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2. Trauma MCQs

Practice Set 198 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 3941

Topic: 2. Trauma

A 26-year-old male sustains a closed comminuted tibial shaft fracture. Two hours post-injury, he complains of severe pain out of proportion to the injury. Which of the following objective measurements is most highly diagnostic for acute compartment syndrome and an absolute indication for 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 < 30 mmHg

Correct Answer & Explanation

. Absolute compartment pressure > 20 mmHg

Explanation

The diagnosis of acute compartment syndrome is most accurately made using the delta P, calculated as Diastolic Blood Pressure minus Compartment Pressure. A delta P of less than 30 mmHg represents inadequate tissue perfusion pressure and is an absolute indication for emergency fasciotomy.

Question 3942

Topic: Upper Extremity Trauma

A 30-year-old cyclist undergoes surgical reconstruction for a severe Type V acromioclavicular (AC) joint separation. To accurately restore the native anatomy of the coracoclavicular ligaments, the surgeon must account for their respective insertions. Which of the following is true regarding the conoid and trapezoid ligaments?

. The conoid inserts anterolaterally and the trapezoid inserts posteromedially on the clavicle.
. The conoid inserts posteromedially and the trapezoid inserts anterolaterally on the clavicle.
. Both ligaments insert strictly on the anterior margin of the clavicle.
. The trapezoid is the primary restraint to superior translation of the clavicle.
. The conoid is the primary restraint to anterior-posterior translation of the clavicle.

Correct Answer & Explanation

. The conoid inserts anterolaterally and the trapezoid inserts posteromedially on the clavicle.

Explanation

The conoid ligament inserts more posteromedially on the conoid tubercle of the clavicle and serves as the primary restraint to superior translation. The trapezoid ligament inserts more anterolaterally on the trapezoid line and is the primary restraint to axial compression (anterior-posterior translation).

Question 3943

Topic: 2. Trauma

A 72-year-old male sustains an acetabular fracture after a low-energy fall. Radiographs demonstrate an anterior column and posterior hemitransverse fracture pattern, and a "gull sign" is present on the AP pelvis radiograph. What does the "gull sign" signify in this context?

. Intrapelvic displacement of the quadrilateral plate
. Superomedial impaction of the acetabular roof
. Marginal impaction of the posterior wall
. Intra-articular loose body in the fovea
. Protrusio acetabuli of the femoral head

Correct Answer & Explanation

. Intrapelvic displacement of the quadrilateral plate

Explanation

The "gull sign" on an AP radiograph of an older patient with an acetabular fracture (typically anterior column posterior hemitransverse) signifies superomedial osteochondral impaction of the acetabular dome (roof). It is a poor prognostic indicator for joint-preserving internal fixation and often prompts consideration for acute total hip arthroplasty.

Question 3944

Topic: Pelvic & Acetabular Trauma
In the Young-Burgess classification of pelvic ring injuries, which of the following structures fails in an Anteroposterior Compression Type III (APC-III) injury but remains completely intact in an APC-II injury?
. Symphysis pubis
. Anterior sacroiliac ligament
. Sacrotuberous ligament
. Posterior sacroiliac ligament
. Sacrospinous ligament

Correct Answer & Explanation

. Posterior sacroiliac ligament

Explanation

An APC-II injury is characterized by symphyseal diastasis and disruption of the anterior sacroiliac, sacrotuberous, and sacrospinous ligaments, resulting in a 'vertically stable but rotationally unstable' pelvis (opening like a book). The defining feature that differentiates an APC-III injury from an APC-II is the complete disruption of the posterior sacroiliac complex (posterior sacroiliac ligaments), rendering the hemipelvis both rotationally and vertically unstable.

Question 3945

Topic: 2. Trauma

A 35-year-old patient sustains a coronal plane fracture of the distal femur (Hoffa fracture) following a high-energy motor vehicle accident. Which portion of the distal femur is most commonly involved in this specific fracture pattern?

. Lateral femoral condyle
. Medial femoral condyle
. Trochlear groove
. Intercondylar notch
. Medial epicondyle

Correct Answer & Explanation

. Lateral femoral condyle

Explanation

A Hoffa fracture (AO/OTA 33-B3) is a coronal shear fracture of the distal femur. It most commonly involves the lateral femoral condyle. The mechanism of injury is typically an axial load applied to a knee in 90 degrees or more of flexion with an associated valgus force. Because of normal physiologic valgus, the lateral condyle receives greater axial stress, making it more prone to this specific shear fracture pattern.

Question 3946

Topic: 2. Trauma

A surgeon is performing an open reduction and internal fixation of a Schatzker IV (medial) tibial plateau fracture utilizing a posteromedial approach. Which of the following defines the primary internervous/intermuscular interval for this surgical approach?

. Between the medial head of the gastrocnemius and the soleus
. Between the semimembranosus and the semitendinosus
. Between the pes anserinus (anteriorly) and the medial head of the gastrocnemius (posteriorly)
. Between the sartorius and the gracilis
. Between the soleus and the flexor digitorum longus

Correct Answer & Explanation

. Between the medial head of the gastrocnemius and the soleus

Explanation

The posteromedial approach to the tibial plateau is the standard workhorse for medial plateau shear fractures. The surgical interval is developed between the pes anserinus tendons (sartorius, gracilis, semitendinosus) anteriorly, and the medial head of the gastrocnemius posteriorly. Retracting the medial gastroc posteriorly protects the neurovascular bundle.

Question 3947

Topic: Upper Extremity Trauma

A 24-year-old professional baseball pitcher presents with posterior elbow pain during the deceleration phase of throwing and loss of terminal extension. He is diagnosed with valgus extension overload syndrome. Where is the characteristic osteophyte located in this condition?

. Anteromedial coronoid process
. Posterolateral olecranon tip
. Anterolateral capitellum
. Radial head
. Posteromedial tip of the olecranon

Correct Answer & Explanation

. Anteromedial coronoid process

Explanation

Valgus extension overload (VEO) syndrome in overhead athletes results from repetitive valgus stress and extreme extension forces. It leads to impingement of the olecranon in the olecranon fossa, characteristically producing an osteophyte at the posteromedial tip of the olecranon.

Question 3948

Topic: 2. Trauma

According to Hertel's radiographic criteria, which of the following is considered the most reliable predictor of humeral head ischemia (avascular necrosis) following a complex proximal humerus fracture?

. Greater tuberosity displacement greater than 5 mm
. Metaphyseal head extension (calcar length) less than 8 mm
. Varus angulation of the head greater than 20 degrees
. Medial hinge remaining intact with 3 mm of displacement
. Disruption of the transverse humeral ligament

Correct Answer & Explanation

. Greater tuberosity displacement greater than 5 mm

Explanation

Hertel described specific criteria predicting ischemia of the humeral head in proximal humerus fractures. The most significant risk factors for AVN include a short metaphyseal head extension (calcar segment attached to the head < 8 mm), disruption of the medial hinge (> 2 mm displacement), and an anatomical neck fracture pattern.

Question 3949

Topic: 2. Trauma

A 30-year-old male is 8 weeks status post open reduction and internal fixation of a Hawkins type II talar neck fracture. An AP radiograph of the ankle demonstrates a subchondral radiolucent band extending across the talar dome. What does this radiographic finding indicate?

. Impending avascular necrosis (AVN) of the talar body
. Subchondral collapse indicative of severe post-traumatic arthritis
. Revascularization of the talar body and a low risk of AVN
. Nonunion of the talar neck fracture
. Active osteomyelitis of the talar dome

Correct Answer & Explanation

. Impending avascular necrosis (AVN) of the talar body

Explanation

The finding described is the 'Hawkins sign', which is a subchondral radiolucent band seen on the AP or mortise radiograph 6-8 weeks following a talar neck fracture. It represents subchondral osteopenia secondary to disuse and active hyperemia, which confirms that the talar body has an intact vascular supply. Its presence is a highly reliable indicator that AVN will NOT occur.

Question 3950

Topic: Upper Extremity Trauma

The coracoclavicular (CC) ligaments are the primary restraints to superior translation of the clavicle relative to the acromion. In normal anatomy, the footprint of the conoid ligament on the undersurface of the clavicle is located in what position relative to the footprint of the trapezoid ligament?

. Posteromedial
. Posterolateral
. Anteromedial
. Anterolateral
. Directly superior

Correct Answer & Explanation

. Posteromedial

Explanation

The CC ligament complex consists of the conoid and trapezoid ligaments. The conoid is located posteromedial to the trapezoid. It attaches to the conoid tubercle of the clavicle and is the primary restraint to superior/inferior translation. The trapezoid is situated anterolateral to the conoid and primarily resists axial compression to the acromioclavicular joint.

Question 3951

Topic: 2. Trauma
A 25-year-old patient sustains a high-energy Pauwels Type III (vertical) femoral neck fracture. Due to the vertical fracture angle, significant shear forces act across the fracture site. Biomechanically, which of the following internal fixation constructs provides the greatest resistance to these vertical shear forces?
. Two parallel 6.5 mm cancellous screws
. Three 6.5 mm cancellous screws placed in an inverted triangle
. A 4.5 mm broad dynamic compression plate
. External fixation using a mono-lateral frame
. A sliding hip screw (fixed-angle device) with a supplemental anti-rotation screw

Correct Answer & Explanation

. A sliding hip screw (fixed-angle device) with a supplemental anti-rotation screw

Explanation

Pauwels Type III femoral neck fractures have a fracture angle > 50 degrees from the horizontal, subjecting the fracture to severe vertical shear forces. Multiple biomechanical studies have proven that a fixed-angle construct, such as a sliding hip screw (often augmented with a derotation screw), is biomechanically superior to multiple parallel cancellous screws at resisting these high shear forces, thereby reducing the rate of nonunion and varus collapse.

Question 3952

Topic: 2. Trauma
A 28-year-old man sustains a displaced, vertical (Pauwels III) femoral neck fracture. To maximize biomechanical stability during internal fixation, which construct is most appropriate?
. Three parallel cancellous screws
. Sliding hip screw with a derotational screw
. Cephalomedullary nail
. Proximal femoral locking plate
. Cannulated screws in an inverted triangle

Correct Answer & Explanation

. Sliding hip screw with a derotational screw

Explanation

Displaced, vertically oriented (Pauwels III) femoral neck fractures in young adults experience high shear forces. A sliding hip screw with a derotational screw provides superior biomechanical stability against vertical shear compared to multiple cancellous screws.

Question 3953

Topic: 2. Trauma

A 40-year-old woman sustains a Schatzker VI tibial plateau fracture. Postoperatively, she develops severe pain with passive stretch of her hallux. Intracompartmental pressure testing is ordered. Which of the following pressure readings definitively indicates the need for emergent fasciotomy?

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

Correct Answer & Explanation

. Absolute pressure > 20 mmHg

Explanation

Compartment syndrome is best diagnosed using the delta pressure, calculated as diastolic blood pressure minus compartment pressure. A delta pressure of less than 30 mmHg is an accepted indication for emergent fasciotomy.

Question 3954

Topic: 2. Trauma

A 35-year-old man sustains a closed distal third spiral fracture of the humerus (Holstein-Lewis fracture) with an immediate, complete radial nerve palsy. What is the most appropriate initial management?

. Immediate open reduction internal fixation with radial nerve exploration
. Closed reduction and coaptation splinting
. Electromyography (EMG) followed by surgical planning
. External fixation
. Functional bracing immediately without reduction

Correct Answer & Explanation

. Immediate open reduction internal fixation with radial nerve exploration

Explanation

Immediate radial nerve palsy associated with a closed humeral shaft fracture is initially treated observationally, usually with a coaptation splint or functional brace. Nerve exploration is indicated if the palsy develops after a closed reduction attempt or fails to recover by 3-4 months.

Question 3955

Topic: 2. Trauma
A 27-year-old man sustains a displaced talar neck fracture (Hawkins Type III). Radiographs obtained 8 weeks post-operatively demonstrate a subchondral radiolucent line in the talar dome. What does this finding indicate?
. Early onset of avascular necrosis
. Osteochondral defect
. Revascularization and intact blood supply
. Post-traumatic osteoarthritis
. Nonunion of the fracture

Correct Answer & Explanation

. Revascularization and intact blood supply

Explanation

The Hawkins sign is a subchondral radiolucent band seen 6-8 weeks post-injury on an AP or mortise view of the ankle. It represents subchondral osteopenia due to hyperemia, indicating an intact blood supply and effectively ruling out avascular necrosis.

Question 3956

Topic: 2. Trauma

A 65-year-old osteoporotic woman undergoes locked plating for a supracondylar distal femur fracture. Which of the following biomechanical principles will increase the working length and decrease the stiffness of the construct, promoting secondary bone healing?

. Placing all screws close to the fracture site
. Using bicortical locking screws exclusively
. Omitting screws in the holes immediately adjacent to the fracture
. Using a plate made of stainless steel instead of titanium
. Applying absolute stability with lag screws

Correct Answer & Explanation

. Placing all screws close to the fracture site

Explanation

Omitting screws close to the fracture increases the working length of the plate. This reduces construct stiffness and allows for controlled micromotion, which promotes secondary bone healing via robust callus formation.

Question 3957

Topic: 2. Trauma

An extensile lateral approach is planned for open reduction and internal fixation of a displaced intra-articular calcaneus fracture. The full-thickness soft tissue flap must be carefully elevated deep to the periosteum to protect the flap's primary blood supply. Which artery provides this primary blood supply?

. Medial plantar artery
. Lateral calcaneal artery
. Sural artery
. Dorsalis pedis artery
. Peroneal artery

Correct Answer & Explanation

. Medial plantar artery

Explanation

The lateral calcaneal artery, a terminal branch of the peroneal artery, provides the primary blood supply to the lateral soft tissues of the heel. The extensile lateral approach relies on creating a full-thickness subperiosteal flap to protect this critical vascular network.

Question 3958

Topic: 2. Trauma

A 19-year-old soccer player sustains an ACL tear. Radiographs show a small avulsion fracture from the lateral tibial plateau (Segond fracture). This avulsion represents the bony attachment of which capsuloligamentous structure?

. Iliotibial band
. Lateral collateral ligament
. Anterolateral ligament
. Popliteofibular ligament
. Biceps femoris tendon

Correct Answer & Explanation

. Iliotibial band

Explanation

A Segond fracture is a pathognomonic avulsion fracture of the lateral tibial plateau heavily associated with ACL tears. It is recognized as the tibial insertion of the anterolateral ligament (ALL) and the meniscotibial band of the lateral capsule.

Question 3959

Topic: 2. Trauma

A 25-year-old man sustains a low-velocity gunshot wound to the thigh resulting in a comminuted femoral shaft fracture. There is no evidence of an expanding hematoma, and distal pulses are intact and symmetric. What is the most appropriate initial management of the wound and fracture?

. Emergent open debridement of the bullet track and external fixation
. Local wound care, IV antibiotics, and retrograde or antegrade intramedullary nailing
. Excision of the bullet, extensive fascial release, and plate fixation
. Arteriography followed by immediate intramedullary nailing
. Primary closure of the wound and cast bracing

Correct Answer & Explanation

. Emergent open debridement of the bullet track and external fixation

Explanation

Low-velocity gunshot wounds with associated femur fractures and no hard signs of vascular injury can be safely managed with local wound care, a short course of IV antibiotics, and standard intramedullary nailing without formal surgical debridement of the bullet track.

Question 3960

Topic: Pelvic & Acetabular Trauma

A 35-year-old male sustains an anteroposterior compression (APC-II) pelvic ring injury following a motorcycle collision. Based on the Young-Burgess classification, which of the following posterior pelvic ligaments remains intact by definition in this injury pattern?

. Anterior sacroiliac ligament
. Sacrotuberous ligament
. Sacrospinous ligament
. Posterior sacroiliac ligament
. Symphyseal ligament

Correct Answer & Explanation

. Anterior sacroiliac ligament

Explanation

An APC-II injury is characterized by symphyseal diastasis and disruption of the anterior sacroiliac, sacrotuberous, and sacrospinous ligaments. The posterior sacroiliac ligaments remain intact, providing rotational instability but maintaining vertical stability.

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