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2. Trauma MCQs

Practice Set 578 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 11541

Topic: 2. Trauma

Based on the Lower Extremity Assessment Project (LEAP) study, which of the following is true regarding severe lower extremity trauma?

. The MESS score is highly sensitive for predicting the need for amputation.
. Initial absence of plantar sensation is an absolute indication for primary amputation.
. Limb salvage results in significantly better long-term psychological outcomes than amputation.
. There is no significant difference in functional outcomes at 2 years between amputation and successful limb salvage.
. Early flap coverage (less than 72 hours) increases the risk of deep infection.

Correct Answer & Explanation

. The MESS score is highly sensitive for predicting the need for amputation.

Explanation

The LEAP study demonstrated no significant difference in functional outcomes at 2 years between patients who underwent amputation and those who had successful limb salvage. It also proved that the absence of plantar sensation is not an absolute indication for amputation.

Question 11542

Topic: 2. Trauma

Which of the following femoral fracture patterns in a non-ambulatory 8-month-old infant is most highly specific for non-accidental trauma (child abuse)?

. Midshaft transverse fracture
. Distal femoral physeal separation
. Spiral fracture of the diaphysis
. Buckle fracture of the distal metaphysis
. Proximal metaphyseal corner fracture

Correct Answer & Explanation

. Midshaft transverse fracture

Explanation

Metaphyseal corner fractures (or classic metaphyseal lesions - CMLs) are highly specific for non-accidental trauma in infants. They result from violent pulling, twisting, or flailing of the extremity. While any fracture (including spiral) in a non-ambulatory infant is suspicious, the metaphyseal corner fracture carries the highest specificity for abuse.

Question 11543

Topic: 2. Trauma

A 9-year-old boy presents with a pathologic fracture through a centrally located, completely radiolucent lesion in the proximal humerus metaphysis. Radiographs show a 'fallen leaf' sign. What is the most appropriate initial management?

. Immediate curettage and bone grafting
. Sling immobilization and observation to allow fracture healing
. Intralesional steroid injection
. Flexible intramedullary nailing
. En bloc resection

Correct Answer & Explanation

. Immediate curettage and bone grafting

Explanation

The 'fallen leaf' (or fallen fragment) sign is pathognomonic for a Unicameral Bone Cyst (UBC). When a UBC presents with a pathologic fracture, the standard initial management is non-operative (sling immobilization) to allow the fracture to heal. Fracture hematoma can sometimes stimulate spontaneous resolution of the cyst.

Question 11544

Topic: 2. Trauma

A 4-year-old boy sustains an isolated, closed spiral midshaft femur fracture after a fall from a slide. There is 1.5 cm of shortening. What is the gold standard treatment for this patient?

. Early spica casting
. Flexible intramedullary nailing
. Rigid antegrade locked intramedullary nailing
. Open reduction and internal fixation with a compression plate
. External fixation

Correct Answer & Explanation

. Early spica casting

Explanation

For children between the ages of 6 months and 5 years with a diaphyseal femur fracture and less than 2 cm of shortening, early hip spica casting is the gold standard treatment. Flexible nailing is generally reserved for older children (ages 5-11 years).

Question 11545

Topic: Pelvic & Acetabular Trauma

A 2-year-old girl is diagnosed with late-presenting unilateral Developmental Dysplasia of the Hip (DDH). During open reduction, a Salter osteotomy is performed. Through which structural hinge does the distal fragment rotate to improve anterior and lateral coverage?

. Sacroiliac joint
. Triradiate cartilage
. Pubic symphysis
. Ischial tuberosity
. Acetabular roof

Correct Answer & Explanation

. Sacroiliac joint

Explanation

The Salter innominate osteotomy is an incomplete, directional transiliac osteotomy that hinges on a flexible pubic symphysis. It redirects the entire acetabulum to improve anterolateral coverage of the femoral head without changing acetabular volume.

Question 11546

Topic: 2. Trauma

A 9-year-old boy weighing 65 kg (143 lbs) sustains a length-unstable, comminuted midshaft femur fracture. Which of the following fixation methods is associated with the highest risk of loss of reduction and poor outcomes in this specific patient?

. Submuscular bridge plating
. Rigid lateral-entry intramedullary nailing
. Titanium elastic nails (TENs)
. External fixation
. Open reduction and internal fixation with compression plating

Correct Answer & Explanation

. Submuscular bridge plating

Explanation

Titanium elastic nails (TENs) are contraindicated in children weighing more than 50 kg (110 lbs) or for length-unstable (comminuted) fractures due to a high risk of implant failure, malunion, and loss of reduction.

Question 11547

Topic: Lower Extremity Trauma

A 10-year-old boy is evaluated for a suspected limb length discrepancy. Bone age is calculated, and the multiplier method is used. On average, how much longitudinal growth is contributed per year by the distal femoral and proximal tibial physes, respectively?

. 6 mm and 4 mm
. 9 mm and 6 mm
. 12 mm and 9 mm
. 15 mm and 10 mm
. 3 mm and 2 mm

Correct Answer & Explanation

. 6 mm and 4 mm

Explanation

The distal femur contributes approximately 9 mm per year, and the proximal tibia contributes approximately 6 mm per year to longitudinal growth. This rule of thumb is critical for timing epiphysiodesis procedures.

Question 11548

Topic: Lower Extremity Trauma

A 6-year-old girl complains of a snapping sensation and pain on the lateral side of her knee. MRI reveals a thickened meniscus that covers the entire lateral tibial plateau. During arthroscopy, the meniscus lacks posterior capsular attachments. What is the name of this specific variant?

. Incomplete discoid meniscus
. Complete discoid meniscus
. Wrisberg variant discoid meniscus
. Meniscal cyst
. Bucket-handle meniscal tear

Correct Answer & Explanation

. Incomplete discoid meniscus

Explanation

The Wrisberg variant of a discoid lateral meniscus lacks normal posterior coronary ligament attachments. It is solely tethered by the meniscofemoral ligament of Wrisberg, making it highly hypermobile and responsible for the classic 'snapping knee' syndrome.

Question 11549

Topic: 2. Trauma

A 4-year-old child sustains a closed, isolated midshaft femur fracture. The fracture has 1.5 cm of shortening and is angulated 10 degrees. What is the most appropriate definitive management?

. Rigid intramedullary nailing via the piriformis fossa
. Flexible intramedullary nailing (TENs)
. Spica casting
. Open reduction and internal fixation with a compression plate
. Skeletal traction for 6 weeks

Correct Answer & Explanation

. Rigid intramedullary nailing via the piriformis fossa

Explanation

For children aged 6 months to 5 years with a femur fracture having acceptable alignment (<2 cm shortening), early spica casting is the gold standard treatment. Flexible nailing is generally indicated for older children (ages 5-11).

Question 11550

Topic: Upper Extremity Trauma

An asymptomatic 40-year-old female has an incidental finding of a well-circumscribed cartilaginous lesion in the proximal humerus with punctate calcifications. There is no endosteal scalloping or periosteal reaction. Which of the following is the most appropriate management?

. Wide surgical excision
. Intralesional curettage and grafting
. Neoadjuvant chemotherapy
. Observation with serial radiographs
. Prophylactic internal fixation

Correct Answer & Explanation

. Wide surgical excision

Explanation

This is a classic presentation of an asymptomatic enchondroma. Without signs of aggressive behavior (e.g., deep endosteal scalloping >2/3, rest pain, cortical breakthrough), the standard of care is observation with serial imaging.

Question 11551

Topic: 2. Trauma

A 9-year-old boy sustains a minor fall and presents with arm pain. Radiographs reveal a fracture through a centrally located, completely lytic lesion in the proximal humerus metaphysis. A 'fallen leaf' sign is noted. What is the most appropriate initial management for the cyst after the fracture has healed?

. Wide resection
. Observation or corticosteroid injection
. Radiation therapy
. Radiofrequency ablation
. Intravenous bisphosphonates

Correct Answer & Explanation

. Wide resection

Explanation

The lesion is a Unicameral (Simple) Bone Cyst (UBC), indicated by its central location, purely lytic nature, and the pathognomonic 'fallen leaf' (fallen fragment) sign. After fracture healing, treatment options include observation (some resolve spontaneously after fracture) or less invasive interventions like corticosteroid or bone marrow aspirate injections.

Question 11552

Topic: 2. Trauma

A 9-year-old boy sustains a pathologic fracture through a radiolucent lesion in the proximal humerus with a "fallen leaf" sign. Radiographs show the lesion is located 2 cm distal to the open physis. What is the best initial management of the underlying lesion once the fracture has healed?

. En bloc resection and allograft reconstruction
. Curettage and bone grafting
. Aspiration and injection of methylprednisolone or bone marrow
. Observation with serial radiographs
. Radiofrequency ablation

Correct Answer & Explanation

. Aspiration and injection of methylprednisolone or bone marrow

Explanation

This is a latent unicameral bone cyst (UBC), as it has migrated away from the physis. For symptomatic or structurally compromising UBCs, minimally invasive treatment like aspiration and injection of corticosteroids or bone marrow aspirate is the preferred initial management.

Question 11553

Topic: 2. Trauma

Following the application of an unreamed intramedullary nail for a tibial shaft fracture, the local osseous blood flow is temporarily altered. In a normal, uninjured adult long bone diaphysis, the primary direction of cortical blood flow is:

. Centrifugal (from the medullary canal outward to the periosteum)
. Centripetal (from the periosteum inward to the medullary canal)
. Exclusively supplied by metaphyseal anastomotic vessels
. Bidirectional with equal contribution from periosteal and endosteal vessels
. Dependent entirely on the nutrient artery without any capsular/periosteal contribution

Correct Answer & Explanation

. Centrifugal (from the medullary canal outward to the periosteum)

Explanation

In the mature, uninjured diaphyseal cortex, the nutrient artery provides a high-pressure system within the medullary canal, resulting in a centrifugal flow pattern (from the endosteum outward to the periosteum), supplying the inner 2/3 of the cortex. Following major trauma or intramedullary reaming, the medullary supply is disrupted, and the flow temporarily reverses to a centripetal pattern from the periosteal vessels.

Question 11554

Topic: 2. Trauma

In the setting of an acute tibia fracture, which of the following physiologic changes is the earliest event in the pathophysiology of acute compartment syndrome?

. Loss of palpable distal pulses
. Arterial spasm
. Decreased arteriovenous pressure gradient leading to compromised local blood flow
. Irreversible nerve ischemia and necrosis
. Rhabdomyolysis

Correct Answer & Explanation

. Decreased arteriovenous pressure gradient leading to compromised local blood flow

Explanation

Acute compartment syndrome begins when increased tissue pressure within a closed fascial space reduces the arteriovenous (AV) pressure gradient. This limits local capillary perfusion, causing ischemia and edema. Loss of pulses is a very late and unreliable sign.

Question 11555

Topic: 2. Trauma

A 25-year-old sustains a closed tibial shaft fracture and develops acute compartment syndrome. What is the critical microvascular event that initiates the hypoxic cascade in this condition?

. Arterial occlusion
. Venous outflow obstruction
. Arteriovenous shunting
. Capillary endothelial apoptosis
. Lymphatic failure

Correct Answer & Explanation

. Venous outflow obstruction

Explanation

Compartment syndrome begins when rising tissue pressure exceeds the low pressure within the post-capillary venules, leading to venous outflow obstruction. This collapse of the venous beds halts capillary perfusion, causing tissue hypoxia even while arterial inflow initially persists.

Question 11556

Topic: 2. Trauma
A 40-year-old male sustains a closed midshaft humerus fracture and is unable to actively extend his wrist. EMG at 3 weeks shows fibrillation potentials. Which of Sunderland's nerve injury grades is represented by an injury where the axon is disrupted but the endoneurium remains intact?
. Grade I
. Grade II
. Grade III
. Grade IV
. Grade V

Correct Answer & Explanation

. Grade II

Explanation

Sunderland Grade II injury corresponds to axonotmesis, where the axon is disrupted leading to Wallerian degeneration, but the endoneurial tubes remain intact. This allows for excellent functional recovery as regenerating axons are guided by the intact anatomy.

Question 11557

Topic: 2. Trauma

A 32-year-old male is brought to the trauma bay after a high-speed motor vehicle collision. He has severe neck pain. A lateral cervical radiograph demonstrates 60% anterior translation of the C4 vertebral body over C5. What is the primary mechanism of injury leading to this specific radiologic finding?

. Compressive-flexion
. Vertical compression
. Flexion-distraction
. Hyperextension-axial loading
. Extension-distraction

Correct Answer & Explanation

. Flexion-distraction

Explanation

Anterior translation of a cervical vertebral body greater than 50% over the body below is pathognomonic for bilateral facet dislocation. According to the Allen-Ferguson classification, the mechanism of injury for bilateral facet dislocations is hyperflexion-distraction. This results in tearing of the posterior ligamentous complex, facet capsules, and often the intervertebral disc and posterior longitudinal ligament.

Question 11558

Topic: 2. Trauma

An 80-year-old male presents with neck pain after a fall from standing. A CT scan reveals a Type II odontoid fracture with 2 mm of posterior displacement. Which of the following factors places this patient at the highest risk for developing a nonunion?

. Age greater than 65 years
. Fracture displacement of 2 mm
. Male gender
. Presence of cervical spondylosis
. Mechanism of injury being a low-energy fall

Correct Answer & Explanation

. Age greater than 65 years

Explanation

Risk factors for nonunion of a Type II odontoid fracture include patient age greater than 50-65 years, displacement greater than 5 mm, angulation greater than 10 degrees, delayed diagnosis, and posterior displacement > 5 mm. While this fracture has posterior displacement, it is only 2 mm (displacement < 5 mm is a lower risk). The patient's advanced age (80 years) is the most significant independent risk factor for nonunion presented.

Question 11559

Topic: 2. Trauma

A 72-year-old woman sustains an Anderson and D'Alonzo Type II odontoid fracture after a fall. Which of the following factors is most strongly associated with an increased risk of nonunion if this fracture is treated non-operatively with a hard cervical collar?

. Age greater than 50 years
. Anterior displacement of 2 mm
. Concurrent posterior arch fracture of C1
. Treatment initiated within 24 hours
. Impacted fracture pattern

Correct Answer & Explanation

. Age greater than 50 years

Explanation

Anderson and D'Alonzo Type II odontoid fractures (fractures through the base of the dens) have a notoriously high rate of nonunion due to watershed vascularity. Recognized risk factors for nonunion with conservative management include age > 50 years, initial displacement > 5 mm, posterior displacement, angulation > 10 degrees, and a delay in diagnosis/treatment. Therefore, age > 50 years is a major predictor of nonunion, and surgical stabilization is often recommended in this demographic.

Question 11560

Topic: 2. Trauma

A 72-year-old male sustains a Type II odontoid fracture after a fall from standing. Which of the following is the most significant risk factor for nonunion if treated non-operatively with a rigid cervical collar?

. Anterior displacement of 3mm
. Age > 50 years
. Female gender
. Concurrent C1 posterior arch fracture
. Fracture line angulation extending into the C2 body

Correct Answer & Explanation

. Age > 50 years

Explanation

Risk factors for nonunion of Type II odontoid fractures include age > 50 years, initial displacement > 5 mm, posterior displacement, and delay in treatment. Non-operative management in elderly patients often leads to fibrous nonunion, requiring careful consideration of surgical morbidity.

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