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2. Trauma MCQs

Practice Set 554 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 11061

Topic: Pelvic & Acetabular Trauma
A hemodynamically unstable 45-year-old male arrives in the trauma bay following a high-speed motor vehicle collision. He has a mechanically unstable pelvic ring injury (APC Type III). Despite placement of a pelvic binder and aggressive fluid/blood resuscitation, he remains hypotensive. FAST exam is negative. What is the most common anatomical source of retroperitoneal hemorrhage in this specific injury pattern?
. Superior gluteal artery
. Presacral venous plexus and bleeding from cancellous bone surfaces
. Internal pudendal artery
. Corona mortis
. External iliac vein

Correct Answer & Explanation

. Presacral venous plexus and bleeding from cancellous bone surfaces

Explanation

The vast majority (80-90%) of bleeding in severe pelvic ring disruptions is of venous or osseous origin, most commonly from the presacral venous plexus and the raw cancellous bone ends of the fractured pelvis. While arterial bleeding (such as from the superior gluteal artery or internal pudendal artery) can occur and is often the target for angioembolization, it accounts for only 10-20% of cases. Venous and osseous bleeding is initially managed by reducing pelvic volume (pelvic binder) and may require preperitoneal pelvic packing if hemodynamic instability persists.

Question 11062

Topic: 2. Trauma
A 30-year-old construction worker sustains an isolated Gustilo-Anderson Type IIIA open tibial shaft fracture. Assuming the patient receives appropriate early intravenous antibiotics in the emergency department, what does current orthopedic trauma literature dictate regarding the optimal timing of the initial surgical debridement?
. Mandatory debridement within 6 hours to significantly reduce the risk of osteomyelitis
. Debridement within 24 hours has comparable infection rates to debridement within 6 hours
. Immediate soft tissue coverage (flap) is required within 12 hours regardless of wound evolution
. Debridement can be safely delayed past 48 hours without any increase in infection risk
. Timing of debridement is irrelevant as long as local antibiotic beads are placed

Correct Answer & Explanation

. Debridement within 24 hours has comparable infection rates to debridement within 6 hours

Explanation

Historically, the '6-hour rule' was strictly taught for open fractures. However, modern evidence, including multiple systematic reviews and large prospective cohort studies, demonstrates that if appropriate early intravenous antibiotics are administered, surgical debridement within 24 hours does not increase the risk of deep infection or nonunion compared to debridement within 6 hours. This allows for safe optimization of the patient and performance of the procedure during daylight hours by experienced personnel.

Question 11063

Topic: 2. Trauma
An intubated, obtunded polytrauma patient is admitted to the ICU with a severely comminuted closed tibial shaft fracture. The nursing staff notes a tense calf. Which of the following criteria is the most widely accepted and accurate threshold for diagnosing acute compartment syndrome in this obtunded patient and indicating a four-compartment fasciotomy?
. Absolute compartment pressure > 20 mmHg
. Absolute compartment pressure > 30 mmHg
. Delta pressure (Diastolic Blood Pressure - Compartment Pressure) < 30 mmHg
. Delta pressure (Mean Arterial Pressure - Compartment Pressure) < 30 mmHg
. Delta pressure (Systolic Blood Pressure - Compartment Pressure) < 40 mmHg

Correct Answer & Explanation

. Delta pressure (Diastolic Blood Pressure - Compartment Pressure) < 30 mmHg

Explanation

In obtunded or unexaminable patients, objective compartment pressure monitoring is required. The most accurate predictor of acute compartment syndrome is the delta pressure (∆P), defined as the Diastolic Blood Pressure minus the Intra-compartmental Pressure. A delta pressure of less than 30 mmHg indicates inadequate tissue perfusion and is the standard threshold to proceed with fasciotomy. Relying on absolute pressure alone can lead to unnecessary fasciotomies, as normal perfusion gradients vary with the patient's systemic blood pressure.

Question 11064

Topic: 2. Trauma

During a massive transfusion protocol (MTP) for a patient with bilateral femoral shaft fractures and a crushed pelvis, the anesthesiologist notes worsening hypotension and coagulopathy. Which of the following electrolyte abnormalities is an expected complication of massive transfusion that directly exacerbates coagulopathy and requires active replacement?

. Hyperkalemia
. Hypocalcemia
. Hypernatremia
. Hypomagnesemia
. Hypercalcemia

Correct Answer & Explanation

. Hyperkalemia

Explanation

Hypocalcemia is a frequent and dangerous complication of massive blood transfusion. Banked blood products contain citrate, which is used as an anticoagulant. Citrate chelates serum calcium in the patient's bloodstream, leading to profound hypocalcemia. Calcium is a vital cofactor (Factor IV) in the coagulation cascade. Its depletion exacerbates coagulopathy and impairs myocardial contractility (worsening shock), making proactive calcium administration critical during MTP.

Question 11065

Topic: 2. Trauma

A 22-year-old male sustains an isolated, closed midshaft femur fracture. Due to operating room unavailability, he is placed in skeletal traction overnight. 36 hours later, he develops acute confusion, tachypnea, and a petechial rash over his axilla and conjunctiva. Which of the following interventions has definitively been shown to reduce the incidence of this specific syndrome?

. Administration of high-dose systemic corticosteroids on admission
. Early operative stabilization of the long-bone fracture (within 24 hours)
. Placement of a prophylactic inferior vena cava (IVC) filter
. Aggressive early administration of fresh frozen plasma
. Empiric therapeutic anticoagulation with intravenous heparin

Correct Answer & Explanation

. Administration of high-dose systemic corticosteroids on admission

Explanation

The patient is presenting with the classic triad of Fat Embolism Syndrome (FES): hypoxemia, neurological abnormalities, and a petechial rash. The most effective, evidence-based strategy to prevent FES in patients with long-bone fractures is early operative stabilization (ideally within 24 hours). While corticosteroids have been studied and may reduce the incidence of hypoxemia in some trials, they are not universally recommended as standard prophylaxis over early fracture fixation.

Question 11066

Topic: 2. Trauma
A 40-year-old female sustains a U-shaped sacral fracture with spinopelvic dissociation after a fall from a height. According to the Denis classification of sacral fractures, which zone is primarily involved in determining the highest risk of neurologic injury, and what is the approximate historical rate of neurologic injury associated with this zone?
. Zone I; 5%
. Zone II; 28%
. Zone III; 57%
. Zone I; 100%
. Zone II; 5%

Correct Answer & Explanation

. Zone III; 57%

Explanation

The Denis classification divides sacral fractures into three zones. Zone I (alar) has a 5% rate of nerve injury. Zone II (foraminal) has a 28% rate. Zone III (central canal) involves the spinal canal, including transverse and U-type fractures with spinopelvic dissociation, and carries the highest rate of neurologic injury, historically cited as 57%.

Question 11067

Topic: 2. Trauma



In the setting of a complex ankle fracture, the anterior inferior tibiofibular ligament (AITFL) is typically attached to specific osseous landmarks. An avulsion fracture of the anterolateral distal tibia by the AITFL is eponymously known as which of the following?

. Volkmann fragment
. Wagstaffe-Le Fort fragment
. Tillaux-Chaput fragment
. Earle's fragment
. Cedell fragment

Correct Answer & Explanation

. Volkmann fragment

Explanation

The Tillaux-Chaput fragment is an avulsion of the anterolateral distal tibia by the anterior inferior tibiofibular ligament (AITFL). A Wagstaffe-Le Fort fragment is an avulsion of the anteromedial fibula by the AITFL. The Volkmann fragment is an avulsion of the posterolateral tibia by the posterior inferior tibiofibular ligament (PITFL).

Question 11068

Topic: 2. Trauma



A 28-year-old professional basketball player sustains a fracture at the base of the fifth metatarsal. Radiographs show a transverse fracture at the metaphyseal-diaphyseal junction extending into the 4th-5th intermetatarsal articulation (Zone 2). What is the recommended treatment to minimize nonunion and expedite return to play in this elite athlete?

. Non-weight bearing in a short leg cast for 6-8 weeks
. Weight bearing as tolerated in a stiff-soled shoe
. Open reduction and internal fixation with a tension band construct
. Intramedullary screw fixation
. Excision of the proximal fragment and peroneus brevis advancement

Correct Answer & Explanation

. Non-weight bearing in a short leg cast for 6-8 weeks

Explanation

A Zone 2 fifth metatarsal fracture (Jones fracture) occurs at the metaphyseal-diaphyseal junction and involves the 4th-5th intermetatarsal articulation. Due to the watershed blood supply, it has a high rate of nonunion. In elite athletes, early intramedullary screw fixation is the gold standard to decrease nonunion rates and allow a faster return to play.

Question 11069

Topic: 2. Trauma

A 30-year-old skier presents with lateral ankle pain and a snapping sensation behind the lateral malleolus after a fall. The injury occurred during forced ankle dorsiflexion and eversion. Radiographs show a thin cortical flake of bone avulsed from the posterolateral border of the fibula. What is the most likely diagnosis?

. Anterior talofibular ligament tear
. Calcaneofibular ligament tear
. Superior peroneal retinaculum avulsion with peroneal tendon dislocation
. Inferior extensor retinaculum tear
. Osteochondral fracture of the lateral talar dome

Correct Answer & Explanation

. Anterior talofibular ligament tear

Explanation

The clinical presentation (snapping behind lateral malleolus, forced dorsiflexion/eversion) and radiographic finding ('fleck sign' from the posterolateral fibula) are pathognomonic for an injury to the superior peroneal retinaculum (SPR) and subsequent peroneal tendon subluxation or dislocation.

Question 11070

Topic: 2. Trauma



A 25-year-old male sustains a severe crush injury to his foot and develops compartment syndrome. The human foot is traditionally described as having nine anatomical compartments. Which of the following structures is exclusively located within the calcaneal compartment?

. Abductor hallucis
. Flexor digitorum brevis
. Quadratus plantae
. Adductor hallucis
. Plantar interossei

Correct Answer & Explanation

. Abductor hallucis

Explanation

The foot has 9 compartments: Medial, Lateral, Superficial (contains flexor digitorum brevis), Calcaneal (contains quadratus plantae), Adductor (contains adductor hallucis), and four interosseous compartments. The quadratus plantae resides in the calcaneal compartment, which communicates with the deep posterior compartment of the leg.

Question 11071

Topic: 2. Trauma



A 21-year-old track athlete presents with insidious onset of vague midfoot pain. Examination reveals point tenderness over the dorsal 'N-spot'. CT scan confirms a navicular stress fracture. This fracture typically originates in which specific region of the navicular due to a vascular watershed area and maximum shear stress?

. Plantar pole
. Medial tuberosity
. Central third, extending from dorsal to plantar
. Lateral articular margin
. Plantar-medial articular surface

Correct Answer & Explanation

. Plantar pole

Explanation

Navicular stress fractures typically occur in the central third of the bone, extending from the dorsal margin towards the plantar aspect. This area is a known relative avascular 'watershed' zone between the medial and lateral blood supplies and sustains high shear forces during the foot strike phase in athletes.

Question 11072

Topic: 2. Trauma

A 21-year-old collegiate basketball player sustains a fracture of the fifth metatarsal. Radiographs show a transverse fracture at the metaphyseal-diaphyseal junction involving the fourth-fifth intermetatarsal articulation. He is treated with intramedullary screw fixation. To minimize the risk of nonunion or construct failure, which of the following is the most critical technical factor regarding the screw?

. Using a partially threaded screw with a diameter of 3.0 mm
. Using the largest diameter screw that fits the canal (typically 4.5 mm to 5.5 mm)
. Ensuring the screw threads completely cross into the distal metaphysis
. Using a bioabsorbable screw to avoid symptomatic hardware
. Placing the screw via a plantar approach to avoid the peroneus brevis insertion

Correct Answer & Explanation

. Using a partially threaded screw with a diameter of 3.0 mm

Explanation

In surgical fixation of Zone 2 (Jones) fractures in athletes, using the largest solid or cannulated screw that accommodates the medullary canal (usually 4.5-5.5 mm) provides superior biomechanical stability. Smaller screws have a high failure and nonunion rate.

Question 11073

Topic: 2. Trauma

A 19-year-old cross-country runner presents with insidious onset dorsal midfoot pain. Plain radiographs are negative. A CT scan confirms an incomplete, non-displaced stress fracture of the dorsal cortex of the tarsal navicular. Why is this specific anatomic region highly susceptible to nonunion?

. It represents an avascular watershed zone between the medial and lateral vascular supplies
. It is the primary insertion site of the tibialis anterior tendon
. It experiences continuous compressive forces during the swing phase of gait
. It lacks a robust periosteal layer compared to the cuneiforms
. It is subjected to constant shear forces from the extensor hallucis longus

Correct Answer & Explanation

. It represents an avascular watershed zone between the medial and lateral vascular supplies

Explanation

Navicular stress fractures typically occur in the central third of the bone, which is an avascular watershed zone between the branches of the dorsalis pedis and medial plantar arteries. This tenuous blood supply significantly increases the risk of delayed union or nonunion.

Question 11074

Topic: Lower Extremity Trauma

A 28-year-old male sustains an acute distal tibiofibular syndesmotic injury. During surgical stabilization, the surgeon meticulously evaluates the individual syndesmotic ligaments. Which of the following ligaments provides the greatest resistance to lateral displacement of the fibula and is mechanically the strongest?

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

Correct Answer & Explanation

. Anterior inferior tibiofibular ligament (AITFL)

Explanation

The posterior inferior tibiofibular ligament (PITFL) is the strongest component of the syndesmotic complex, contributing approximately 42% of the resistance to lateral fibular displacement. The AITFL contributes approximately 35%.

Question 11075

Topic: 2. Trauma

A 38-year-old male sustains a high-energy pilon fracture. CT imaging demonstrates significant comminution, but distinct fracture fragments are identifiable. The anterolateral distal tibial articular fragment, often avulsed during the injury, is attached to which ligament?

. Posterior inferior tibiofibular ligament (PITFL)
. Anterior inferior tibiofibular ligament (AITFL)
. Deltoid ligament
. Spring ligament
. Anterior talofibular ligament (ATFL)

Correct Answer & Explanation

. Posterior inferior tibiofibular ligament (PITFL)

Explanation

The anterolateral distal tibial fragment in a pilon or syndesmotic injury is known as the Chaput fragment. It serves as the tibial attachment for the anterior inferior tibiofibular ligament (AITFL).

Question 11076

Topic: Lower Extremity Trauma

A 25-year-old equestrian falls from a horse, sustaining a subtle Lisfranc injury with instability of the first, second, and third tarsometatarsal (TMT) joints. The surgeon opts for open reduction and internal fixation utilizing dorsal spanning plates rather than transarticular screws. What is the primary biomechanical and biologic advantage of using dorsal spanning plates in this scenario?

. Greater resistance to plantarflexion forces
. Prevention of iatrogenic damage to the TMT articular cartilage
. Elimination of the need for future hardware removal
. Decreased risk of superficial peroneal nerve injury
. Immediate full weight-bearing capabilities post-operatively

Correct Answer & Explanation

. Greater resistance to plantarflexion forces

Explanation

Dorsal spanning plates 'bridge' the tarsometatarsal joints without violating the joint surfaces, thereby preventing iatrogenic damage to the articular cartilage. This is thought to lower the incidence of secondary post-traumatic osteoarthritis compared to transarticular screws.

Question 11077

Topic: 2. Trauma

During an extensile lateral approach for open reduction and internal fixation of a displaced intra-articular calcaneus fracture, protecting the primary blood supply to the apex of the corner flap is critical. Which of the following arteries is primarily responsible for perfusing this flap?

. Medial calcaneal artery
. Lateral calcaneal artery
. Dorsalis pedis artery
. Lateral plantar artery
. Anterior tibial artery

Correct Answer & Explanation

. Medial calcaneal artery

Explanation

The lateral calcaneal artery, a branch of the peroneal artery, provides the primary blood supply to the lateral cutaneous flap of the heel. An extensile lateral approach must maintain full-thickness subperiosteal dissection to avoid flap necrosis.

Question 11078

Topic: 2. Trauma

A 22-year-old professional basketball player presents with lateral foot pain after landing awkwardly. Radiographs reveal an acute, non-displaced fracture at the metaphyseal-diaphyseal junction of the fifth metatarsal (Zone 2). What is the recommended treatment to minimize the risk of nonunion and allow the fastest return to play?

. Non-weight-bearing in a short leg cast for 6 weeks
. Weight-bearing as tolerated in a stiff-soled shoe
. Open reduction and plate fixation
. Percutaneous intramedullary screw fixation
. Excision of the fracture fragment and peroneus brevis advancement

Correct Answer & Explanation

. Non-weight-bearing in a short leg cast for 6 weeks

Explanation

Zone 2 base of 5th metatarsal fractures (Jones fractures) have a high rate of nonunion due to watershed vascularity. Intramedullary screw fixation is the gold standard for high-level athletes to promote reliable healing and expedite return to sports.

Question 11079

Topic: 2. Trauma

A 40-year-old male is undergoing open reduction and internal fixation of a bimalleolar equivalent ankle fracture. Intraoperatively, the Cotton test demonstrates syndesmotic instability. On an AP and Mortise radiograph, what is the normal limit for the tibiofibular clear space when evaluating reduction?

. Less than 2 mm
. Less than 4 mm
. Less than 6 mm
. Less than 8 mm
. Less than 10 mm

Correct Answer & Explanation

. Less than 2 mm

Explanation

The tibiofibular clear space is the most reliable radiographic parameter for syndesmotic integrity. It should measure < 6 mm on both AP and Mortise views, measured 1 cm proximal to the joint line.

Question 11080

Topic: 2. Trauma

A 19-year-old track athlete experiences vague dorsal midfoot pain for three months. A CT scan confirms a non-displaced stress fracture of the tarsal navicular. In which anatomic zone of the navicular do these stress fractures most commonly occur due to an area of relative avascularity?

. Plantar tuberosity
. Medial third
. Central third
. Lateral third
. Dorsal lip

Correct Answer & Explanation

. Plantar tuberosity

Explanation

Tarsal navicular stress fractures predominantly occur in the central third of the bone. This area represents a vascular watershed zone between the medial and lateral blood supplies, predisposing it to poor healing and nonunion.

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