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2. Trauma MCQs

Practice Set 568 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 11341

Topic: Pelvic & Acetabular Trauma
A 35-year-old male presents to the trauma bay following a motorcycle collision. Pelvic radiographs demonstrate a 3.5 cm symphyseal diastasis. A CT scan confirms an anteroposterior compression type II (APC-II) pelvic ring injury with disruption of the anterior sacroiliac ligaments but intact posterior sacroiliac ligaments. He is hemodynamically stable. What is the most appropriate definitive management for this patient's pelvic injury?
. Pelvic binder application and strict bed rest for 6 weeks
. Open reduction and internal fixation of the pubic symphysis alone
. Open reduction and internal fixation of the pubic symphysis combined with percutaneous posterior iliosacral screws
. External fixation of the anterior pelvis without internal fixation
. Percutaneous iliosacral screws bilaterally without anterior fixation

Correct Answer & Explanation

. Open reduction and internal fixation of the pubic symphysis alone

Explanation

An APC-II pelvic ring injury represents a rotationally unstable but vertically stable injury characterized by disruption of the symphysis pubis and the anterior sacroiliac ligaments, while the strong posterior sacroiliac ligaments remain intact. Because vertical stability is maintained, anterior ring stabilization alone (most commonly via open reduction and internal fixation of the pubic symphysis with a plate) is sufficient definitive treatment to restore rotational stability. Adding posterior fixation (iliosacral screws) is indicated for APC-III injuries, which involve disruption of both anterior and posterior SI ligaments, rendering the pelvis both rotationally and vertically unstable.

Question 11342

Topic: 2. Trauma

A 64-year-old female presents with insidious onset of right thigh pain. She has been on oral alendronate for the past 9 years for osteoporosis. Radiographs of the right femur reveal a fracture. Which of the following radiographic characteristics is most highly associated with a bisphosphonate-related atypical femur fracture?

. A long oblique fracture line originating on the medial cortex
. A transverse or short oblique fracture line originating on the lateral cortex with focal cortical thickening
. A highly comminuted mid-diaphyseal fracture
. An intertrochanteric fracture with significant posteromedial comminution
. A spiral fracture in the distal third of the femoral diaphysis

Correct Answer & Explanation

. A long oblique fracture line originating on the medial cortex

Explanation

Atypical femur fractures (AFFs) are associated with prolonged bisphosphonate use (typically >5 years), which heavily suppresses bone turnover and allows microdamage accumulation. The American Society for Bone and Mineral Research (ASBMR) criteria for an AFF include a location anywhere from just distal to the lesser trochanter to just proximal to the supracondylar flare. Major features include a transverse or short oblique fracture line, origin at the lateral cortex, noncomminuted or minimally comminuted morphology, and localized periosteal or endosteal thickening of the lateral cortex (beaking) at the fracture site.

Question 11343

Topic: 2. Trauma

A 45-year-old male sustains a high-energy Schatzker Type IV tibial plateau fracture following a fall from a height. Radiographs show a fracture of the medial tibial plateau. Which of the following specific anatomical mechanisms and associated soft-tissue injuries makes this fracture pattern particularly dangerous?

. Impaction of the lateral meniscus causing common peroneal nerve stretch
. Displacement of the posteromedial fragment leading to popliteal artery injury
. Avulsion of the anterior cruciate ligament from the tibial eminence
. Rupture of the patellar tendon leading to superior patellar tracking
. Traction injury to the saphenous nerve from extreme valgus stress

Correct Answer & Explanation

. Impaction of the lateral meniscus causing common peroneal nerve stretch

Explanation

A Schatzker Type IV tibial plateau fracture involves the medial plateau. It is typically a high-energy injury resulting from varus and axial loading. The medial plateau is anatomically larger and stronger than the lateral plateau, so fractures here require more energy. A characteristic sub-variant is the posteromedial shear fragment. Displacement of this posteromedial fragment is extremely hazardous due to its proximity to the popliteal artery as it exits the popliteal fossa beneath the soleus arch. Popliteal artery injury or intimal tear must be meticulously ruled out via thorough vascular examination and ABI/CT angiography if suspected.

Question 11344

Topic: 2. Trauma
A 25-year-old male sustains a comminuted fracture of the tibial diaphysis. In the emergency department, he complains of severe pain out of proportion to the injury, especially with passive stretch of his toes. His blood pressure is 120/70 mmHg. Intracompartmental pressure measurements are obtained. Which of the following thresholds represents an absolute indication for emergency four-compartment fasciotomy?
. Absolute compartment pressure > 20 mmHg
. Systolic blood pressure minus compartment pressure < 40 mmHg
. Diastolic blood pressure minus compartment pressure < 30 mmHg
. Mean arterial pressure minus compartment pressure < 45 mmHg
. Absolute compartment pressure > 25 mmHg

Correct Answer & Explanation

. Diastolic blood pressure minus compartment pressure < 30 mmHg

Explanation

The diagnosis of acute compartment syndrome is primarily clinical, but intracompartmental pressure monitoring is critical in obtunded or polytrauma patients, or when the clinical picture is ambiguous. The most universally accepted objective criterion for performing a fasciotomy is a Delta P (ΔP) of less than 30 mmHg. Delta P is calculated as the patient's Diastolic Blood Pressure minus the Intracompartmental Pressure. Utilizing an absolute compartment pressure threshold (e.g., >30 or >40 mmHg) without accounting for the patient's systemic blood pressure can lead to both under-diagnosis in hypotensive patients and over-diagnosis in hypertensive patients.

Question 11345

Topic: 2. Trauma
A hemodynamically unstable 45-year-old male is brought to the trauma bay after a severe motorcycle crash. A pelvic binder is applied for an anterior-posterior compression (APC) III pelvic ring injury. FAST examination is negative. Despite massive transfusion protocol, the patient remains persistently hypotensive. What is the most appropriate next step in management?
. CT angiography of the pelvis
. Preperitoneal pelvic packing
. Immediate open reduction and internal fixation of the anterior ring
. Bilateral internal iliac artery ligation
. Retrograde urethrogram

Correct Answer & Explanation

. Preperitoneal pelvic packing

Explanation

In a hemodynamically unstable patient with a pelvic fracture, a negative FAST scan, and a properly placed pelvic binder, persistent shock is typically due to retroperitoneal venous or cancellous bone bleeding. Preperitoneal pelvic packing is the immediate treatment of choice in extremis to mechanically tamponade the bleeding. Angiography may follow if packing fails to control arterial bleeding.

Question 11346

Topic: 2. Trauma

A 32-year-old female sustains a closed distal-third spiral fracture of the humeral shaft (Holstein-Lewis fracture). On initial examination in the emergency department, she has a complete radial nerve palsy. What is the most appropriate initial management of the nerve injury?

. Immediate surgical exploration and nerve repair
. Electromyography (EMG) and nerve conduction studies within 24 hours
. Observation and supportive wrist splinting
. Immediate open reduction and internal fixation to decompress the nerve
. Ultrasound-guided perineural steroid injection

Correct Answer & Explanation

. Immediate surgical exploration and nerve repair

Explanation

A primary radial nerve palsy in the setting of a closed humeral shaft fracture (including the Holstein-Lewis type) has a high rate of spontaneous recovery (70-90%). The standard of care is observation and supportive splinting (e.g., dynamic extension splint). Surgical exploration is generally indicated for open fractures, associated vascular injuries, or secondary nerve palsies that develop after closed reduction.

Question 11347

Topic: Lower Extremity Trauma
A 45-year-old pedestrian is struck by a motor vehicle and sustains a severe right knee injury. Radiographs and CT imaging demonstrate a bicondylar fracture involving both the medial and lateral tibial plateaus, with complete dissociation of the articular surfaces from the underlying tibial diaphysis. According to the Schatzker classification, what is the grade of this fracture?
. Schatzker III
. Schatzker IV
. Schatzker V
. Schatzker VI

Correct Answer & Explanation

. Schatzker VI

Explanation

The Schatzker classification divides tibial plateau fractures into six types. Schatzker V is a bicondylar fracture but maintains continuity between the epiphysis/metaphysis and the diaphysis. Schatzker VI involves a bicondylar fracture with complete metaphyseal-diaphyseal dissociation, separating the articular block from the shaft.

Question 11348

Topic: 2. Trauma

When utilizing a posteromedial approach for the open reduction and internal fixation of a posterior shearing tibial plateau fracture, the deep surgical interval is created between which two muscular structures?

. Medial gastrocnemius and Soleus
. Semimembranosus and Medial collateral ligament
. Pes anserinus and Medial head of the gastrocnemius
. Tibialis posterior and Flexor digitorum longus
. Popliteus and Soleus

Correct Answer & Explanation

. Medial gastrocnemius and Soleus

Explanation

The classic posteromedial approach to the tibial plateau relies on developing the interval between the pes anserinus tendons (anteriorly/medially) and the medial head of the gastrocnemius (posteriorly). The medial gastrocnemius is retracted laterally along with the popliteal neurovascular bundle to expose the posterior joint capsule and posteromedial tibia.

Question 11349

Topic: 2. Trauma

In a posterior pelvic ring disruption involving a severe sacroiliac joint dislocation, which arterial vessel is most vulnerable to direct injury and represents the most common source of major pelvic arterial hemorrhage?

. Superior gluteal artery
. Inferior gluteal artery
. Internal pudendal artery
. Obturator artery
. Iliolumbar artery

Correct Answer & Explanation

. Superior gluteal artery

Explanation

In unstable pelvic ring fractures with posterior disruption (e.g., severe sacroiliac joint dislocation or sacral fractures), the superior gluteal artery is the most frequently injured artery. It exits the pelvis through the greater sciatic notch in close proximity to the sacroiliac joint. Anterior ring fractures (like pubic rami fractures) are more associated with obturator or internal pudendal artery injuries, or the corona mortis.

Question 11350

Topic: 2. Trauma

Which type of osteosynthesis provides absolute stability, resulting in primary (direct) bone healing without the formation of a visible fracture callus?

. Intramedullary nailing of a diaphyseal femur fracture
. Bridge plating of a comminuted humeral shaft fracture
. Compression plating of a transverse radius shaft fracture
. External fixation of a severe pilon fracture
. Casting of a non-displaced distal radius fracture

Correct Answer & Explanation

. Intramedullary nailing of a diaphyseal femur fracture

Explanation

Primary (direct) bone healing occurs under conditions of absolute stability (no interfragmentary strain) and direct bone contact. It involves direct Haversian remodeling across the fracture without intermediate callus formation. Compression plating of a transverse fracture provides this absolute stability. Nailing, bridge plating, external fixation, and casting provide relative stability, leading to secondary bone healing (with endochondral ossification and visible callus).

Question 11351

Topic: 2. Trauma
According to the Schatzker classification for tibial plateau fractures, a bicondylar fracture involving both the medial and lateral plateaus is classified as which type?
. Type III
. Type IV
. Type V
. Type VI
. Type II

Correct Answer & Explanation

. Type V

Explanation

The Schatzker classification separates tibial plateau fractures into six types: I (lateral split), II (lateral split-depression), III (lateral pure depression), IV (medial plateau), V (bicondylar plateau), and VI (plateau with diaphyseal-metaphyseal dissociation). A bicondylar fracture without complete dissociation from the diaphysis is a Type V.

Question 11352

Topic: 2. Trauma

A 35-year-old man sustains a closed spiral fracture of the tibial shaft. In the emergency department, his blood pressure is 110/70 mmHg. He is complaining of severe, unrelenting pain out of proportion to the injury. Which of the following compartment pressure measurements represents the most widely accepted absolute threshold for performing an emergent fasciotomy?

. Absolute compartment pressure > 15 mmHg
. Absolute compartment 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 compartment pressure > 15 mmHg

Explanation

The most widely accepted threshold for diagnosing acute compartment syndrome and indicating fasciotomy is a delta pressure (diastolic blood pressure minus compartment pressure) of less than 30 mmHg. Relying on an absolute pressure threshold can result in unnecessary surgeries or missed diagnoses in hypotensive patients.

Question 11353

Topic: 2. Trauma

In evaluating a displaced proximal humerus fracture in an elderly patient, which radiographic parameter is the strongest predictor of humeral head ischemia and potential avascular necrosis?

. Greater tuberosity displacement > 5 mm
. Disruption of the medial calcar hinge (>8 mm length)
. Varus angulation > 20 degrees
. Valgus impaction
. Lesser tuberosity displacement

Correct Answer & Explanation

. Greater tuberosity displacement > 5 mm

Explanation

Disruption of the medial calcar hinge, specifically a metaphyseal head extension of less than 8 mm, is a critical predictor of humeral head ischemia. Other Hertel criteria for ischemia include disruption of the medial hinge and an anatomic neck fracture pattern.

Question 11354

Topic: 2. Trauma

A 40-year-old man sustains a closed spiral fracture of the distal third of the humeral shaft (Holstein-Lewis fracture) with an intact radial nerve on initial exam. Following closed reduction and splinting, he develops a complete radial nerve palsy. What is the most appropriate management?

. Observation and EMG at 6 weeks
. Immediate surgical exploration and fracture fixation
. Change splint to a functional brace
. Administration of high-dose corticosteroids
. Ultrasound-guided nerve block

Correct Answer & Explanation

. Observation and EMG at 6 weeks

Explanation

A secondary radial nerve palsy that develops after closed reduction of a humeral shaft fracture is an absolute indication for immediate surgical exploration. The nerve may be entrapped in the fracture site during the reduction maneuver.

Question 11355

Topic: 2. Trauma

A 35-year-old male develops severe heterotopic ossification (HO) and elbow stiffness 6 months following operative fixation of a distal humerus fracture. He has normal nerve function. What is the optimal timing for surgical excision of the HO?

. Immediately, to prevent further stiffness
. At 3 months, once soft tissues heal
. When trabecular patterns are radiographically mature and alkaline phosphatase is normal
. Wait at least 2 years post-injury
. Once range of motion drops below 30 degrees

Correct Answer & Explanation

. Immediately, to prevent further stiffness

Explanation

Surgical excision of heterotopic ossification around the elbow should be performed when the bone is metabolically quiet and radiographically mature. This is indicated by distinct trabecular margins on X-ray and a normalization of serum alkaline phosphatase.

Question 11356

Topic: 2. Trauma

A 28-year-old cyclist sustains a type IIB distal clavicle fracture according to the Neer classification. What is the primary reason this fracture pattern is associated with a high rate of nonunion with conservative management?

. Disruption of the acromioclavicular (AC) ligaments
. Detachment of the coracoclavicular (CC) ligaments from the proximal fragment
. Poor vascular supply to the lateral clavicle
. Interposition of the deltoid fascia
. Concomitant coracoid process fracture

Correct Answer & Explanation

. Disruption of the acromioclavicular (AC) ligaments

Explanation

In a Neer Type IIB distal clavicle fracture, the CC ligaments remain attached to the distal fragment while the proximal fragment is detached and pulled superiorly by the trapezius. This significant displacement and lack of ligamentous restraint lead to a high nonunion rate.

Question 11357

Topic: 2. Trauma

According to the Hertel criteria, which combination of radiographic findings in a proximal humerus fracture is the strongest predictor for the development of avascular necrosis?

. Calcar length greater than 8 mm and intact medial hinge
. Fracture of the anatomical neck, calcar length less than 8 mm, and disrupted medial hinge
. Fracture of the surgical neck with greater tuberosity displacement
. Four-part valgus impacted fracture with an intact medial periosteal hinge
. Three-part fracture with a calcar length of 12 mm

Correct Answer & Explanation

. Calcar length greater than 8 mm and intact medial hinge

Explanation

Hertel identified that a calcar length of less than 8 mm attached to the articular segment, a disrupted medial hinge, and an anatomical neck fracture are the most reliable predictors of ischemia. This combination yields a 97% positive predictive value for AVN.

Question 11358

Topic: 2. Trauma

According to Hertel's criteria, which of the following radiographic findings is the most reliable predictor of humeral head ischemia in a proximal humerus fracture?

. Greater tuberosity displacement > 5 mm
. Varus angulation of 20 degrees
. Medial calcar hinge length < 8 mm
. Disruption of the lateral periosteum
. Fracture extension into the bicipital groove

Correct Answer & Explanation

. Greater tuberosity displacement > 5 mm

Explanation

A medial metaphyseal head extension (calcar hinge) of less than 8 mm highly predicts humeral head ischemia. This risk is further compounded when combined with an anatomical neck fracture and a disrupted medial hinge.

Question 11359

Topic: Upper Extremity Trauma

During reconstruction of chronic acromioclavicular joint instability, anatomic placement of the coracoclavicular ligament grafts is critical. What are the average distances of the conoid and trapezoid insertions from the distal end of the clavicle?

. Conoid at 1.5 cm, Trapezoid at 3.0 cm
. Conoid at 3.0 cm, Trapezoid at 4.5 cm
. Conoid at 4.5 cm, Trapezoid at 3.0 cm
. Conoid at 2.0 cm, Trapezoid at 5.0 cm
. Conoid at 5.0 cm, Trapezoid at 2.0 cm

Correct Answer & Explanation

. Conoid at 1.5 cm, Trapezoid at 3.0 cm

Explanation

The conoid ligament inserts more medially and posteriorly, averaging 4.5 cm from the distal clavicle. The trapezoid inserts more laterally and anteriorly, averaging 3.0 cm from the distal end.

Question 11360

Topic: 2. Trauma

When treating a comminuted intra-articular distal humerus fracture (AO/OTA 13-C3) with parallel locked plating, which biomechanical principle is essential for construct stability?

. Plates should be placed at a 90-degree angle to each other
. A supracondylar lag screw must be utilized
. Interdigitating screws should tie the medial and lateral columns together
. The lateral plate must be applied to the posterior aspect of the capitellum
. Non-locking screws are strictly contraindicated

Correct Answer & Explanation

. Plates should be placed at a 90-degree angle to each other

Explanation

The parallel plating technique relies on creating a robust arch that maximizes distal fixation. This requires long, interdigitating screws that pass from plate to plate to structurally tie the medial and lateral columns together.

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