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2. Trauma MCQs

Practice Set 24 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 461

Topic: 2. Trauma

A 28-year-old male sustains a closed tibia fracture and develops acute compartment syndrome. During a four-compartment fasciotomy via a two-incision technique, which nerve is at greatest risk of injury during the lateral incision?

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

Correct Answer & Explanation

. Superficial peroneal nerve

Explanation

The lateral incision for a two-incision lower leg fasciotomy is typically placed between the anterior and lateral compartments. The superficial peroneal nerve is at high risk during this incision as it exits the deep fascia in the distal third of the leg.

Question 462

Topic: Pelvic & Acetabular Trauma
A 35-year-old hemodynamically unstable male is brought to the trauma bay after a high-speed motor vehicle collision. Radiographs demonstrate an anteroposterior compression type III (APC-III) pelvic ring injury. Following application of a pelvic binder and initiation of a massive transfusion protocol, the patient remains hypotensive. A FAST exam is negative. What is the most appropriate next step in management?
. Immediate exploratory laparotomy
. Preperitoneal pelvic packing or pelvic angiography
. Application of a lower extremity traction pin
. Transfer to the CT scanner for a contrast-enhanced scan
. Administration of intravenous mannitol

Correct Answer & Explanation

. Preperitoneal pelvic packing or pelvic angiography

Explanation

In hemodynamically unstable patients with pelvic ring injuries and a negative FAST, the source of bleeding is presumed to be the pelvis. Immediate mechanical stabilization followed by preperitoneal packing or angiography is critical to control venous and arterial hemorrhage.

Question 463

Topic: 2. Trauma

A 28-year-old male is admitted with a closed midshaft tibia fracture. Six hours post-admission, he requires increasing doses of opioids and complains of excruciating pain with passive stretch of his toes. A compartment pressure measurement using a Stryker needle shows 45 mmHg. His diastolic blood pressure is 60 mmHg. What is the indicated treatment?

. Elevate the leg above the level of the heart and reassess in 2 hours
. Bivalve the cast and apply ice
. Administer intravenous mannitol and hypertonic saline
. Perform a four-compartment fasciotomy of the leg
. Proceed to immediate internal fixation with an intramedullary nail

Correct Answer & Explanation

. Perform a four-compartment fasciotomy of the leg

Explanation

The patient has signs of acute compartment syndrome, confirmed by a delta pressure (diastolic BP - compartment pressure) of less than 30 mmHg (60 - 45 = 15 mmHg). A four-compartment fasciotomy is the definitive and urgent surgical treatment.

Question 464

Topic: 2. Trauma

A 32-year-old male sustains a diaphyseal fracture of the proximal third of the radial shaft. Following the fracture, the proximal fragment assumes a characteristic resting position. Which of the following describes the typical position of the proximal fragment and its primary deforming forces?

. Flexed and supinated due to the action of the biceps and supinator
. Extended and pronated due to the action of the triceps and pronator teres
. Flexed and pronated due to the action of the brachialis and pronator quadratus
. Extended and supinated due to the action of the extensor carpi radialis longus
. Neutral position due to balanced forces from the interosseous membrane

Correct Answer & Explanation

. Flexed and supinated due to the action of the biceps and supinator

Explanation

In proximal-third radius fractures, the proximal fragment is acted upon by the supinator and the biceps brachii, leading to a flexed and supinated position. The distal fragment is pulled into pronation by the pronator teres and pronator quadratus.

Question 465

Topic: 2. Trauma

A 25-year-old male presents to the emergency department with a grossly contaminated, open middle-third humeral shaft fracture. Upon neurologic examination, he is unable to extend his wrist or fingers, and lacks sensation in the first dorsal web space. What is the most appropriate management plan regarding the fracture and nerve injury?

. Irrigation and debridement, application of a functional brace, and observation of the nerve
. Irrigation and debridement, ORIF of the humerus, and exploration of the radial nerve
. Irrigation and debridement, external fixation, and delayed nerve repair
. Immediate amputation due to the combination of open fracture and nerve palsy
. Intravenous antibiotics and splinting, deferring surgery until soft tissues heal

Correct Answer & Explanation

. Irrigation and debridement, ORIF of the humerus, and exploration of the radial nerve

Explanation

While closed humeral shaft fractures with radial nerve palsies are typically observed, an open humeral shaft fracture is an absolute indication for surgical intervention. In the setting of an open fracture with a nerve palsy, simultaneous nerve exploration is indicated during the I&D and ORIF.

Question 466

Topic: Pelvic & Acetabular Trauma
A 24-year-old motorcyclist sustains an Anteroposterior Compression (APC) III pelvic ring injury. Disruption of which of the following ligamentous structures distinguishes an APC III injury from an APC II injury?
. Anterior sacroiliac ligament
. Sacrotuberous ligament
. Sacrospinous ligament
. Posterior sacroiliac ligament
. Iliolumbar ligament

Correct Answer & Explanation

. Posterior sacroiliac ligament

Explanation

An APC II injury involves disruption of the anterior sacroiliac, sacrotuberous, and sacrospinous ligaments. An APC III injury is characterized by the additional complete disruption of the posterior sacroiliac ligaments, leading to complete hemipelvic instability.

Question 467

Topic: 2. Trauma

In the treatment of a proximal pole scaphoid nonunion, vascularized bone grafting is being considered. The major blood supply to the scaphoid enters distally and is derived primarily from which of the following vessels?

. Anterior interosseous artery
. Dorsal carpal branch of the radial artery
. Superficial palmar arch
. Deep palmar arch
. Ulnar artery

Correct Answer & Explanation

. Dorsal carpal branch of the radial artery

Explanation

The scaphoid is predominantly supplied by the dorsal carpal branch of the radial artery, which enters the dorsal ridge distally. This retrograde blood supply puts the proximal pole at high risk for avascular necrosis following fracture.

Question 468

Topic: Lower Extremity Trauma

A 45-year-old man sustains a Schatzker IV tibial plateau fracture featuring a displaced posteromedial fragment. Which surgical approach provides the most direct access for the application of a buttress plate to this specific fragment?

. Anterolateral approach
. Direct anterior approach
. Posteromedial approach between the medial gastrocnemius and pes anserinus
. Posterolateral approach with fibular osteotomy
. Medial parapatellar approach

Correct Answer & Explanation

. Posteromedial approach between the medial gastrocnemius and pes anserinus

Explanation

A posteromedial approach utilizing the interval between the medial head of the gastrocnemius and the pes anserinus allows for direct visualization and the application of an anti-glide buttress plate to the posteromedial fragment.

Question 469

Topic: 2. Trauma
A 25-year-old man sustains a high-energy Pauwels type III femoral neck fracture. Biomechanically, which of the following internal fixation constructs provides the most stability against the high shear forces inherent to this specific fracture pattern?
. Three parallel cancellous screws placed in an inverted triangle
. A dynamic hip screw (DHS) with a supplemental derotation screw
. Two parallel cancellous screws placed inferiorly
. A fully threaded solitary intramedullary nail
. A short-thread cannulated screw construct

Correct Answer & Explanation

. A dynamic hip screw (DHS) with a supplemental derotation screw

Explanation

Pauwels III fractures have a vertically oriented fracture line, generating extremely high shear forces across the fracture site. A fixed-angle device such as a dynamic hip screw (often combined with a derotation screw) provides superior biomechanical stability compared to multiple independent cancellous screws.

Question 470

Topic: 2. Trauma

A 32-year-old man undergoes intramedullary nailing of a closed, highly comminuted tibial shaft fracture. In the recovery room, he complains of unrelenting pain out of proportion to the injury. Which of the following pressure measurement profiles unequivocally confirms the diagnosis of acute compartment syndrome?

. Absolute compartment pressure > 20 mmHg
. Absolute compartment pressure > 25 mmHg
. Mean arterial pressure minus absolute compartment pressure < 40 mmHg
. Diastolic blood pressure minus absolute compartment pressure < 30 mmHg
. Systolic blood pressure minus absolute compartment pressure < 30 mmHg

Correct Answer & Explanation

. Diastolic blood pressure minus absolute compartment pressure < 30 mmHg

Explanation

The Delta P (diastolic blood pressure minus absolute compartment pressure) is the most reliable and validated indicator of acute compartment syndrome. A Delta P of less than 30 mmHg indicates critically inadequate tissue perfusion and is a strict clinical indication for emergent, four-compartment fasciotomy.

Question 471

Topic: Pelvic & Acetabular Trauma

A 45-year-old male presents following a high-speed motorcycle accident. Radiographs reveal an Antero-Posterior Compression (APC) Type II pelvic ring injury. In this specific injury pattern, which of the following structures remains intact, thereby preserving vertical stability?

. Symphysis pubis
. Sacrotuberous ligament
. Sacrospinous ligament
. Posterior sacroiliac ligament
. Anterior sacroiliac ligament

Correct Answer & Explanation

. Posterior sacroiliac ligament

Explanation

In an APC II injury, the anterior sacroiliac, sacrotuberous, and sacrospinous ligaments are ruptured alongside a symphyseal diastasis. The strong posterior sacroiliac ligaments remain intact, which preserves vertical stability despite the rotational instability.

Question 472

Topic: 2. Trauma

A 22-year-old female sustains a displaced basicervical femoral neck fracture. Which of the following fixation constructs provides the most biomechanical stability for this specific fracture pattern?

. Three cancellous lag screws
. Sliding hip screw (SHS) with a derotation screw
. Cephalomedullary nail
. Dynamic condylar screw
. Proximal femoral locking plate

Correct Answer & Explanation

. Sliding hip screw (SHS) with a derotation screw

Explanation

Basicervical fractures behave biomechanically like intertrochanteric fractures. A sliding hip screw (SHS), often combined with a derotation screw, provides superior biomechanical stability compared to multiple cancellous screws for this pattern.

Question 473

Topic: Pelvic & Acetabular Trauma
In anteroposterior compression (APC) type III pelvic ring injuries, massive hemorrhage is most commonly associated with disruption of which of the following structures?
. Superior gluteal artery
. Inferior gluteal artery
. Pre-sacral venous plexus
. Femoral artery
. Internal pudendal artery

Correct Answer & Explanation

. Pre-sacral venous plexus

Explanation

While arterial bleeding (e.g., internal pudendal or obturator) can occur in APC injuries, the most common source of massive hemorrhage in pelvic ring disruptions is the presacral venous plexus and cancellous bone.

Question 474

Topic: 2. Trauma

A 40-year-old male sustains a closed transverse fracture of the middle third of the humerus. On examination, he is unable to extend his wrist or digits. What is the most appropriate initial management of the nerve palsy?

. Immediate surgical exploration of the radial nerve
. Electromyography (EMG) within 48 hours
. Observation and conservative fracture management
. Ultrasound-guided corticosteroid injection
. Open reduction internal fixation with nerve transposition

Correct Answer & Explanation

. Observation and conservative fracture management

Explanation

Primary radial nerve palsy in the setting of a closed humeral shaft fracture has a high rate of spontaneous recovery (>70%). The standard initial management is observation and conservative fracture care (e.g., functional brace or coaptation splint).

Question 475

Topic: 2. Trauma

A 24-year-old male is admitted with a closed midshaft femur fracture. 36 hours post-injury, he develops progressive tachypnea, confusion, and a petechial rash over his axilla. Arterial blood gas reveals a PaO2 of 55 mmHg. What is the most appropriate initial management for this patient's condition?

. Immediate intramedullary nailing of the femur
. Administration of high-dose systemic corticosteroids
. Supportive care with supplemental oxygen and mechanical ventilation if required
. Administration of low molecular weight heparin
. Urgent administration of intravenous antibiotics

Correct Answer & Explanation

. Supportive care with supplemental oxygen and mechanical ventilation if required

Explanation

This patient has classic Fat Embolism Syndrome (FES) manifesting with hypoxia, confusion, and petechial rash. The mainstay of treatment for FES is supportive care, particularly maintaining adequate oxygenation and ventilation. Corticosteroids have not been proven to change mortality once FES develops.

Question 476

Topic: 2. Trauma

A 28-year-old male presents with a closed tibial plateau fracture. He complains of pain out of proportion to his injury and worsening paresthesia in his first web space. His diastolic blood pressure is 80 mmHg. Intracompartmental pressure monitoring reveals an anterior compartment pressure of 55 mmHg. What is the delta pressure, and what is the indicated treatment?

. 25 mmHg; elevate the leg and re-evaluate in 2 hours
. 25 mmHg; emergent four-compartment fasciotomy
. 35 mmHg; observation
. 55 mmHg; emergent four-compartment fasciotomy
. 80 mmHg; application of a bivalved cast

Correct Answer & Explanation

. 55 mmHg; emergent four-compartment fasciotomy

Explanation

Delta pressure is calculated as diastolic blood pressure minus intracompartmental pressure (80 - 55 = 25 mmHg). A delta pressure of less than 30 mmHg is highly indicative of acute compartment syndrome and necessitates emergent four-compartment fasciotomy.

Question 477

Topic: 2. Trauma

A 42-year-old male with multiple pelvic and lower extremity fractures develops acute respiratory distress syndrome (ARDS) on postoperative day 3. His chest radiograph shows diffuse bilateral infiltrates. Which of the following mechanical ventilation strategies is most appropriate to minimize ventilator-induced lung injury?

. High tidal volume and low positive end-expiratory pressure (PEEP)
. Low tidal volume and high PEEP
. High inspiratory flow rate with zero PEEP
. Continuous positive airway pressure (CPAP) without intubation
. High-frequency oscillatory ventilation as first-line therapy

Correct Answer & Explanation

. Low tidal volume and high PEEP

Explanation

The ARDSnet protocol recommends low tidal volumes (6 mL/kg predicted body weight) to prevent volutrauma and appropriately high PEEP to recruit alveoli and prevent atelectrauma. This lung-protective strategy has been shown to significantly reduce mortality in ARDS patients.

Question 478

Topic: 2. Trauma

An 82-year-old female undergoes intramedullary nailing for an intertrochanteric femur fracture. On postoperative day 2, she becomes acutely confused, agitated, and experiences visual hallucinations. Her vital signs are stable, and her laboratory results are unremarkable. What is the most appropriate initial pharmacological intervention if non-pharmacological measures fail?

. Intravenous diazepam
. Oral lorazepam
. Low-dose oral haloperidol
. Intravenous propofol
. Oral zolpidem

Correct Answer & Explanation

. Low-dose oral haloperidol

Explanation

The patient is experiencing postoperative delirium. If non-pharmacological measures fail and the patient requires pharmacological management, a low-dose typical antipsychotic such as haloperidol is the treatment of choice. Benzodiazepines can worsen delirium in the elderly.

Question 479

Topic: 2. Trauma

A 65-year-old female on alendronate for 10 years presents with a non-traumatic, transverse subtrochanteric fracture of her left femur. Radiographs show cortical thickening and a lateral cortical beak. During surgical planning for intramedullary nailing, what specific technical consideration must be accounted for?

. The femur is likely to have an increased anterior bow requiring an over-reamed or smaller radius of curvature nail
. The fracture should be fixed with a sliding hip screw instead of a nail
. Immediate bone grafting is required at the fracture site
. A cephalomedullary nail is contraindicated
. Prophylactic plating of the contralateral femur should be performed simultaneously

Correct Answer & Explanation

. The femur is likely to have an increased anterior bow requiring an over-reamed or smaller radius of curvature nail

Explanation

Atypical femur fractures (AFF) are often associated with an increased anterior and lateral bowing of the femur. Surgeons must account for this by using a nail with a smaller radius of curvature, over-reaming, or using a smaller diameter nail to avoid iatrogenic fracture during insertion.

Question 480

Topic: 2. Trauma

A 32-year-old male presents 8 months after intramedullary nailing of a closed tibial shaft fracture. He reports persistent pain with weight-bearing. Radiographs demonstrate a hypertrophic nonunion at the fracture site. What is the most appropriate surgical treatment?

. Removal of hardware and application of an Ilizarov frame
. Exchange nailing with a larger diameter reamed intramedullary nail
. Autologous iliac crest bone grafting without hardware exchange
. Pulsed electromagnetic field therapy
. Plate osteosynthesis with decortication

Correct Answer & Explanation

. Exchange nailing with a larger diameter reamed intramedullary nail

Explanation

Hypertrophic nonunions possess adequate biology but lack sufficient mechanical stability. Exchange nailing with a larger, reamed intramedullary nail provides the necessary biomechanical stability and stimulates osteogenesis via the reamings, leading to high union rates.

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