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2. Trauma MCQs

Practice Set 339 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 6761

Topic: Pelvic & Acetabular Trauma
A 35-year-old man presents with an anteroposterior compression type III (APC-III) pelvic ring injury following a motorcycle collision. He arrives hypotensive, and a pelvic binder is applied. After receiving 2 units of packed red blood cells, his blood pressure remains 75/40 mm Hg. A Focused Assessment with Sonography for Trauma (FAST) exam is negative. What is the most appropriate next step in management?
. Immediate exploratory laparotomy
. Application of a spanning anterior external fixator
. Preperitoneal pelvic packing or pelvic angiography
. Definitive open reduction and internal fixation of the symphysis pubis
. Bilateral internal iliac artery ligation

Correct Answer & Explanation

. Preperitoneal pelvic packing or pelvic angiography

Explanation

In a hemodynamically unstable patient with a pelvic ring injury and a negative FAST exam, the source of bleeding is likely retroperitoneal. Preperitoneal pelvic packing or pelvic angiography with embolization are the interventions of choice. Exploratory laparotomy is contraindicated for isolated extraperitoneal bleeding.

Question 6762

Topic: 2. Trauma

A 40-year-old man falls from a height and sustains a displaced acetabular fracture. Plain radiographs demonstrate the "spur sign" on the obturator oblique view. Which of the following acetabular fracture patterns is pathognomonic for this radiographic finding?

. Transverse fracture
. Anterior column with posterior hemitransverse fracture
. Both-column fracture
. T-type fracture
. Isolated posterior wall fracture

Correct Answer & Explanation

. Both-column fracture

Explanation

The "spur sign" represents the fractured inferior aspect of the intact iliac wing (the strut) protruding outward and is classically seen on the obturator oblique radiograph. It is pathognomonic for a both-column acetabular fracture, indicating complete dissociation of all articular segments from the axial skeleton.

Question 6763

Topic: 2. Trauma
A 24-year-old male sustains a vertically oriented, displaced femoral neck fracture (Pauwels type III) after a fall from a roof. To minimize shear forces and maximize biomechanical stability, which of the following constructs is most appropriate for definitive fixation?
. Three parallel 7.3-mm cannulated screws
. Sliding hip screw with a derotational cancellous screw
. Uncemented bipolar hemiarthroplasty
. Dynamic condylar screw
. Two parallel 6.5-mm partially threaded screws

Correct Answer & Explanation

. Sliding hip screw with a derotational cancellous screw

Explanation

Pauwels type III femoral neck fractures have a vertical fracture line that subjects the repair to high shear forces, increasing the risk of varus collapse and nonunion. A fixed-angle device such as a sliding hip screw, supplemented with a derotational screw, provides superior biomechanical stability compared to multiple parallel cancellous screws.

Question 6764

Topic: 2. Trauma

A 38-year-old male is brought to the emergency department after a severe crush injury to his right leg. Radiographs reveal a highly comminuted Schatzker VI tibial plateau fracture. He complains of severe, unrelenting leg pain despite intravenous narcotics. Compartment pressure testing reveals an absolute anterior compartment pressure of 42 mm Hg. His current blood pressure is 110/65 mm Hg. What is the most appropriate management?

. Elevation of the leg and observation with serial clinical exams
. Application of a bridging external fixator alone
. Application of a bridging external fixator and four-compartment fasciotomy
. Immediate definitive open reduction and internal fixation with dual plating
. Intravenous administration of mannitol and dexamethasone

Correct Answer & Explanation

. Application of a bridging external fixator and four-compartment fasciotomy

Explanation

The patient has a delta pressure (Diastolic BP - Compartment Pressure) of 23 mm Hg (65 - 42). A delta pressure of 30 mm Hg or less is the threshold for diagnosing acute compartment syndrome, necessitating emergent four-compartment fasciotomy. A bridging external fixator provides necessary skeletal stability while deferring definitive fixation until soft tissues heal.

Question 6765

Topic: 2. Trauma

A 50-year-old construction worker presents with a severe, displaced OTA/AO type 43C3 (pilon) fracture of the distal tibia. Examination reveals marked soft tissue swelling, hemorrhagic fracture blisters, and threatened skin over the medial malleolus. What is the current standard of care for the initial orthopedic management of this injury?

. Immediate open reduction and internal fixation with medial and lateral plating
. Spanning external fixation with delayed definitive internal fixation
. Primary ankle arthrodesis using a retrograde intramedullary nail
. Closed reduction and casting for 6 weeks followed by bracing
. Immediate intramedullary nailing of the tibia with percutaneous screw fixation

Correct Answer & Explanation

. Spanning external fixation with delayed definitive internal fixation

Explanation

High-energy pilon fractures are associated with profound soft-tissue compromise. The standard of care is a two-staged approach: immediate application of a spanning external fixator to restore length and alignment, followed by definitive internal fixation 10-21 days later once the soft tissue swelling and blisters have resolved.

Question 6766

Topic: 2. Trauma

A 26-year-old man sustains bilateral closed femoral shaft fractures, severe pulmonary contusions, and a severe closed head injury (GCS 6) following a motor vehicle accident. He requires aggressive resuscitation and is chemically paralyzed. According to the principles of Damage Control Orthopedics (DCO), what is the most appropriate initial management of his femoral fractures?

. Immediate reamed intramedullary nailing of both femurs
. Immediate unreamed intramedullary nailing of both femurs
. Bilateral skeletal traction until neurosurgical clearance is obtained
. Application of bilateral spanning external fixators
. Bilateral open reduction and internal fixation with locked plates

Correct Answer & Explanation

. Application of bilateral spanning external fixators

Explanation

In a polytrauma patient who is unstable, borderline, or "in extremis" (e.g., severe head injury, lung injury, or shock), the Damage Control Orthopedics (DCO) protocol dictates rapid stabilization to minimize the "second hit." Application of temporary spanning external fixators is the safest and most effective initial treatment.

Question 6767

Topic: 2. Trauma

During the extensile lateral approach for open reduction and internal fixation of a displaced intra-articular calcaneus fracture, the surgeon elevates a full-thickness "no-touch" subperiosteal flap. Which of the following nerves is located within this flap and is at highest risk for iatrogenic injury or entrapment during retraction?

. Deep peroneal nerve
. Superficial peroneal nerve
. Sural nerve
. Medial plantar nerve
. Saphenous nerve

Correct Answer & Explanation

. Sural nerve

Explanation

The sural nerve courses along the lateral aspect of the hindfoot and is intimately involved with the soft tissues elevated during an extensile lateral approach to the calcaneus. A full-thickness subperiosteal flap must be elevated carefully to keep the sural nerve protected within the flap and avoid direct trauma or retraction injury.

Question 6768

Topic: 2. Trauma

A 68-year-old woman sustains a lateral compression type 1 (LC-1) pelvic ring injury after a ground-level fall, presenting with a sacral ala fracture and ipsilateral rami fractures. She is hemodynamically stable. Radiographs show less than 1 cm of posterior displacement. What is the most appropriate initial management strategy?

. Protected weight-bearing and early mobilization
. Percutaneous iliosacral screw fixation
. Open reduction and internal fixation of the pubic symphysis
. Application of an anterior external fixator
. Bed rest in a pelvic binder for 6 weeks

Correct Answer & Explanation

. Protected weight-bearing and early mobilization

Explanation

LC-1 pelvic ring fractures are inherently stable, both rotationally and vertically, due to intact posterior tension band ligaments. In the absence of extreme pain or dynamic instability, nonoperative management with protected weight-bearing and early mobilization is the standard of care.

Question 6769

Topic: 2. Trauma

A 28-year-old man sustains a closed right femoral shaft fracture and severe blunt chest trauma in a motorcycle collision. In the trauma bay, he is hypotensive, tachycardic, and responsive only to pain. A chest radiograph demonstrates bilateral pulmonary contusions, and his serum lactate is 4.5 mmol/L. What is the most appropriate initial orthopaedic management of his femur fracture?

. Antegrade reamed intramedullary nailing
. Spanning external fixation
. Retrograde intramedullary nailing
. Traction pin placement and ICU admission without fracture stabilization
. Open reduction and internal fixation with a dynamic compression plate

Correct Answer & Explanation

. Spanning external fixation

Explanation

In a borderline or unstable polytrauma patient (elevated lactate, severe pulmonary contusion, hypotension), Damage Control Orthopedics (DCO) using rapid spanning external fixation is indicated to minimize the second hit of systemic inflammation.

Question 6770

Topic: 2. Trauma

A 35-year-old woman is involved in a high-speed motor vehicle crash. She sustains a closed midshaft femur fracture and an ipsilateral, highly comminuted midshaft tibia fracture (floating knee). She is hemodynamically stable. Which surgical strategy is most advantageous for definitive management of her femur?

. Antegrade intramedullary nailing
. Open reduction and internal fixation with a locking plate
. Spanning external fixation
. Retrograde intramedullary nailing
. Conservative management in skeletal traction

Correct Answer & Explanation

. Retrograde intramedullary nailing

Explanation

Retrograde femoral nailing is highly advantageous in floating knee injuries because it allows a single sterile setup and a single incisional approach for both the femur and tibia intramedullary nails, saving operative time and minimizing positioning changes.

Question 6771

Topic: 2. Trauma

A 42-year-old man is intubated in the ICU following severe polytrauma. He has a comminuted closed right tibial shaft fracture treated with a spanning external fixator. The nurse reports his leg feels exceptionally tight. Which of the following is the most reliable criterion to diagnose acute compartment syndrome requiring fasciotomy in this obtunded patient?

. Diastolic blood pressure minus compartment pressure < 30 mmHg
. Absolute compartment pressure > 30 mmHg
. Mean arterial pressure minus compartment pressure < 40 mmHg
. Absolute compartment pressure > 20 mmHg
. Loss of the dorsalis pedis pulse

Correct Answer & Explanation

. Diastolic blood pressure minus compartment pressure < 30 mmHg

Explanation

In intubated or obtunded patients where clinical examination is unreliable, continuous compartment pressure monitoring is indicated. A delta pressure (diastolic blood pressure minus compartment pressure) of less than 30 mmHg is the most reliable threshold for diagnosing compartment syndrome.

Question 6772

Topic: 2. Trauma

A 24-year-old man with an isolated closed femoral shaft fracture is placed in skeletal traction overnight due to operating room unavailability. The next morning, he develops sudden hypoxia, a petechial rash over his axillae and chest, and acute confusion. What is the primary pathophysiological mechanism causing this clinical syndrome?

. Deep vein thrombosis traveling to the pulmonary vasculature
. Intimal flap of the femoral artery causing distal ischemia
. Acute respiratory distress syndrome secondary to massive transfusion
. Unrecognized pulmonary contusion evolving into edema
. Release of marrow fat and inflammatory mediators into the systemic venous circulation

Correct Answer & Explanation

. Release of marrow fat and inflammatory mediators into the systemic venous circulation

Explanation

Fat embolism syndrome presents with the classic triad of hypoxia, neurologic abnormalities, and a petechial rash. It is caused by marrow fat entering the venous circulation, which incites a severe systemic inflammatory response.

Question 6773

Topic: 2. Trauma

A 28-year-old male is brought to the ED after a high-speed motorcycle collision. He has bilateral closed femur fractures, a pulmonary contusion, and a closed head injury. His blood pressure is 85/50 mm Hg, heart rate is 125 bpm, and initial serum lactate is 6.5 mmol/L. After initial fluid resuscitation, his lactate remains at 5.0 mmol/L. What is the most appropriate initial management for his femur fractures?

. Early total care with reamed intramedullary nails
. Bilateral unreamed intramedullary nails
. Damage control orthopedics with bilateral spanning external fixators
. Skeletal traction and delayed internal fixation at day 10
. Open reduction and internal fixation with locking plates

Correct Answer & Explanation

. Damage control orthopedics with bilateral spanning external fixators

Explanation

This patient is in a borderline/unstable physiologic state (high lactate, hypotension) indicating inadequate resuscitation. Damage control orthopedics (temporary external fixation) is indicated to avoid the 'second hit' phenomenon associated with prolonged definitive surgery.

Question 6774

Topic: 2. Trauma

A 35-year-old man sustained a closed transverse middle-third tibial shaft fracture treated with a reamed intramedullary nail. Six months postoperatively, he reports persistent pain with weight-bearing. Radiographs demonstrate an oligotrophic nonunion with intact hardware and no signs of infection. What is the most appropriate next step in management?

. Observation and protected weight-bearing for 3 more months
. Autologous bone grafting alone
. Plate augmentation without hardware removal
. Exchange intramedullary nailing with a larger diameter reamed nail
. Removal of hardware and application of a circular external fixator

Correct Answer & Explanation

. Exchange intramedullary nailing with a larger diameter reamed nail

Explanation

Oligotrophic nonunions lack adequate stability despite having some biologic potential. Exchange intramedullary nailing with a larger reamed nail provides increased mechanical stability and stimulates local biology through reaming.

Question 6775

Topic: 2. Trauma

A 28-year-old male polytrauma patient (ISS 38) presents with a severe closed head injury, pulmonary contusions, and a closed midshaft femur fracture. His initial lactate is 5.8 mmol/L and pH is 7.18. What is the most appropriate initial orthopedic management of the femur fracture?

. Intramedullary nailing within 24 hours
. External fixation
. Traction pin and delayed intramedullary nailing at 7 days
. Plate osteosynthesis
. Nonoperative management in a cast

Correct Answer & Explanation

. External fixation

Explanation

This patient is physiologically unstable with severe head and chest injuries, acidosis, and elevated lactate, making him a classic candidate for Damage Control Orthopedics (DCO). External fixation provides rapid skeletal stability while minimizing the physiological hit of systemic embolization from intramedullary reaming. Early total care (ETC) is contraindicated in the setting of severe physiologic exhaustion.

Question 6776

Topic: 2. Trauma

A 34-year-old man sustains a closed midshaft tibial fracture. Twelve hours later, he complains of severe leg pain poorly controlled by opioids. Passive stretch of his hallux elicits excruciating pain. Which of the following compartment pressure measurements is the most accepted threshold for performing a four-compartment fasciotomy?

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

Correct Answer & Explanation

. Diastolic blood pressure minus compartment pressure < 30 mm Hg

Explanation

The delta pressure (diastolic blood pressure minus compartment pressure) is the most reliable objective measure for diagnosing acute compartment syndrome. A delta pressure of less than 30 mm Hg is an absolute indication for emergent four-compartment fasciotomy. Absolute pressures are less reliable due to systemic blood pressure variations.

Question 6777

Topic: 2. Trauma

A 22-year-old man is admitted with a closed transverse femoral shaft fracture. Two days post-injury, he develops a petechial rash over his axilla, confusion, and hypoxemia. Which of the following is the most effective prophylactic measure to prevent this specific complication?

. Administration of high-dose corticosteroids
. Prophylactic placement of an inferior vena cava filter
. Early operative stabilization of the fracture
. Administration of low-molecular-weight heparin
. Aggressive diuresis

Correct Answer & Explanation

. Early operative stabilization of the fracture

Explanation

The patient is presenting with Fat Embolism Syndrome (FES), characterized by the classic triad of hypoxemia, neurological abnormalities, and a petechial rash. The most effective method to reduce the incidence and severity of FES is early operative stabilization of long bone fractures, which limits the release of marrow fat into the venous circulation.

Question 6778

Topic: Pelvic & Acetabular Trauma
An unrestrained driver presents hypotensive and tachycardic after a high-speed collision. Pelvic radiographs reveal an anteroposterior compression (APC) type III pelvic ring injury with complete disruption of the sacroiliac joints. Which of the following is the most appropriate initial step in acute orthopedic management?
. Immediate application of an external fixator
. Application of a pelvic binder centered over the iliac crests
. Application of a pelvic binder centered over the greater trochanters
. Emergent pelvic angiography with embolization
. Immediate retroperitoneal packing

Correct Answer & Explanation

. Application of a pelvic binder centered over the greater trochanters

Explanation

In a hemodynamically unstable patient with an open-book pelvic ring injury, the initial orthopedic step is reducing pelvic volume to assist in tamponading venous bleeding. A pelvic binder must be centered over the greater trochanters to effectively close the pelvic ring; placement over the iliac crests is ineffective and can paradoxically widen the pelvis.

Question 6779

Topic: 2. Trauma

A 30-year-old man sustains a closed fracture of the distal third of the humeral shaft (Holstein-Lewis fracture). On initial presentation, his radial nerve function is intact. Following a closed reduction and splint application, he loses the ability to extend his wrist and fingers. What is the most appropriate next step in management?

. Observation and electromyography (EMG) in 6 weeks
. Immediate surgical exploration and fracture fixation
. Change the splint to a functional brace
. Magnetic resonance imaging (MRI) of the arm
. Ultrasound-guided nerve block

Correct Answer & Explanation

. Immediate surgical exploration and fracture fixation

Explanation

A secondary radial nerve palsy that develops immediately following closed reduction of a humeral shaft fracture is an absolute indication for surgical exploration. The nerve may be entrapped between the fracture fragments. Observation is appropriate for primary radial nerve palsies present before manipulation, but not for secondary palsies post-reduction.

Question 6780

Topic: 2. Trauma

A 45-year-old man undergoes intramedullary nailing of a tibial shaft fracture. Which of the following complications is most frequently reported following this procedure, regardless of whether a parapatellar or transpatellar surgical approach is used?

. Nonunion
. Infection
. Anterior knee pain
. Compartment syndrome
. Hardware failure

Correct Answer & Explanation

. Anterior knee pain

Explanation

Anterior knee pain is the most common complication following intramedullary nailing of the tibia, affecting up to 40-50% of patients. Studies have demonstrated that the incidence of anterior knee pain is not significantly different between transpatellar and medial parapatellar approaches. Prominence of the nail and damage to the infrapatellar branch of the saphenous nerve are implicated.

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