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2. Trauma MCQs

Practice Set 247 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 4921

Topic: 2. Trauma

In a completely displaced proximal third subtrochanteric femur fracture, the proximal fragment is typically displaced in which of the following directions due to unresisted muscle forces?

. Flexion, adduction, and internal rotation
. Extension, abduction, and external rotation
. Flexion, abduction, and external rotation
. Extension, adduction, and internal rotation
. Flexion, abduction, and internal rotation

Correct Answer & Explanation

. Flexion, abduction, and external rotation

Explanation

The proximal fragment is pulled into flexion by the iliopsoas, abduction by the gluteus medius and minimus, and external rotation by the short external rotators. Understanding these deforming forces is critical for obtaining an anatomic reduction during intramedullary nailing.

Question 4922

Topic: Pelvic & Acetabular Trauma
A hemodynamically unstable trauma patient with an APC-III pelvic ring injury requires emergent pelvic binder application in the trauma bay. For maximum biomechanical efficacy, over which anatomic landmark should the binder be centered?
. Iliac crests
. Anterior superior iliac spines
. Greater trochanters
. Pubic symphysis
. Subtrochanteric region

Correct Answer & Explanation

. Greater trochanters

Explanation

Pelvic binders are most effective at reducing pelvic volume and stabilizing the ring when centered directly over the greater trochanters. Placement over the iliac crests is a common error and provides suboptimal reduction.

Question 4923

Topic: 2. Trauma

A 25-year-old male sustains a severe closed tibial shaft fracture. You suspect acute compartment syndrome but the patient is obtunded. Which of the following intracompartmental pressure measurements represents the most reliable threshold for diagnosing compartment syndrome and proceeding with fasciotomy?

. Absolute compartment pressure > 20 mmHg
. Absolute compartment 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 < 50 mmHg

Correct Answer & Explanation

. Diastolic blood pressure minus compartment pressure < 30 mmHg

Explanation

The delta pressure (diastolic blood pressure minus intracompartmental pressure) is the most reliable physiologic indicator for compartment syndrome. A delta P of less than 30 mmHg is the widely accepted threshold indicating the need for emergent fasciotomy.

Question 4924

Topic: 2. Trauma

A 22-year-old elite collegiate soccer player sustains an acute, non-displaced fracture at the metaphyseal-diaphyseal junction of the fifth metatarsal. What is the most appropriate management to minimize time off the field and reduce the risk of nonunion?

. Strict non-weight bearing in a short leg cast for 6 weeks
. Protected weight bearing in a CAM boot for 4 weeks
. Intramedullary screw fixation
. Tension band wiring
. Open reduction and locking plate fixation

Correct Answer & Explanation

. Intramedullary screw fixation

Explanation

Fractures at the metaphyseal-diaphyseal junction (Jones fractures) have a high rate of nonunion due to watershed vascularity. In high-level athletes, early intramedullary screw fixation significantly reduces nonunion risk and accelerates return to play compared to conservative management.

Question 4925

Topic: 2. Trauma

A 40-year-old sustains a bicondylar tibial plateau fracture with a large, displaced posteromedial fragment. Through which anatomic interval is the standard posteromedial approach to the tibia performed?

. Between the medial gastrocnemius and soleus
. Between the semitendinosus and medial gastrocnemius
. Between the medial head of the gastrocnemius and the pes anserinus tendons
. Between the tibialis anterior and extensor hallucis longus
. Between the peroneus brevis and flexor hallucis longus

Correct Answer & Explanation

. Between the medial head of the gastrocnemius and the pes anserinus tendons

Explanation

The posteromedial approach to the tibial plateau typically exploits the interval between the medial head of the gastrocnemius (which is retracted posteriorly) and the pes anserinus tendons (which are retracted anteriorly). This provides direct access to the posteromedial buttress.

Question 4926

Topic: 2. Trauma

The Sanders classification is utilized for preoperative planning of intra-articular calcaneus fractures. This classification is based on the number and location of fracture lines viewed on which specific imaging sequence?

. Lateral plain radiograph
. Axial plain radiograph (Harris view)
. Sagittal CT reconstruction
. Coronal CT reconstruction
. Axial CT reconstruction

Correct Answer & Explanation

. Coronal CT reconstruction

Explanation

The Sanders classification specifically evaluates the posterior facet of the calcaneus. It is based exclusively on the number and location of primary fracture lines seen on the coronal CT reconstruction at the widest point of the posterior facet.

Question 4927

Topic: 2. Trauma
A 30-year-old male sustains a vertically oriented (Pauwels type III) femoral neck fracture. Which of the following internal fixation constructs provides the highest biomechanical stability against the high shear forces inherent to this specific fracture pattern?
. Three parallel cancellous screws in an inverted triangle configuration
. A sliding hip screw combined with a derotational cancellous screw
. Two parallel cancellous screws placed centrally
. A short retrograde intramedullary nail
. A proximal femoral hook plate

Correct Answer & Explanation

. A sliding hip screw combined with a derotational cancellous screw

Explanation

Pauwels type III (vertical) femoral neck fractures experience extremely high shear forces leading to varus collapse and nonunion. Biomechanical studies consistently show that a sliding hip screw combined with a derotational screw provides superior fixation and higher load-to-failure compared to multiple cancellous screws.

Question 4928

Topic: 2. Trauma

A 42-year-old sustains a severe, closed tibial pilon fracture with massive soft tissue swelling. Initial management consists of a spanning external fixator. What specific clinical sign dictates the safest appropriate timing for definitive open reduction and internal fixation?

. Presence of a positive 'wrinkle sign' on the ankle soft tissues
. Normalization of acute phase reactants (CRP and ESR)
. Radiographic evidence of initial bridging callus formation
. CT demonstration of less than 5 mm of articular step-off
. Return of biphasic signals on doppler of the dorsalis pedis artery

Correct Answer & Explanation

. Presence of a positive 'wrinkle sign' on the ankle soft tissues

Explanation

Definitive open fixation of a severe pilon fracture should be delayed until the soft tissue envelope has adequately recovered to minimize wound complications. The reappearance of skin wrinkles (the 'wrinkle sign') indicates the resolution of profound edema and readiness for surgical incision.

Question 4929

Topic: 2. Trauma

A polytrauma patient with a severe bilateral pulmonary contusion and bilateral closed femoral shaft fractures presents in extremis with a serum lactate of 5.0 mmol/L. What is the primary physiologic rationale for performing temporary external fixation rather than immediate intramedullary nailing of the femurs?

. To reduce the risk of femoral head avascular necrosis
. To avoid the 'second hit' phenomenon and minimize the risk of ARDS
. To provide superior biomechanical stability for immediate mobilization
. To preserve the fracture hematoma for faster endochondral ossification
. To allow for continuous minimally invasive compartment pressure monitoring

Correct Answer & Explanation

. To avoid the 'second hit' phenomenon and minimize the risk of ARDS

Explanation

In critically ill polytrauma patients (borderline or in extremis), early definitive surgery such as intramedullary reaming and nailing acts as an inflammatory 'second hit'. This releases inflammatory mediators and marrow fat that can precipitate ARDS or multi-organ failure, a risk mitigated by damage control orthopedics (external fixation).

Question 4930

Topic: 2. Trauma

A 42-year-old female presents with a medial tibial plateau fracture. Examination reveals tense leg compartments and pain with passive toe extension. What is the most appropriate sequence of surgical management?

. Fasciotomy alone followed by delayed fixation
. External fixation followed by fasciotomy
. Four-compartment fasciotomy with simultaneous definitive or temporary skeletal stabilization
. Definitive ORIF followed by fasciotomy
. Observation and elevation of the limb

Correct Answer & Explanation

. Four-compartment fasciotomy with simultaneous definitive or temporary skeletal stabilization

Explanation

In the setting of a tibial plateau fracture with compartment syndrome, skeletal stabilization (temporary spanning external fixation or definitive ORIF) should be performed concurrently with a four-compartment fasciotomy. This prevents further soft tissue injury and protects the fasciotomy repairs.

Question 4931

Topic: 2. Trauma
A 25-year-old male sustains a vertically oriented, displaced Pauwels type III femoral neck fracture. Biomechanically, which fixation construct provides the most stable construct to resist shear forces?
. Three parallel cancellous screws
. Dynamic hip screw (DHS) with a derotational screw
. Cephalomedullary nail
. Two crossed partially threaded screws
. Cannulated screws with a medial buttress plate

Correct Answer & Explanation

. Dynamic hip screw (DHS) with a derotational screw

Explanation

Pauwels type III fractures have a high vertical angle, generating high shear forces. A fixed-angle device, such as a sliding hip screw (DHS) with an anti-rotation screw, is biomechanically superior to parallel screws in resisting these vertical shear forces.

Question 4932

Topic: 2. Trauma
A polytrauma patient presents in hemorrhagic shock with an anteroposterior compression (APC) type III pelvic ring injury. A pelvic binder is to be applied. At what anatomic level should the binder be centered to optimally reduce the pelvic volume?
. Anterior superior iliac spines
. Greater trochanters
. Iliac crests
. Pubic symphysis
. Sacral promontory

Correct Answer & Explanation

. Greater trochanters

Explanation

Pelvic binders must be centered over the greater trochanters to effectively reduce the pelvic volume by closing the pubic symphysis. Placement over the iliac crests is incorrect and can paradoxically widen the pelvic floor.

Question 4933

Topic: 2. Trauma
A 35-year-old construction worker sustains a Gustilo-Anderson type IIIB open tibia fracture. What is the recommended timeframe for achieving definitive soft-tissue coverage to minimize the risk of deep infection?
. Within 24 hours
. Within 72 hours
. Within 5 to 7 days
. Within 14 days
. After 21 days when granulation tissue forms

Correct Answer & Explanation

. Within 5 to 7 days

Explanation

Evidence demonstrates that achieving definitive soft-tissue coverage (e.g., free flap or rotational flap) within 5 to 7 days of injury significantly reduces the risk of deep infection. Coverage beyond this period is associated with substantially higher flap failure and infection rates.

Question 4934

Topic: 2. Trauma

A 29-year-old male sustains a closed distal third spiral fracture of the humerus (Holstein-Lewis) with an intact radial nerve on initial presentation. Following closed reduction and splinting, he develops a complete radial nerve palsy. What is the most appropriate management?

. Observation with EMG at 6 weeks
. Immediate surgical exploration and fracture fixation
. Conversion to a functional brace
. Administration of high-dose corticosteroids
. Ultrasound-guided nerve block

Correct Answer & Explanation

. Immediate surgical exploration and fracture fixation

Explanation

A secondary (post-reduction) radial nerve palsy in the setting of a Holstein-Lewis fracture is an absolute indication for immediate surgical exploration. The nerve is at high risk of becoming entrapped within the fracture site during the reduction maneuver.

Question 4935

Topic: 2. Trauma
A 30-year-old male sustains a displaced talar neck fracture with subluxation of the subtalar joint, but the ankle joint remains congruous. According to the Hawkins classification, what type of fracture is this, and what is the approximate risk of avascular necrosis (AVN)?
. Hawkins I; 0-10% risk
. Hawkins II; 20-50% risk
. Hawkins III; 80-100% risk
. Hawkins IV; 100% risk
. Hawkins II; 80-100% risk

Correct Answer & Explanation

. Hawkins II; 20-50% risk

Explanation

A Hawkins type II fracture is characterized by a talar neck fracture with subtalar joint subluxation or dislocation while the tibiotalar joint remains intact. The reported risk of avascular necrosis (AVN) for type II fractures is approximately 20-50%.

Question 4936

Topic: 2. Trauma

A 50-year-old female driver presents after a high-speed motor vehicle collision with an isolated, displaced sternal fracture. Her initial ECG shows sinus tachycardia, and her vital signs are stable. Which of the following is the most appropriate next step in evaluating for blunt cardiac injury?

. Immediate transesophageal echocardiography
. Cardiac troponin I and 12-lead ECG
. Coronary angiography
. CT angiogram of the chest
. Discharge with outpatient cardiology follow-up

Correct Answer & Explanation

. Cardiac troponin I and 12-lead ECG

Explanation

In patients with blunt chest trauma and suspected blunt cardiac injury, screening with an admission 12-lead ECG and cardiac troponin is recommended. If both are normal, clinically significant blunt cardiac injury is effectively ruled out.

Question 4937

Topic: 2. Trauma

A 40-year-old male sustains a high-energy closed tibial pilon fracture. The soft tissues are severely swollen with fracture blisters. What is the standard staged protocol to minimize soft-tissue complications?

. Immediate definitive ORIF with dual plating
. Spanning external fixation with fibular fixation, followed by delayed tibial ORIF
. Application of a circular frame within 24 hours
. Closed reduction and casting for 6 weeks
. Immediate definitive ORIF of the tibia, delaying the fibula

Correct Answer & Explanation

. Spanning external fixation with fibular fixation, followed by delayed tibial ORIF

Explanation

High-energy pilon fractures with severe soft-tissue compromise are best managed with a staged protocol. Initial spanning external fixation allows soft tissue recovery, followed by delayed definitive tibial ORIF once swelling subsides and the 'wrinkle sign' appears.

Question 4938

Topic: 2. Trauma

What is the most common fracture associated with acute compartment syndrome in the pediatric population?

. Supracondylar humerus fracture
. Femoral shaft fracture
. Tibial shaft fracture
. Both-bone forearm fracture
. Distal radius fracture

Correct Answer & Explanation

. Tibial shaft fracture

Explanation

Tibial shaft fractures are the most common cause of acute compartment syndrome in children, similar to adults. Although supracondylar humerus fractures are a classic cause of upper extremity compartment syndrome, tibial fractures hold the highest overall incidence.

Question 4939

Topic: 2. Trauma

A 35-year-old male presents with a Schatzker IV medial tibial plateau fracture following a high-energy motorcycle collision. Which of the following is true regarding this specific injury pattern compared to Schatzker II lateral plateau fractures?

. Higher association with isolated peroneal nerve palsy
. Usually results from a low-energy valgus mechanism
. Higher incidence of popliteal artery injury
. Routinely treated with isolated lateral locking plating
. Associated with a significantly lower rate of compartment syndrome

Correct Answer & Explanation

. Higher incidence of popliteal artery injury

Explanation

Schatzker IV (medial plateau) fractures typically result from high-energy varus and axial loading forces and are considered knee dislocation equivalents. Consequently, they carry a significantly higher rate of popliteal artery injury and compartment syndrome compared to lateral plateau fractures.

Question 4940

Topic: 2. Trauma

A 25-year-old male sustains a high-energy distal femur fracture. CT imaging reveals a coronal plane fracture of the posterior aspect of the lateral femoral condyle (Hoffa fracture). What is the biomechanically optimal fixation strategy for this specific articular component?

. Anterior-to-posterior directed lag screws
. Posterior-to-anterior directed lag screws
. Isolated lateral locking plate
. Medial and lateral spanning external fixation
. Retrograde intramedullary nail without independent screws

Correct Answer & Explanation

. Anterior-to-posterior directed lag screws

Explanation

A Hoffa fracture is a coronal shear fracture of the posterior femoral condyle. Biomechanical studies demonstrate that anterior-to-posterior (AP) directed lag screws placed perpendicular to the fracture line provide superior fixation and stability compared to posterior-to-anterior screws.

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