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2. Trauma MCQs

Practice Set 453 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 9041

Topic: 2. Trauma

A 78-year-old female sustains a comminuted 4-part proximal humerus fracture after a fall. Radiographs demonstrate a valgus-impacted head, a head-split component, and severe osteopenia. Which of the following surgical options offers the most reliable restoration of forward elevation in this patient?

. Closed reduction and percutaneous pinning
. Open reduction and internal fixation with a locking plate
. Intramedullary nailing
. Hemiarthroplasty
. Reverse total shoulder arthroplasty

Correct Answer & Explanation

. Reverse total shoulder arthroplasty

Explanation

In elderly patients with complex 4-part proximal humerus fractures and poor bone quality, reverse total shoulder arthroplasty provides reliable pain relief and functional restoration. It bypasses the need for tuberosity healing to achieve active forward elevation.

Question 9042

Topic: Upper Extremity Trauma

A 25-year-old cyclist falls directly onto the point of his right shoulder. Clinical examination reveals profound tenting of the skin over the AC joint. Radiographs show the distal clavicle is displaced superiorly by 150% of the acromion width. The coracoclavicular distance is 28 mm (normal 11-13 mm). According to the Rockwood classification, what is the best treatment option?

. Sling immobilization for 2 weeks followed by range of motion
. Figure-of-eight brace for 6 weeks
. Corticosteroid injection into the AC joint
. Distal clavicle excision (Mumford procedure)
. Operative reconstruction of the coracoclavicular ligaments

Correct Answer & Explanation

. Operative reconstruction of the coracoclavicular ligaments

Explanation

A Rockwood Type V acromioclavicular joint injury involves >100% superior displacement of the clavicle with stripping of the deltopectoral fascia. Due to the severe instability, it typically requires operative intervention with coracoclavicular (CC) ligament reconstruction.

Question 9043

Topic: 2. Trauma

When evaluating a displaced proximal humerus fracture, which of the following radiographic findings is the most reliable predictor of subsequent humeral head ischemia?

. Metaphyseal extension of the head fragment greater than 8 mm
. An intact medial calcar hinge greater than 2 mm
. Disruption of the medial calcar hinge
. Greater tuberosity displacement of 5 mm
. Angulation of the surgical neck greater than 20 degrees

Correct Answer & Explanation

. Disruption of the medial calcar hinge

Explanation

According to Hertel's criteria, the most reliable predictors of humeral head ischemia are a disrupted medial hinge, a short calcar length attached to the articular segment (<8 mm), and an anatomic neck fracture. Disruption of the medial calcar hinge compromises the ascending branches of the anterior humeral circumflex artery.

Question 9044

Topic: 2. Trauma
A 35-year-old cyclist falls directly onto his shoulder and sustains a closed fracture of the distal clavicle. Radiographs show the fracture line is medial to the coracoclavicular ligaments, and the proximal fragment is displaced superiorly by 100%. What is the most appropriate classification and typical treatment for this injury?
. Neer Type I; nonoperative management
. Neer Type II; operative fixation
. Neer Type III; nonoperative management
. Neer Type IV; operative fixation
. Neer Type V; nonoperative management

Correct Answer & Explanation

. Neer Type II; operative fixation

Explanation

This describes a Neer Type II distal clavicle fracture, characterized by a fracture medial to intact coracoclavicular ligaments with significant superior displacement of the proximal fragment. Due to a high rate of nonunion with conservative care, operative fixation is recommended.

Question 9045

Topic: Upper Extremity Trauma

A 25-year-old cyclist falls directly onto the point of his shoulder. Radiographs show a type V acromioclavicular (AC) joint dislocation with 150% superior displacement of the clavicle relative to the acromion. What is the most appropriate management?

. Sling for 1-2 weeks followed by early range of motion
. Corticosteroid injection into the AC joint
. Distal clavicle excision
. Operative AC joint reconstruction
. Figure-of-eight bracing

Correct Answer & Explanation

. Operative AC joint reconstruction

Explanation

Type V AC joint injuries involve severe superior displacement of the clavicle due to disruption of the AC and coracoclavicular ligaments and the deltotrapezial fascia. They are typically treated with operative reconstruction.

Question 9046

Topic: 2. Trauma

A 30-year-old male sustains a midshaft clavicle fracture. Which of the following is considered an absolute indication for open reduction and internal fixation?

. 1 cm of shortening
. 100% displacement
. Open fracture
. Comminuted fracture pattern
. Z-type fracture configuration

Correct Answer & Explanation

. Open fracture

Explanation

Absolute indications for operative treatment of clavicle fractures include open fractures, skin tenting threatening to progress to an open fracture, associated neurovascular compromise, and polytrauma.

Question 9047

Topic: 2. Trauma

According to Hertel's radiographic criteria, which of the following features is the most reliable predictor of subsequent avascular necrosis following a proximal humerus fracture?

. Displaced greater tuberosity fracture
. Metaphyseal head extension less than 8 mm
. Integrity of the medial hinge
. Angulation of the surgical neck
. Displacement of the lesser tuberosity

Correct Answer & Explanation

. Metaphyseal head extension less than 8 mm

Explanation

Hertel identified specific radiographic predictors for ischemia of the humeral head, including a short calcar segment (<8 mm metaphyseal extension), disrupted medial hinge, and complex fracture patterns. A short calcar is highly predictive of AVN.

Question 9048

Topic: 2. Trauma

Which of the following is considered an absolute indication for operative fixation of an acute midshaft clavicle fracture?

. 100% displacement
. 1.5 cm of shortening
. Skin tenting
. Open fracture
. Z-type fracture pattern

Correct Answer & Explanation

. Open fracture

Explanation

Open fractures, compromised skin (impending open), subclavian vessel injury, and symptomatic nonunion are absolute indications for clavicle fracture fixation. Displacement and shortening are relative indications based on patient factors.

Question 9049

Topic: Upper Extremity Trauma

During an anatomic reconstruction of a high-grade acromioclavicular joint separation, the surgeon targets the coracoclavicular ligaments. Which of the following statements regarding the native anatomy is correct?

. The conoid ligament inserts anterolateral to the trapezoid ligament
. The trapezoid ligament inserts posteromedial to the conoid ligament
. The conoid ligament inserts posteromedial to the trapezoid ligament
. Both ligaments insert at the exact same medial-lateral location on the clavicle
. The trapezoid is a cone-shaped ligament providing primary resistance to superior displacement

Correct Answer & Explanation

. The conoid ligament inserts posteromedial to the trapezoid ligament

Explanation

The conoid ligament is cone-shaped and inserts posteromedial to the trapezoid on the conoid tubercle. The trapezoid inserts anterolaterally and acts as the primary restraint to axial compression.

Question 9050

Topic: 2. Trauma

An orthopedic surgeon decides to increase the diameter of a solid titanium intramedullary nail from 10 mm to 12 mm for a femoral shaft fracture. How does this diameter change affect the nail's theoretical bending rigidity?

. Increases by a factor of 1.2
. Increases by a factor of 1.44
. Increases by a factor of 2.07
. Increases by a factor of 4.0
. Increases by a factor of 16.0

Correct Answer & Explanation

. Increases by a factor of 2.07

Explanation

The bending rigidity of a solid cylindrical implant is proportional to the radius to the fourth power (r^4). Increasing the diameter from 10 to 12 mm increases rigidity by (1.2)^4, which equals approximately 2.07.

Question 9051

Topic: 2. Trauma

When applying a dynamic compression plate (DCP) to stabilize a transverse diaphyseal fracture, placing the plate specifically on the tension side of the bone achieves which distinct biomechanical advantage?

. It promotes uninhibited secondary bone healing through significant cyclic micromotion.
. It prevents fracture gap opening by converting bending forces into compressive forces.
. It acts purely as a rigid internal fixator by utilizing angle-stable locking screws.
. It completely eliminates the physiological stress shielding of the underlying cortical bone.
. It redirects pure shear forces into multidirectional torsional forces.

Correct Answer & Explanation

. It prevents fracture gap opening by converting bending forces into compressive forces.

Explanation

Applying a plate to the tension side of an eccentrically loaded bone neutralizes distracting tensile forces. It effectively converts the bending moment into stabilizing compressive forces across the far cortex of the fracture.

Question 9052

Topic: 2. Trauma

In the treatment of a tibial shaft fracture, reaming the medullary canal and inserting a larger diameter intramedullary nail increases the bending stiffness of the construct. Bending stiffness of a solid cylindrical rod is proportional to the radius raised to which power?

. First power
. Second power (squared)
. Third power (cubed)
. Fourth power
. Fifth power

Correct Answer & Explanation

. Fourth power

Explanation

The bending stiffness of a solid cylinder is determined by the area moment of inertia, which is proportional to the radius to the fourth power (r^4). Therefore, a small increase in nail diameter significantly increases stiffness.

Question 9053

Topic: 2. Trauma

When plating a comminuted diaphyseal fracture using a bridge plating technique, increasing the "working length" of the plate will have which of the following biomechanical effects?

. Increase the stiffness of the construct
. Decrease the strain at the fracture site
. Increase the strain at the fracture site
. Decrease the bending flexibility of the plate
. Increase the risk of primary bone healing

Correct Answer & Explanation

. Decrease the strain at the fracture site

Explanation

The working length of a plate is the distance between the two closest screws on either side of the fracture. Increasing the working length decreases construct stiffness, allowing the deformation to be spread over a larger area and thereby decreasing the strain at the fracture gap.

Question 9054

Topic: 2. Trauma

In fracture fixation, the pullout strength of a cortical bone screw is mathematically proportional to several design parameters. Which of the following alterations will most significantly increase the screw's pullout strength?

. Decreasing the outer (thread) diameter
. Increasing the inner (root) diameter
. Increasing the outer (thread) diameter
. Decreasing the thread pitch
. Increasing the length of the unthreaded shank

Correct Answer & Explanation

. Increasing the outer (thread) diameter

Explanation

The pullout strength of a screw is most significantly determined by its outer (thread) diameter. Increasing the outer diameter maximizes the thread depth and volume of bone captured between threads, thereby increasing resistance to pullout.

Question 9055

Topic: 2. Trauma

A 22-year-old football player sustains a non-contact pivoting injury to his knee. Radiographs reveal an avulsion fracture of the lateral tibial plateau (Segond fracture). This radiographic finding is considered pathognomonic for an anterior cruciate ligament tear and represents an avulsion of which structure?

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

Correct Answer & Explanation

. Anterolateral ligament

Explanation

A Segond fracture is an avulsion of the anterolateral ligament (ALL) and capsular tissue from the lateral tibial plateau. It is highly associated with ACL tears and indicates severe rotational instability.

Question 9056

Topic: 2. Trauma

A surgeon is performing a lateral compartment fasciotomy for chronic exertional compartment syndrome. To avoid injuring the superficial peroneal nerve, the surgeon must be aware that the nerve typically pierces the deep fascia to become subcutaneous at what location?

. 2-3 cm proximal to the lateral malleolus
. 10-12 cm proximal to the lateral malleolus
. Within the sinus tarsi
. Posterior to the fibular head
. At the level of the tibial tuberosity

Correct Answer & Explanation

. 10-12 cm proximal to the lateral malleolus

Explanation

The superficial peroneal nerve exits the lateral compartment by piercing the deep crural fascia approximately 10-12 cm proximal to the lateral malleolus. An anterolateral portal or incision in this area puts the nerve at risk.

Question 9057

Topic: 2. Trauma

A 72-year-old woman sustains a displaced femoral neck fracture. She is counseled on the high risk of avascular necrosis and nonunion. The primary blood supply to the adult femoral head comes from the:

. Ligamentum teres artery
. Lateral femoral circumflex artery
. Medial femoral circumflex artery
. Inferior gluteal artery
. Obturator artery

Correct Answer & Explanation

. Medial femoral circumflex artery

Explanation

The medial femoral circumflex artery (MFCA) provides the dominant blood supply to the adult femoral head via the lateral epiphyseal artery. Injury to these vessels during a displaced neck fracture leads to avascular necrosis.

Question 9058

Topic: Lower Extremity Trauma

The popliteal artery is at high risk of stretch injury or transection during high-energy knee dislocations. It is particularly vulnerable due to firm tethering proximally at the adductor hiatus and distally at the:

. Popliteus fascia
. Tendinous arch of the soleus
. Interosseous membrane
. Medial head of the gastrocnemius
. Posterior tibial plateau

Correct Answer & Explanation

. Tendinous arch of the soleus

Explanation

The popliteal artery is firmly fixed distally by the tendinous arch of the soleus muscle, and proximally by the adductor hiatus. These rigid tethering points prevent the artery from accommodating extreme translational forces during knee dislocations.

Question 9059

Topic: 2. Trauma

Avascular necrosis of the scaphoid after fracture is highly dependent on its specific arterial supply. Which statement accurately describes the primary blood supply to the scaphoid?

. It enters the proximal pole and flows distally
. It enters the distal pole and flows proximally via the dorsal carpal branch of the radial artery
. It enters the waist exclusively from the ulnar artery
. It is supplied primarily by the anterior interosseous artery
. It is supplied entirely by the superficial palmar arch

Correct Answer & Explanation

. It enters the distal pole and flows proximally via the dorsal carpal branch of the radial artery

Explanation

The primary blood supply to the scaphoid is from the dorsal carpal branch of the radial artery, which enters the distal pole and provides retrograde flow proximally. This retrograde supply accounts for the high rate of proximal pole nonunions and AVN.

Question 9060

Topic: Lower Extremity Trauma

In the setting of an ankle syndesmotic injury, which ligament provides the greatest resistance to lateral displacement of the fibula?

. Anterior inferior tibiofibular ligament (AITFL)
. Posterior inferior tibiofibular ligament (PITFL)
. Interosseous ligament
. Transverse tibiofibular ligament
. Deltoid ligament

Correct Answer & Explanation

. Posterior inferior tibiofibular ligament (PITFL)

Explanation

Biomechanical studies have shown that the posterior inferior tibiofibular ligament (PITFL) provides the largest contribution (approximately 42%) of the syndesmotic resistance to fibular displacement. The interosseous ligament provides about 22%, and the AITFL provides about 35%.

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