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2. Trauma MCQs

Practice Set 264 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 5261

Topic: Upper Extremity Trauma
A 42-year-old female presents with a highly comminuted, displaced radial head fracture (Mason Type III) and an associated tear of the medial ulnar collateral ligament, causing elbow instability. Which of the following is the most appropriate surgical treatment?
. Open reduction and internal fixation of the radial head
. Radial head excision alone
. Radial head excision with prosthetic replacement
. Closed reduction and casting for 6 weeks
. Distal humerus replacement

Correct Answer & Explanation

. Radial head excision with prosthetic replacement

Explanation

In a Mason Type III (comminuted) radial head fracture with associated ligamentous instability (e.g., Essex-Lopresti, terrible triad, or MUCL tear), radial head excision alone is contraindicated because the radial head is a crucial secondary stabilizer to valgus stress and longitudinal forearm stability. If ORIF is not possible due to severe comminution, radial head excision with prosthetic replacement is the treatment of choice to restore stability.

Question 5262

Topic: 2. Trauma

A 21-year-old collegiate basketball player sustains a fracture of the fifth metatarsal located at the metaphyseal-diaphyseal junction, extending into the fourth-fifth intermetatarsal articulation. He wishes to return to play as safely and quickly as possible. What is the most appropriate management?

. Non-weight bearing in a short leg cast for 6-8 weeks
. Immediate weight bearing in a hard-soled shoe
. Intramedullary screw fixation
. Open reduction and tension band wiring
. Excision of the proximal fragment and peroneus brevis advancement

Correct Answer & Explanation

. Intramedullary screw fixation

Explanation

The patient has a Zone 2 (Jones) fracture of the fifth metatarsal. Because this is an intra-articular fracture at the metaphyseal-diaphyseal junction in a high-demand athlete, intramedullary screw fixation is the gold standard. It offers the highest union rate, fastest return to play, and lowest risk of non-union or re-fracture compared to conservative management, which has a higher rate of delayed union or non-union in this hypovascular zone.

Question 5263

Topic: 2. Trauma

A lateral radiograph of the elbow in a trauma patient reveals a 'double-arc sign.' This radiographic finding indicates which of the following injury patterns?

. A terrible triad injury of the elbow
. A radial head fracture with an associated Essex-Lopresti lesion
. A capitellum fracture extending into the lateral trochlear ridge
. An isolated coronoid tip fracture
. A non-displaced supracondylar humerus fracture

Correct Answer & Explanation

. A capitellum fracture extending into the lateral trochlear ridge

Explanation

The 'double-arc sign' on a true lateral radiograph of the elbow is pathognomonic for a capitellum fracture that extends medially to include the lateral portion of the trochlea (lateral trochlear ridge), known as a McKee Type IV fracture. One arc represents the subchondral bone of the capitellum, and the second arc represents the lateral trochlear ridge.

Question 5264

Topic: 2. Trauma

A 35-year-old female is evaluated 8 weeks after open reduction and internal fixation of a Hawkins Type II talar neck fracture. An AP mortise radiograph demonstrates a subchondral radiolucent band in the talar dome. What does this radiographic finding indicate?

. Early avascular necrosis of the talar body
. Impending nonunion of the fracture site
. Viable vascular supply to the talar body
. Post-traumatic osteomyelitis of the talus
. Osteochondral defect of the talar dome requiring excision

Correct Answer & Explanation

. Viable vascular supply to the talar body

Explanation

The presence of a subchondral radiolucent band in the talar dome 6 to 8 weeks after a talar neck fracture is known as Hawkins' sign. It represents subchondral osteopenia (bone resorption) secondary to disuse. Because bone resorption is an active cellular process that requires an intact blood supply, its presence is a highly reliable indicator that the talar body remains vascularized, thus effectively excluding the diagnosis of complete avascular necrosis (AVN).

Question 5265

Topic: Pelvic & Acetabular Trauma

During a Bernese periacetabular osteotomy (PAO) for symptomatic developmental dysplasia of the hip, the posterior column of the pelvis is deliberately preserved to maintain pelvic stability and allow for early mobilization. Which of the following osteotomy cuts is NOT performed during a standard PAO?

. Incomplete osteotomy of the ischium
. Complete osteotomy of the superior pubic ramus
. Complete transverse osteotomy of the ilium
. Complete osteotomy of the posterior column of the ischium
. Osteotomy of the anterior aspect of the acetabulum

Correct Answer & Explanation

. Complete osteotomy of the posterior column of the ischium

Explanation

The Bernese periacetabular osteotomy (PAO) reorients the acetabulum while preserving the mechanical integrity of the pelvic ring. This is achieved by keeping the posterior column of the hemipelvis intact. Therefore, a complete osteotomy of the posterior column is NOT performed. The cuts include an incomplete ischial osteotomy (stopping short of the posterior column), a complete pubic root osteotomy, and an incomplete iliac osteotomy that joins the ischial cut, freeing the acetabular fragment while maintaining posterior pelvic continuity.

Question 5266

Topic: 2. Trauma

A 75-year-old male sustains an Anderson and D'Alonzo Type II odontoid fracture after a ground-level fall. The fracture is displaced 6 mm posteriorly. If treated non-operatively with a rigid cervical collar, which of the following characteristics is the strongest predictor of nonunion?

. Mechanism of injury (low energy)
. Fracture displacement > 5 mm
. Associated anterior arch of C1 fracture
. Patient gender
. Use of a rigid cervical collar vs. a halo vest

Correct Answer & Explanation

. Fracture displacement > 5 mm

Explanation

Type II odontoid fractures have a high rate of nonunion. Risk factors for nonunion include fracture displacement > 5 mm, patient age > 50 years, posterior displacement, and comminution. Displacement greater than 5 mm is a classically tested, major independent risk factor that often directs surgeons toward operative management (e.g., posterior C1-C2 fusion or anterior odontoid screw) in surgical candidates.

Question 5267

Topic: 2. Trauma
A 28-year-old man is involved in a high-speed motor vehicle collision and sustains a vertically oriented (Pauwels type III) femoral neck fracture. Which fixation construct provides the most biomechanically stable construct for this specific fracture pattern?
. Three parallel cancellous screws
. Dynamic hip screw with an anti-rotation screw
. Intramedullary nail
. Hemiarthroplasty
. Total hip arthroplasty

Correct Answer & Explanation

. Dynamic hip screw with an anti-rotation screw

Explanation

Pauwels type III fractures are highly unstable due to significant vertical shear forces across the fracture line. A dynamic hip screw (fixed-angle device) supplemented with a derotational screw provides superior biomechanical stability against shear stress compared to multiple cancellous screws.

Question 5268

Topic: 2. Trauma

A 22-year-old skier hears a pop in her knee after a twisting injury. Radiographs show a small avulsion fracture of the lateral tibial plateau (Segond fracture). This radiographic finding is virtually pathognomonic for an injury to which of the following structures?

. Posterior cruciate ligament
. Medial collateral ligament
. Lateral meniscus
. Anterior cruciate ligament
. Iliotibial band

Correct Answer & Explanation

. Anterior cruciate ligament

Explanation

A Segond fracture is a cortical avulsion of the anterolateral capsule from the lateral tibial plateau. It is considered highly pathognomonic for an anterior cruciate ligament (ACL) tear.

Question 5269

Topic: 2. Trauma

A 42-year-old roofer falls 15 feet, landing on his feet. He complains of severe back pain. CT shows an L1 burst fracture with 60% canal compromise. He is neurologically intact. Which of the following is the strongest indication for operative stabilization?

. Canal compromise greater than 50%
. Presence of a concomitant calcaneus fracture
. Loss of vertebral body height of 20%
. Posterior ligamentous complex (PLC) disruption
. Isolated anterior column comminution

Correct Answer & Explanation

. Posterior ligamentous complex (PLC) disruption

Explanation

In a neurologically intact patient with a thoracolumbar burst fracture, disruption of the posterior ligamentous complex (PLC) indicates gross spinal instability and is a primary indication for surgery. Canal compromise alone, without neurological deficit or PLC injury, can often be managed conservatively.

Question 5270

Topic: 2. Trauma

A 35-year-old pedestrian is struck by a car and sustains a medial tibial plateau fracture with depression and a fractured medial intercondylar eminence (Schatzker Type IV). What is the classic mechanism of injury for this fracture pattern?

. Valgus force with axial loading
. Varus force with axial loading
. Hyperextension with internal rotation
. Hyperflexion with direct anterior blow
. Isolated external rotation

Correct Answer & Explanation

. Varus force with axial loading

Explanation

Schatzker IV fractures involve the medial tibial plateau and are typically caused by a high-energy varus force combined with axial loading. They have a higher association with peroneal nerve traction injuries and popliteal artery damage than lateral plateau fractures.

Question 5271

Topic: Pelvic & Acetabular Trauma

A 25-year-old man is brought in hypotensive after a motorcycle crash. Pelvic radiographs reveal a 4 cm diastasis of the pubic symphysis and disruption of the anterior sacroiliac joints, but intact posterior sacroiliac ligaments. What is the most appropriate initial management for his hemodynamic instability?

. Immediate open reduction and internal fixation of the symphysis
. Application of a pelvic binder centered over the iliac crests
. Application of a pelvic binder centered over the greater trochanters
. Bilateral internal iliac artery embolization
. External fixation using iliac crest pins

Correct Answer & Explanation

. Application of a pelvic binder centered over the greater trochanters

Explanation

This is an anteroposterior compression (APC) Type II injury resulting in an open-book pelvis and increased pelvic volume. A pelvic binder should be applied immediately and centered over the greater trochanters to effectively close the pelvic ring and aid in hemorrhage control.

Question 5272

Topic: Pelvic & Acetabular Trauma
A hemodynamically unstable 35-year-old male sustains an anteroposterior compression type III (APC-III) pelvic ring injury. A circumferential pelvic binder is applied in the trauma bay. To optimally reduce the pelvic volume and stabilize the fracture, the binder should be centered over which anatomic landmark?
. Anterior superior iliac spines
. Iliac crests
. Greater trochanters
. Pubic symphysis
. Ischial tuberosities

Correct Answer & Explanation

. Greater trochanters

Explanation

A pelvic binder must be centered directly over the greater trochanters to effectively close the pelvic ring and reduce pelvic volume. Placement over the iliac crests or ASIS can paradoxically open the pelvis further and exacerbate hemorrhage.

Question 5273

Topic: 2. Trauma

A 45-year-old male sustains a high-energy Schatzker type IV tibial plateau fracture. Which of the following vascular structures is at highest risk of injury due to the specific mechanism and displacement pattern of this fracture?

. Anterior tibial artery
. Posteromedial genicular artery
. Popliteal artery
. Peroneal artery
. Dorsalis pedis artery

Correct Answer & Explanation

. Popliteal artery

Explanation

Schatzker IV fractures involve the medial tibial plateau and often result from high-energy varus forces with potential knee subluxation. This specific displacement pattern places the popliteal artery at high risk of tethering and intimal injury at the fibrous arch of the soleus.

Question 5274

Topic: 2. Trauma

A 28-year-old male sustains an isolated, closed midshaft femur fracture. He undergoes reamed intramedullary nailing 12 hours after injury. Postoperatively, he develops acute hypoxia, a petechial rash on the axillae, and altered mental status. What is the primary pathophysiologic mechanism for this condition?

. Bacterial seeding of the pulmonary vasculature
. Thrombus propagation from deep calf veins
. Release of marrow fat and inflammatory mediators into the venous circulation
. Direct lung contusion from unrecognized blunt trauma
. Transfusion-related acute lung injury

Correct Answer & Explanation

. Release of marrow fat and inflammatory mediators into the venous circulation

Explanation

The classic triad of hypoxia, petechial rash, and neurologic abnormalities indicates Fat Embolism Syndrome (FES). It is caused by the systemic release of bone marrow fat globules and inflammatory mediators into the venous circulation following long bone fractures and reaming.

Question 5275

Topic: 2. Trauma
A 45-year-old woman has a distal radius fracture, which is treated with open reduction and internal fixation. The surgery was uncomplicated, and the patient is discharged to home. At the first follow-up appointment, the patient demonstrates signs that are concerning for complex regional pain syndrome (CRPS). What factor is included in the International Association for the Study of Pain (IASP) criteria (Budapest criteria) for the diagnosis of CRPS?
. Hypoesthesia
. Elevated white blood cell count
. Elevated C-reactive protein level
. Pain disproportionate to the inciting event

Correct Answer & Explanation

. Pain disproportionate to the inciting event

Explanation

The diagnosis of CRPS is complex. The IASP has approved diagnostic criteria to standardize both the diagnosis and the study of CRPS. The criteria include: continuing pain disproportionate to any inciting event, and at least one symptom/sign in categories including sensory (hyperesthesia/allodynia), vasomotor (temperature/color asymmetry), sudomotor/edema, and motor/trophic changes. Decreased sensation and focal numbness are not consistent with CRPS. Laboratory and imaging studies can be helpful in evaluating for the exclusion of differential diagnoses for CRPS, including infection, rheumatic disease, fracture, nonunion, tenosynovitis, or osteomyelitis.

Question 5276

Topic: 2. Trauma

A 28-year-old male sustains a Hawkins Type II talar neck fracture. At 8 weeks post-operation, an anteroposterior (AP) radiograph of the ankle reveals a distinct subchondral radiolucent band in the dome of the talus. What does this radiographic finding represent?

. Avascular necrosis of the talar dome
. Osteomyelitis of the talus
. Intact vascular supply to the talar dome
. Nonunion of the talar neck
. Early post-traumatic osteoarthritis

Correct Answer & Explanation

. Intact vascular supply to the talar dome

Explanation

This finding is known as the Hawkins sign. The subchondral radiolucent band represents subchondral osteopenia secondary to hyperemia and active bone resorption. It is a highly reliable indicator that the talar dome retains an intact vascular supply, essentially ruling out complete avascular necrosis.

Question 5277

Topic: 2. Trauma

A 21-year-old elite basketball player is diagnosed with a Jones fracture (fracture at the metaphyseal-diaphyseal junction of the 5th metatarsal). Surgical fixation with an intramedullary screw is planned. What anatomic feature is the primary reason for the notoriously high nonunion rate in this specific location?

. High repetitive tensile forces from the insertion of the peroneus brevis
. Lack of a periosteal blood supply to the entire 5th metatarsal
. A watershed vascular zone between the metaphyseal and diaphyseal blood supplies
. Constant direct compressive forces from the plantar aponeurosis
. Intra-articular extension of the fracture line into the cuboid articulation

Correct Answer & Explanation

. A watershed vascular zone between the metaphyseal and diaphyseal blood supplies

Explanation

The high nonunion rate of a Jones fracture (Zone 2 of the 5th metatarsal) is primarily due to its location in a vascular watershed area. The blood supply to the base of the 5th metatarsal comes from metaphyseal vessels proximally and a nutrient artery distally, leaving the metaphyseal-diaphyseal junction relatively avascular.

Question 5278

Topic: 2. Trauma

Six weeks after open reduction and internal fixation of a displaced talar neck fracture, an AP ankle radiograph reveals a subchondral radiolucent band in the dome of the talus (Hawkins sign). This radiographic finding indicates:

. Inevitable progression to talar body avascular necrosis (AVN)
. Intact vascularity to the talar body due to active hyperemic bone resorption
. Failure of fixation leading to early nonunion
. Subchondral impaction fracture not recognized at index surgery
. Post-traumatic osteolysis of the distal tibia

Correct Answer & Explanation

. Intact vascularity to the talar body due to active hyperemic bone resorption

Explanation

The Hawkins sign is a subchondral radiolucent band seen in the talar dome on AP or mortise views at 6 to 8 weeks post-injury. It represents subchondral bone atrophy resulting from active hyperemia. This physiologic response requires an intact blood supply; therefore, the presence of a Hawkins sign is a highly reliable indicator that the talar body has preserved vascularity and that AVN is unlikely.

Question 5279

Topic: 2. Trauma

A 21-year-old collegiate basketball player sustains a zone 2 fracture (Jones fracture) of the proximal fifth metatarsal. Intramedullary screw fixation is planned. To optimize biomechanical stability and reduce the risk of nonunion or refracture, what are the ideal characteristics of the implant?

. Small diameter (3.0 mm) partially threaded cannulated screw
. Fully threaded solid screw that is smaller than the medullary canal diameter
. Largest diameter solid screw that fits the canal with a length that engages the curvature of the diaphysis
. Headless compression screw entirely within the proximal fragment
. K-wire fixation crossing the fracture site

Correct Answer & Explanation

. Largest diameter solid screw that fits the canal with a length that engages the curvature of the diaphysis

Explanation

In elite athletes, intramedullary screw fixation for Jones fractures is preferred to optimize early return to play. The biomechanically superior construct uses the largest diameter screw that comfortably fits the canal (usually 4.5 mm to 5.5 mm) to maximize bending stiffness. Solid screws are stronger than cannulated screws. The screw should ideally be long enough that all threads bypass the fracture site, gaining purchase in the diaphyseal isthmus.

Question 5280

Topic: 2. Trauma

Proximal pole fractures of the scaphoid are notorious for a high rate of avascular necrosis and nonunion. This complication is driven by the retrograde blood supply of the scaphoid. The primary intraosseous vascular supply enters the scaphoid at which of the following anatomic locations?

. Volar scaphoid tubercle
. Dorsal ridge on the distal half of the scaphoid
. Proximal pole articular surface
. Scaphotrapeziotrapezoid (STT) ligamentous insertion
. Radioscaphocapitate ligament insertion

Correct Answer & Explanation

. Dorsal ridge on the distal half of the scaphoid

Explanation

The primary blood supply to the scaphoid is derived from the dorsal carpal branch of the radial artery, which enters the bone via the dorsal ridge located on the distal half (roughly 70-80% of the blood supply). Because blood flows retrograde from distal to proximal, fractures at the waist or proximal pole disrupt perfusion to the proximal segment, making it highly susceptible to avascular necrosis (AVN).

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