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2. Trauma MCQs

Practice Set 246 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 4901

Topic: 2. Trauma

A 21-year-old elite collegiate basketball player sustains an acute, undisplaced fracture at the metaphyseal-diaphyseal junction of the fifth metatarsal (Zone 2) during a game. What is the most appropriate treatment to optimize his safe return to play?

. Hard-soled shoe with weight-bearing as tolerated
. Short leg walking cast for 4 weeks
. Strict non-weight-bearing in a cast for 6-8 weeks
. Intramedullary screw fixation
. Open reduction and internal fixation with a neutralization plate

Correct Answer & Explanation

. Intramedullary screw fixation

Explanation

Zone 2 fractures (Jones fractures) have a watershed blood supply and a high risk of nonunion. In elite athletes, early intramedullary screw fixation is recommended to decrease nonunion rates and expedite return to play compared to non-operative management.

Question 4902

Topic: 2. Trauma

Six weeks after sustaining a displaced talar neck fracture treated with open reduction and internal fixation, a patient's anteroposterior ankle radiograph demonstrates a subchondral radiolucent band in the talar dome. This radiographic finding indicates:

. Impending avascular necrosis of the talar body
. Septic arthritis of the tibiotalar joint
. Intact vascularity to the talar body
. Hardware loosening
. Nonunion of the talar neck

Correct Answer & Explanation

. Intact vascularity to the talar body

Explanation

This finding is the Hawkins sign, which represents subchondral osteopenia secondary to hyperemia. It is a highly reliable indicator that the vascular supply to the talar body is intact, effectively ruling out avascular necrosis.

Question 4903

Topic: 2. Trauma

When utilizing a lateral extensile approach for the open reduction and internal fixation of a displaced intra-articular calcaneal fracture, which of the following structures is at greatest risk of iatrogenic injury during the inferior horizontal limb of the incision?

. Deep peroneal nerve
. Superficial peroneal nerve
. Sural nerve
. Posterior tibial artery
. Tibial nerve

Correct Answer & Explanation

. Sural nerve

Explanation

The sural nerve crosses the lateral aspect of the hindfoot and is at significant risk during the creation of the inferior horizontal limb of the lateral extensile approach. Care must be taken to create full-thickness flaps to protect the nerve and the vascular supply to the skin.

Question 4904

Topic: 2. Trauma

Which set of patient characteristics has the highest risk of developing osteonecrosis after an intracapsular femoral neck fracture?

. year-old woman with a displaced fracture
. year-old man with a nondisplaced fracture
. year-old woman with a nondisplaced fracture
. year-old man with a displaced fracture
. year-old woman with a displaced fracture

Correct Answer & Explanation

. year-old woman with a displaced fracture

Explanation

Loizou and associates prospectively studied 1,023 patients who sustained an intracapsular hip fracture that was treated with internal fixation using contemporary methods. The overall incidence of osteonecrosis was 6.6%. Osteonecrosis was less common for undisplaced (4.0%) than for displaced fractures (9.5%) and in men (4.9%) than women (11.4%) who had a displaced fracture. The incidence of osteonecrosis for those patients younger than 60 years and who sustained a displaced fracture was 20.6%, compared with 12.5% for those aged 60 to 80 years and 2.5% for those older than age 80 years. Barnes and associates reported that late segmental collapse was more common in displaced fractures in women younger than age 75 years than in those older than age 75 years.

Question 4905

Topic: 2. Trauma

A 45-year-old male presents with a pelvic ring injury and an associated acetabular fracture. An obturator oblique plain radiograph demonstrates the classic 'spur sign'. What anatomical structure does this radiographic sign represent?

. The medially displaced anterior column
. The impacted superior acetabular dome
. The intact posterior ilium (axial skeleton)
. The displaced ischial spine
. The intact quadrilateral plate

Correct Answer & Explanation

. The intact posterior ilium (axial skeleton)

Explanation

The 'spur sign' is a classic radiographic finding seen on the obturator oblique view in both-column acetabular fractures. It represents the intact portion of the posterior ilium (strut of the axial skeleton) extending inferiorly, relative to the medially and internally displaced articular fracture segments.

Question 4906

Topic: 2. Trauma

Which of the following findings is the most reliable predictor of a poor long-term functional outcome in a patient diagnosed with scapulothoracic dissociation?

. Complete avulsion of the brachial plexus
. Transection of the subclavian artery
. Severe comminution of the scapular body
. Massive soft tissue degloving of the posterior shoulder
. Concomitant displaced midshaft clavicle fracture

Correct Answer & Explanation

. Complete avulsion of the brachial plexus

Explanation

Scapulothoracic dissociation is a devastating injury characterized by complete disruption of the scapulothoracic articulation. While vascular injuries (subclavian artery) are life-threatening and dictate immediate surgical priorities, the long-term functional outcome of the limb is most heavily dependent on the neurologic status. A complete brachial plexus avulsion is the most reliable predictor of a flail, functionless limb, often eventually requiring a forequarter amputation.

Question 4907

Topic: 2. Trauma
A 30-year-old male sustains a Pauwels type III femoral neck fracture (70-degree vertical shear angle). Biomechanical studies suggest that which of the following internal fixation constructs provides the greatest stability against vertical shear forces for this fracture pattern?
. Three parallel cancellous screws placed in an inverted triangle
. Three parallel cancellous screws placed in an upright triangle
. A sliding hip screw with an additional superior derotation screw
. Two large-diameter fully threaded cancellous screws
. A standard trochanteric entry cephalomedullary nail

Correct Answer & Explanation

. A sliding hip screw with an additional superior derotation screw

Explanation

Pauwels type III femoral neck fractures in young adults have a high vertical orientation, exposing them to massive shear forces and a high risk of varus collapse/nonunion. Biomechanical studies have consistently shown that a fixed-angle device, such as a sliding hip screw (SHS) combined with an anti-rotation (derotation) screw, provides superior resistance to vertical shear compared to multiple cancellous screws.

Question 4908

Topic: 2. Trauma

A 35-year-old female sustains an isolated lateral Hoffa fracture (coronal shear fracture of the lateral femoral condyle). To achieve the most biomechanically stable fixation, in which direction should the primary lag screws be inserted?

. Anterior to posterior
. Posterior to anterior
. Superior to inferior
. Inferior to superior
. Medial to lateral

Correct Answer & Explanation

. Posterior to anterior

Explanation

A Hoffa fracture is a coronal shear fracture of the femoral condyle (most commonly lateral). Biomechanically, posterior-to-anterior (PA) lag screw placement is stronger than anterior-to-posterior (AP) placement. This is because PA screws allow the screw head to purchase the smaller posterior fragment, achieving optimal interfragmentary compression against the larger, stable anterior segment. AP screws rely on thread purchase in the relatively small and often osteoporotic posterior fragment, which has a higher risk of pull-out.

Question 4909

Topic: 2. Trauma
A patient with a diaphyseal tibia fracture complains of escalating, severe leg pain. The clinical team suspects acute compartment syndrome. The patient's blood pressure is 115/65 mmHg (MAP 82 mmHg). Continuous compartment pressure monitoring is initiated. According to McQueen et al., an absolute indication for emergent fasciotomy is a Delta P (ΔP) below what threshold, and how is it calculated?
. ΔP < 30 mmHg (Mean Arterial Pressure minus Compartment Pressure)
. ΔP < 30 mmHg (Diastolic Blood Pressure minus Compartment Pressure)
. ΔP < 45 mmHg (Mean Arterial Pressure minus Compartment Pressure)
. ΔP < 45 mmHg (Systolic Blood Pressure minus Compartment Pressure)
. ΔP < 20 mmHg (Diastolic Blood Pressure minus Compartment Pressure)

Correct Answer & Explanation

. ΔP < 30 mmHg (Diastolic Blood Pressure minus Compartment Pressure)

Explanation

The diagnosis of acute compartment syndrome using intracompartmental pressure monitoring is most reliably determined by the Delta P (ΔP) concept. McQueen established that a ΔP of less than 30 mmHg is the threshold for emergent fasciotomy. ΔP is calculated as Diastolic Blood Pressure minus Compartment Pressure. MAP and absolute compartment pressures (e.g., >30 mmHg alone) are less reliable due to variations in systemic perfusion pressure.

Question 4910

Topic: 2. Trauma

A 55-year-old female presents with a severely displaced proximal humerus fracture. According to Hertel's radiographic criteria, which combination of findings is the most highly predictive of subsequent humeral head ischemia?

. Calcar length < 8 mm, disrupted medial hinge, and an anatomic neck fracture pattern
. Calcar length > 8 mm, intact medial hinge, and a surgical neck fracture pattern
. Greater tuberosity displacement > 1 cm, calcar length > 8 mm, and bicipital groove comminution
. Lesser tuberosity displacement, head-shaft angulation > 45 degrees, and diaphyseal extension
. Disrupted medial hinge, surgical neck fracture pattern, and head split component

Correct Answer & Explanation

. Calcar length < 8 mm, disrupted medial hinge, and an anatomic neck fracture pattern

Explanation

Hertel described specific radiographic criteria predictive of humeral head ischemia (AVN) following proximal humerus fractures. The three strongest predictors are an anatomic neck fracture (disruption of the articular surface from the metaphysis), a short calcar segment attached to the head (<8 mm), and a disrupted medial hinge (medial shaft displaced >2 mm from the head). When all three are present, the positive predictive value for ischemia is 97%.

Question 4911

Topic: 2. Trauma
A 25-year-old patient presents with an open Gustilo-Anderson IIIB distal-third tibial shaft fracture with massive anterior soft tissue loss. Bone stabilization is achieved with an intramedullary nail. Which of the following is the most appropriate definitive soft-tissue coverage option for this specific anatomic zone?
. Medial gastrocnemius rotational muscle flap
. Soleus rotational muscle flap
. Free tissue transfer (e.g., anterolateral thigh or latissimus dorsi flap)
. Reverse sural fasciocutaneous local flap only
. Healing by secondary intention with negative pressure wound therapy

Correct Answer & Explanation

. Free tissue transfer (e.g., anterolateral thigh or latissimus dorsi flap)

Explanation

For soft tissue coverage of the tibia, local rotational muscle flaps are generally defined by thirds: the proximal third is covered by the gastrocnemius, and the middle third by the soleus. The distal third of the tibia lacks adequate local muscle bulk for reliable rotational coverage. Therefore, severe soft tissue defects (Gustilo IIIB) in the distal third require free tissue transfer (free flap), such as an anterolateral thigh (ALT) or latissimus dorsi flap, for definitive coverage.

Question 4912

Topic: 2. Trauma

During the posteromedial approach to the tibial plateau for fixation of a complex medial plateau fracture-dislocation, the surgical interval is developed between which two anatomical structures?

. Lateral head of the gastrocnemius and the soleus
. Medial head of the gastrocnemius and the pes anserinus
. Tibialis anterior and the extensor hallucis longus
. Semimembranosus and the semitendinosus
. Flexor digitorum longus and the tibialis posterior

Correct Answer & Explanation

. Medial head of the gastrocnemius and the pes anserinus

Explanation

The posteromedial approach to the tibial plateau is the standard approach for isolated posteromedial shear fragments (e.g., Moore Type I). The internervous/intermuscular interval is developed by retracting the pes anserinus anteriorly and the medial head of the gastrocnemius posteriorly, exposing the underlying popliteus and posteromedial border of the tibia.

Question 4913

Topic: 2. Trauma

A 65-year-old female who has been taking alendronate for 8 years presents with a non-traumatic thigh fracture. According to the revised 2013 American Society for Bone and Mineral Research (ASBMR) task force criteria, which of the following is an absolute MAJOR criterion required for the diagnosis of an atypical femoral fracture (AFF)?

. Bilateral presentation
. Prodromal thigh or groin pain
. Delayed fracture healing
. Transverse or short oblique fracture configuration
. Comminution of more than three fragments

Correct Answer & Explanation

. Transverse or short oblique fracture configuration

Explanation

According to the ASBMR 2013 criteria for Atypical Femoral Fractures (AFF), major criteria must be present to diagnose an AFF. Major criteria include: location between the subtrochanteric region and supracondylar flare, associated with minimal/no trauma, transverse or short oblique configuration, noncomminuted or minimally comminuted, and localized periosteal/endosteal thickening of the lateral cortex (beaking). Bilateral symptoms, prodromal pain, and delayed healing are considered MINOR criteria.

Question 4914

Topic: 2. Trauma

The Lower Extremity Assessment Project (LEAP) study comprehensively evaluated outcomes comparing limb salvage versus amputation for severe lower extremity trauma. At the 2-year follow-up, which of the following was a primary finding regarding functional outcomes based on the Sickness Impact Profile (SIP)?

. Amputation resulted in significantly better functional outcomes than limb salvage.
. Limb salvage resulted in significantly better functional outcomes than amputation.
. There was no significant difference in functional outcomes between the amputation and limb salvage groups.
. The MESS (Mangled Extremity Severity Score) accurately predicted which patients would have superior outcomes with amputation.
. Patients undergoing primary amputation had statistically significantly lower rates of PTSD.

Correct Answer & Explanation

. There was no significant difference in functional outcomes between the amputation and limb salvage groups.

Explanation

The LEAP study is a landmark multicenter prospective study evaluating severe limb trauma. Its most famous finding is that at 2 years, there is no significant difference in functional outcomes (as measured by SIP scores) between patients who underwent reconstruction/salvage versus those who underwent amputation. Furthermore, the study demonstrated that trauma scores (like the MESS) have low clinical utility for predicting the need for amputation or final functional outcome.

Question 4915

Topic: 2. Trauma

According to the Sanders classification system for intra-articular calcaneal fractures, the severity and type of the fracture are determined by the number and location of articular fracture lines. Which specific imaging modality and slice dictates this classification?

. An axial CT slice at the level of the sustentaculum tali
. A sagittal CT slice demonstrating the angle of Gissane
. A coronal CT slice showing the widest undersurface of the posterior facet
. A Harris axial plain radiograph
. A Broden's view radiograph at 40 degrees of internal rotation

Correct Answer & Explanation

. A coronal CT slice showing the widest undersurface of the posterior facet

Explanation

The Sanders classification is highly prognostic for functional outcomes in calcaneus fractures. It is based strictly on a coronal computed tomography (CT) image of the calcaneus, specifically the slice demonstrating the widest transverse dimension of the posterior facet of the subtalar joint. It categorizes fractures into types I-IV based on the number of fracture lines running through this facet.

Question 4916

Topic: 2. Trauma

A 30-year-old male presents with a Maisonneuve fracture (a proximal third fibular fracture associated with an unstable syndesmotic injury). According to the Lauge-Hansen classification, this injury is best described as a Pronation-External Rotation (PER) stage 3 injury. What is the defining characteristic of the Stage 1 injury in this specific mechanistic sequence?

. Rupture of the anterior inferior tibiofibular ligament (AITFL)
. Transverse fracture of the medial malleolus or rupture of the deltoid ligament
. Spiral fracture of the distal lateral malleolus
. Rupture of the posterior inferior tibiofibular ligament (PITFL)
. Vertical shear fracture of the medial malleolus

Correct Answer & Explanation

. Transverse fracture of the medial malleolus or rupture of the deltoid ligament

Explanation

In the Lauge-Hansen Pronation-External Rotation (PER) mechanism, the foot is pronated (placing tension on medial structures) before external rotation forces are applied. Thus, Stage 1 is a medial-sided injury: a transverse fracture of the medial malleolus or a rupture of the deltoid ligament. Stage 2 is rupture of the AITFL. Stage 3 is a high or mid-shaft spiral/oblique fibula fracture (e.g., Maisonneuve). Stage 4 is rupture of the PITFL or a posterior malleolus fracture.

Question 4917

Topic: 2. Trauma

A 22-year-old male sustains a low-velocity gunshot wound to the right knee. Plain radiographs demonstrate a retained bullet entirely within the intra-articular space of the knee joint, with no associated fractures. Which of the following is the most appropriate long-term management strategy for the retained projectile?

. Observation alone, as low-velocity bullets are sterilized by the heat of firing
. Arthroscopic or open surgical removal of the intra-articular bullet
. Intra-articular injection of chelating agents followed by immobilization
. Six weeks of intravenous antibiotics and strict non-weight bearing
. Immediate above-knee amputation to prevent systemic lead toxicity

Correct Answer & Explanation

. Arthroscopic or open surgical removal of the intra-articular bullet

Explanation

While many low-velocity gunshot wounds to soft tissue and bone can be managed non-operatively with local wound care and antibiotics, a bullet lodged within a synovial joint space is an absolute indication for surgical removal. If left in synovial fluid, the lead dissolves over time, leading to severe hypertrophic lead arthropathy (joint destruction) and systemic lead toxicity (plumbism).

Question 4918

Topic: 2. Trauma

The Denis classification categorizes sacral fractures into three anatomic zones. Fractures involving which zone are associated with the highest incidence of neurologic deficits, including saddle anesthesia and bowel/bladder dysfunction?

. Zone 1 (Alar zone)
. Zone 2 (Foraminal zone)
. Zone 3 (Central canal zone)
. Zone 4 (Sacrococcygeal junction)
. Zone 5 (Iliolumbar zone)

Correct Answer & Explanation

. Zone 3 (Central canal zone)

Explanation

The Denis classification of sacral fractures comprises three zones: Zone 1 (ala, lateral to the foramina), Zone 2 (transforaminal), and Zone 3 (central sacral canal). Zone 3 fractures have the highest rate of significant neurologic deficit (>50%), frequently involving the lower sacral roots (S2-S4) and causing cauda equina syndrome, characterized by saddle anesthesia and loss of bowel and bladder sphincter control.

Question 4919

Topic: 2. Trauma
A 25-year-old male sustains a vertically oriented (Pauwels III) femoral neck fracture. Biomechanically, what is the primary advantage of a fixed-angle construct (e.g., sliding hip screw with derotation screw) over three parallel cannulated screws?
. Improved resistance to vertical shear forces
. Better preservation of the femoral head blood supply
. Decreased risk of implant cut-out in osteoporotic bone
. Increased rotational stability during early weight-bearing
. Lower rates of postoperative infection

Correct Answer & Explanation

. Improved resistance to vertical shear forces

Explanation

A fixed-angle construct resists the high vertical shear forces inherent to Pauwels III fractures better than parallel cannulated screws. This minimizes inferior displacement, varus collapse, and subsequent nonunion.

Question 4920

Topic: 2. Trauma
A polytrauma patient presents with hemodynamic instability and an anteroposterior compression (APC-III) pelvic ring injury. A circumferential pelvic binder is applied. To optimally reduce the pelvic volume and stabilize the fracture, the binder should be centered over which anatomical landmark?
. Anterior superior iliac spines
. Iliac crests
. Symphysis pubis
. Greater trochanters
. Subtrochanteric femur

Correct Answer & Explanation

. Greater trochanters

Explanation

Pelvic binders must be centered directly over the greater trochanters to effectively close the pelvic ring and reduce intra-pelvic volume. Placing them higher over the iliac crests can inadvertently widen the true pelvis or fail to provide adequate compression.

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