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2. Trauma MCQs

Practice Set 498 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 9941

Topic: 2. Trauma

A patient suffers a traumatic radial nerve palsy after a humerus shaft fracture. After 4 months of observation with no clinical recovery, a surgical exploration is performed. The MRI

guided the decision. Intraoperatively, the nerve is intact in continuity but encased in fibrotic scar tissue disrupting the endoneurial tubes, while the perineurium remains entirely intact. This represents which Sunderland classification of nerve injury?

. First degree
. Second degree
. Third degree
. Fourth degree
. Fifth degree

Correct Answer & Explanation

. Third degree

Explanation

Sunderland classified nerve injuries into five degrees. A Third-degree injury involves disruption of the axon and endoneurium, with an intact perineurium and epineurium. Intrafascicular scarring often misdirects regenerating axons or blocks them entirely, meaning spontaneous recovery is variable and often incomplete, frequently necessitating surgical intervention.

Question 9942

Topic: Lower Extremity Trauma

A patient with a well-documented history of advanced breast carcinoma presents with a solitary lytic lesion in the distal femur, confirmed on MRI

. What is the most common physiological route through which this carcinoma metastasized to the appendicular skeleton?

. Lymphatic spread
. Direct extension
. Hematogenous spread via the venous system
. Hematogenous spread via the arterial system
. Perineural invasion

Correct Answer & Explanation

. Hematogenous spread via the venous system

Explanation

The overwhelming majority of bone metastases from carcinomas (such as breast, prostate, lung, kidney, and thyroid) disseminate via hematogenous spread, specifically through the venous system. Batson's venous plexus is a valveless paraspinal venous network that provides a direct pathway for tumor emboli to reach the axial skeleton, and venous sinuses facilitate spread to the appendicular long bones.

Question 9943

Topic: 2. Trauma

When stabilizing a highly comminuted diaphyseal fracture using bridge plating techniques, orthopedic surgeons frequently opt for a locked plating construct over conventional non-locked plates. From a biological and biomechanical standpoint, what is the primary advantage of utilizing locked screws in this scenario?

. Increased interfragmentary compression across the fracture site
. Decreased reliance on friction between the plate and bone surface
. Promotion of primary bone healing via absolute rigidity in all planes
. Increased pull-out strength due to deeper thread purchase in cortical bone
. Superior resistance to pure axial loads compared to intramedullary nails

Correct Answer & Explanation

. Decreased reliance on friction between the plate and bone surface

Explanation

Locked plates function as internal fixators. Because the screw heads thread directly into the plate, the construct acts as a single fixed-angle device. This provides stability without the need to aggressively compress the plate against the bone, thereby preserving the periosteal blood supply. In contrast, conventional plates rely on the friction generated by compressing the plate against the bone, which can strangulate local periosteal perfusion.

Question 9944

Topic: 2. Trauma
A high-energy open tibial shaft fracture with a 6 cm wound and extensive soft tissue stripping is classified as Gustilo-Anderson IIIB. Following debridement and skeletal stabilization, coverage of a middle-third tibial defect is most appropriately achieved with which of the following?
. Split-thickness skin graft
. Gastrocnemius rotational flap
. Soleus rotational flap
. Reverse sural artery flap
. Anterolateral thigh free flap

Correct Answer & Explanation

. Soleus rotational flap

Explanation

The soleus rotational flap is the workhorse for soft tissue coverage of the middle third of the tibia. The gastrocnemius flap is preferred for the proximal third, while free tissue transfer is typically required for the distal third.

Question 9945

Topic: 2. Trauma

A 25-year-old male sustains a severe crush injury to his lower extremity.

Compartment syndrome is suspected. Which of the following delta pressure measurements definitively indicates the need for emergent fasciotomy?

. Diastolic blood pressure minus compartment pressure is less than 30 mmHg
. Mean arterial pressure minus compartment pressure is greater than 40 mmHg
. Systolic blood pressure minus compartment pressure is less than 20 mmHg
. Absolute compartment pressure greater than 20 mmHg
. Diastolic blood pressure minus compartment pressure is greater than 45 mmHg

Correct Answer & Explanation

. Diastolic blood pressure minus compartment pressure is less than 30 mmHg

Explanation

A delta pressure (Diastolic Blood Pressure minus Compartment Pressure) of less than 30 mmHg is considered the most reliable threshold for diagnosing acute compartment syndrome. Relying purely on absolute pressure readings can be misleading.

Question 9946

Topic: Pelvic & Acetabular Trauma
A 28-year-old male is brought to the trauma bay following a high-speed motor vehicle collision. He is hypotensive and tachycardic. Pelvic radiographs reveal an anteroposterior compression type III (APC-III) pelvic ring injury. A circumferential pelvic binder is requested to reduce pelvic volume. To be most effective, the binder should be centered directly over which of the following anatomic landmarks?
. Anterior superior iliac spines (ASIS)
. Iliac crests
. Greater trochanters
. Symphysis pubis
. Umbilicus

Correct Answer & Explanation

. Greater trochanters

Explanation

To effectively reduce pelvic volume and stabilize the pelvic ring, a pelvic binder must be centered over the greater trochanters. Placement higher over the iliac crests can actually paradoxically open the pelvic ring further or fail to reduce it.

Question 9947

Topic: 2. Trauma

A 24-year-old male sustains a closed bilateral femoral shaft fracture. On post-injury day two, he develops confusion, tachypnea, and a petechial rash over his axillae and conjunctivae. Based on Gurd's criteria for Fat Embolism Syndrome (FES), which of the following is considered a major criterion?

. Tachycardia > 120 bpm
. Fever > 39°C
. Petechial rash
. Retinal changes (cotton wool spots)
. Sudden drop in hemoglobin

Correct Answer & Explanation

. Petechial rash

Explanation

Gurd's major criteria for Fat Embolism Syndrome include respiratory insufficiency, cerebral involvement (altered mental status), and a petechial rash. Tachycardia, fever, retinal changes, and anemia are considered minor criteria.

Question 9948

Topic: 2. Trauma

A 30-year-old male sustains an isolated open fracture of the tibial shaft (Gustilo-Anderson Type II) without severe soft tissue stripping or gross contamination. According to current evidence-based guidelines, which of the following is true regarding the timing of initial surgical debridement?

. It must be performed within exactly 6 hours to reduce infection rates.
. It must be performed within 12 hours regardless of antibiotic administration.
. It can safely be performed within 24 hours provided early broad-spectrum antibiotics are administered.
. It should be delayed for 48 hours to allow the zone of injury to demarcate.
. Debridement is not necessary if high-dose intravenous antibiotics are given.

Correct Answer & Explanation

. It can safely be performed within 24 hours provided early broad-spectrum antibiotics are administered.

Explanation

Recent high-level evidence demonstrates that the historical '6-hour rule' is not strictly required. As long as early intravenous antibiotics are administered, surgical debridement within 24 hours yields comparable infection rates for Type I and II open fractures.

Question 9949

Topic: Lower Extremity Trauma

During clinical evaluation of a patient with a suspected anterior cruciate ligament (ACL) tear, the examiner performs a pivot shift test. The palpable clunk that occurs during knee flexion from an extended position represents the reduction of the anteriorly subluxated tibia. Which structure is mechanically responsible for providing the force that reduces the tibia during this maneuver?

. Posterior cruciate ligament
. Medial collateral ligament
. Iliotibial band
. Biceps femoris
. Popliteus tendon

Correct Answer & Explanation

. Iliotibial band

Explanation

The pivot shift test relies on the iliotibial (IT) band. As the knee flexes past approximately 20-30 degrees, the IT band transitions from an extensor to a flexor, creating a posterior force vector that reduces the anteriorly subluxated lateral tibial plateau.

Question 9950

Topic: 2. Trauma

A 35-year-old male presents 8 months after a tibial shaft fracture treated with cast immobilization. Radiographs reveal a hypertrophic nonunion characterized by abundant callus formation but a persistent radiolucent line at the fracture site. What is the most appropriate management strategy for this condition?

. Autologous iliac crest bone grafting alone
. Application of an external bone stimulator
. Rigid internal fixation to provide mechanical stability
. Prolonged immobilization in a patellar tendon-bearing cast
. Administration of systemic teriparatide

Correct Answer & Explanation

. Rigid internal fixation to provide mechanical stability

Explanation

Hypertrophic nonunions have adequate biology and blood supply (evidenced by callus formation) but lack sufficient mechanical stability. The optimal treatment is to provide rigid stabilization, typically with internal fixation (plating or intramedullary nailing), which alone will allow the fracture to heal.

Question 9951

Topic: 2. Trauma

A 19-year-old male sustains a low-velocity civilian handgun injury to the right thigh. Radiographs demonstrate a minimally displaced midshaft femur fracture with retained bullet fragments in the soft tissues. Distal pulses are intact, and the neurologic exam is normal. Which of the following is the most appropriate initial management?

. Immediate operative exploration to remove all bullet fragments
. Formal open debridement of the bullet tract followed by external fixation
. Local wound care, tetanus prophylaxis, antibiotics, and intramedullary nailing
. Primary amputation above the knee due to high risk of lead toxicity
. Observation alone without antibiotic prophylaxis

Correct Answer & Explanation

. Local wound care, tetanus prophylaxis, antibiotics, and intramedullary nailing

Explanation

Low-velocity gunshot wounds resulting in fractures are generally treated as Gustilo-Anderson Type I open fractures. They do not routinely require formal tract debridement or bullet removal unless inside a joint; they are managed with local wound care, antibiotics, and appropriate stabilization (such as IM nailing).

Question 9952

Topic: 2. Trauma
A 32-year-old male sustains a high-energy trauma resulting in a vertically oriented (Pauwels type III) femoral neck fracture. Which of the following fixation constructs provides the greatest biomechanical stability for this specific fracture pattern?
. Three parallel partially threaded cancellous screws
. Fixed-angle sliding hip screw (with or without a derotation screw)
. Proximal femoral locking plate alone
. Two divergent cannulated screws
. Cementless hemiarthroplasty

Correct Answer & Explanation

. Fixed-angle sliding hip screw (with or without a derotation screw)

Explanation

Pauwels type III femoral neck fractures are highly vertical and experience significant shear forces. A fixed-angle sliding hip screw provides superior biomechanical stability compared to parallel cancellous screws, reducing the risk of varus collapse and nonunion.

Question 9953

Topic: Pelvic & Acetabular Trauma
A hemodynamically unstable patient is brought to the trauma bay after a high-speed motor vehicle collision. The anteroposterior pelvic radiograph shows an APC-III injury with >2.5 cm widening of the pubic symphysis. To properly apply a pelvic binder to reduce pelvic volume, over which anatomic landmark should the binder be centered?
. Iliac crests
. Greater trochanters
. Anterior superior iliac spines
. Pubic symphysis
. Subtrochanteric femur

Correct Answer & Explanation

. Greater trochanters

Explanation

A pelvic binder must be applied directly over the greater trochanters to effectively close an open-book pelvic ring injury. Placing the binder higher, over the iliac crests or anterior superior iliac spines, can paradoxically worsen the pubic diastasis and is less effective at reducing pelvic volume and controlling hemorrhage.

Question 9954

Topic: 2. Trauma

A 21-year-old man falls on an outstretched hand. Imaging

shows a displaced fracture through the proximal third of the scaphoid. The patient is counseled regarding a high risk of avascular necrosis (AVN). The primary blood supply to the proximal pole of the scaphoid enters the bone at which location?

. Volar aspect of the proximal pole directly
. Dorsal ridge at the waist
. Volar tubercle
. Scapholunate interosseous ligament insertion
. Radial collateral ligament insertion

Correct Answer & Explanation

. Dorsal ridge at the waist

Explanation

The scaphoid receives its primary blood supply (70-80%) via branches of the radial artery that enter distally at the dorsal ridge near the waist and flow retrograde to supply the proximal pole. Because of this tenuous retrograde blood supply, fractures at the waist or proximal pole carry a high risk of nonunion and avascular necrosis.

Question 9955

Topic: 2. Trauma

A 45-year-old male sustains a severe high-energy knee injury. Radiographs and CT

show a Schatzker IV tibial plateau fracture with a predominant, displaced posteromedial fragment. To adequately apply a buttress plate to this fragment and prevent varus collapse, which surgical approach is most appropriate?

. Anterolateral approach
. Posteromedial approach between the medial gastrocnemius and pes anserinus
. Direct posterior approach (Carlson)
. Medial parapatellar approach
. Anteromedial approach

Correct Answer & Explanation

. Posteromedial approach between the medial gastrocnemius and pes anserinus

Explanation

Schatzker IV fractures involve the medial plateau. When a significant posteromedial fragment is present, it is best addressed with an anti-glide buttress plate. The standard posteromedial approach utilizes the interval between the medial head of the gastrocnemius (retracted laterally) and the pes anserinus (retracted medially or anteriorly) to directly access the posteromedial cortex.

Question 9956

Topic: 2. Trauma

A 65-year-old man presents with diffuse bone pain, anemia, and hypercalcemia. Radiographs show multiple 'punched-out' lytic lesions in the pelvis and proximal femur.

Serum protein electrophoresis demonstrates a monoclonal spike. What is the most appropriate initial surgical management for an impending pathologic fracture of the subtrochanteric femur in this patient?

. En bloc resection and endoprosthetic reconstruction
. Prophylactic intramedullary nailing followed by radiation therapy
. Curettage, phenol adjuvant, and cementation
. Primary observation with initiation of bisphosphonate therapy
. Wide margin excision with structural allograft

Correct Answer & Explanation

. Prophylactic intramedullary nailing followed by radiation therapy

Explanation

The patient has Multiple Myeloma, the most common primary bone malignancy in adults. Because myeloma lesions are highly responsive to radiation and are systemic, the standard of care for impending or actual pathologic fractures in the long bones is stabilization (e.g., prophylactic intramedullary nailing) followed by postoperative radiation therapy. En bloc resection is not indicated for this systemic, radiosensitive disease.

Question 9957

Topic: 2. Trauma

A 32-year-old man sustains a closed high-energy tibial shaft fracture. Clinical concern for acute compartment syndrome arises.

According to standard orthopedic practice, which of the following objective pressure criteria is most predictive of the need for emergent fasciotomy?

. Absolute compartment pressure strictly greater than 20 mmHg
. Absolute compartment pressure strictly greater than 25 mmHg
. Delta P (Diastolic blood pressure minus compartment pressure) less than 30 mmHg
. Delta P (Diastolic blood pressure minus compartment pressure) greater than 45 mmHg
. Mean arterial pressure minus compartment pressure less than 50 mmHg

Correct Answer & Explanation

. Delta P (Diastolic blood pressure minus compartment pressure) less than 30 mmHg

Explanation

The Delta P concept is the most reliable objective measure for diagnosing acute compartment syndrome. A Delta P (Diastolic Blood Pressure - Intra-compartmental Pressure) of less than 30 mmHg is an absolute indication for emergent four-compartment fasciotomy, as muscle perfusion becomes critically compromised below this threshold.

Question 9958

Topic: 2. Trauma
When measuring intracompartmental pressures to evaluate for acute compartment syndrome of the lower extremity, which of the following absolute or differential pressure measurements is the most reliable and generally accepted threshold indicating the need for emergency fasciotomy?
. Absolute compartment pressure > 20 mmHg
. Absolute compartment pressure > 25 mmHg
. Delta pressure (Diastolic BP - Compartment Pressure) < 30 mmHg
. Delta pressure (Mean Arterial BP - Compartment Pressure) < 40 mmHg
. Delta pressure (Systolic BP - Compartment Pressure) < 30 mmHg

Correct Answer & Explanation

. Delta pressure (Diastolic BP - Compartment Pressure) < 30 mmHg

Explanation

The most widely accepted parameter for diagnosing acute compartment syndrome is the delta pressure (ΔP). A delta pressure (Diastolic Blood Pressure minus Intracompartmental Pressure) of less than 30 mmHg indicates critically impaired microcirculation and is an indication for fasciotomy. Absolute pressure thresholds (e.g., >30 or >40 mmHg) are less reliable due to individual variations in blood pressure.

Question 9959

Topic: 2. Trauma

A 32-year-old male sustains a closed comminuted tibial shaft fracture. Within 8 hours, he develops severe leg pain with passive toe stretch. What is the generally accepted threshold for a diagnostic "delta p" indicating the need for immediate fasciotomy?

. Absolute pressure > 20 mmHg
. Absolute pressure > 30 mmHg
. Diastolic blood pressure minus compartment pressure < 30 mmHg
. Mean arterial pressure minus compartment pressure < 40 mmHg
. Systolic blood pressure minus compartment pressure < 20 mmHg

Correct Answer & Explanation

. Diastolic blood pressure minus compartment pressure < 30 mmHg

Explanation

A delta pressure (diastolic blood pressure minus compartment pressure) of less than 30 mmHg is the accepted threshold for diagnosing acute compartment syndrome. Absolute pressures are less reliable due to variations in systemic blood pressure.

Question 9960

Topic: 2. Trauma
A 40-year-old male sustains a severe open tibia fracture with exposed bone devoid of periosteum that cannot be closed primarily (Gustilo-Anderson IIIB). According to recent evidence, when should definitive soft tissue coverage ideally be performed to minimize infection?
. Within 24 hours of injury
. Within 3 to 7 days
. Between 2 and 3 weeks
. After 4 weeks when granulation tissue forms
. Immediately in the trauma bay

Correct Answer & Explanation

. Within 3 to 7 days

Explanation

Early soft tissue coverage (ideally within 3 to 7 days) for severe open tibia fractures significantly decreases the risk of deep infection and promotes union. Delays beyond 7-10 days drastically increase complication rates.

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