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2. Trauma MCQs

Practice Set 496 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 9901

Topic: 2. Trauma
A 32-year-old male sustains a high-energy Pauwels Type III femoral neck fracture. Biomechanically, which of the following internal fixation constructs provides the greatest stability and is most appropriate to counteract the predominant deforming forces in this specific fracture pattern?
. Three parallel cancellous screws placed in an inverted triangle configuration
. A fixed-angle construct such as a sliding hip screw (DHS) with an anti-rotation screw
. A cephalomedullary nail without a supplementary anti-rotation screw
. Two parallel cancellous screws placed superiorly and inferiorly
. A laterally based proximal femoral locking plate alone

Correct Answer & Explanation

. A fixed-angle construct such as a sliding hip screw (DHS) with an anti-rotation screw

Explanation

Pauwels Type III fractures are characterized by a vertical fracture line (angle > 50 degrees), which subjects the fracture to high shear forces and varus instability. Multiple biomechanical and clinical studies have demonstrated that a fixed-angle construct (such as a sliding hip screw) with a supplementary anti-rotation screw provides superior resistance to shear and varus collapse compared to multiple cancellous screws, reducing the risk of nonunion and hardware failure in young patients.

Question 9902

Topic: 2. Trauma

A 28-year-old polytrauma patient is intubated in the ICU following a high-speed motorcycle collision. He has a comminuted closed tibia fracture. The nursing staff reports a tight, swollen calf. Which of the following intracompartmental pressure measurements is widely accepted as an absolute indication for emergent four-compartment fasciotomy?

. An absolute compartment pressure greater than 20 mmHg
. A delta pressure (Mean Arterial Pressure minus Compartment Pressure) less than 40 mmHg
. A delta pressure (Diastolic Blood Pressure minus Compartment Pressure) less than 30 mmHg
. A delta pressure (Systolic Blood Pressure minus Compartment Pressure) less than 50 mmHg
. An absolute compartment pressure greater than 25 mmHg

Correct Answer & Explanation

. A delta pressure (Diastolic Blood Pressure minus Compartment Pressure) less than 30 mmHg

Explanation

The diagnosis of acute compartment syndrome in an obtunded or intubated patient relies on objective pressure measurements. The 'delta pressure' concept is standard, defined as Diastolic Blood Pressure (DBP) minus intracompartmental pressure. A delta pressure of less than 30 mmHg (meaning the compartment pressure is within 30 mmHg of the diastolic pressure) is the widely accepted threshold indicating inadequate tissue perfusion and the need for emergent fasciotomy.

Question 9903

Topic: 2. Trauma
A 40-year-old male presents with a Gustilo-Anderson Type IIIB open fracture of the tibia midshaft. After initial adequate surgical debridement and stabilization, plastic surgery is consulted for a free tissue transfer. According to classic and contemporary literature, what is the optimal timing for definitive soft tissue coverage to minimize deep infection rates?
. Within 24 hours of injury, immediately after the first debridement
. Between 3 and 5 days, allowing for a second-look debridement and prior to peak bacterial colonization
. Between 10 and 14 days, once the zone of injury has completely demarcated
. After 3 weeks, to allow for adequate granulation tissue formation
. Timing does not affect infection rates provided broad-spectrum antibiotics are continued

Correct Answer & Explanation

. Between 3 and 5 days, allowing for a second-look debridement and prior to peak bacterial colonization

Explanation

Godina's classic paper advocated for coverage within 72 hours; however, modern multidisciplinary approaches (including the LEAP study) have shown that soft tissue coverage performed within 3 to 7 days (optimally before 5-7 days) provides the lowest risk of deep infection and flap failure. Delaying coverage beyond 7 days significantly increases the risk of deep infection, while immediate coverage (< 24h) is often impractical in polytrauma and may obscure evolving necrosis.

Question 9904

Topic: 2. Trauma

Review the clinical scenario associated with this image:

A 25-year-old motorcyclist is brought to the trauma bay after being thrown into a tree. The right upper extremity is pulseless and flail. A chest radiograph demonstrates lateral displacement of the scapula with widening of the acromioclavicular and sternoclavicular joints. What is the most likely associated diagnosis?

. Isolated axillary artery intimal tear
. Scapulothoracic dissociation with massive brachial plexus and subclavian vessel avulsion
. Floating shoulder with an isolated musculocutaneous nerve injury
. Anterior shoulder dislocation with concomitant Bankart lesion
. Thoracic outlet syndrome secondary to clavicular malunion

Correct Answer & Explanation

. Scapulothoracic dissociation with massive brachial plexus and subclavian vessel avulsion

Explanation

The clinical presentation (flail, pulseless arm) and radiographic finding of lateral displacement of the scapula with clavicular/sternoclavicular/acromioclavicular disruption is pathognomonic for scapulothoracic dissociation. This is essentially a 'closed forequarter amputation' and carries a devastating prognosis, almost universally associated with complete or partial brachial plexus avulsion and severe subclavian/axillary vascular injury.

Question 9905

Topic: 2. Trauma

On an anteroposterior (AP) radiograph of the pelvis in a patient with an acetabular fracture, a 'Spur sign' is identified. This radiographic finding is pathognomonic for which type of acetabular fracture according to the Judet-Letournel classification?

. T-type fracture
. Anterior column posterior hemitransverse
. Transverse with posterior wall
. Posterior column
. Both-column fracture

Correct Answer & Explanation

. Both-column fracture

Explanation

The 'Spur sign' is seen on the obturator oblique view (or occasionally AP) and represents the intact portion of the ilium (the strut) that remains attached to the axial skeleton, while the entire articular surface is separated from it. This indicates a complete dissociation of the articular surface from the axial skeleton, which is the defining characteristic of a both-column acetabular fracture.

Question 9906

Topic: 2. Trauma

A 40-year-old male sustains a posterior knee dislocation during a football game. The dislocation is reduced in the emergency department, and distal pulses are palpable but weak. His Ankle-Brachial Index (ABI) is measured at 0.85. What is the most appropriate next step in management?

. Discharge with urgent outpatient orthopedic follow-up in 3 days
. Admit for serial clinical vascular examinations every 4 hours without further imaging
. Immediate CT angiography of the lower extremity
. Immediate transport to the operating room for prophylactic four-compartment fasciotomy
. Application of a hinged knee brace locked in 30 degrees of flexion and weight-bearing as tolerated

Correct Answer & Explanation

. Immediate CT angiography of the lower extremity

Explanation

An Ankle-Brachial Index (ABI) or Arterial Pressure Index (API) less than 0.9 in the setting of a knee dislocation is highly sensitive for a significant arterial injury (popliteal artery). The standard of care mandates advanced vascular imaging (typically CT angiography) when the ABI is < 0.9, or emergent vascular surgery intervention if there are hard signs of ischemia (absent pulses, expanding hematoma, active bleeding).

Question 9907

Topic: 2. Trauma

Based on the fracture pattern typically seen in the coronal plane of the distal femur (Hoffa fracture) as demonstrated in clinical practice:

Which femoral condyle is most commonly involved, and what is the preferred trajectory of lag screw fixation?

. Medial condyle; anterior-to-posterior (AP) lag screws
. Lateral condyle; anterior-to-posterior (AP) lag screws
. Lateral condyle; posterior-to-anterior (PA) lag screws
. Medial condyle; posterior-to-anterior (PA) lag screws
. Both condyles equally; superior-to-inferior lag screws

Correct Answer & Explanation

. Lateral condyle; anterior-to-posterior (AP) lag screws

Explanation

A Hoffa fracture (AO/OTA 33-B3) is a coronal shear fracture of the distal femur. It most commonly involves the lateral femoral condyle due to the physiologic valgus of the lower extremity and direction of ground reaction forces. Because the fracture is posterior, fixing it with anterior-to-posterior (AP) lag screws (often countersunk to avoid patellofemoral articulation) provides excellent biomechanical compression across the coronal fracture plane.

Question 9908

Topic: 2. Trauma

A 26-year-old male sustains a low-velocity civilian gunshot wound to the thigh, resulting in a comminuted midshaft femur fracture. The bullet passed cleanly through the thigh, leaving small entrance and exit wounds without gross contamination. Distal pulses are intact, and there is no expanding hematoma. What is the most appropriate initial management of the soft tissues and fracture?

. Immediate formal operative debridement of the entire bullet tract followed by external fixation
. Pulsatile lavage of the wounds in the emergency department and conservative management in a cast
. Emergent exploration of the femoral artery due to the high kinetic energy of the bullet
. Local wound care, intravenous antibiotics for 24-48 hours, and antegrade intramedullary nailing without formal tract debridement
. Surgical excision of the entrance and exit wounds with immediate primary closure and plating

Correct Answer & Explanation

. Local wound care, intravenous antibiotics for 24-48 hours, and antegrade intramedullary nailing without formal tract debridement

Explanation

Low-velocity civilian gunshot wounds with associated long bone fractures behave similarly to Gustilo Type I open fractures. Unless there is gross contamination (e.g., shotgun wadding, bowel involvement), vascular injury, or intra-articular extension, formal operative debridement of the bullet tract is unnecessary. Standard care involves superficial local wound cleansing, short-course IV antibiotics (typically a first-generation cephalosporin), and definitive fixation (e.g., IM nailing).

Question 9909

Topic: 2. Trauma
A 45-year-old female sustains a 'floating shoulder' following a motor vehicle collision. Which of the following combinations of specific injury characteristics (Goss's criteria) most strongly indicates the need for operative fixation?
. Any displacement of the clavicle regardless of the scapular neck position
. A non-displaced clavicle fracture with 5 mm of scapular neck translation
. Medialization (translation) of the glenoid fragment > 10 mm or angulation > 40 degrees
. Concomitant fracture of the acromion without clavicular displacement
. An associated nondisplaced rib fracture

Correct Answer & Explanation

. Medialization (translation) of the glenoid fragment > 10 mm or angulation > 40 degrees

Explanation

A 'floating shoulder' typically involves ipsilateral fractures of the clavicular shaft and the scapular neck. Nonoperative management is successful for minimally displaced injuries. However, surgical intervention (usually fixing the clavicle first, which often indirectly reduces the scapula) is indicated based on Goss's criteria/Bartonรญฤek's criteria: scapular neck translation > 1 cm (10 mm) or angulation > 40 degrees, as these lead to altered glenohumeral mechanics and poor functional outcomes.

Question 9910

Topic: Pelvic & Acetabular Trauma
In the acute trauma bay: A hemodynamically unstable patient with an Anteroposterior Compression Type III (APC-III) pelvic ring injury is receiving a circumferential pelvic binder. To be maximally effective in reducing pelvic volume and controlling hemorrhage without causing paradoxical widening, where must the binder be centered?
. Over the greater trochanters
. Over the iliac crests
. At the level of the umbilicus
. Directly over the anterior superior iliac spines (ASIS)
. Mid-thigh bilaterally

Correct Answer & Explanation

. Over the greater trochanters

Explanation

A common and potentially fatal error in trauma management is placing a pelvic binder too high. If placed over the iliac crests, it can cause the iliac wings to act as a fulcrum, paradoxically widening the true pelvis and exacerbating hemorrhage. The binder must be centered exactly over the greater trochanters of the femur to directly close the pubic symphysis and reduce the pelvic volume.

Question 9911

Topic: 2. Trauma

A 25-year-old male is brought to the trauma center after a high-speed MVC. He has bilateral femur fractures, blunt chest trauma, and a closed head injury. The decision between Early Total Care (ETC, immediate intramedullary nailing) and Damage Control Orthopedics (DCO, external fixation) is being made. Which of the following physiologic parameters is the best indicator that the patient is adequately resuscitated and may safely undergo ETC?

. Core body temperature of 34.5ยฐC
. Platelet count of 75,000/mcL
. Arterial pH of 7.15
. Serum lactate < 2.5 mmol/L with a normalizing base deficit
. Systolic blood pressure transiently responding to 2 liters of crystalloid

Correct Answer & Explanation

. Serum lactate < 2.5 mmol/L with a normalizing base deficit

Explanation

Damage Control Orthopedics (DCO) is indicated for patients who are hemodynamically unstable, in extremis, or 'borderline'. The lethal triad includes acidosis, hypothermia, and coagulopathy. Indicators of adequate resuscitation permitting Early Total Care (ETC) include a serum lactate < 2.5 mmol/L (often < 2.0 is preferred), a base deficit normalizing to > -2, normal coagulation parameters, and normothermia. Options A, B, and C reflect a severely deranged physiologic state mandating DCO.

Question 9912

Topic: 2. Trauma

A 45-year-old male sustains a high-energy Schatzker Type IV tibial plateau fracture (medial plateau involvement). A coronal CT scan demonstrates a large posteromedial fracture fragment. What is the optimal surgical approach and internal fixation strategy for this specific fragment?

. Anterolateral approach with a laterally based locking plate to 'raft' the medial side
. Posteromedial approach with an under-contoured anti-glide plate applied to the posteromedial cortex
. Direct medial approach utilizing multiple AP lag screws without a plate
. Midline anterior approach with a dual-plate construct applied over the tibial tubercle
. Arthroscopically-assisted percutaneous screw fixation from anterior to posterior

Correct Answer & Explanation

. Posteromedial approach with an under-contoured anti-glide plate applied to the posteromedial cortex

Explanation

Schatzker IV fractures (medial plateau) frequently possess a significant posteromedial fragment with a vertical coronal split, driven by a varus/extension or axial load. This fragment tends to displace distally and posteriorly. Laterally based locking screws cannot effectively capture or buttress this fragment. The optimal biomechanical solution is a posteromedial approach with a buttress (or anti-glide) plate applied directly to the apex of the posteromedial fragment.

Question 9913

Topic: 2. Trauma

A 28-year-old male is brought to the trauma bay after a high-speed motorcycle collision. He has bilateral closed femoral shaft fractures, a pulmonary contusion, and a closed head injury. His blood pressure is 95/60 mmHg, heart rate is 115 bpm, and his initial serum lactate is 3.5 mmol/L. According to the Hannover/Pape criteria for Damage Control Orthopedics (DCO) versus Early Total Care (ETC), which of the following is the most appropriate initial management for his femoral fractures?

. Immediate bilateral reamed intramedullary nailing
. Immediate bilateral unreamed intramedullary nailing
. Bilateral spanning external fixation
. Open reduction and internal fixation with compression plating
. Skeletal traction until day 5, followed by intramedullary nailing

Correct Answer & Explanation

. Bilateral spanning external fixation

Explanation

This patient fits the criteria for a 'borderline' or 'unstable' polytrauma patient. An initial lactate > 2.5 mmol/L, base excess < -4, concurrent severe chest trauma, and bilateral femur fractures place him at high risk for a "second hit" phenomenon (such as ARDS or multiorgan failure) if subjected to prolonged surgery like bilateral intramedullary nailing. Damage Control Orthopedics (DCO), which involves rapid stabilization with bilateral external fixation, is the gold standard here to minimize the systemic inflammatory response while waiting for physiologic stabilization.

Question 9914

Topic: 2. Trauma

A 45-year-old female presents with a complex bicondylar tibial plateau fracture after a fall from a height.

The surgeon plans a dual-incision approach, utilizing a standard anterolateral approach and a posteromedial approach. When dissecting through the posteromedial interval to apply a buttress plate, which of the following structures is at the greatest risk of iatrogenic injury if the dissection strays too superficial and anterior?

. Common peroneal nerve
. Tibial nerve
. Saphenous nerve
. Popliteal artery
. Sural nerve

Correct Answer & Explanation

. Saphenous nerve

Explanation

The posteromedial approach to the tibial plateau typically utilizes the interval between the medial head of the gastrocnemius (posterior) and the pes anserinus (anterior). The saphenous nerve and the greater saphenous vein run superficial to the pes anserinus and are at risk if the incision or superficial dissection is carried too far anteriorly or carelessly retracted. The common peroneal nerve is lateral, and the popliteal bundle/tibial nerve is central/posterior and protected by the gastrocnemius.

Question 9915

Topic: 2. Trauma

A 32-year-old female sustains a distal femur fracture. Radiographs show a coronal plane fracture of the lateral femoral condyle (Hoffa fracture). Which of the following anatomical structures primarily remains attached to this osteochondral fragment, leading to characteristic posterior and proximal displacement?

. Anterior cruciate ligament and lateral head of the gastrocnemius
. Popliteus tendon and lateral collateral ligament
. Medial collateral ligament and medial head of the gastrocnemius
. Biceps femoris and iliotibial band
. Posterior cruciate ligament and plantaris

Correct Answer & Explanation

. Popliteus tendon and lateral collateral ligament

Explanation

A Hoffa fracture is a coronal shear fracture of the distal femoral condyle, most commonly involving the lateral condyle. The lateral condylar fragment typically displaces proximally and posteriorly due to the pull of the structures attached to it, primarily the lateral head of the gastrocnemius, the popliteus tendon, and the lateral collateral ligament (LCL).

Question 9916

Topic: Pelvic & Acetabular Trauma
Review the radiograph of a hemodynamically unstable trauma patient. The patient has an Anteroposterior Compression (APC) type injury to the pelvic ring. Disruption of which of the following structures differentiates a rotationally unstable but vertically stable APC II injury from a globally unstable APC III injury?
. Symphysis pubis
. Anterior sacroiliac ligaments
. Sacrospinous ligaments
. Posterior sacroiliac ligaments
. Iliolumbar ligaments

Correct Answer & Explanation

. Posterior sacroiliac ligaments

Explanation

In the Young-Burgess classification, an APC II injury involves disruption of the symphysis pubis, the anterior sacroiliac (SI) ligaments, and the sacrotuberous/sacrospinous ligaments, leading to rotational instability but preserving vertical stability because the strong posterior SI ligaments are intact. An APC III injury implies complete disruption of both the anterior and posterior SI ligaments, leading to both rotational and vertical instability.

Question 9917

Topic: 2. Trauma
According to the findings of the Lower Extremity Assessment Project (LEAP) study regarding severe lower extremity trauma (Gustilo IIIB/IIIC injuries), which of the following variables was found to be the most significant predictor of poor functional outcome at 2 years post-injury?
. Decision to amputate versus attempt limb salvage
. Presence of an insensate plantar surface at initial presentation
. Poor patient psychosocial and economic status
. Use of a free tissue transfer versus a rotational flap
. Initial wound size greater than 10 centimeters

Correct Answer & Explanation

. Poor patient psychosocial and economic status

Explanation

The LEAP study was a landmark prospective trial comparing amputation versus limb salvage in severe lower extremity trauma. It concluded that at 2 years, there was no significant difference in functional outcomes between the two groups. The most significant predictors of poor functional outcomes were not injury-specific or treatment-specific variables, but rather patient-related socioeconomic and psychosocial factors (e.g., lack of insurance, low education level, smoking, lack of social support).

Question 9918

Topic: 2. Trauma

A 40-year-old intoxicated male is found down after an unknown period and is brought to the emergency department. He has severe swelling of his right lower leg, which is cold, pulseless, and completely insensate. Passive stretch elicits no pain, and there is no active motion. Compartment pressures measure 65 mmHg, and his diastolic blood pressure is 80 mmHg. The exact time of injury is unknown but is estimated to be over 48 hours ago. What is the most appropriate management?

. Immediate four-compartment fasciotomy
. Immediate single-incision fasciotomy
. Administration of IV mannitol and observation
. Nonoperative management, allowing the leg to contracture
. Hyperbaric oxygen therapy followed by delayed fasciotomy

Correct Answer & Explanation

. Nonoperative management, allowing the leg to contracture

Explanation

This patient presents with a 'missed' or late-presenting compartment syndrome (>24-48 hours) where the muscle is already dead (indicated by pulseless, insensate limb with no stretch pain and lack of active motion). Performing a fasciotomy in this setting is contraindicated due to a highly prohibitive risk of introducing infection into necrotic tissue, which frequently leads to severe sepsis and death. The standard of care is nonoperative management, allowing the leg to fibrose and form a contracture, or an amputation if it becomes infected or for definitive functional management later.

Question 9919

Topic: 2. Trauma
In the treatment of a displaced, vertically oriented (Pauwels Type III) femoral neck fracture in a 25-year-old patient, a sliding hip screw (SHS) with a derotational screw is often preferred over three parallel cancellous lag screws. What is the primary biomechanical advantage of the SHS construct in this specific fracture pattern?
. Increased resistance to vertical shear forces
. Greater preservation of the lateral epiphyseal artery
. Prevention of femoral head avascular necrosis
. Enhanced compression along the axis of the femoral neck
. Reduced risk of intra-articular screw penetration

Correct Answer & Explanation

. Increased resistance to vertical shear forces

Explanation

Pauwels Type III femoral neck fractures are characterized by a highly vertical fracture line (angle > 50 degrees to the horizontal). This vertical orientation subjects the fracture to immense vertical shear forces rather than compressive forces. A fixed-angle construct, such as a sliding hip screw (often supplemented with an anti-rotation screw), provides superior biomechanical resistance to these vertical shear forces compared to multiple parallel cancellous screws, reducing the risk of varus collapse and nonunion.

Question 9920

Topic: 2. Trauma

A 35-year-old right-hand-dominant male presents with a closed distal-third spiral fracture of the humeral shaft (Holstein-Lewis type) following an arm-wrestling match.

On examination, he is unable to actively extend his wrist or digits, though his triceps function is intact. His pulses are palpable. What is the most appropriate initial management?

. Immediate surgical exploration of the radial nerve and ORIF
. Application of a coaptation splint and observation of the nerve palsy
. Electromyography (EMG) to determine the extent of nerve injury before treatment
. Immediate external fixation to stabilize the nerve environment
. Closed reduction with immediate intraoperative nerve exploration if reduction fails

Correct Answer & Explanation

. Application of a coaptation splint and observation of the nerve palsy

Explanation

A primary radial nerve palsy associated with a closed humeral shaft fracture (even a Holstein-Lewis distal third fracture) is generally treated conservatively with a coaptation splint or functional brace and observation. Over 70-80% of these palsies represent neurapraxia and will recover spontaneously. Immediate exploration is indicated for open fractures, penetrating trauma, vascular compromise, or a secondary nerve palsy that developsaftera closed reduction attempt.

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