Menu

2. Trauma MCQs

Practice Set 570 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 11381

Topic: Pelvic & Acetabular Trauma
According to the Young-Burgess classification, an Anteroposterior Compression Type II (APC-II) pelvic ring injury is characterized by rupture of the anterior sacroiliac ligaments while maintaining the integrity of which specific posterior structures?
. Sacrotuberous ligaments
. Sacrospinous ligaments
. Posterior sacroiliac ligaments
. Symphysis pubis
. Iliolumbar ligaments

Correct Answer & Explanation

. Posterior sacroiliac ligaments

Explanation

An APC-II injury involves pubic symphyseal diastasis and rupture of the anterior sacroiliac ligaments, sacrotuberous, and sacrospinous ligaments. The strong posterior sacroiliac ligaments remain intact, providing vertical stability but resulting in rotational instability ('open book' pelvis). An APC-III injury involves disruption of both anterior and posterior SI ligaments, resulting in both rotational and vertical instability.

Question 11382

Topic: 2. Trauma

A 45-year-old male sustains a posteromedial shear fracture of the tibial plateau (Schatzker IV). To appropriately buttress this fracture fragment, a posteromedial surgical approach is planned. Between which two anatomical structures is the primary internervous/intermuscular interval for this approach?

. Pes anserinus/semimembranosus and the medial head of the gastrocnemius
. Pes anserinus and the superficial medial collateral ligament
. Tibialis anterior and the extensor hallucis longus
. Soleus and the flexor hallucis longus
. Popliteus and the lateral head of the gastrocnemius

Correct Answer & Explanation

. Pes anserinus/semimembranosus and the medial head of the gastrocnemius

Explanation

The posteromedial approach to the tibial plateau utilizes the interval between the pes anserinus and semimembranosus (anteriorly) and the medial head of the gastrocnemius (posteriorly). This retracts the neurovascular bundle posteriorly with the gastrocnemius, allowing safe access to the posteromedial cortex for the placement of an anti-glide or buttress plate.

Question 11383

Topic: 2. Trauma
A 28-year-old male sustains a closed, comminuted midshaft femur fracture. He is hemodynamically stable. The surgeon considers using an unreamed intramedullary nail instead of a reamed intramedullary nail. Which of the following is the most significant clinical disadvantage of unreamed nailing compared to reamed nailing in this specific setting?
. Increased risk of pulmonary embolism and ARDS
. Lower rates of fracture union requiring secondary procedures
. Higher risk of heterotopic ossification
. Longer operative time
. Increased intraoperative blood loss

Correct Answer & Explanation

. Lower rates of fracture union requiring secondary procedures

Explanation

Multiple randomized controlled trials and meta-analyses, including data from the SPRINT trial, have demonstrated that reamed intramedullary nailing of closed femoral shaft fractures yields significantly higher union rates and lowers the need for secondary bone grafting or dynamization compared to unreamed nailing. There is no significant difference in the incidence of pulmonary embolism, ARDS, or mortality between the two techniques, even in multiple trauma patients, provided they are adequately resuscitated.

Question 11384

Topic: 2. Trauma
A 40-year-old female presents to the trauma bay following a high-speed motor vehicle collision. Pelvic radiographs and CT scans demonstrate a transverse sacral fracture with fracture lines extending transversely across the central sacral canal. According to the Denis classification of sacral fractures, which of the following neurologic deficits is most specifically associated with this injury zone compared to lateral zones?
. Ipsilateral foot drop
. Decreased sensation over the first dorsal web space
. Loss of voluntary anal sphincter control
. Diminished patellar tendon reflex
. Weakness of great toe extension

Correct Answer & Explanation

. Loss of voluntary anal sphincter control

Explanation

The patient has a Denis Zone III sacral fracture, which involves the central sacral canal. Zone I (alar) fractures are associated with L5 nerve root injuries (foot drop, great toe extension weakness). Zone II (foraminal) fractures commonly present with sciatica-type symptoms (L5, S1, S2). Zone III (central) fractures carry the highest risk of neurologic injury (up to 57%), specifically involving the sacral nerve roots S2-S4, which present as saddle anesthesia and loss of bowel, bladder, or sexual function (loss of voluntary anal sphincter control).

Question 11385

Topic: 2. Trauma

A 25-year-old male is evaluated for worsening leg pain following a closed tibial shaft fracture sustained in a fall. He requires increasing doses of opioids. Examination reveals tense compartments and pain with passive toe extension. Which of the following pressure measurements is the most widely accepted and accurate threshold for diagnosing acute compartment syndrome and indicating a four-compartment fasciotomy?

. Absolute intracompartmental pressure > 20 mmHg
. Absolute intracompartmental pressure > 25 mmHg
. Delta pressure (Diastolic Blood Pressure - Compartment Pressure) < 30 mmHg
. Delta pressure (Systolic Blood Pressure - Compartment Pressure) < 45 mmHg
. Delta pressure (Mean Arterial Pressure - Compartment Pressure) > 40 mmHg

Correct Answer & Explanation

. Absolute intracompartmental pressure > 20 mmHg

Explanation

The most widely accepted threshold for fasciotomy in acute compartment syndrome is a delta pressure (Diastolic Blood Pressure minus Intracompartmental Pressure) of less than 30 mmHg. Relying on an absolute pressure threshold (e.g., > 30 mmHg) can lead to unnecessary fasciotomies, especially in hypertensive patients, whereas delta pressure accounts for the perfusion gradient necessary to maintain tissue viability.

Question 11386

Topic: 2. Trauma

The Canadian Orthopaedic Trauma Society (COTS) conducted a landmark multicenter randomized clinical trial comparing nonoperative management to open reduction and internal fixation (ORIF) for completely displaced midshaft clavicle fractures. According to the results of this trial, which of the following outcomes was significantly associated with ORIF compared to nonoperative management?

. A higher rate of nonunion
. A significantly decreased incidence of symptomatic malunion
. A higher rate of permanent brachial plexus injury
. A significantly slower time to clinical union
. Decreased patient satisfaction scores at 1-year follow-up

Correct Answer & Explanation

. A higher rate of nonunion

Explanation

The COTS trial for completely displaced midshaft clavicle fractures demonstrated that ORIF significantly decreased the rate of nonunion and symptomatic malunion compared to nonoperative treatment. ORIF also led to faster times to clinical and radiographic union, and improved early functional outcomes, although complication profiles (like hardware prominence requiring removal in ORIF) differed.

Question 11387

Topic: 2. Trauma

A 30-year-old male undergoes intramedullary nailing of a closed tibial shaft fracture. Six hours postoperatively, he complains of escalating leg pain requiring increasing doses of IV opioids. Which of the following physical examination findings is the most sensitive early clinical indicator of acute compartment syndrome?

. Absence of dorsalis pedis and posterior tibial pulses
. Capillary refill time greater than 3 seconds
. Pain out of proportion elicited by passive stretch of the toes
. Decreased two-point discrimination in the deep peroneal nerve distribution
. Flaccid paralysis of the anterior compartment musculature

Correct Answer & Explanation

. Absence of dorsalis pedis and posterior tibial pulses

Explanation

Pain with passive stretch of the muscles in the affected compartment is the most sensitive and earliest clinical sign of acute compartment syndrome. Loss of pulses and paralysis are late and ominous findings indicating established ischemia.

Question 11388

Topic: 2. Trauma
A 25-year-old male presents with a Pauwels type III femoral neck fracture after a fall from a height. Which of the following fixation constructs provides the most biomechanical stability against vertical shear forces for this specific fracture pattern?
. Three parallel cannulated screws in an inverted triangle
. Sliding hip screw with a derotation screw
. Cephalomedullary nail
. Bipolar hemiarthroplasty
. Three parallel cannulated screws in a standard triangle

Correct Answer & Explanation

. Sliding hip screw with a derotation screw

Explanation

Pauwels type III fractures have a high shear angle (>50 degrees). Biomechanical studies demonstrate that a sliding hip screw (fixed-angle device) with a derotation screw provides superior resistance to vertical shear compared to cannulated screws.

Question 11389

Topic: 2. Trauma

A 28-year-old male with a closed tibial shaft fracture develops severe leg pain. His resting diastolic blood pressure is 70 mmHg. Intracompartmental pressure is measured. Which of the following pressure criteria is most reliable for diagnosing acute compartment syndrome?

. Absolute pressure > 20 mmHg
. Absolute pressure > 30 mmHg
. Delta P (Diastolic BP - compartment pressure) < 30 mmHg
. Delta P (Systolic BP - compartment pressure) < 30 mmHg
. Mean arterial pressure - compartment pressure < 40 mmHg

Correct Answer & Explanation

. Absolute pressure > 20 mmHg

Explanation

The Delta P (diastolic blood pressure minus intracompartmental pressure) is the most reliable indicator for acute compartment syndrome. A Delta P of less than 30 mmHg is the standard threshold indicating the need for emergent fasciotomy.

Question 11390

Topic: 2. Trauma
A 35-year-old male sustains a vertical, displaced femoral neck fracture (Pauwels Type III). He undergoes closed reduction and internal fixation with three parallel cancellous screws. Which of the following biomechanical forces is most responsible for the high rate of nonunion in this specific fracture pattern?
. Compressive forces
. Tensile forces
. Torsional forces
. Shear forces
. Bending forces

Correct Answer & Explanation

. Shear forces

Explanation

Pauwels Type III femoral neck fractures have a vertically oriented fracture line (angle > 50 degrees). This vertical orientation subjects the fracture site to high shear forces during weight-bearing, which is the primary cause of fixation failure and nonunion.

Question 11391

Topic: 2. Trauma

A 45-year-old skier sustains a Schatzker type VI tibial plateau fracture. He has tense, swollen leg compartments with pain out of proportion to the injury. A pressure monitor displays a compartment pressure of 45 mmHg. His diastolic blood pressure is 60 mmHg. What is the delta pressure, and is a fasciotomy indicated?

. 15 mmHg; fasciotomy indicated
. 15 mmHg; fasciotomy not indicated
. 105 mmHg; fasciotomy indicated
. 105 mmHg; fasciotomy not indicated
. 45 mmHg; fasciotomy indicated

Correct Answer & Explanation

. 15 mmHg; fasciotomy indicated

Explanation

Delta pressure is calculated as Diastolic BP minus Compartment Pressure (60 - 45 = 15 mmHg). A delta pressure less than 30 mmHg is an absolute indication for emergency four-compartment fasciotomy.

Question 11392

Topic: 2. Trauma

When designing a locked plating construct for a comminuted diaphyseal fracture to promote secondary bone healing via callus formation, which of the following modifications effectively increases the working length and construct flexibility?

. Using a shorter plate
. Placing screws in holes immediately adjacent to the fracture
. Leaving screw holes empty adjacent to the fracture
. Increasing the number of screws per fragment
. Using thicker, non-locking screws

Correct Answer & Explanation

. Using a shorter plate

Explanation

Leaving screw holes empty immediately adjacent to the fracture increases the working length of the plate. This enhances the flexibility of the construct, allowing interfragmentary micro-motion which stimulates secondary bone healing.

Question 11393

Topic: Pelvic & Acetabular Trauma
A 28-year-old male arrives in hemorrhagic shock after a motorcycle accident. Radiographs reveal an AP compression type III (APC-III) pelvic ring injury. To be maximally effective in reducing pelvic volume, where should a pelvic binder be centered?
. Over the iliac crests
. Over the greater trochanters
. Over the umbilicus
. Over the proximal femurs below the lesser trochanter
. Over the mid-lumbar spine

Correct Answer & Explanation

. Over the greater trochanters

Explanation

Pelvic binders are most effective at reducing pelvic volume and controlling hemorrhage when centered precisely over the greater trochanters. Placement over the iliac crests is less effective and may exacerbate certain fracture patterns.

Question 11394

Topic: 2. Trauma
A 35-year-old male presents in hemorrhagic shock after a motorcycle collision. Pelvic radiographs show a symphyseal diastasis of 4 cm and complete disruption of the bilateral sacroiliac joints. After initial fluid resuscitation and application of a pelvic binder, his hemodynamics stabilize. What is the definitive management of his anterior pelvic ring injury once he is hemodynamically optimized?
. External fixation alone
. Anterior plate osteosynthesis of the symphysis pubis
. Percutaneous sacroiliac screws alone
. Closed reduction and spica casting
. Non-operative management

Correct Answer & Explanation

. Anterior plate osteosynthesis of the symphysis pubis

Explanation

This patient has an APC-III pelvic ring injury, involving complete disruption of both anterior and posterior pelvic ligaments resulting in global instability. Once hemodynamically optimized, definitive treatment typically requires anterior plate osteosynthesis for the symphyseal disruption, usually in combination with posterior ring fixation. External fixation is generally temporary or adjunctive and not definitive for this level of instability.

Question 11395

Topic: 2. Trauma

During the evaluation of an acetabulum fracture, the presence of a 'spur sign' is noted on the obturator oblique radiograph of the pelvis. What specific fracture pattern does this radiographic finding indicate?

. Transverse fracture
. T-type fracture
. Associated both column fracture
. Anterior column/posterior hemitransverse fracture
. Posterior wall fracture

Correct Answer & Explanation

. Transverse fracture

Explanation

The 'spur sign' on an obturator oblique radiograph is pathognomonic for an associated both-column acetabulum fracture. It represents the intact portion of the ilium that remains attached to the axial skeleton, projecting posteriorly like a spur, while the articular columns are completely dissociated from the axial skeleton.

Question 11396

Topic: Upper Extremity Trauma

Recent anatomical studies utilizing gadolinium and quantitative MRI have refined our understanding of the primary arterial blood supply to the proximal humerus. Which of the following vessels provides the majority of the vascularity to the humeral head articular segment?

. Arcuate branch of the anterior humeral circumflex artery
. Posterior humeral circumflex artery
. Thoracoacromial artery
. Subscapular artery
. Profunda brachii artery

Correct Answer & Explanation

. Arcuate branch of the anterior humeral circumflex artery

Explanation

Historically, the anterior humeral circumflex artery (specifically the arcuate branch) was considered the main vascular supply. However, recent studies (e.g., Hettrich et al.) have demonstrated that the posterior humeral circumflex artery supplies the vast majority (approximately 64%) of the blood to the humeral head, particularly the posteromedial and inferior aspects.

Question 11397

Topic: 2. Trauma

Which of the following scenarios represents an absolute indication for open reduction and internal fixation of an acute midshaft clavicle fracture?

. Shortening greater than 1.5 cm
. Z-deformity on the AP radiograph
. Concomitant ipsilateral scapula neck fracture (floating shoulder)
. Skin tenting that threatens skin viability
. Patient occupation as an overhead athlete

Correct Answer & Explanation

. Shortening greater than 1.5 cm

Explanation

Absolute indications for operative fixation of a clavicle fracture include open fracture, associated neurovascular injury, and severe skin tenting that threatens skin viability (imminent open fracture). Factors like shortening >2 cm, floating shoulder, Z-deformity, and athletic demands are considered relative indications.

Question 11398

Topic: 2. Trauma
A 25-year-old male sustains a vertically oriented femoral neck fracture (Pauwels type III). What biomechanical force is predominantly responsible for the high rate of fixation failure and nonunion in this specific fracture pattern?
. Compressive forces
. Bending moments
. Torsional forces
. Shear forces
. Tensile forces

Correct Answer & Explanation

. Shear forces

Explanation

Pauwels type III femoral neck fractures have a fracture line angulation of >50 degrees from the horizontal. This highly vertical orientation makes them inherently mechanically unstable. Shear forces predominate at the fracture site rather than compressive forces, predisposing the construct to displacement, varus collapse, and nonunion.

Question 11399

Topic: 2. Trauma

When treating an intertrochanteric femur fracture with a sliding hip screw or cephalomedullary nail, optimizing the Tip-Apex Distance (TAD) is critical to prevent hardware failure. To significantly minimize the risk of lag screw cut-out, the TAD should strictly be kept below:

. 15 mm
. 20 mm
. 25 mm
. 30 mm
. 35 mm

Correct Answer & Explanation

. 15 mm

Explanation

Baumgaertner et al. demonstrated that keeping the Tip-Apex Distance (TAD) to less than 25 mm—calculated by summing the AP and lateral radiographic distances from the tip of the screw to the apex of the femoral head—significantly reduces the rate of lag screw cut-out in the operative treatment of intertrochanteric fractures.

Question 11400

Topic: 2. Trauma
A 28-year-old male polytrauma patient with bilateral femoral shaft fractures, a grade III spleen laceration, and a severe traumatic brain injury is brought to the operating room. His lactate is 4.5 mmol/L and base deficit is -8. According to damage control orthopedics (DCO) principles, what is the most appropriate initial management for his femur fractures?
. Bilateral reamed intramedullary nailing
. Bilateral unreamed intramedullary nailing
. Bilateral external fixation
. Bilateral plate osteosynthesis
. Skeletal traction

Correct Answer & Explanation

. Bilateral external fixation

Explanation

This patient is in the 'borderline' or 'unstable' physiological category based on his elevated lactate, significant base deficit, and concomitant head and abdominal injuries. Damage Control Orthopedics (DCO) dictates rapid, temporary stabilization of major long bone fractures with external fixation to minimize the systemic inflammatory response ('second hit') associated with prolonged surgery and intramedullary reaming.

Test Yourself

Switch to an interactive, timed exam simulation to truly master this topic.

On this Page