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2. Trauma MCQs

Practice Set 560 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 11181

Topic: 2. Trauma

A 19-year-old cyclist falls directly onto his shoulder and sustains a midshaft clavicle fracture. Which of the following is an absolute indication for open reduction and internal fixation?

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

Correct Answer & Explanation

. 1.5 cm of shortening

Explanation

Absolute indications for operative fixation of a clavicle fracture include open fractures, associated neurovascular injury, and "floating shoulder" (scapular neck fracture with clavicle fracture). Skin tenting, 100% displacement, and shortening > 2 cm are generally considered relative indications depending on the patient's activity level and expectations.

Question 11182

Topic: 2. Trauma

A 30-year-old male presents with a high-velocity knee dislocation. Upon assessment, he has absent pulses in the foot. An ABI is 0.7. An emergency arteriogram confirms a popliteal artery occlusion. What is the most appropriate sequence of operative treatment?

. Immediate vascular repair followed by external fixation and staged ligament reconstruction.
. Immediate open ligament repair followed by vascular repair.
. Spanning external fixation followed by vascular repair, then staged ligament reconstruction.
. Fasciotomy, then external fixation, followed by vascular repair.
. Observation for 2 hours, then vascular repair if no improvement.

Correct Answer & Explanation

. Immediate vascular repair followed by external fixation and staged ligament reconstruction.

Explanation

In the setting of a knee dislocation with vascular injury (Schenck KD IV/V with vascular compromise), the accepted protocol is to quickly stabilize the knee with a spanning external fixator to prevent disruption of the vascular repair. This is followed by immediate vascular repair (or a temporary shunt depending on ischemia time), and fasciotomies if indicated. Definitive ligamentous reconstruction is typically staged.

Question 11183

Topic: Upper Extremity Trauma
A 28-year-old cyclist falls directly onto his shoulder. Radiographs demonstrate a 150% superior displacement of the clavicle relative to the acromion with no posterior displacement on the axillary view. Which ligaments/structures are disrupted in this injury?
. Acromioclavicular (AC) ligaments only.
. Coracoclavicular (CC) ligaments only.
. Both AC and CC ligaments, with intact deltotrapezial fascia.
. Both AC and CC ligaments, with disruption of the deltotrapezial fascia.
. Coracoacromial (CA) ligament and AC ligaments.

Correct Answer & Explanation

. Both AC and CC ligaments, with disruption of the deltotrapezial fascia.

Explanation

A Type V AC joint injury involves >100% (often up to 300%) superior displacement of the clavicle. This degree of displacement requires disruption of the AC ligaments, CC ligaments, and the stabilizing deltotrapezial fascia. Type III involves up to 100% displacement, where AC and CC are torn, but the deltotrapezial fascia is largely intact.

Question 11184

Topic: Pelvic & Acetabular Trauma

A 21-year-old hockey player presents with groin pain exacerbated by hip flexion and internal rotation. Radiographs demonstrate a pistol grip deformity and an alpha angle of 65 degrees.

In an isolated Cam impingement, where does cartilage delamination typically first occur?

. Posteroinferior acetabulum.
. Anterosuperior acetabulum.
. Central fovea.
. Ligamentum teres insertion.
. Posterior femoral head.

Correct Answer & Explanation

. Posteroinferior acetabulum.

Explanation

Cam morphology involves an aspherical femoral head (reduced head-neck offset) that creates shear forces on the anterosuperior acetabular cartilage during hip flexion and internal rotation. This leads to chondral delamination from the underlying subchondral bone and subsequent labral tears in the anterosuperior quadrant. Pincer impingement typically causes direct labral compression and 'contrecoup' cartilage lesions in the posteroinferior acetabulum.

Question 11185

Topic: 2. Trauma

A 22-year-old cross-country runner presents with bilateral exercise-induced leg pain that forces him to stop running after 2 miles. Symptoms resolve 30 minutes after rest. Compartment pressure testing of the anterior compartment yields a pre-exercise pressure of 20 mmHg, 1-minute post-exercise pressure of 40 mmHg, and 5-minute post-exercise pressure of 30 mmHg. What is the most appropriate management?

. Urgent four-compartment fasciotomy.
. Endoscopic anterior and lateral compartment fasciotomy.
. Change in running footwear only.
. Botulinum toxin injection into the tibialis anterior.
. Medial tibial stress syndrome taping.

Correct Answer & Explanation

. Urgent four-compartment fasciotomy.

Explanation

The patient has Chronic Exertional Compartment Syndrome (CECS). Pedowitz criteria for diagnosis include one or more of the following: resting pressure >= 15 mmHg, 1-minute post-exercise pressure >= 30 mmHg, or 5-minute post-exercise pressure >= 20 mmHg. Given his pressures meet the criteria and he seeks definitive management for athletic limiting pain, an elective fasciotomy (typically anterior and lateral compartments) is the most effective surgical treatment.

Question 11186

Topic: 2. Trauma

A 20-year-old collegiate runner presents with bilateral leg pain that occurs consistently after 15 minutes of running and resolves within 30 minutes of rest. Which of the following intracompartmental pressure measurements confirms the diagnosis of chronic exertional compartment syndrome (CECS)?

. Resting pressure > 10 mm Hg
. 1-minute post-exercise pressure > 30 mm Hg
. 5-minute post-exercise pressure > 15 mm Hg
. 15-minute post-exercise pressure > 20 mm Hg
. Resting pressure > 20 mm Hg

Correct Answer & Explanation

. Resting pressure > 10 mm Hg

Explanation

Pedowitz criteria for chronic exertional compartment syndrome (CECS) include one or more of the following: resting pressure >= 15 mm Hg, 1-minute post-exercise pressure >= 30 mm Hg, or 5-minute post-exercise pressure >= 20 mm Hg.

Question 11187

Topic: Upper Extremity Trauma

During an open coracoclavicular (CC) ligament reconstruction for a type V acromioclavicular joint separation, the surgeon must be aware of the anatomic orientations of the CC ligaments. Which of the following statements is true regarding the conoid and trapezoid ligaments?

. The trapezoid is medial to the conoid
. The conoid originates posterior to the pectoralis minor insertion and attaches to the conoid tubercle on the posterior-inferior clavicle
. The trapezoid primarily resists superior displacement of the clavicle
. The conoid primarily resists anterior-posterior displacement
. Both ligaments attach onto the superior surface of the coracoid process

Correct Answer & Explanation

. The trapezoid is medial to the conoid

Explanation

The conoid ligament is medial to the trapezoid ligament. It originates on the base of the coracoid (posterior to pec minor) and inserts on the conoid tubercle (posterior-inferior clavicle). The conoid primarily resists superior/inferior translation, while the trapezoid primarily resists horizontal (AP) compression/translation.

Question 11188

Topic: 2. Trauma
A 30-year-old male is involved in a high-speed motor vehicle collision and sustains a knee dislocation (Schenck KD-III). Following closed reduction, distal pulses are symmetric but the ankle-brachial index (ABI) is 0.85. What is the most appropriate next step in management?
. Observation and serial vascular checks
. CT Angiography of the lower extremity
. Immediate exploration and vascular bypass
. Immediate open ligamentous reconstruction
. Fasciotomy

Correct Answer & Explanation

. CT Angiography of the lower extremity

Explanation

Following a knee dislocation, vascular assessment is critical to rule out popliteal artery injury. An ABI < 0.9, even with symmetric palpable pulses, necessitates further imaging, typically CT angiography (or arterial duplex ultrasound), to definitively rule out a vascular intimal tear or occlusion. Immediate exploration is indicated for hard signs of vascular injury (e.g., absent pulses after reduction, expanding hematoma).

Question 11189

Topic: 2. Trauma

A 24-year-old marathon runner presents with chronic, bilateral anterolateral leg pain that reliably begins 15 minutes into a run and resolves shortly after resting. Suspecting chronic exertional compartment syndrome (CECS), intracompartmental pressures are measured. According to the Pedowitz criteria, which of the following measurements confirms the diagnosis?

. Resting pressure of 10 mmHg and 1-minute post-exercise pressure of 25 mmHg
. Resting pressure of 12 mmHg and 5-minute post-exercise pressure of 15 mmHg
. Resting pressure of 14 mmHg and 1-minute post-exercise pressure of 28 mmHg
. Resting pressure of 16 mmHg and 1-minute post-exercise pressure of 35 mmHg
. Resting pressure of 8 mmHg and 5-minute post-exercise pressure of 18 mmHg

Correct Answer & Explanation

. Resting pressure of 10 mmHg and 1-minute post-exercise pressure of 25 mmHg

Explanation

The modified Pedowitz criteria for chronic exertional compartment syndrome (CECS) are: (1) Resting pre-exercise pressure >= 15 mmHg; (2) 1-minute post-exercise pressure >= 30 mmHg; or (3) 5-minute post-exercise pressure >= 20 mmHg. A resting pressure of 16 mmHg and 1-minute post-exercise pressure of 35 mmHg meets two of these criteria.

Question 11190

Topic: 2. Trauma

A 19-year-old female collegiate distance runner presents with bilateral anterior leg pain and paresthesias on the dorsum of her foot that reliably occur 15 minutes into a run and resolve 30 minutes after stopping. She undergoes intracompartmental pressure testing. According to the Pedowitz criteria, which of the following pressure measurements is diagnostic for Chronic Exertional Compartment Syndrome (CECS)?

. Pre-exercise pressure > 5 mmHg
. 1-minute post-exercise pressure > 15 mmHg
. 5-minute post-exercise pressure > 20 mmHg
. 15-minute post-exercise pressure > 10 mmHg
. Continuous dynamic pressure > 25 mmHg for 1 minute

Correct Answer & Explanation

. Pre-exercise pressure > 5 mmHg

Explanation

The modified Pedowitz criteria for diagnosing Chronic Exertional Compartment Syndrome (CECS) require one or more of the following intracompartmental pressure values: a pre-exercise (resting) pressure >15 mmHg, a 1-minute post-exercise pressure >30 mmHg, or a 5-minute post-exercise pressure >20 mmHg.

Question 11191

Topic: 2. Trauma

A 22-year-old lacrosse player sustains a rotational ankle injury. Radiographs show no fracture, but the external rotation stress view reveals a medial clear space of 6 mm. MRI confirms a syndesmotic injury.

Which ligament is the first to tear in this sequence and provides the primary resistance to anterior translation of the distal fibula?

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

Correct Answer & Explanation

. Posterior inferior tibiofibular ligament (PITFL)

Explanation

In a syndesmotic 'high ankle' sprain, the anterior inferior tibiofibular ligament (AITFL) is typically the first structure to tear during an external rotation mechanism. It provides approximately 35% of the resistance to lateral displacement of the fibula and is the primary restraint to anterior translation of the distal fibula.

Question 11192

Topic: 2. Trauma

When performing an olecranon osteotomy to gain exposure for fixing a complex intra-articular distal humerus fracture (AO/OTA 13-C3), what is the optimal shape of the osteotomy to maximize postoperative stability, healing surface area, and rotational control?

. Transverse osteotomy at the bare area
. Chevron-shaped osteotomy with the apex pointing distally
. Chevron-shaped osteotomy with the apex pointing proximally
. Oblique osteotomy from proximal-dorsal to distal-volar
. Step-cut osteotomy exiting at the coronoid

Correct Answer & Explanation

. Transverse osteotomy at the bare area

Explanation

A chevron osteotomy with the apex pointing distally is preferred. It provides greater surface area for healing and affords intrinsic rotational stability compared to a standard transverse osteotomy. It is typically directed into the 'bare area' of the trochlear notch.

Question 11193

Topic: 2. Trauma

Which of the following factors has been shown in the literature to be the most significant independent risk factor for nonunion in the nonoperative management of midshaft clavicle fractures?

. Female gender
. Smoking
. Displacement greater than 100% (no cortical contact)
. Comminution
. Fracture shortening of 1.0 cm

Correct Answer & Explanation

. Female gender

Explanation

While smoking and comminution are recognized risk factors, severe displacement (greater than 100%, indicating no cortical contact) and significant shortening (typically >2.0 cm) are the most significant independent predictors of nonunion in nonoperatively treated midshaft clavicle fractures.

Question 11194

Topic: Upper Extremity Trauma

In the surgical treatment of high-grade acromioclavicular (AC) joint separations, reconstruction often targets the coracoclavicular (CC) ligaments. Which of the following accurately describes the anatomy of the native CC ligaments?

. The conoid ligament is medial and posterior to the trapezoid ligament.
. The conoid ligament is lateral and anterior to the trapezoid ligament.
. The trapezoid ligament inserts onto the conoid tubercle of the clavicle.
. The trapezoid ligament provides primary restraint to superior translation of the clavicle.
. The conoid ligament provides primary restraint to axial compression of the AC joint.

Correct Answer & Explanation

. The conoid ligament is medial and posterior to the trapezoid ligament.

Explanation

The coracoclavicular (CC) ligaments consist of the conoid and trapezoid. The conoid ligament is located posteromedially and is the primary restraint to superior translation. The trapezoid is located anterolaterally and provides primary restraint against axial compression.

Question 11195

Topic: 2. Trauma

A 35-year-old female sustains a highly comminuted radial head fracture from a fall. Intraoperatively, the radial head is deemed unreconstructable. Prior to deciding on a radial head arthroplasty versus excision, what intraoperative finding strongly dictates the absolute necessity for a radial head prosthesis?

. Concomitant olecranon fracture
. Positive intraoperative lateral pivot shift test
. Proximal migration of the radius by 3mm under longitudinal traction
. Disruption of the central band of the interosseous membrane
. A tear of the lateral ulnar collateral ligament

Correct Answer & Explanation

. Concomitant olecranon fracture

Explanation

An Essex-Lopresti injury involves a radial head fracture, disruption of the central band of the interosseous membrane, and DRUJ instability. In this setting, the radial head cannot simply be excised; it must be replaced with a prosthesis to prevent severe proximal radial migration and subsequent ulnocarpal impaction.

Question 11196

Topic: 2. Trauma
A 45-year-old female presents with a coronal shear fracture of the distal humerus. The radiograph demonstrates a 'double arc' sign on the lateral view. This radiographic finding is pathognomonic for which specific injury pattern?
. A McKee modification (Type IV) capitellar fracture involving both the capitellum and the majority of the trochlea.
. An isolated Hahn-Steinthal (Type I) capitellar fracture.
. A Kocher-Lorenz (Type II) capitellar fracture with minimal subchondral bone.
. A Broberg-Morrey (Type III) comminuted capitellar fracture.
. An isolated shear fracture of the lateral epicondyle.

Correct Answer & Explanation

. A McKee modification (Type IV) capitellar fracture involving both the capitellum and the majority of the trochlea.

Explanation

The 'double arc' sign on a lateral radiograph of the elbow represents the subchondral bone of the capitellum (one arc) and the lateral ridge of the trochlea (the second arc). It is pathognomonic for a Type IV (McKee modification of the Bryan and Morrey classification) coronal shear fracture, which involves the capitellum extending medially to include most of the trochlea.

Question 11197

Topic: Upper Extremity Trauma

During an anatomic coracoclavicular (CC) ligament reconstruction for a chronic Type V acromioclavicular joint separation, bone tunnels are drilled in the clavicle to recreate the native anatomy. What is the approximate anatomical distance from the distal end of the clavicle to the center of the conoid and trapezoid insertions, respectively?

. Conoid 4.5 cm, Trapezoid 3.0 cm
. Conoid 3.0 cm, Trapezoid 4.5 cm
. Conoid 2.0 cm, Trapezoid 1.0 cm
. Conoid 5.5 cm, Trapezoid 2.5 cm
. Conoid 1.5 cm, Trapezoid 3.0 cm

Correct Answer & Explanation

. Conoid 4.5 cm, Trapezoid 3.0 cm

Explanation

The native coracoclavicular ligaments consist of the conoid (medial and posterior) and the trapezoid (lateral and anterior). The center of the trapezoid insertion is approximately 3.0 cm from the distal clavicle, while the center of the conoid insertion is approximately 4.5 cm from the distal end.

Question 11198

Topic: 2. Trauma

In the surgical management of a displaced 3-part proximal humerus fracture using a locking plate, failure to restore adequate medial cortical support (the medial hinge) most frequently leads to which of the following mechanical failures?

. Excessive valgus collapse of the humeral head.
. Varus collapse of the humeral head and secondary intra-articular screw penetration.
. Atrophic nonunion of the greater tuberosity.
. Anterior dislocation of the humeral head.
. Subacromial impingement secondary to superior plate migration.

Correct Answer & Explanation

. Excessive valgus collapse of the humeral head.

Explanation

Loss of medial calcar support (the medial hinge) in proximal humerus fractures deprives the construct of its structural buttress. With the deforming forces of the rotator cuff, this predictably leads to varus collapse of the humeral head, resulting in the superior screws cutting out and penetrating the articular surface.

Question 11199

Topic: 2. Trauma

Varus posteromedial rotatory instability (VPMRI) of the elbow is characterized by a fracture of the anteromedial facet of the coronoid. What is the typical mechanism of injury that produces this specific instability pattern?

. Axial load, valgus stress, and supination
. Axial load, varus stress, and supination
. Axial load, varus stress, and pronation
. Axial load, valgus stress, and pronation
. Pure hyperextension with sudden elbow flexion

Correct Answer & Explanation

. Axial load, valgus stress, and supination

Explanation

Varus posteromedial rotatory instability (VPMRI) typically occurs from a fall on an outstretched hand resulting in an axial load, varus stress, and pronation. This forces the anteromedial facet of the coronoid against the medial trochlea, causing a fracture, and usually results in rupture of the lateral collateral ligament (LCL) complex.

Question 11200

Topic: 2. Trauma

When evaluating a proximal humerus fracture to determine the risk of developing avascular necrosis (AVN), which of the following radiographic findings (Hertel's criteria) is the most reliable predictor of ischemia to the humeral head?

. Metaphyseal head extension (calcar length) less than 8 mm
. Metaphyseal head extension (calcar length) greater than 15 mm
. Intact medial hinge
. Greater tuberosity displacement greater than 5 mm
. Angulation of the humeral head greater than 45 degrees

Correct Answer & Explanation

. Metaphyseal head extension (calcar length) less than 8 mm

Explanation

Hertel identified specific predictors for AVN in proximal humerus fractures. The highest risk occurs with a metaphyseal head extension (calcar length) of less than 8 mm, disruption of the medial hinge, and a true anatomical neck fracture. A short calcar segment indicates that the ascending branch of the anterior humeral circumflex artery is likely disrupted.

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