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2. Trauma MCQs

Practice Set 541 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 10801

Topic: 2. Trauma

A 32-year-old male sustains a closed distal-third humeral shaft fracture (Holstein-Lewis type). On initial evaluation, his radial nerve function is completely intact. Following closed reduction and splint application, he is found to have an inability to extend his wrist and fingers. What is the most appropriate next step in management?

. Immediate surgical exploration of the radial nerve
. Observation with serial clinical examinations for 3 months
. Electromyography (EMG) and nerve conduction studies
. Application of a functional fracture brace and early range of motion
. Ultrasound-guided perineural corticosteroid injection

Correct Answer & Explanation

. Immediate surgical exploration of the radial nerve

Explanation

A secondary radial nerve palsy that develops immediately after a closed reduction attempt of a humeral shaft fracture is an absolute indication for surgical exploration, as the nerve may be entrapped in the fracture site.

Question 10802

Topic: 2. Trauma



In the evaluation of a displaced proximal humerus fracture, which of the following radiographic criteria is the most reliable predictor of subsequent avascular necrosis of the humeral head?

. Greater tuberosity displacement greater than 5 mm
. Posterior medial hinge disruption with a calcar segment less than 8 mm
. Lesser tuberosity comminution
. Varus angulation of 20 degrees
. Diaphyseal extension of the fracture

Correct Answer & Explanation

. Greater tuberosity displacement greater than 5 mm

Explanation

The Hertel criteria for predicting ischemia and avascular necrosis in proximal humerus fractures include a metaphyseal head extension (calcar length) of less than 8 mm and disruption of the medial hinge.

Question 10803

Topic: 2. Trauma

A 32-year-old male sustains a closed, isolated, distal third spiral fracture of the humeral shaft (Holstein-Lewis fracture). On initial presentation, he is unable to actively extend his wrist or fingers. What is the most appropriate initial management?

. Immediate open reduction internal fixation with radial nerve exploration
. Application of a coaptation splint or functional brace, with EMG/NCS at 6 weeks if no recovery
. Application of a functional brace and immediate nerve exploration
. External fixation of the humerus to restore length
. Primary tendon transfers to restore wrist and finger extension

Correct Answer & Explanation

. Immediate open reduction internal fixation with radial nerve exploration

Explanation

Primary radial nerve palsy in the setting of a closed humeral shaft fracture is typically a neuropraxia and is managed observationally. If there is no clinical improvement by 6 weeks, baseline EMG/NCS should be obtained.

Question 10804

Topic: 2. Trauma

A 28-year-old female undergoes open reduction and internal fixation of a displaced midshaft clavicle fracture. Postoperatively, she has normal motor function but complains of significant numbness over the anterior chest wall immediately inferior to the surgical incision. Injury to which nerve is the most likely cause?

. Suprascapular nerve
. Medial pectoral nerve
. Supraclavicular nerve
. Intercostobrachial nerve
. Spinal accessory nerve

Correct Answer & Explanation

. Suprascapular nerve

Explanation

The supraclavicular nerve branches cross over the clavicle and are frequently sacrificed or injured during standard surgical approaches to the midshaft clavicle. This results in an expected area of numbness over the anterior chest wall.

Question 10805

Topic: 2. Trauma

An 82-year-old female presents with acute severe midline back pain after lifting a heavy box. Radiographs reveal a new T12 compression fracture with 20% loss of anterior height and no posterior wall involvement. She is neurologically intact. What is the best initial management?

. Percutaneous vertebroplasty
. Kyphoplasty
. Short-segment pedicle screw fixation
. Short period of rest, analgesics, and progressive mobilization
. TLSO bracing for 12 weeks

Correct Answer & Explanation

. Percutaneous vertebroplasty

Explanation

The vast majority of osteoporotic vertebral compression fractures are stable and should initially be treated conservatively with a short period of bed rest, pain control, and early mobilization to prevent further deconditioning.

Question 10806

Topic: 2. Trauma

An 82-year-old female presents with neck pain following a motor vehicle collision. CT scan reveals a Type II odontoid fracture. Comorbidities include severe COPD and osteoporosis. She is neurologically intact. If she is managed non-operatively with a rigid cervical collar, which of the following is an established major risk factor for non-union?

. Initial fracture displacement > 5 mm
. Anterior fracture displacement of 2 mm
. Associated C1 ring fracture
. Concomitant degenerative changes of the C1-C2 articulation
. Fracture gap < 1 mm

Correct Answer & Explanation

. Initial fracture displacement > 5 mm

Explanation

Major risk factors for non-union of a Type II odontoid fracture include age over 65 years, initial fracture displacement > 5 mm, posterior displacement, and a fracture gap > 1 mm. Given her age, she is already at high risk, but among the choices provided, displacement > 5 mm is the classic, highly significant risk factor that strongly correlates with non-union in collar management.

Question 10807

Topic: 2. Trauma
A 22-year-old male falls from a height of 30 feet. He has bilateral lower extremity weakness and perineal numbness. Imaging demonstrates a transverse fracture through the S1-S2 level connecting bilateral longitudinal transforaminal sacral fractures (U-type fracture). What is the primary biomechanical goal of surgical fixation for this specific pattern?
. Restoration of the anterior pelvic ring
. Compression across the sacroiliac joints
. Reconstitution of spinopelvic continuity
. Prevention of progressive sacral kyphosis using anterior plating
. Distraction of the lumbosacral disc space

Correct Answer & Explanation

. Reconstitution of spinopelvic continuity

Explanation

A U-type sacral fracture (Denis Zone III) creates a functional spinopelvic dissociation, meaning the axial skeleton (lumbar spine) is disconnected from the pelvis. The primary biomechanical goal of surgery is to reconstitute spinopelvic continuity and stabilize the spine to the pelvis, typically using lumbopelvic fixation (e.g., L4/L5 pedicle screws connected to iliac screws), combined with neural decompression if indicated.

Question 10808

Topic: 2. Trauma

A 75-year-old man falls and complains of severe neck pain. Radiographs reveal a Type II odontoid fracture. Which of the following parameters is the most significant risk factor for nonunion if managed conservatively?

. Age less than 40 years
. Initial fracture displacement greater than 5 mm
. Anterior displacement of 2 mm
. Impaction of the fracture site
. Type IIA fracture pattern with comminution

Correct Answer & Explanation

. Age less than 40 years

Explanation

Risk factors for nonunion in Type II odontoid fractures include initial displacement > 5 mm, age > 50 years, and posterior displacement. Surgery is generally indicated in these high-risk patients to prevent nonunion.

Question 10809

Topic: 2. Trauma

A 25-year-old male involved in a high-speed motor vehicle collision sustains a thoracolumbar fracture. Radiographs and CT demonstrate a fracture extending horizontally through the spinous process, pedicles, and vertebral body of L1. What is the primary pathomechanism of this specific injury pattern?

. Pure axial compression causing failure of anterior and middle columns
. Hyperextension with failure of the anterior longitudinal ligament
. Flexion-distraction around an axis anterior to the anterior longitudinal ligament
. Rotational translation with disruption of all three columns
. Lateral compression causing unilateral facet dislocation

Correct Answer & Explanation

. Pure axial compression causing failure of anterior and middle columns

Explanation

A Chance fracture is a flexion-distraction injury where the axis of rotation is anterior to the anterior longitudinal ligament. This results in tension failure of the posterior, middle, and anterior columns.

Question 10810

Topic: 2. Trauma

An 82-year-old woman sustains a Type II odontoid fracture after a ground-level fall. Which of the following is considered a significant risk factor for nonunion if treated conservatively with a hard cervical collar?

. Initial fracture displacement less than 2 mm
. Anterior fracture displacement
. Age greater than 50 years with initial displacement >5 mm
. Impacted fracture pattern without angulation
. Absence of comminution

Correct Answer & Explanation

. Initial fracture displacement less than 2 mm

Explanation

Risk factors for nonunion in Type II odontoid fractures include patient age >50 years, initial displacement >5 mm, posterior displacement, and significant comminution.

Question 10811

Topic: Lower Extremity Trauma

When planning a medial opening wedge high tibial osteotomy (HTO) for isolated medial compartment osteoarthritis in a varus knee, the surgeon intends to shift the mechanical axis to the Fujisawa point. Where is the Fujisawa point located on the tibial plateau?

. At exactly 50% of the tibial width (center of the knee)
. At 62% of the tibial width, measured from the medial to lateral edge
. At 38% of the tibial width, measured from the medial to lateral edge
. At the lateral edge of the lateral meniscus
. At the medial tibial spine

Correct Answer & Explanation

. At exactly 50% of the tibial width (center of the knee)

Explanation

The Fujisawa point is traditionally targeted in HTO for medial compartment OA to slightly overcorrect the varus deformity and unload the medial compartment. It is located at 62% of the tibial plateau width from the medial edge (i.e., slightly lateral to the lateral tibial spine in the lateral compartment). This aligns the mechanical axis to pass through the lateral compartment, providing optimal unloading of the damaged medial cartilage while preventing excessive valgus overload.

Question 10812

Topic: 2. Trauma



A 72-year-old female presents with acute thigh pain and an inability to bear weight after a minor fall, 10 years post-THA. Radiographs demonstrate a fracture around the tip of the well-fixed femoral stem, extending into the diaphysis. The bone stock proximally remains intact. Which principle must be strictly adhered to during the surgical fixation of this fracture?

. Removal of the stable stem to allow for intramedullary nailing
. Use of a long locking plate spanning the fracture with bicortical fixation distal to the fracture and unicortical screws/cables proximally
. Revision to a fully porous-coated cylindrical stem extending past the fracture
. Impaction bone grafting alone without osteosynthesis
. Application of a bridging external fixator

Correct Answer & Explanation

. Removal of the stable stem to allow for intramedullary nailing

Explanation

This describes a Vancouver B1 periprosthetic fracture (fracture around a well-fixed stem with good bone stock). The treatment of choice is osteosynthesis with a long bridging plate. To prevent creating a stress riser at the tip of the stem, the plate should overlap the stem proximally using cerclage cables or unicortical screws, while achieving solid bicortical screw fixation distally in the native diaphysis.

Question 10813

Topic: Lower Extremity Trauma

Popliteal artery injury is a rare but devastating complication of primary TKA. During which specific surgical maneuver is the artery at the highest risk of direct traumatic injury?

. Resection of the anterior femoral condyles
. Removal of medial osteophytes from the tibial plateau
. Release of the superficial medial collateral ligament (sMCL)
. Resection of the posterior tibial plateau and posterior femoral condyles
. Preparation and resurfacing of the patella

Correct Answer & Explanation

. Resection of the anterior femoral condyles

Explanation

The popliteal artery is situated directly posterior to the posterior capsule of the knee, at the level of the joint line. It is at greatest risk of direct laceration from the oscillating saw blade penetrating the posterior capsule during the proximal tibial cut or the posterior femoral condylar cuts.

Question 10814

Topic: 2. Trauma

A 78-year-old female sustains a periprosthetic femur fracture 10 years after a cemented THA. Radiographs show a fracture around the tip of the stem with a loose femoral component and poor proximal bone stock, but adequate diaphyseal bone.

What is the most appropriate surgical treatment?

. Open reduction internal fixation with cables and a laterally based plate
. Revision to a standard length uncemented proximally coated stem
. Revision to a fully porous-coated cylindrical long stem or fluted tapered modular stem with cerclage
. Revision to a proximal femoral replacement
. Cortical strut allograft only with prolonged protected weight-bearing

Correct Answer & Explanation

. Open reduction internal fixation with cables and a laterally based plate

Explanation

Vancouver B2 fractures involve a loose stem with adequate remaining distal bone stock. The standard of care is revision arthroplasty using a diaphyseal-fitting stem (such as a fluted tapered modular stem) that bypasses the fracture by at least 2 cortical diameters, along with fracture stabilization.

Question 10815

Topic: 2. Trauma

A 68-year-old male sustains a distal femur periprosthetic fracture (Lewis and Rorabeck Type II) directly above a well-fixed PS TKA femoral component. The fracture is displaced. What is the most appropriate management?

. Non-operative management in a hinged knee brace
. Revision to a distal femoral replacement
. Open reduction and internal fixation with a lateral locking plate
. Revision to a rotating hinge TKA
. Knee arthrodesis

Correct Answer & Explanation

. Non-operative management in a hinged knee brace

Explanation

Lewis and Rorabeck Type II fractures are displaced fractures where the femoral prosthesis remains well-fixed. The standard of care is open reduction and internal fixation (ORIF), typically utilizing a pre-contoured lateral locking plate or retrograde nail.

Question 10816

Topic: Lower Extremity Trauma

An asymptomatic 10-year-old boy undergoes a radiograph after a minor knee sprain. The plain film reveals an incidental finding: an eccentric, cortically based, multilocular radiolucency with a well-defined sclerotic border in the distal femur metaphysis.

Which of the following is the most appropriate management for this lesion?

. Observation and reassurance
. Curettage and bone grafting
. Wide en bloc resection
. Radiofrequency ablation
. Neoadjuvant chemotherapy followed by resection

Correct Answer & Explanation

. Observation and reassurance

Explanation

The radiograph describes a Non-Ossifying Fibroma (NOF) or Fibrous Cortical Defect. These are benign, asymptomatic, self-limiting developmental defects of bone rather than true neoplasms. They typically present as eccentric, cortically based, 'bubbly' metaphyseal lesions with sclerotic margins. The standard of care is observation and reassurance, as the vast majority will ossify and resolve spontaneously as the child reaches skeletal maturity.

Question 10817

Topic: Upper Extremity Trauma

A 15-year-old boy presents with shoulder pain. Radiographs reveal a well-circumscribed, lytic lesion in the epiphysis of the proximal humerus with a thin sclerotic margin. Histological examination shows mononuclear cells with grooved nuclei and areas of 'chicken-wire' calcification. Which specific genetic mutation drives this neoplasm?

. H3F3A (G34W)
. H3F3B (K36M)
. IDH1 (R132C)
. GNAS (R201H)
. BRAF (V600E)

Correct Answer & Explanation

. H3F3A (G34W)

Explanation

The clinical presentation and histology (chicken-wire calcification) are diagnostic of a chondroblastoma. Chondroblastomas are uniquely driven by a specific K36M mutation in the H3F3B histone gene.

Question 10818

Topic: 2. Trauma

A 65-year-old female sustains a fall on an outstretched hand. Imaging reveals a proximal humerus fracture with the articular segment dislocated from the glenoid, and the lesser tuberosity displaced. According to the Neer classification, what is the primary determinant of a "part"?

. Number of fracture lines
. Displacement of >1 cm or angulation of >45 degrees
. Articular surface involvement
. Number of fragments regardless of displacement
. Neurovascular compromise

Correct Answer & Explanation

. Number of fracture lines

Explanation

In Neer's classification of proximal humerus fractures, a fragment is only considered a "part" if it is displaced by >1 cm or angulated by >45 degrees relative to the other fragments. This functional classification dictates management and prognosis.

Question 10819

Topic: 2. Trauma

A 19-year-old cyclist falls onto his shoulder. Radiographs demonstrate a midshaft clavicle fracture. Which of the following is considered an absolute indication for immediate open reduction and internal fixation (ORIF)?

. Shortening of 1.5 cm
. Displacement of 100%
. Skin tenting with progressive blanching
. Z-type comminution
. Patient preference to return to sports early

Correct Answer & Explanation

. Shortening of 1.5 cm

Explanation

Absolute indications for ORIF of a clavicle fracture include open fractures, associated neurovascular compromise, and impending skin breakdown (manifested by severe skin tenting with blanching). Shortening >2cm and 100% displacement are relative indications.

Question 10820

Topic: Upper Extremity Trauma
A 35-year-old male falls directly onto the point of his shoulder. Radiographs show a 150% superior displacement of the distal clavicle relative to the acromion, and the coracoclavicular distance is increased by 50% compared to the normal side. According to the Rockwood classification, what type of injury is this?
. Type II
. Type III
. Type IV
. Type V
. Type VI

Correct Answer & Explanation

. Type V

Explanation

In Rockwood Type V AC joint injuries, the distal clavicle is displaced superiorly by 100% to 300% relative to the acromion, often stripping or piercing the deltotrapezial fascia. Type III is up to 100% superior displacement. Type IV is posterior displacement into or through the trapezius.

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