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2. Trauma MCQs

Practice Set 222 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 4421

Topic: 2. Trauma
A 28-year-old man sustains a displaced, vertically oriented (Pauwels Type III) femoral neck fracture. Which of the following fixation constructs is shown biomechanically to provide the greatest stability against the high shear forces in this fracture pattern?
. Three parallel partially threaded cancellous screws placed in an inverted triangle
. Two parallel partially threaded cancellous screws
. A sliding hip screw (SHS) combined with an anti-rotation screw
. A long cephalomedullary nail
. A fully threaded single cancellous lag screw

Correct Answer & Explanation

. A sliding hip screw (SHS) combined with an anti-rotation screw

Explanation

Pauwels Type III fractures are highly vertical shear fractures (angle > 50 degrees) that are prone to varus collapse and nonunion. Biomechanical studies have demonstrated that fixed-angle devices, such as a sliding hip screw (SHS) supplemented with an anti-rotation screw, provide superior biomechanical stability against vertical shear forces compared to multiple parallel cancellous screws.

Question 4422

Topic: 2. Trauma

A 28-year-old comatose male is admitted to the ICU following a motor vehicle accident resulting in a closed tibia fracture. His blood pressure is 100/60 mmHg. Intracompartmental pressure monitoring of the anterior compartment of the injured leg reads 35 mmHg. What is the most appropriate next step in management?

. Administer intravenous mannitol
. Elevate the leg above the level of the heart
. Perform emergent four-compartment fasciotomies of the leg
. Repeat the intracompartmental pressure measurement in 2 hours
. Apply a tight compression dressing to reduce swelling

Correct Answer & Explanation

. Administer intravenous mannitol

Explanation

In obtunded or comatose patients, the diagnosis of acute compartment syndrome relies on objective pressure measurements. The 'delta P' (diastolic blood pressure minus compartment pressure) is the standard metric. A delta P of 30 mmHg or less is an absolute indication for emergent fasciotomy. In this patient, the diastolic BP is 60 mmHg and the compartment pressure is 35 mmHg, yielding a delta P of 25 mmHg. Therefore, an emergent four-compartment fasciotomy is indicated.

Question 4423

Topic: 2. Trauma
A 45-year-old pedestrian is struck by a car. Radiographs and CT reveal a depressed fracture of the lateral tibial plateau accompanied by a transverse fracture line separating the condyles from the tibial shaft (metaphyseal-diaphyseal dissociation). A representative image is shown. According to the Schatzker classification, what type of fracture is this?
. Schatzker Type II
. Schatzker Type IV
. Schatzker Type V
. Schatzker Type VI
. Schatzker Type III

Correct Answer & Explanation

. Schatzker Type VI

Explanation

The Schatzker classification is used for tibial plateau fractures. Schatzker Type VI is defined by metaphyseal-diaphyseal dissociation, meaning a fracture line totally separates the articular condyles from the tibial diaphysis. This is a high-energy injury often associated with significant soft-tissue damage and compartment syndrome. Schatzker I-III involve only the lateral plateau; Schatzker IV involves the medial plateau; Schatzker V is a bicondylar fracture but the metaphysis remains attached to the diaphysis.

Question 4424

Topic: 2. Trauma

A patient sustains a sacral fracture with a vertical fracture line passing directly through the neural foramina. According to the Denis classification, what zone is this fracture, and what is the approximate risk of neurologic injury?

. Zone 1, 5% risk
. Zone 2, 28% risk
. Zone 3, 57% risk
. Zone 1, 28% risk
. Zone 2, 57% risk

Correct Answer & Explanation

. Zone 1, 5% risk

Explanation

According to the Denis classification of sacral fractures: Zone 1 (alar) is lateral to the foramina and has a 5% risk of nerve injury (usually L5). Zone 2 (foraminal) passes through the neural foramina, carrying a 28% risk of neurologic injury (typically radiculopathy). Zone 3 (central canal) involves the central sacral canal medial to the foramina and has a 57% risk of neurologic injury, frequently presenting with bowel or bladder dysfunction.

Question 4425

Topic: 2. Trauma

A 45-year-old male sustains an acetabular fracture in a motor vehicle collision.

Representative radiographs demonstrate disruption of both the anterior and posterior columns. A 'spur sign' is clearly visible on the obturator oblique view. Which of the following is the most likely diagnosis?

. Transverse fracture
. T-type fracture
. Both-column fracture
. Anterior column posterior hemitransverse fracture
. Posterior column fracture

Correct Answer & Explanation

. Transverse fracture

Explanation

The 'spur sign' seen on the obturator oblique radiograph is a pathognomonic finding for a both-column acetabular fracture. It represents the posteroinferior aspect of the intact ilium that has completely dissociated from the articular surface. The presence of this sign confirms that no portion of the articular surface remains attached to the axial skeleton.

Question 4426

Topic: 2. Trauma

A 35-year-old female sustains a complex bicondylar tibial plateau fracture. The CT scan reveals a large posteromedial shear fragment extending to the joint line. Which of the following surgical approaches provides the most direct and optimal access for anti-glide or buttress plating of this specific fragment?

. Anterolateral approach
. Medial parapatellar approach
. Posteromedial approach between the medial gastrocnemius and pes anserinus
. Posterolateral approach between the lateral gastrocnemius and biceps femoris
. Extensile anterior approach with tibial tubercle osteotomy

Correct Answer & Explanation

. Anterolateral approach

Explanation

The standard posteromedial approach to the tibia utilizes the interval between the pes anserinus anteriorly and the medial head of the gastrocnemius posteriorly. It allows direct visualization and orthogonal placement of a buttress or anti-glide plate to neutralize the shear forces of a posteromedial plateau fragment, which is biomechanically superior to anterior-to-posterior lag screws alone.

Question 4427

Topic: 2. Trauma
A 25-year-old male sustains a vertically oriented (Pauwels type III) femoral neck fracture. Which of the following fixation constructs provides the greatest biomechanical stability for this high-shear fracture pattern?
. Three parallel cannulated screws in an inverted triangle
. Three parallel cannulated screws in an upright triangle
. Dynamic hip screw (DHS) with a derotational screw
. Two parallel cannulated screws
. Retrograde intramedullary nail

Correct Answer & Explanation

. Dynamic hip screw (DHS) with a derotational screw

Explanation

Vertically oriented femoral neck fractures (Pauwels III) experience significant shear forces leading to varus collapse. Biomechanical studies have shown that fixed-angle devices, such as a sliding hip screw (DHS), provide superior stability against shear and varus stress compared to multiple cancellous screws. A derotational screw is often added superiorly to prevent rotation during lag screw insertion and to improve overall construct rigidity.

Question 4428

Topic: 2. Trauma



A 40-year-old male sustains a high-energy closed tibial pilon fracture, as demonstrated in the representative clinical image showing severe soft tissue swelling and clear fracture blisters. What is the most appropriate initial management?

. Immediate open reduction and internal fixation (ORIF) of the fibula and tibia
. External fixation spanning the ankle joint with or without fibular fixation
. Cast immobilization for 6 weeks
. Immediate definitive circular external fixation
. Primary ankle arthrodesis

Correct Answer & Explanation

. Immediate open reduction and internal fixation (ORIF) of the fibula and tibia

Explanation

High-energy pilon fractures are notorious for severe soft-tissue compromise. The standard of care is a staged protocol: initial application of a spanning external fixator across the ankle joint (often with limited open fixation of the fibula to restore length, though optional) to allow the soft tissue envelope to recover. Definitive ORIF is delayed until swelling subsides and the 'wrinkle sign' appears, usually 1-3 weeks later.

Question 4429

Topic: 2. Trauma
A 28-year-old male sustains a Gustilo-Anderson Type IIIB open fracture of the distal third of the tibial shaft. After thorough debridement and skeletal stabilization, a 6 cm x 4 cm soft tissue defect with exposed bone devoid of periosteum remains. Which of the following soft tissue coverage options is most appropriate?
. Split-thickness skin graft
. Medial gastrocnemius rotational flap
. Soleus rotational flap
. Free tissue transfer (e.g., anterolateral thigh or latissimus dorsi flap)
. Sural artery neurofasciocutaneous flap

Correct Answer & Explanation

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

Explanation

Soft tissue coverage for the tibia is divided into thirds. The proximal third is typically covered by a medial gastrocnemius flap. The middle third is covered by a soleus flap. The distal third lacks adequate local muscle bulk with a reliable arc of rotation, so Type IIIB defects in the distal third generally require free tissue transfer (such as an ALT, gracilis, or latissimus dorsi free flap) for robust coverage.

Question 4430

Topic: 2. Trauma
A 35-year-old male sustains a displaced Pauwels type III femoral neck fracture in a motor vehicle collision. He is taken to the operating room for open reduction and internal fixation. Which of the following biomechanical constructs provides the most stable fixation for this specific fracture pattern?
. Three parallel cancellous screws placed in an inverted triangle
. A sliding hip screw (SHS) supplemented with an anti-rotation screw
. Two parallel cancellous screws
. Fully threaded cortical lag screws
. A dynamic condylar screw

Correct Answer & Explanation

. A sliding hip screw (SHS) supplemented with an anti-rotation screw

Explanation

Pauwels type III femoral neck fractures are highly vertical (angle > 50 degrees from the horizontal) and experience significant shear forces across the fracture site, predisposing to varus collapse and nonunion. Biomechanical studies have demonstrated that a fixed-angle device, such as a sliding hip screw (SHS), provides superior stability against these shear forces compared to multiple cancellous screws. The addition of a derotational cancellous screw superior to the SHS provides necessary rotational control of the femoral head.

Question 4431

Topic: 2. Trauma
A 34-year-old male cyclist is struck by a motor vehicle and presents to the trauma bay. Radiographs demonstrate a displaced midshaft clavicle fracture and a displaced fracture of the ipsilateral scapular neck, representing a 'floating shoulder' injury. Which of the following represents a generally accepted, strong indication for operative fixation of the clavicle (and potentially the scapula) in this setting?
. The presence of any coracoclavicular ligament disruption
. Medial displacement of the glenoid fragment greater than 10 mm
. The presence of ipsilateral rib fractures
. The 'floating shoulder' pattern is an absolute indication for surgery regardless of displacement
. Any degree of scapular body comminution

Correct Answer & Explanation

. Medial displacement of the glenoid fragment greater than 10 mm

Explanation

A 'floating shoulder' is a double disruption of the superior shoulder suspensory complex (SSSC). While historically thought to be inherently unstable and an absolute indication for surgery, modern evidence suggests that minimally displaced floating shoulders can be treated nonoperatively. However, significant displacement is an indication for surgery. Medialization of the glenoid > 10 mm or angular displacement > 40 degrees are recognized indications for operative fixation (often fixing the clavicle alone is sufficient to restore stability, though both may be addressed).

Question 4432

Topic: Lower Extremity Trauma
A 45-year-old female pedestrian is struck by a motor vehicle. Radiographs of her right knee demonstrate a displaced fracture of the medial tibial plateau with extension into the metaphysis. The lateral tibial plateau is completely intact. How is this fracture classified according to the Schatzker classification system?
. Schatzker II
. Schatzker III
. Schatzker IV
. Schatzker V
. Schatzker VI

Correct Answer & Explanation

. Schatzker IV

Explanation

The Schatzker classification is widely used for tibial plateau fractures. Schatzker I is a lateral split; II is a lateral split-depression; III is a pure lateral depression. Schatzker IV is a fracture of the medial tibial plateau. Schatzker V is a bicondylar fracture, and Schatzker VI involves metaphyseal-diaphyseal dissociation. This isolated medial plateau fracture is a Schatzker IV. It represents a high-energy injury and is highly associated with peroneal nerve and popliteal artery injuries, as well as knee dislocation variants.

Question 4433

Topic: 2. Trauma

A 40-year-old male sustains a Schatzker IV tibial plateau fracture extending into the posteromedial quadrant following a motor vehicle collision. Which of the following best describes the optimal fixation strategy for the posteromedial fragment?

. Anterolateral locking plate with long screws directed posteromedially
. Posteromedial approach with an antiglide buttress plate
. Isolated anterior-to-posterior lag screws
. External fixation spanning the knee without internal fixation
. Medial external fixator with lateral locked plating

Correct Answer & Explanation

. Anterolateral locking plate with long screws directed posteromedially

Explanation

The posteromedial fragment in a Schatzker IV fracture pattern typically involves a vertical shear mechanism. A posteromedial approach with an antiglide buttress plate provides optimal biomechanical stability to counteract the apical shear forces.

Question 4434

Topic: 2. Trauma

A 32-year-old male sustains a high-energy distal femur fracture. CT imaging reveals a coronal plane intra-articular fracture of the lateral femoral condyle (Hoffa fracture).

What is the biomechanically superior method for independent lag screw fixation of this specific fragment?

. Anterior-to-posterior directed lag screws
. Posterior-to-anterior directed lag screws
. Medial-to-lateral directed lag screws
. Lateral-to-medial directed lag screws
. Inferior-to-superior directed lag screws

Correct Answer & Explanation

. Anterior-to-posterior directed lag screws

Explanation

Hoffa fractures are coronal shear fractures of the femoral condyle. Biomechanical studies have demonstrated that posterior-to-anterior (PA) directed lag screws provide significantly greater pullout strength and stability compared to anterior-to-posterior (AP) screws.

Question 4435

Topic: 2. Trauma

A 45-year-old female sustains a lateral compression type II (LC-II) pelvic ring injury, which includes a crescent fracture of the posterior ilium. The stability of the remaining posterior sacroiliac complex hinges on which intact ligamentous structure?

. Anterior sacroiliac ligament
. Posterior sacroiliac ligament
. Sacrotuberous ligament
. Sacrospinous ligament
. Iliolumbar ligament

Correct Answer & Explanation

. Anterior sacroiliac ligament

Explanation

In an LC-II injury, the fracture line exits through the posterior ilium (crescent fracture). The posterior sacroiliac ligaments remain intact, keeping the posterior portion of the ilium tightly bound to the sacrum.

Question 4436

Topic: 2. Trauma

A 35-year-old roofer falls from a ladder and sustains an intra-articular calcaneus fracture.

The Sanders classification is used for surgical planning. This classification is primarily based on the fracture lines seen on which specific imaging view?

. Sagittal CT reconstruction of the anterior process
. Axial CT scan at the level of the sustentaculum tali
. Coronal CT scan at the widest portion of the posterior facet
. Harris axial view radiograph
. Broden's view radiograph

Correct Answer & Explanation

. Sagittal CT reconstruction of the anterior process

Explanation

The Sanders classification for calcaneus fractures is based on the number and location of articular fracture lines through the posterior facet. It is determined using the coronal CT slice at the widest portion of the posterior facet.

Question 4437

Topic: 2. Trauma

A 35-year-old male sustains a comminuted distal femur fracture (OTA/AO 33-C3) with significant articular involvement. During open reduction and internal fixation utilizing a lateral locked plate, the surgeon recognizes a coronal plane fracture of the medial femoral condyle (Hoffa fragment). What is the optimal fixation strategy for this specific fragment?

. Lag screws directed from anterior to posterior
. Lag screws directed from posterior to anterior
. A single fully threaded positioning screw
. Incorporation into the lateral locking plate with a long transcortical screw
. Medial buttress plate placed via a separate subvastus approach

Correct Answer & Explanation

. Lag screws directed from anterior to posterior

Explanation

Medial Hoffa fractures are optimally fixed with anterior-to-posterior oriented lag screws placed perpendicular to the fracture line to maximize compression. Posterior-to-anterior screws are biomechanically strong but surgically difficult to place without extensive soft tissue stripping.

Question 4438

Topic: 2. Trauma

A 42-year-old male sustains a high-energy Schatzker type VI tibial plateau fracture. He presents with massive swelling, fracture blisters, and shortening of the limb. A spanning external fixator is applied. When considering the definitive surgical approach, which structure defines the safe interval for a posteromedial approach to the medial plateau?

. Between the medial head of the gastrocnemius and the soleus
. Between the pes anserinus and the medial collateral ligament
. Between the semimembranosus and the medial head of the gastrocnemius
. Between the medial head of the gastrocnemius and the posterior tibial vessels
. Between the flexor digitorum longus and the tibialis posterior

Correct Answer & Explanation

. Between the medial head of the gastrocnemius and the soleus

Explanation

The posteromedial approach to the tibial plateau utilizes the interval between the medial head of the gastrocnemius (retracted laterally with the neurovascular bundle) and the pes/semimembranosus (retracted medially). This provides direct access to posteromedial shear fragments.

Question 4439

Topic: Pelvic & Acetabular Trauma
A 25-year-old male is brought to the trauma bay after a severe crush injury to the pelvis. AP pelvis radiograph demonstrates widening of the pubic symphysis to 4 cm and disruption of the right sacroiliac joint. Based on the Young-Burgess classification, this anteroposterior compression (APC) III injury involves complete disruption of all the following ligaments EXCEPT:
. Anterior sacroiliac ligaments
. Sacrotuberous ligaments
. Sacrospinous ligaments
. Posterior sacroiliac ligaments
. Iliolumbar ligaments

Correct Answer & Explanation

. Iliolumbar ligaments

Explanation

In an APC III injury, the symphysis is widely disrupted, and the hemipelvis is completely unstable due to tearing of the anterior SI, sacrotuberous, sacrospinous, and posterior SI ligaments. The iliolumbar ligament attaches the L5 transverse process to the iliac crest and is typically disrupted in vertical shear (VS) injuries, not classically in APC injuries.

Question 4440

Topic: 2. Trauma
A 52-year-old woman underwent open reduction and internal fixation for radial and ulnar shaft fractures 2 months ago. In a second fall she refractured her forearm and required revision surgery with bone grafting. One month after the second operation she notes erythema, swelling, and drainage from the volar radial incision. In addition to antibiotic treatment, management should consist of
. observation and splinting.
. local wound drainage under local anesthesia.
. incision and drainage, deep wound cultures, removal of the plates and screws, and cast application.
. incision and drainage, deep wound cultures, and removal of the fixation only if it is loose.
. incision and drainage, deep wound cultures, and bone grafting.

Correct Answer & Explanation

. incision and drainage, deep wound cultures, removal of the plates and screws, and cast application.

Explanation

Deep infections after plating of closed fractures of the forearm are unusual. However, the risk increases with repeat surgeries. Debridement of all infected, nonviable tissue is the initial step in management. The fixation may be retained if it is stable, but if the plate and screws are loose, they should be removed and revision performed after removal of nonviable bone. Either external fixation or repeat plating may be performed. Late infections after fracture union may be treated with plate and screw removal, debridement, and IV antibiotics.

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