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2. Trauma MCQs

Practice Set 242 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 4821

Topic: 2. Trauma

A 35-year-old man sustains a closed spiral fracture of the distal third of the humeral shaft. Upon initial evaluation, he is unable to extend his wrist or fingers. Following a successful closed reduction and splinting, his radial nerve palsy persists but has not worsened. What is the most appropriate next step in management?

. Immediate surgical exploration of the radial nerve
. EMG and nerve conduction studies within 24 hours
. Observation and supportive splinting for 3 to 4 months
. Ultrasound-guided diagnostic nerve block
. Immediate open reduction and internal fixation

Correct Answer & Explanation

. Observation and supportive splinting for 3 to 4 months

Explanation

Primary radial nerve palsies associated with closed humeral shaft fractures are typically a neuropraxia and should be treated with observation and supportive splinting. Surgical exploration is indicated for open fractures, penetrating trauma, or if a secondary palsy develops after a closed reduction.

Question 4822

Topic: 2. Trauma

A 32-year-old man is admitted with a comminuted fracture of the tibial diaphysis. Twelve hours post-injury, his diastolic blood pressure is 85 mmHg and he complains of severe, unremitting leg pain. Intracompartmental pressure monitoring of the anterior compartment reveals a pressure of 60 mmHg. What is the most appropriate next step in management?

. Elevate the leg above heart level and recheck pressures in 2 hours
. Perform an immediate four-compartment fasciotomy of the leg
. Administer intravenous mannitol and observe closely
. Perform a two-compartment fasciotomy utilizing a single lateral incision
. Obtain urgent CT angiography to rule out arterial injury

Correct Answer & Explanation

. Perform an immediate four-compartment fasciotomy of the leg

Explanation

The patient has a Delta P (Diastolic BP - Compartment Pressure) of 25 mmHg (85 - 60). A Delta P of 30 mmHg or less is an absolute indication for an immediate four-compartment fasciotomy to prevent irreversible muscle and nerve necrosis.

Question 4823

Topic: 2. Trauma

A 63-year-old woman with osteopenia is struck by a motor vehicle and sustains a Schatzker 2 (AO/OTA Type B) fracture of the lateral tibial plateau. She has 1.5 cm of joint depression and 7 mm of condylar widening. What is the most appropriate surgical fixation for this injury?

. Lateral non-locking construct
. Percutaneous screws
. External fixation
. Lateral locking construct
. Medial and lateral plating

Correct Answer & Explanation

. Lateral non-locking construct

Explanation

The patient has a significantly displaced partial articular fracture of the tibial plateau. Surgical treatment is preferred in an effort to restore the axis of the knee, achieve an articular reduction, and allow for repair of commonly associated soft-tissue injuries such as meniscal tears. This requires direct reduction, and fixation should provide subarticular support, interfragmentary compression, and buttress. This is best achieved with an undercontoured lateral nonlocking plate.Illustration A shows a tibial plateau fracture. Incorrect Answers:2: Screws alone are unlikely to be adequately stable in this patient.3: External fixation is not enough to reduce and hold the joint reduced. 4: Locking plates do not provide buttress effect when used in pure locking mode. In addition, locking plates add significant incremental cost to the procedure. 5: A unicondylar injury does not require dual plating.

Question 4824

Topic: Pelvic & Acetabular Trauma
During surgical hip dislocation for the management of femoroacetabular impingement, preservation of what structure is paramount to maintaining vascularity to the femoral head?
. Metaphyseal vessels
. Medial epiphyseal artery
. Superficial branch of the medial femoral circumflex artery
. Deep branch of the lateral femoral circumflex artery
. Deep branch of the medial femoral circumflex artery

Correct Answer & Explanation

. Deep branch of the medial femoral circumflex artery

Explanation

DISCUSSION: When a trochanteric osteotomy is performed with the desire to maintain vascularity to the femoral head, as in the approach for a surgical hip dislocation, the deep branch of the medial femoral circumflex artery must be maintained. This branch courses along the posterior aspect of the greater trochanter, posterior to the tendon of obturator externus, and anterior to the tendons of superior gemellus, obturator internus, and inferior gemellus. It perforates the capsule above the superior gemellus and distal to the tendon of piriformis, before dividing into two to four terminal retinacular branches. Maintaining the attachment of the external rotators maintains the blood supply to the femoral head. Additionally, the superior-lateral retinacular vessels must also be maintained during femoral neck osteoplasty.

Question 4825

Topic: Upper Extremity Trauma
A 14-year-old boy who is right-handed reports right shoulder pain. Radiographs show a lucent lesion of the proximal humeral epiphysis with a narrow zone of transition. Results of an open biopsy confirm the presence of a chondroblastoma. Based on these findings, the next most appropriate step in management should consist of:
. Intralesional curettage and bone grafting
. Intra-articular resection of the proximal humerus and endoprosthetic replacement
. Intra-articular resection of the proximal humerus and osteoarticular allograft reconstruction
. Extra-articular resection of the proximal humerus and allograft arthrodesis of the shoulder
. Observation and serial radiographs

Correct Answer & Explanation

. Intralesional curettage and bone grafting

Explanation

DISCUSSION: The patient has a chondroblastoma of the proximal humerus; therefore, the treatment of choice is curettage and bone grafting. Surgical resection of the proximal humerus is not indicated in the initial treatment of an intraosseous chondroblastoma.

Question 4826

Topic: Pelvic & Acetabular Trauma
A 35-year-old male is brought to the trauma bay after a motorcycle collision. He is hemodynamically unstable with a blood pressure of 80/50 mmHg and a heart rate of 130 bpm. A FAST exam is negative. An anteroposterior pelvic radiograph reveals an anteroposterior compression Type III (APC-III) pelvic ring injury, and a pelvic binder is immediately placed. What is the most common anatomic source of major hemorrhage in this specific injury pattern?
. Superior gluteal artery
. Obturator artery
. Presacral venous plexus
. Internal pudendal artery
. External iliac vein

Correct Answer & Explanation

. Presacral venous plexus

Explanation

In pelvic ring injuries, particularly those involving disruption of the posterior elements (like APC-III and vertical shear patterns), the most common source of major hemorrhage is venous bleeding, accounting for up to 80% of cases. The presacral venous plexus and prevesical venous plexus are the primary venous sources. Arterial bleeding (e.g., superior gluteal, internal pudendal) accounts for approximately 10-20% of cases.

Question 4827

Topic: 2. Trauma

According to the Hertel radiographic criteria for evaluating proximal humerus fractures, which of the following fracture characteristics is considered the most reliable predictor of subsequent avascular necrosis (AVN) of the humeral head?

. Posteromedial hinge disruption greater than 2 mm
. Calcar length greater than 8 mm attached to the articular segment
. Fracture of the greater tuberosity with 5 mm displacement
. Varus angulation of 15 degrees
. Simple two-part surgical neck fracture

Correct Answer & Explanation

. Posteromedial hinge disruption greater than 2 mm

Explanation

Hertel et al. described key radiographic predictors for ischemia of the humeral head in proximal humerus fractures. The most significant predictors for AVN are: an attached posteromedial calcar length of less than 8 mm, disruption of the medial hinge greater than 2 mm, and a basicervical fracture pattern. A medial hinge disruption >2 mm disrupts the ascending branches of the anterior humeral circumflex artery and capsular vessels, critically depriving the head of its blood supply.

Question 4828

Topic: 2. Trauma

A 45-year-old poorly controlled diabetic male presents with a draining sinus over his left anterior tibia. Radiographs demonstrate an infected tibial nonunion with diffuse mechanical instability, though the fibula is intact. According to the Cierny-Mader classification of osteomyelitis, how is this infection staged?

. Stage 1A
. Stage 2B
. Stage 3A
. Stage 4B
. Stage 4C

Correct Answer & Explanation

. Stage 4B

Explanation

The Cierny-Mader classification uses anatomic stage (1: medullary, 2: superficial, 3: localized, 4: diffuse) and host physiologic status (A: normal, B: compromised locally or systemically, C: treatment worse than disease). An infected nonunion or mechanically unstable segment represents a diffuse lesion (Stage 4). Because the patient is a poorly controlled diabetic, he is a systemically compromised host (B-host). Therefore, the correct classification is Stage 4B.

Question 4829

Topic: 2. Trauma

A 28-year-old male polytrauma patient sustains bilateral femoral shaft fractures and severe pulmonary contusions. The surgical team is debating between Early Total Care (ETC) with intramedullary nailing and Damage Control Orthopedics (DCO) with temporary external fixation. According to accepted DCO criteria, which of the following is considered an absolute indication for proceeding with DCO rather than ETC?

. Serum lactate of 2.0 mmol/L
. Platelet count of 110,000 /mm3
. Arterial pH < 7.24
. Core temperature of 35.5°C
. Base deficit of 4 mmol/L

Correct Answer & Explanation

. Arterial pH < 7.24

Explanation

Pape and Giannoudis established clinical parameters for managing polytrauma. Criteria for an 'unstable' patient mandating Damage Control Orthopedics (DCO) rather than Early Total Care (ETC) include: Arterial pH < 7.24, core temperature < 32°C, base deficit > 6-8 mmol/L, coagulopathy, and transfusion requirements of multiple units of packed RBCs. A pH < 7.24 represents severe acidosis, putting the patient at extreme risk for the 'lethal triad' if a lengthy IM nailing is performed.

Question 4830

Topic: 2. Trauma
A 34-year-old male falls from a roof and sustains an isolated, extra-articular fracture of the scapular body and neck. Operative fixation is being considered. Based on the established indications for operative management of extra-articular scapular neck fractures, which of the following is a recognized indication for open reduction and internal fixation?
. Glenopolar angle (GPA) ≤ 22 degrees
. Medial/lateral translation of 5 mm
. Angular deformity of 10 degrees
. Glenopolar angle (GPA) of 35 degrees
. Coracoid base fracture with 2 mm displacement

Correct Answer & Explanation

. Glenopolar angle (GPA) of 35 degrees

Explanation

Operative indications for extra-articular scapular neck fractures are based on severe displacement that severely alters glenohumeral mechanics. Accepted absolute or strong relative indications include: Medial/lateral translation > 20 mm, angular deformity > 45 degrees, and a glenopolar angle (GPA) ≤ 22 degrees. A normal GPA is roughly 30-45 degrees; a decreased angle (<22 degrees) signifies severe rotational malalignment of the glenoid fragment, predisposing to poor functional outcomes.

Question 4831

Topic: 2. Trauma

A 30-year-old male develops acute compartment syndrome of the leg following a closed tibial shaft fracture. He undergoes a standard 4-compartment fasciotomy via a two-incision technique. When making the lateral incision to decompress the anterior and lateral compartments, extending the proximal aspect of the incision too close to the fibular head places which of the following structures at greatest risk of iatrogenic injury?

. Superficial peroneal nerve
. Deep peroneal nerve
. Common peroneal nerve
. Saphenous nerve
. Sural nerve

Correct Answer & Explanation

. Common peroneal nerve

Explanation

The lateral incision in a two-incision leg fasciotomy is used to decompress the anterior and lateral compartments. The incision should stay at least 5 cm distal to the fibular head to avoid iatrogenic injury to the common peroneal nerve, which wraps around the fibular neck before dividing into the deep and superficial peroneal nerves.

Question 4832

Topic: 2. Trauma

A 24-year-old male cyclist falls onto his left shoulder and sustains a closed midshaft clavicle fracture. Which of the following initial radiographic displacement patterns has been shown in large prospective randomized trials to carry the highest risk of nonunion if treated nonoperatively?

. Undisplaced butterfly fragment
. < 1 cm of shortening with a simple oblique pattern
. Fracture translation of 50% without shortening
. Z-type comminution with > 2 cm of shortening
. Inferior angulation of 10 degrees

Correct Answer & Explanation

. Z-type comminution with > 2 cm of shortening

Explanation

Prospective trials (such as those by the Canadian Orthopaedic Trauma Society - COTS) have identified predictors of nonunion for midshaft clavicle fractures. The most significant predictors for nonunion in nonoperatively treated clavicle fractures are complete displacement (lack of cortical contact), severe comminution (Z-type), and initial shortening of greater than 1.5 to 2.0 cm. Z-type comminution with > 2 cm shortening carries an exceptionally high nonunion risk if treated conservatively.

Question 4833

Topic: 2. Trauma
A 35-year-old male sustains an anteroposterior compression (APC III) pelvic ring injury in a motorcycle collision. He arrives in hemorrhagic shock. What is the most common anatomical source of massive retroperitoneal hemorrhage in this specific injury pattern?
. Superior gluteal artery
. Obturator artery
. Internal pudendal artery
. Presacral venous plexus and bleeding cancellous bone
. Corona mortis

Correct Answer & Explanation

. Presacral venous plexus and bleeding cancellous bone

Explanation

While arterial bleeding (e.g., from the internal pudendal or obturator arteries in APC patterns, or superior gluteal in lateral compression patterns) can be severe and life-threatening, approximately 80-90% of all major pelvic hemorrhage arises from the low-pressure, high-volume presacral venous plexus and exposed cancellous bone surfaces at fracture sites.

Question 4834

Topic: 2. Trauma

A 28-year-old male sustains a high-energy distal femur fracture. CT scanning reveals a coronal plane fracture of the lateral femoral condyle. When using independent lag screw fixation for this specific fragment, which of the following screw orientations is considered the most biomechanically sound?

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

Correct Answer & Explanation

. Posterior-to-anterior

Explanation

The injury described is a Hoffa fracture (coronal shear fracture of the femoral condyle). Biomechanical studies demonstrate that posterior-to-anterior directed lag screws are significantly stronger than anterior-to-posterior screws. This is because the screw threads engage the thicker, denser cortical bone of the anterior femur, providing better compression and resistance to shear forces.

Question 4835

Topic: 2. Trauma

A 45-year-old man falls from a 12-foot ladder and sustains an isolated extra-articular scapular body and neck fracture. According to established treatment guidelines (e.g., Ada and Miller / OTA), which of the following radiographic parameters is an absolute indication for open reduction and internal fixation?

. Medial/lateral displacement of 10 mm
. Scapular neck angulation of 25 degrees
. Glenopolar angle (GPA) of 45 degrees
. Scapular body fracture with 15 mm of displacement
. Scapular neck fracture with 45 degrees of angulation

Correct Answer & Explanation

. Scapular neck fracture with 45 degrees of angulation

Explanation

The vast majority of extra-articular scapula fractures are treated non-operatively. Operative indications include: scapular neck angulation >40 degrees, medial/lateral translation >20 mm, and a glenopolar angle <22 degrees (normal is 30-45 degrees). Therefore, a neck fracture with 45 degrees of angulation is an indication for surgery.

Question 4836

Topic: 2. Trauma

During an open reduction and internal fixation of a severe proximal humerus fracture, the surgeon carefully preserves the soft tissue attachments to the tuberosities to maintain perfusion. Recent quantitative anatomical studies have demonstrated that the primary arterial blood supply to the humeral head is provided by which vessel?

. Anterior humeral circumflex artery
. Posterior humeral circumflex artery
. Suprascapular artery
. Thoracoacromial artery
. Circumflex scapular artery

Correct Answer & Explanation

. Posterior humeral circumflex artery

Explanation

Historically, the arcuate branch of the anterior humeral circumflex artery was believed to be the primary blood supply to the humeral head. However, modern quantitative studies (e.g., Hettrich et al.) have proven that the posterior humeral circumflex artery actually supplies the vast majority (approximately 64%) of the blood to the humeral head.

Question 4837

Topic: 2. Trauma

A 24-year-old male sustains a closed comminuted tibial shaft fracture. Three hours after admission, he complains of excruciating pain that is out of proportion to the injury. Which of the following is recognized as the earliest and most sensitive clinical sign of acute compartment syndrome?

. Loss of distal pulses in the dorsalis pedis artery
. Paresthesias in the first web space
. Severe pain with passive stretch of the toes
. Palpably tense and non-compressible compartments
. Pallor and poikilothermia of the foot

Correct Answer & Explanation

. Severe pain with passive stretch of the toes

Explanation

Pain out of proportion to the injury and pain elicited by passive stretch of the muscles traversing the affected compartment are the earliest and most sensitive clinical findings in acute compartment syndrome. Loss of pulses, pallor, and paralysis are late signs, often indicating that irreversible ischemic necrosis has already occurred.

Question 4838

Topic: Upper Extremity Trauma
A 25-year-old mountain biker falls directly onto his shoulder point. Radiographs show a significantly displaced distal clavicle. The injury is classified as a Rockwood Type III acromioclavicular (AC) joint dislocation. Which of the following describes the status of the stabilizing soft tissues in this specific injury grade?
. Acromioclavicular ligaments disrupted, coracoclavicular ligaments intact
. Coracoclavicular ligaments disrupted, acromioclavicular ligaments intact
. Both AC and CC ligaments disrupted, deltotrapezial fascia intact
. Both AC and CC ligaments disrupted, deltotrapezial fascia disrupted
. Isolated disruption of the coracoacromial ligament

Correct Answer & Explanation

. Both AC and CC ligaments disrupted, deltotrapezial fascia intact

Explanation

In a Rockwood Type III injury, both the acromioclavicular (AC) and coracoclavicular (CC) ligaments are completely torn, leading to superior displacement of the clavicle by 25-100% compared to the normal side. The deltotrapezial fascia remains intact. If the deltotrapezial fascia is disrupted, allowing severe subcutaneous displacement, it is classified as a Type V injury.

Question 4839

Topic: 2. Trauma

A 45-year-old male sustains a highly comminuted, high-energy tibial pilon fracture (OTA/AO 43-C3). The soft tissues are severely swollen with extensive fracture blisters. The surgeon places a spanning external fixator across the ankle joint. According to the standard two-stage treatment protocol (Sirkin and Sanders), when is the optimal time to proceed with definitive open reduction and internal fixation of the tibial plafond?

. Within 24 hours of the initial injury
. 3 to 5 days post-injury when initial swelling plateaus
. Once the 'wrinkle sign' appears and fracture blisters have epithelialized (typically 10-21 days)
. Immediately after the ESR and CRP normalize
. After 6 weeks of external fixation

Correct Answer & Explanation

. Once the 'wrinkle sign' appears and fracture blisters have epithelialized (typically 10-21 days)

Explanation

The standard two-stage protocol for severe pilon fractures with compromised soft tissues involves immediate application of a joint-spanning external fixator. Definitive ORIF is delayed until the soft tissues have adequately recovered, which is indicated clinically by the resolution of edema (appearance of the 'wrinkle sign') and epithelialization of fracture blisters. This typically occurs between 10 to 21 days post-injury.

Question 4840

Topic: 2. Trauma
A 42-year-old male sustains a closed transverse acetabular fracture with an associated large Morel-Lavallée lesion over the lateral hip. He requires operative fixation via a Kocher-Langenbeck approach. What is the most appropriate management of the soft tissue lesion to minimize infection risk?
. Ignore the lesion as the skin is closed and intact.
. Percutaneous needle aspiration immediately prior to the surgical incision.
. Open debridement and excision of the pseudocapsule prior to or concurrent with the fracture fixation.
. Placement of a percutaneous drain left in place during fixation without debridement.
. Sclerotherapy with doxycycline 2 weeks prior to surgical fixation.

Correct Answer & Explanation

. Open debridement and excision of the pseudocapsule prior to or concurrent with the fracture fixation.

Explanation

A Morel-Lavallée lesion is a closed internal degloving injury where subcutaneous tissue is separated from the underlying fascia, filling with blood and necrotic fat. If an operative approach must traverse the lesion, open debridement, excision of the necrotic fat and pseudocapsule, and copious irrigation are required to decrease the very high risk of deep postoperative infection. Aspiration alone is insufficient due to retained necrotic debris.

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