic: 2. Trauma
A 26-year-old man sustains a displaced fracture of the talar neck (Hawkins type III) following a fall from height. Which radiographic sign, if present at 6-8 weeks post-injury, is an encouraging indicator that avascular necrosis is unlikely to develop?
. Sclerotic appearance of the entire talar dome
. Subchondral radiolucent band in the talar dome
. Cortical hypertrophy of the talar neck
. Periosteal reaction along the medial malleolus
. Complete resorption of the talar body

Correct Answer & Explanation

. Subchondral radiolucent band in the talar dome

Explanation

Hawkins sign is a subchondral radiolucent band seen in the talar dome on the AP or mortise view at 6 to 8 weeks post-injury. It indicates intact vascularity and active bone resorption, meaning that avascular necrosis is highly unlikely.

Question 12684

Topic: 2. Trauma
A 45-year-old male sustains an APC-III pelvic ring injury and arrives hemodynamically unstable. A pelvic binder is applied in the trauma bay. To optimally reduce the pelvic volume and control hemorrhage, over which anatomical structure must the binder be centered?
. Iliac crests
. Greater trochanters
. Anterior superior iliac spines
. Symphysis pubis
. Ischial tuberosities

Correct Answer & Explanation

. Greater trochanters

Explanation

Pelvic binders should be centered directly over the greater trochanters to effectively close the pelvic ring and reduce volume. Placement higher over the iliac crests is less effective and can paradoxically open the true pelvis in certain fracture patterns.

Question 12685

Topic: 2. Trauma
A 28-year-old man sustains a vertically oriented (Pauwels type III) femoral neck fracture in a high-speed motor vehicle collision. Which of the following biomechanical forces is most prominent at the fracture site, dictating the need for specific surgical fixation constructs?
. Compression
. Tension
. Shear
. Torsion
. Bending

Correct Answer & Explanation

. Shear

Explanation

Pauwels type III fractures have a highly vertical angle (>50 degrees), which subjects the fracture site to significant shear forces rather than compressive forces. Construct choice must neutralize these shear forces to prevent varus collapse and nonunion.

Question 12686

Topic: 2. Trauma

A 35-year-old man sustains a closed midshaft tibia fracture. Four hours post-injury, he develops severe pain out of proportion to the injury that is exacerbated by passive stretch of his hallux. Which of the following intracompartmental pressure measurements is the most accepted threshold for diagnosing acute compartment syndrome?

. Absolute pressure > 20 mmHg
. Absolute pressure > 25 mmHg
. Delta pressure (Diastolic BP minus compartment pressure) < 30 mmHg
. Delta pressure (Mean arterial pressure minus compartment pressure) < 40 mmHg
. Delta pressure (Systolic BP minus compartment pressure) < 20 mmHg

Correct Answer & Explanation

. Delta pressure (Diastolic BP minus compartment pressure) < 30 mmHg

Explanation

The most reliable physiological indicator for acute compartment syndrome is a delta pressure (diastolic blood pressure minus absolute intracompartmental pressure) of less than 30 mmHg. Relying on absolute pressures alone can lead to unnecessary fasciotomies, especially in hypertensive patients.

Question 12687

Topic: 2. Trauma

Which of the following best describes the epidemiological distribution of ankle fractures as highlighted in the provided text?

. Unimodal distribution peaking in young females
. Bimodal distribution with peaks in young males and older females
. Bimodal distribution with peaks in young females and older males
. Unimodal distribution peaking in elderly males
. Equal distribution across all age groups and genders

Correct Answer & Explanation

. Bimodal distribution with peaks in young males and older females

Explanation

Correct Answer: Bimodal distribution with peaks in young males and older femalesAnkle fractures are among the most prevalent lower extremity injuries. They demonstrate a bimodal distribution, with a peak in young males (often due to high-energy trauma or sports-related injuries) and a second peak in older females (typically associated with lower-energy fragility fractures due to osteoporosis).

Question 12688

Topic: 2. Trauma

When performing an anterolateral approach to the distal fibula for open reduction and internal fixation of a lateral malleolus fracture, which nerve is at greatest risk and must be meticulously identified and protected?

. Sural nerve
. Deep peroneal nerve
. Saphenous nerve
. Superficial peroneal nerve
. Tibial nerve

Correct Answer & Explanation

. Superficial peroneal nerve

Explanation

Correct Answer: Superficial peroneal nerveDuring the anterolateral approach to the distal fibula, the superficial peroneal nerve is at significant risk. It typically crosses the surgical field anteriorly within the subcutaneous tissue or superficial fascia. Meticulous dissection and protection of this nerve are essential to prevent painful neuromas or sensory deficits over the dorsum of the foot.

Question 12689

Topic: 2. Trauma

During the surgical room setup and patient positioning for open reduction and internal fixation of a lateral malleolus fracture in the supine position, what is the primary rationale for placing a bump under the ipsilateral hip?

. To externally rotate the leg and expose the medial malleolus
. To internally rotate the leg and facilitate access to the lateral malleolus
. To elevate the leg above the level of the heart to reduce swelling
. To prevent pressure ulcers on the sacrum
. To flex the knee and relax the gastrocnemius muscle

Correct Answer & Explanation

. To internally rotate the leg and facilitate access to the lateral malleolus

Explanation

Correct Answer: To internally rotate the leg and facilitate access to the lateral malleolusThe text states that a bump may be placed under the ipsilateral hip to internally rotate the leg, which facilitates access to the lateral malleolus during surgery in the supine position.

Question 12690

Topic: 2. Trauma

Which of the following best describes the epidemiological distribution of ankle fractures as highlighted in the provided text?

. Unimodal distribution peaking in young males
. Bimodal distribution peaking in young males and older females
. Bimodal distribution peaking in young females and older males
. Unimodal distribution peaking in older females
. Even distribution across all age groups and genders

Correct Answer & Explanation

. Bimodal distribution peaking in young males and older females

Explanation

Correct Answer: BAccording to the text, ankle fractures have an incidence of approximately 187 per 100,000 person-years and demonstrate a bimodal distribution. The peaks occur in young males (often due to high-energy trauma or sports injuries) and older females (typically related to osteoporotic fragility fractures). Understanding this epidemiological pattern is important for anticipating injury mechanisms and bone quality during surgical planning.

Question 12691

Topic: 2. Trauma

While plain radiographs are the initial step in evaluating an ankle injury, which imaging modality is considered the preferred method for directly visualizing and diagnosing soft tissue injuries such as an acute syndesmotic tear or deltoid ligament rupture?

. Computed Tomography (CT) without contrast
. Weight-bearing plain radiographs
. Magnetic Resonance Imaging (MRI)
. Ultrasound
. Bone scintigraphy

Correct Answer & Explanation

. Magnetic Resonance Imaging (MRI)

Explanation

Correct Answer: Magnetic Resonance Imaging (MRI)According to the text, while CT scans are invaluable for assessing complex fractures and articular comminution, Magnetic Resonance Imaging (MRI) is the preferred modality for evaluating soft tissue injuries, including syndesmotic tears, deltoid ligament ruptures, osteochondral lesions, and tendon pathologies.

Question 12692

Topic: 2. Trauma

A 21-year-old collegiate basketball player sustains a fracture at the metaphyseal-diaphyseal junction of the 5th metatarsal, extending into the fourth-fifth intermetatarsal articulation. What is the most appropriate management for this specific injury in a high-level athlete?

. Non-weight-bearing cast for 6 weeks
. Intramedullary screw fixation
. Excision of the proximal fragment
. Tension band wiring
. Weight-bearing as tolerated in a stiff-soled shoe

Correct Answer & Explanation

. Intramedullary screw fixation

Explanation

This is a Zone 2 (Jones) fracture, which occurs in a vascular watershed area. High-level athletes are treated acutely with intramedullary screw fixation to expedite return to play and decrease nonunion risk.

Question 12693

Topic: 2. Trauma
A patient falls from a height and sustains a displaced fracture of the talar neck. Radiographs demonstrate dislocation of both the subtalar and tibiotalar joints. According to the Hawkins classification, what is the risk of avascular necrosis (AVN) associated with this injury?
. 0-10%
. 20-50%
. Approaching 100%
. Dependent entirely on the timing of surgery
. Negligible if Hawkins sign appears at 2 weeks

Correct Answer & Explanation

. Approaching 100%

Explanation

This describes a Hawkins III fracture (talar neck fracture with subtalar and tibiotalar dislocation). The blood supply to the talar body is severely disrupted, resulting in an AVN rate approaching 100%.

Question 12694

Topic: 2. Trauma

A 38-year-old construction worker sustains a high-energy tibial pilon fracture with severe soft tissue swelling and fracture blisters circumferentially. What is the most appropriate initial management strategy?

. Immediate definitive open reduction and internal fixation with dual plating
. Spanning external fixation across the ankle joint with delayed definitive fixation
. Primary tibiotalar arthrodesis
. Closed reduction and long leg casting
. Intramedullary nailing of the tibia with immediate weight-bearing

Correct Answer & Explanation

. Spanning external fixation across the ankle joint with delayed definitive fixation

Explanation

High-energy pilon fractures are fraught with soft tissue complications. A "span, scan, and plan" approach using an initial spanning external fixator allows soft tissue recovery before delayed definitive ORIF.

Question 12695

Topic: 2. Trauma

During an extensile lateral approach for open reduction and internal fixation of a displaced intra-articular calcaneus fracture, which of the following structures is at the greatest risk of iatrogenic injury if the full-thickness subperiosteal flap is not properly developed?

. Sural nerve
. Deep peroneal nerve
. Medial calcaneal nerve
. Posterior tibial artery
. Saphenous nerve

Correct Answer & Explanation

. Sural nerve

Explanation

The sural nerve crosses the lateral aspect of the hindfoot and is at the highest risk during the extensile lateral approach. A full-thickness subperiosteal "no touch" technique is crucial to minimize the risk of both wound complications and iatrogenic sural nerve injury.

Question 12696

Topic: 2. Trauma

A 40-year-old male sustains a closed, high-energy tibial pilon fracture. The soft tissues are significantly swollen with fracture blisters. What is the preferred strategy regarding the timing and sequence of definitive surgical fixation?

. Immediate single-stage open reduction and internal fixation of the tibia and fibula
. Spanning external fixation followed by definitive internal fixation once soft tissues allow
. Immediate internal fixation of the tibia and external fixation of the fibula
. Conservative management in a long leg cast
. Primary below-knee amputation

Correct Answer & Explanation

. Spanning external fixation followed by definitive internal fixation once soft tissues allow

Explanation

High-energy pilon fractures are frequently associated with severe soft tissue compromise. The standard of care is a two-stage protocol: initial spanning external fixation to allow soft tissues to recover, followed by definitive internal fixation days to weeks later.

Question 12697

Topic: 2. Trauma

A 20-year-old collegiate sprinter presents with vague dorsal midfoot pain. A CT scan reveals a non-displaced stress fracture of the central third of the tarsal navicular. Why is this specific anatomical zone highly prone to delayed union and nonunion?

. It is an area of physiological avascularity due to the watershed arterial supply
. It receives excessive compressive forces from the anterior tibial tendon
. The spring ligament attachment creates a persistent distracting force
. The medial cuneiform blocks adequate revascularization
. The deltoid ligament tethering prevents callus formation

Correct Answer & Explanation

. It is an area of physiological avascularity due to the watershed arterial supply

Explanation

The central third of the tarsal navicular is a recognized vascular watershed area, receiving only marginal blood supply from branches of the dorsalis pedis and medial plantar arteries. This avascularity puts stress fractures here at high risk for nonunion.

Question 12698

Topic: Pelvic & Acetabular Trauma

A 28-year-old man presents with chronic lower back pain and morning stiffness lasting over an hour. Radiographs of the sacroiliac joints are unremarkable.

What is the earliest MRI finding of sacroiliitis in patients with this condition?

. Subchondral sclerosis
. Joint space narrowing
. Bone marrow edema on STIR sequences
. Erosions of the iliac side of the joint
. Ankylosis of the sacroiliac joint

Correct Answer & Explanation

. Bone marrow edema on STIR sequences

Explanation

The earliest sign of sacroiliitis in ankylosing spondylitis is active inflammation manifesting as subchondral bone marrow edema on STIR or T2-weighted fat-suppressed MRI. This finding precedes any structural changes seen on plain radiographs.

Question 12699

Topic: 2. Trauma

You are planning internal fixation for a transverse midshaft femur fracture in a 30-year-old patient with autosomal dominant osteopetrosis. Which of the following technical challenges is most specifically anticipated during surgery?

. Excessive intraoperative hemorrhage from the hypervascular medullary canal
. Inability to negotiate the medullary canal due to obliteration
. Extreme osteopenia causing screw cutout
. Severe periosteal stripping leading to immediate avascular necrosis
. Rapid early callus formation preventing anatomic reduction

Correct Answer & Explanation

. Inability to negotiate the medullary canal due to obliteration

Explanation

Osteopetrosis results in dense, brittle cortical bone and complete or partial obliteration of the medullary canal. This makes intramedullary nailing extremely difficult or impossible, frequently necessitating robust plate fixation instead.

Question 12700

Topic: 2. Trauma

A 28-year-old male with osteopetrosis sustains a displaced subtrochanteric femur fracture after a minor fall. He is scheduled for intramedullary nailing. What specific intraoperative technical challenge is most likely to be encountered?

. Excessive bleeding from a hyperemic bone marrow
. Rapid hardware loosening due to extreme osteopenia
. Difficulty obtaining soft tissue coverage
. Inability to ream the canal due to an obliterated medullary space
. Increased risk of thermal necrosis of surrounding muscle

Correct Answer & Explanation

. Inability to ream the canal due to an obliterated medullary space

Explanation

Due to defective osteoclastic remodeling, the medullary canal in osteopetrosis is filled with dense cortical bone. This makes passing a guide wire and reaming for an intramedullary nail extremely difficult, frequently requiring specialized drills and resulting in frequent drill bit breakage.

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