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2. Trauma MCQs

Practice Set 606 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 12101

Topic: 2. Trauma

A 14-year-old girl sustains an isolated, closed, midshaft femur fracture. She weighs 45 kg (99 lbs). Which of the following stabilization methods is associated with the lowest risk of osteonecrosis of the femoral head while providing optimal stability?

. Pavlik harness
. Immediate hip spica casting
. Elastic stable intramedullary nailing (ESIN)
. Rigid antegrade intramedullary nailing through the piriformis fossa
. External fixation

Correct Answer & Explanation

. Elastic stable intramedullary nailing (ESIN)

Explanation

For pediatric patients weighing less than 50 kg, ESIN provides excellent stability and allows early mobilization. Rigid antegrade nailing through the piriformis fossa carries an unacceptably high risk of avascular necrosis in children.

Question 12102

Topic: 2. Trauma

A healthy 3-year-old boy weighing 16 kg sustains an isolated, closed spiral fracture of the midshaft left femur during a playground fall. Radiographs show 1.5 cm of shortening. Which of the following is the most appropriate definitive management?

. Closed reduction and placement of a one-and-a-half hip spica cast
. Open reduction and internal fixation with a submuscular plate
. Closed reduction and intramedullary flexible nailing
. Rigid antegrade locked intramedullary nailing
. External fixation

Correct Answer & Explanation

. Closed reduction and placement of a one-and-a-half hip spica cast

Explanation

For children under the age of 5 (and typically <20 kg) with an isolated diaphyseal femur fracture and acceptable shortening (<2 cm), closed reduction and hip spica casting is the standard of care with excellent outcomes.

Question 12103

Topic: 2. Trauma

A 28-year-old male sustains a closed tibial shaft fracture. Two hours later, he develops severe leg pain out of proportion to the injury. Which of the following is the most reliable objective diagnostic parameter for acute compartment syndrome?

. Absolute compartment pressure greater than 30 mmHg
. Diastolic blood pressure minus compartment pressure less than 30 mmHg
. Mean arterial pressure minus compartment pressure less than 40 mmHg
. Systolic blood pressure minus compartment pressure less than 30 mmHg
. Loss of palpable dorsalis pedis pulse

Correct Answer & Explanation

. Diastolic blood pressure minus compartment pressure less than 30 mmHg

Explanation

The Delta P (Diastolic Blood Pressure minus Compartment Pressure) is the most reliable indicator for acute compartment syndrome. A Delta P of less than 30 mmHg is an absolute indication for emergent fasciotomy. Absolute pressure alone can be misleading depending on the patient's systemic blood pressure.

Question 12104

Topic: Pelvic & Acetabular Trauma
In a hemodynamically unstable patient with an anteroposterior compression (APC) Type III pelvic ring injury, what is the anatomically correct landmark for the placement of a circumferential pelvic binder?
. Iliac crests
. Anterior superior iliac spines (ASIS)
. Greater trochanters
. Symphysis pubis
. Sacral promontory

Correct Answer & Explanation

. Greater trochanters

Explanation

A pelvic binder must be placed over the greater trochanters to effectively reduce pelvic volume and create a tamponade effect. Placement over the iliac crests is incorrect and can exacerbate an 'open book' deformity by pushing the iliac wings medially and hinging the pubic symphysis wider.

Question 12105

Topic: 2. Trauma
A 30-year-old farmer sustains an open tibial shaft fracture from a tractor accident in a field. The wound is 5 cm long with moderate soil contamination. Adequate soft tissue is available to cover the bone natively, and pedal pulses are normal. According to the Gustilo-Anderson classification, what is the correct grade for this injury?
. Type I
. Type II
. Type IIIA
. Type IIIB
. Type IIIC

Correct Answer & Explanation

. Type IIIA

Explanation

Farm injuries (agricultural accidents) are inherently highly contaminated and are automatically classified as at least a Type IIIA open fracture, regardless of the wound size. Since there is adequate soft tissue coverage (not IIIB) and no vascular injury requiring surgical repair (not IIIC), it remains a Type IIIA.

Question 12106

Topic: 2. Trauma

In the management of a polytrauma patient undergoing Damage Control Orthopedics (DCO), which of the following is the most reliable clinical marker that the patient has been adequately resuscitated to safely undergo definitive fracture fixation?

. Systolic blood pressure > 90 mmHg
. Urine output > 0.5 mL/kg/hr
. Serum lactate < 2.0 mmol/L
. Base excess > +5
. Core body temperature > 34 degrees Celsius

Correct Answer & Explanation

. Serum lactate < 2.0 mmol/L

Explanation

Serum lactate < 2.0 mmol/L and a normalized base excess (typically between -2 and +2) are the most reliable indicators of restored tissue perfusion. Relying solely on vital signs or urine output can miss occult hypoperfusion.

Question 12107

Topic: 2. Trauma
A 35-year-old farmer sustains a Gustilo-Anderson Type IIIB open tibia fracture contaminated with soil. According to standard guidelines, what is the most appropriate initial empiric antibiotic regimen?
. First-generation cephalosporin alone
. Ceftriaxone and clindamycin
. First-generation cephalosporin and an aminoglycoside
. First-generation cephalosporin, an aminoglycoside, and penicillin
. Vancomycin and piperacillin-tazobactam

Correct Answer & Explanation

. First-generation cephalosporin, an aminoglycoside, and penicillin

Explanation

Type III open fractures require coverage for both Gram-positive and Gram-negative organisms, typically a first-generation cephalosporin and an aminoglycoside. The addition of high-dose penicillin is indicated for heavy soil or farm contamination to cover Clostridium species.

Question 12108

Topic: Pelvic & Acetabular Trauma

In the acute management of a hemodynamically unstable patient with an 'open-book' anteroposterior compression pelvic ring injury, where is the optimal anatomic location to apply a circumferential pelvic binder?

. Directly over the iliac crests
. Midway between the ASIS and the umbilicus
. Centered directly over the greater trochanters
. Just superior to the symphysis pubis
. At the level of the ischial tuberosities

Correct Answer & Explanation

. Centered directly over the greater trochanters

Explanation

A pelvic binder must be centered over the greater trochanters to generate the optimal mechanical advantage for closing the disrupted symphysis pubis. Placement over the iliac crests can paradoxically force the pelvis further open.

Question 12109

Topic: 2. Trauma

A 35-year-old male presents with a nonunion of a tibial shaft fracture 8 months post-injury. Radiographs reveal abundant, flared callus formation at both fracture ends without bridging ('elephant foot' appearance). What is the primary cause of this specific type of nonunion?

. Avascularity at the fracture site
. Deep fracture related infection
. Inadequate mechanical stabilization
. Severe systemic malnutrition
. Extensive initial bone loss (gap)

Correct Answer & Explanation

. Inadequate mechanical stabilization

Explanation

A hypertrophic ('elephant foot') nonunion indicates excellent biology and adequate blood supply, but a failure of mechanical stability. The appropriate treatment is improving stabilization (e.g., larger intramedullary nail or compression plating) rather than bone grafting.

Question 12110

Topic: Pelvic & Acetabular Trauma
A 32-year-old male is brought to the trauma bay following a motorcycle collision. He is hypotensive with an anteroposterior compression type III (APC-III) pelvic ring injury. A pelvic binder is applied, and he is resuscitated with blood products but remains hemodynamically unstable. A FAST exam is negative. What is the primary method to initially control the most common source of bleeding in this scenario?
. Immediate exploratory laparotomy
. Bilateral internal iliac artery embolization
. Pelvic ring closure and stabilization
. Administration of tranexamic acid only
. Open preperitoneal pelvic packing without stabilization

Correct Answer & Explanation

. Pelvic ring closure and stabilization

Explanation

The majority of hemorrhage in pelvic ring injuries is venous in origin, arising from the presacral plexus and bleeding cancellous bone. Mechanical volume reduction and stabilization of the ring with a binder or external fixator is the most effective initial method to tamponade this venous bleeding.

Question 12111

Topic: 2. Trauma

A 25-year-old male sustains a closed tibial plateau fracture. Serial examinations demonstrate escalating anterior leg pain with passive toe flexion. Which of the following objective measurement thresholds is the most definitive indicator for emergency fasciotomy?

. Absolute compartment pressure > 15 mmHg
. Mean arterial pressure minus compartment pressure < 40 mmHg
. Diastolic blood pressure minus compartment pressure < 30 mmHg
. Systolic blood pressure minus compartment pressure < 30 mmHg
. Absolute compartment pressure consistently > 20 mmHg

Correct Answer & Explanation

. Diastolic blood pressure minus compartment pressure < 30 mmHg

Explanation

Acute compartment syndrome is best diagnosed objectively using the delta pressure, calculated as diastolic blood pressure minus intracompartmental pressure. A delta pressure of less than 30 mmHg indicates inadequate capillary perfusion and is an absolute indication for emergency fasciotomy.

Question 12112

Topic: 2. Trauma
A 40-year-old construction worker sustains a Gustilo-Anderson Type IIIB open fracture of the distal third of the tibia. Following thorough surgical debridement and skeletal stabilization, an 8 cm soft tissue defect with exposed bone remains. What is the preferred method of soft tissue coverage for this specific anatomical zone?
. Split-thickness skin grafting over bare bone
. Local pedicled soleus muscle flap
. Local pedicled medial gastrocnemius muscle flap
. Free tissue transfer (e.g., anterolateral thigh flap)
. Vacuum-assisted closure as definitive long-term treatment

Correct Answer & Explanation

. Free tissue transfer (e.g., anterolateral thigh flap)

Explanation

For Gustilo-Anderson Type IIIB open fractures in the distal third of the tibia, local muscle flaps are generally inadequate due to limited reach and insufficient bulk. Free tissue transfer (e.g., ALT or latissimus dorsi flap) is the gold standard for achieving robust coverage.

Question 12113

Topic: 2. Trauma
A 45-year-old farmer sustains a severe, heavily contaminated Gustilo-Anderson Type IIIA open tibia fracture after a tractor rollover. According to advanced trauma protocols, what is the most appropriate initial empiric intravenous antibiotic regimen?
. First-generation cephalosporin alone
. First-generation cephalosporin and an aminoglycoside
. First-generation cephalosporin, an aminoglycoside, and high-dose penicillin
. Third-generation cephalosporin alone
. Vancomycin and a fluoroquinolone

Correct Answer & Explanation

. First-generation cephalosporin, an aminoglycoside, and high-dose penicillin

Explanation

Farm and highly contaminated soil injuries carry a high risk of Clostridium infection. The addition of high-dose penicillin provides necessary anaerobic coverage alongside Gram-positive and Gram-negative coverage.

Question 12114

Topic: Pelvic & Acetabular Trauma

A trauma patient presents with an anteroposterior compression type II (APC-II) pelvic ring injury. By definition, which of the following ligamentous complexes have been disrupted?

. Symphysis pubis and anterior sacroiliac ligaments only
. Symphysis pubis, anterior sacroiliac, sacrotuberous, and sacrospinous ligaments
. Symphysis pubis, posterior sacroiliac, and iliolumbar ligaments
. Symphysis pubis and complete disruption of the posterior sacroiliac complex
. Sacrotuberous, sacrospinous, and posterior sacroiliac ligaments only

Correct Answer & Explanation

. Symphysis pubis, anterior sacroiliac, sacrotuberous, and sacrospinous ligaments

Explanation

An APC-II injury (open book pelvis) is characterized by disruption of the symphysis pubis, anterior sacroiliac ligaments, and the pelvic floor (sacrotuberous and sacrospinous ligaments). The posterior sacroiliac ligaments remain intact, providing vertical stability.

Question 12115

Topic: 2. Trauma

A 35-year-old male presents with persistent mid-leg pain 8 months after intramedullary nailing of a closed tibial shaft fracture. Radiographs show a persistent fracture line with abundant bridging callus that fails to cross the defect (hypertrophic nonunion). What is the optimal surgical management?

. Autologous iliac crest bone grafting alone
. Plate augmentation without removal of the intramedullary nail
. Exchange nailing to a larger diameter intramedullary nail
. Injection of bone marrow aspirate concentrate (BMAC)
. Removal of hardware and application of a circular external fixator

Correct Answer & Explanation

. Exchange nailing to a larger diameter intramedullary nail

Explanation

A hypertrophic nonunion is characterized by adequate biology (abundant callus) but inadequate mechanical stability. Exchange nailing with a larger diameter nail provides the necessary rigid stability to allow the fracture to heal.

Question 12116

Topic: 2. Trauma

Which of the following internal fixation constructs provides the absolute stability required to bypass the cartilaginous callus phase and promote direct (primary) bone healing via osteonal cutting cones?

. Reamed intramedullary nail with dynamic locking
. Bridge plate construct spanning a comminuted segment
. Titanium elastic intramedullary nails
. Absolute stability with a lag screw and neutralization plate
. Fine-wire circular external fixator

Correct Answer & Explanation

. Absolute stability with a lag screw and neutralization plate

Explanation

Direct (primary) bone healing requires absolute mechanical stability and no interfragmentary motion, which prevents callus formation. A lag screw coupled with a neutralization plate provides this absolute stability.

Question 12117

Topic: 2. Trauma

A 25-year-old male presents with bilateral femur fractures and blunt chest trauma after an MVA. Which of the following physiologic parameters is the strongest indication for Damage Control Orthopedics (DCO) rather than Early Total Care (ETC)?

. Lactate < 2.0 mmol/L
. Platelet count > 150,000
. Base deficit of -8 mEq/L
. Temperature of 36.5 C
. Urinary output of 1.5 mL/kg/hr

Correct Answer & Explanation

. Base deficit of -8 mEq/L

Explanation

A base deficit worse than -6 mEq/L is a sign of severe physiologic derangement and hypoperfusion, making the patient a borderline or extremis candidate. In such cases, Damage Control Orthopedics (DCO) is indicated over Early Total Care (ETC) to prevent the "second hit" phenomenon.

Question 12118

Topic: 2. Trauma

Which bone morphogenetic protein (BMP) is an FDA-approved osteoinductive agent specifically indicated for the treatment of acute open tibial shaft fractures treated with an intramedullary nail?

. rhBMP-2
. rhBMP-3
. rhBMP-4
. rhBMP-6
. rhBMP-7

Correct Answer & Explanation

. rhBMP-2

Explanation

Recombinant human BMP-2 (rhBMP-2) is FDA-approved for use in acute open tibial shaft fractures treated with an IM nail, as well as for anterior lumbar interbody fusions. rhBMP-7 (osteogenic protein-1) is approved for recalcitrant long bone nonunions.

Question 12119

Topic: 2. Trauma

A 22-year-old male sustains a closed femoral shaft fracture. 36 hours later, he develops hypoxemia, altered mental status, and a petechial rash over his axilla. According to Gurd's criteria for Fat Embolism Syndrome (FES), which of the following is considered a major criterion?

. Tachycardia greater than 120 bpm
. Fever greater than 39°C
. Petechial rash
. Unexplained anemia
. Thrombocytopenia

Correct Answer & Explanation

. Petechial rash

Explanation

According to Gurd's criteria for Fat Embolism Syndrome, the major criteria are a petechial rash, respiratory insufficiency, and cerebral involvement. Tachycardia, fever, anemia, and thrombocytopenia are all considered minor criteria.

Question 12120

Topic: 2. Trauma

Which of the following mechanical environments most strongly promotes fracture healing by secondary intention (callus formation) in a diaphyseal fracture?

. Absolute stability with rigid compression plate fixation
. Interfragmentary compression using multiple lag screws
. Relative stability with a cast or intramedullary nail
. A wide fracture gap greater than 2 cm
. A rigid external fixator with no dynamization

Correct Answer & Explanation

. Relative stability with a cast or intramedullary nail

Explanation

Fracture healing by secondary intention (callus formation) requires a mechanical environment of relative stability, which permits micromotion. This micromotion stimulates chondrogenesis and subsequent endochondral ossification. Absolute stability (plates, lag screws) minimizes interfragmentary strain, leading to primary (Haversian) bone healing without a visible callus.

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