Menu

2. Trauma MCQs

Practice Set 27 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 521

Topic: 2. Trauma
A 35-year-old man sustains a Gustilo-Anderson IIIB open tibia fracture following a motorcycle accident. After aggressive initial debridement, timing of soft tissue flap coverage is planned. For the lowest rate of deep infection, soft tissue coverage should ideally be performed within:
. 12 hours
. 24 hours
. 72 hours
. 5 days
. 10 days

Correct Answer & Explanation

. 72 hours

Explanation

Soft tissue coverage for Gustilo IIIB open fractures performed within 72 hours is associated with the lowest rates of deep infection and flap failure. Delaying beyond this window significantly increases infection risk.

Question 522

Topic: Pelvic & Acetabular Trauma

In an anteroposterior compression type II (APC-II) pelvic ring injury, the pubic symphysis is widened by more than 2.5 cm. Which posterior ligamentous structures remain intact to provide rotational stability?

. Anterior sacroiliac ligaments
. Sacrotuberous ligaments
. Sacrospinous ligaments
. Posterior sacroiliac ligaments
. Iliolumbar ligaments

Correct Answer & Explanation

. Posterior sacroiliac ligaments

Explanation

An APC-II injury involves disruption of the pubic symphysis, anterior sacroiliac, sacrotuberous, and sacrospinous ligaments. The posterior sacroiliac ligaments remain intact, preventing vertical translation.

Question 523

Topic: Lower Extremity Trauma

A 35-year-old man sustains a high-energy Schatzker IV tibial plateau fracture with a large posteromedial shear fragment. Which of the following surgical approaches is most appropriate for direct visualization and buttress plating of this specific fragment?

. Anterolateral approach
. Direct medial approach
. Posteromedial approach utilizing the interval between the medial head of the gastrocnemius and the pes anserinus
. Posterior approach with a classic S-shaped incision
. Lateral approach with a fibular neck osteotomy

Correct Answer & Explanation

. Posteromedial approach utilizing the interval between the medial head of the gastrocnemius and the pes anserinus

Explanation

The posteromedial approach uses the interval between the medial head of the gastrocnemius (retracted laterally) and the pes anserinus (retracted medially). This allows direct, orthogonal access to the posteromedial shear fragment for optimal application of an anti-glide or buttress plate.

Question 524

Topic: 2. Trauma
A 9-year-old boy is examined due to a closed distal forearm fracture. The radius and ulna are both fractured and translated 100%. After manipulation twice with sedation, the translation cannot be reduced. There is 10-mm shortening of the radius and 5-mm shortening of the ulna. The distal radial angulation on the anteroposterior view is 5° less than normal. The next step in treatment should include:
. Closed reduction in the operating room under general anesthesia
. Open reduction and cast application
. Open reduction and percutaneous pin fixation
. Open reduction and plate fixation
. Acceptance of the reduction and maintenance with a cast

Correct Answer & Explanation

. Acceptance of the reduction and maintenance with a cast

Explanation

The translation and shortening are not problems and the amount of angulation will easily remodel with this fracture. There is nothing to be gained from operative reduction.

Question 525

Topic: 2. Trauma
A patient with spina bifida and L5 motor level undergoes tendon transfers about the ankle. After cast removal, he is lost to follow-up for 3 years. Upon re-examination, the patient has no motor power on either side below the knee. The most likely explanation is:
. The tendon transfers have all pulled out.
. His ventriculoperitoneal shunt has malfunctioned.
. His spinal cord has become tethered.
. His muscles have fatigued.
. He has sustained a silent compartment syndrome because of lack of sensation.

Correct Answer & Explanation

. His spinal cord has become tethered.

Explanation

This scenario is common. The most likely explanation of the patient's loss of motor power on either side below the knee is a result of a tethered spinal cord. It is unlikely that all transferred tendons have pulled out and that he has lost function in all of the other L5 muscles that should be active. Shunt malfunction is a common occurrence in patients with spina bifida, but shunt malfunction does not present with a focal deficit at a distal level. Muscle fatigue is not a recognized phenomenon in spina bifida.

Question 526

Topic: 2. Trauma
A 6-year-old boy with spina bifida and L3 motor level presents to the clinic with bilateral swollen legs (below the knees). His legs have been swollen for the past 3 days and his knees are warm. The patient has an oral temperature of 38.1°C. He denies any pain. There is no history of systemic infection or of any other trauma. The problem may be most likely diagnosed by ordering:
. A venogram of both lower extremities
. A duplex ultrasound of both lower extremities and the pelvic veins
. Cell count, gram stain, and culture of synovial fluid of both knees
. Aspirate of both distal femoral metaphyses
. Plain and stress varus-valgus radiographs of both knees

Correct Answer & Explanation

. Plain and stress varus-valgus radiographs of both knees

Explanation

Low-energy fractures are the most likely cause of the patient's bilateral swollen legs. The fractures may occur with everyday activities, and they do not cause pain because of the patient's high neurologic level. If plain radiographs do not give the diagnosis, stress radiographs should be obtained to detect undisplaced physeal fractures. Deep vein thrombosis is rare in this age group, especially bilaterally. Spontaneous joint infection and spontaneous osteomyelitis are not any more likely in patients with spina bifida than in the general population.

Question 527

Topic: 2. Trauma

Which of the following best predicts the risk of nonaccidental injury in young children who sustain a fracture of the femur:

. The fracture pattern
. The location of the fracture
. The socioeconomic status of the family
. Whether the child was previously able to walk
. C oexistence of other disabilities

Correct Answer & Explanation

. Whether the child was previously able to walk

Explanation

Although a spiral fracture is classically consistent with nonaccidental injury, this is not always true. A spiral fracture is often seen in accidental injuries. The location of the fracture in the femur, the socioeconomic status of the family, and the coexistence of other disabilities are all poor predictors. The ability of the child to walk has predictive ability. In one study, nonaccidental injury accounted for 42% of all femur fractures in children before walking age vs. only 2% of fractures after walking age.

Question 528

Topic: Pelvic & Acetabular Trauma

During the percutaneous placement of an iliosacral screw into the S1 vertebral body for a posterior pelvic ring injury, the guidewire inadvertently breaches the anterior cortex of the sacral ala. Which of the following neurological structures is most at risk of injury in this location?

. L4 nerve root
. L5 nerve root
. S1 nerve root
. S2 nerve root
. Sciatic nerve

Correct Answer & Explanation

. L5 nerve root

Explanation

The L5 nerve root courses anteriorly over the sacral ala and is highly vulnerable to injury if an S1 iliosacral screw is misdirected anteriorly. The S1 root is typically protected unless the screw enters the sacral foramen.

Question 529

Topic: 2. Trauma

A 30-year-old male is admitted after a high-energy closed tibial shaft fracture. Twelve hours later, he develops severe pain out of proportion to the injury, exacerbated by passive stretch of the toes. Intracompartmental pressure monitoring is performed. Which of the following pressure measurements is generally accepted as the threshold for diagnosing acute compartment syndrome and indicating emergent fasciotomy?

. Absolute compartment pressure > 20 mmHg
. Delta pressure (Diastolic blood pressure minus Compartment pressure) < 30 mmHg
. Delta pressure (Mean arterial pressure minus Compartment pressure) < 10 mmHg
. Absolute compartment pressure > 15 mmHg
. Delta pressure (Systolic blood pressure minus Compartment pressure) < 50 mmHg

Correct Answer & Explanation

. Delta pressure (Diastolic blood pressure minus Compartment pressure) < 30 mmHg

Explanation

A delta pressure (diastolic blood pressure minus absolute compartment pressure) of less than 30 mmHg is considered the diagnostic threshold for acute compartment syndrome. Absolute compartment pressures are less reliable because tissue perfusion is dependent on systemic blood pressure.

Question 530

Topic: 2. Trauma

A 32-year-old man presents with a closed tibial shaft fracture. He reports excruciating pain out of proportion to the injury and pain with passive toe stretch. Which of the following pressure measurements is most diagnostic of acute compartment syndrome?

. Absolute compartment pressure > 20 mm Hg
. Diastolic blood pressure minus compartment pressure < 30 mm Hg
. Mean arterial pressure minus compartment pressure < 40 mm Hg
. Systolic blood pressure minus compartment pressure < 30 mm Hg
. Absolute compartment pressure > 25 mm Hg

Correct Answer & Explanation

. Diastolic blood pressure minus compartment pressure < 30 mm Hg

Explanation

The delta pressure (diastolic blood pressure minus compartment pressure) is the most reliable indicator for diagnosing acute compartment syndrome. A delta pressure of less than 30 mm Hg is generally considered the threshold for performing an emergency fasciotomy.

Question 531

Topic: 2. Trauma
A 75-year-old man falls from a standing height and sustains a Type II odontoid fracture. Which of the following factors most significantly increases the risk of nonunion with conservative management (e.g., rigid cervical collar) in this patient?
. Initial fracture displacement > 5 mm
. Anterior angulation < 10 degrees
. Patient age < 40 years
. Fracture extending through the base of the dens into the C2 body
. Immediate use of a halo vest instead of a hard collar

Correct Answer & Explanation

. Initial fracture displacement > 5 mm

Explanation

Risk factors for nonunion of a Type II odontoid fracture include age greater than 50 years, initial displacement greater than 5 mm, and posterior displacement. Fracture into the C2 body defines a Type III fracture, which has a higher union rate.

Question 532

Topic: 2. Trauma
A 45-year-old male is brought to the trauma bay with an unstable "open book" pelvic fracture (APC-III) and hemodynamic instability. To optimally reduce the pelvic volume and control hemorrhage, a circumferential pelvic binder should be centered directly over which anatomical landmarks?
. Iliac crests
. Greater trochanters
. Anterior superior iliac spines (ASIS)
. Pubic symphysis
. Sacral promontory

Correct Answer & Explanation

. Greater trochanters

Explanation

A pelvic binder must be centered over the greater trochanters to effectively close the pelvic ring and reduce internal volume. Placing it over the iliac crests is incorrect and can paradoxically open the pelvis further.

Question 533

Topic: 2. Trauma

A 45-year-old male sustains a Schatzker type IV tibial plateau fracture following a high-energy motor vehicle collision. Which of the following neurovascular structures is at the highest risk of injury secondary to the specific fracture pattern and associated displacement?

. Common peroneal nerve
. Superficial peroneal nerve
. Popliteal artery
. Anterior tibial artery
. Saphenous nerve

Correct Answer & Explanation

. Popliteal artery

Explanation

Schatzker type IV fractures (medial tibial plateau) typically result from high-energy trauma and are often associated with knee subluxation or dislocation. Because of the anatomic tethering of the popliteal artery at the adductor hiatus and soleal arch, it is at significant risk of injury in these high-energy fracture patterns.

Question 534

Topic: Pelvic & Acetabular Trauma
A 35-year-old male is crushed by a heavy machine and sustains a pelvic ring injury. Initial radiographs show widening of the pubic symphysis of 3.5 cm with disruption of the anterior sacroiliac, sacrospinous, and sacrotuberous ligaments, but the posterior sacroiliac complex remains intact. Which of the following Young-Burgess classifications best describes this injury?
. Anteroposterior compression (APC) Type I
. Anteroposterior compression (APC) Type II
. Anteroposterior compression (APC) Type III
. Lateral compression (LC) Type II
. Vertical shear (VS)

Correct Answer & Explanation

. Anteroposterior compression (APC) Type II

Explanation

An APC Type II injury is characterized by symphyseal diastasis > 2.5 cm and disruption of the anterior sacroiliac, sacrospinous, and sacrotuberous ligaments, causing rotational instability. The intact posterior sacroiliac ligaments maintain the vertical stability of the hemipelvis.

Question 535

Topic: 2. Trauma
A 9-year-old boy is examined due to a closed distal forearm fracture. The radius and ulna are both fractured and translated 100%. After manipulation twice with sedation, the translation cannot be reduced. There is 10-mm shortening of the radius and 5-mm shortening of the ulna. The distal radial angulation on the anteroposterior view is 5° less than normal. The least invasive treatment which would produce acceptable results is:
. Closed reduction in the operating room under general anesthesia
. Open reduction and cast application
. Open reduction and percutaneous pin fixation
. Open reduction and plate fixation
. Acceptance of the reduction and maintenance with a cast

Correct Answer & Explanation

. Acceptance of the reduction and maintenance with a cast

Explanation

The translation and shortening are not problems and the amount of angulation will easily remodel with this fracture. There is nothing to be gained from operative reduction.

Question 536

Topic: Pelvic & Acetabular Trauma

The primary purpose of osteotomy in the closure of classic exstrophy of the bladder is to:

. Decrease the tension on the closure of the abdominal wall and bladder
. Decrease the strain on the sacroiliac joints
. Prevent degenerative disease of the hip
. Normalize the gait
. Allow reconstruction of a normal symphysis pubis

Correct Answer & Explanation

. Decrease the tension on the closure of the abdominal wall and bladder

Explanation

The primary purpose of osteotomy is to improve the chance of a successful urologic reconstruction. This is achieved by decreasing the tension on the closure of the abdominal wall and bladder. The strain on the sacroiliac joints has not been measured with or without closure; this is not a primary purpose of the osteotomy. There is no conclusive evidence that the hips are at increased risk of degenerative disease in patients with exstrophy, or that osteotomy will alter the condition. In patients with exstrophy, the gait progressively normalizes over time. It is not possible to reconstruct a normal symphysis pubis in exstrophy.

Question 537

Topic: Pelvic & Acetabular Trauma

Which of the following is not a common finding in cloacal exstrophy:

. Omphalocele
. Spinal dysrhaphism
. Hydrocephalus
. Dysplasia of the sacroiliac joints
. Dislocation of the hip(s)

Correct Answer & Explanation

. Hydrocephalus

Explanation

Hydrocephalus is rare because most patients have lipomeningocele, not myelomeningocele. Omphalocele is common in cloacal exstrophy. Most patients with cloacal exstrophy have a lipomeningocele that is a form of spinal dysrhaphism. Many patients have malformations of the sacroiliac joints. Approximately 25% of patients have dislocations of at least one hip.

Question 538

Topic: 2. Trauma

The thickness of a flexible intramedullary nail used in pediatric femur fractures should be which of the following percentages of the diameter of the femoral isthmus:

. 10%
. 25%
. 40%
. 50%
. 75%

Correct Answer & Explanation

. 40%

Explanation

It is recommended that the intramedullary nail be 40% of the diameter of the femoral isthmus.

Question 539

Topic: 2. Trauma

Which of the following is the best discriminator for risk of nonaccidental (child abuse) injury in young children with femoral shaft fractures:

. Pattern of the fracture
. Level of the fracture on the femur
. Socioeconomic class
. Ability to walk
. C oexisting disability in the child

Correct Answer & Explanation

. Ability to walk

Explanation

Nonaccidental injury was a factor in 29% of patients who were unable to walk vs 3% for patients who were able to walk. The fracture pattern and level of fracture do not help determine nonaccidental injury. Socioeconomic class is not the best discriminator and, generally, should not be factored into the decision process. Coexisting disability is not a significant discriminator.

Question 540

Topic: Lower Extremity Trauma

A 10-year-old Jewish boy presents with right hip pain. Radiographs show an Erlenmeyer flask deformity of the distal femurs and avascular necrosis of the right femoral head. A defect in which of the following enzymes is responsible?

. Sphingomyelinase
. Hexosaminidase A
. Glucocerebrosidase
. Alpha-L-iduronidase
. Arylsulfatase B

Correct Answer & Explanation

. Glucocerebrosidase

Explanation

Gaucher disease is a lysosomal storage disorder caused by a deficiency in glucocerebrosidase. Classic orthopedic manifestations include the Erlenmeyer flask deformity of the distal femur, bone pain crises, and avascular necrosis of the femoral head.

Test Yourself

Switch to an interactive, timed exam simulation to truly master this topic.

On this Page