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2. Trauma MCQs

Practice Set 262 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 5221

Topic: 2. Trauma
A 30-year-old male sustains a high-energy Pauwels type III femoral neck fracture in a motor vehicle collision. To biomechanically optimize fixation and minimize the high shear forces that typically lead to varus collapse, which construct is most appropriate?
. Three parallel cancellous screws placed in an inverted triangle
. Non-spanning external fixator
. Cemented bipolar hemiarthroplasty
. Sliding hip screw with a derotational cancellous screw
. Fully threaded cannulated screws placed in a divergent pattern

Correct Answer & Explanation

. Sliding hip screw with a derotational cancellous screw

Explanation

Pauwels type III fractures are highly vertical and subjected to significant shear forces, making them prone to varus collapse. A fixed-angle device such as a sliding hip screw (often supplemented with a derotational screw) provides superior biomechanical stability against vertical shear compared to multiple cancellous screws.

Question 5222

Topic: Pelvic & Acetabular Trauma
A 28-year-old male construction worker is crushed by heavy equipment, sustaining an anteroposterior compression (APC) type III pelvic ring injury. Examination reveals blood at the urethral meatus and a high-riding prostate on digital rectal exam. What is the most appropriate next step in his urologic evaluation?
. CT cystogram
. Suprapubic catheterization
. Retrograde urethrogram
. Pelvic angiography
. Transrectal ultrasound

Correct Answer & Explanation

. Retrograde urethrogram

Explanation

Blood at the meatus and a high-riding prostate strongly suggest a urethral disruption, which is highly associated with pelvic ring disruptions. A retrograde urethrogram (RUG) must be performed prior to the insertion of a Foley catheter to prevent converting a partial tear into a complete transection.

Question 5223

Topic: 2. Trauma
A 45-year-old agricultural worker sustains a Gustilo-Anderson IIIB open tibial shaft fracture deeply contaminated with soil and manure. In addition to immediate tetanus prophylaxis and aggressive surgical debridement, which antibiotic regimen is most appropriate based on current trauma guidelines?
. First-generation cephalosporin alone
. First-generation cephalosporin and an aminoglycoside
. First-generation cephalosporin, an aminoglycoside, and high-dose penicillin
. Third-generation cephalosporin and clindamycin
. Vancomycin and a third-generation cephalosporin

Correct Answer & Explanation

. First-generation cephalosporin, an aminoglycoside, and high-dose penicillin

Explanation

For severe open fractures (Type III), a first-generation cephalosporin and an aminoglycoside provide necessary gram-positive and gram-negative coverage. In the presence of heavy agricultural or fecal contamination, high-dose penicillin must be added to cover Clostridium species to prevent gas gangrene.

Question 5224

Topic: 2. Trauma

A 26-year-old male complains of severe, escalating leg pain 12 hours after an intramedullary nailing of a tibia fracture. He has extreme pain with passive toe stretch. Compartment pressures are measured. Which threshold is currently widely accepted as the absolute indication for four-compartment fasciotomies?

. Absolute pressure greater than 20 mm Hg
. Absolute pressure greater than 25 mm Hg
. Delta P (diastolic blood pressure minus compartment pressure) less than 30 mm Hg
. Delta P (mean arterial pressure minus compartment pressure) less than 45 mm Hg
. Delta P (systolic blood pressure minus compartment pressure) less than 30 mm Hg

Correct Answer & Explanation

. Delta P (diastolic blood pressure minus compartment pressure) less than 30 mm Hg

Explanation

A Delta P (diastolic blood pressure minus the measured compartment pressure) of less than 30 mm Hg is widely accepted as the most reliable objective threshold for diagnosing acute compartment syndrome and mandates emergent fasciotomy.

Question 5225

Topic: 2. Trauma

A 24-year-old male presents after a high-speed motorcycle accident with a posterior knee dislocation. After urgent closed reduction, the patient has symmetric, palpable dorsalis pedis and posterior tibial pulses. However, the Ankle-Brachial Index (ABI) is measured at 0.85. What is the most appropriate next step in management?

. Discharge with an immobilizer and urgent outpatient orthopedic follow-up
. Observation with serial clinical vascular exams every 2 hours
. CT angiography of the lower extremity
. Immediate prophylactic four-compartment fasciotomy
. Emergent exploration by vascular surgery

Correct Answer & Explanation

. CT angiography of the lower extremity

Explanation

In the setting of a knee dislocation, vascular injury (particularly to the popliteal artery) is a major concern. An ABI of < 0.9, even in the presence of palpable pulses, raises strong suspicion for an occult intimal tear or flow-limiting vascular lesion. A CT angiogram (or duplex ultrasound depending on institutional protocol) is strictly indicated to evaluate the vascular integrity before proceeding with further management.

Question 5226

Topic: 2. Trauma
Figures 32a and 32b show the radiographs of a 13-year-old right hand-dominant boy who sustained a closed Salter-Harris type II fracture of the proximal humerus during a hockey game. The shoulder has significant swelling, but is neurovascularly intact. What treatment offers the best chance of reestablishing normal shoulder motion?
. Closed reduction and application of a shoulder spica cast in the outpatient setting
. Closed reduction under fluoroscopy and application of a shoulder spica cast in the operating room
. No active reduction and placement of the upper extremity in a shoulder immobilizer
. Closed or open reduction and percutaneous pin stabilization
. Open reduction and internal fixation

Correct Answer & Explanation

. Closed or open reduction and percutaneous pin stabilization

Explanation

The patient has a significantly angulated proximal humerus fracture with a high degree of varus angulation, and rotational malalignment is likely. Failure to correct the varus angulation will result in permanent loss of shoulder abduction because the patientโ€™s age limits bony remodeling. These fractures are inherently unstable due to the inability to control the proximal fracture alignment. Shoulder spica casts have a high rate of redisplacement after treatment. Adequate open or closed reduction and pin fixation in the operating room optimizes alignment and all but eliminates the chance of redisplacement.

Question 5227

Topic: 2. Trauma
Which of the following statements is true regarding brake travel time after surgical treatment of complex lower extremity trauma?
. Brake travel time is significantly reduced until 6 weeks after patient begins weight bearing
. Return of normal brake travel time takes longer after long bone fracture compared to articular fractures
. Normal brake travel time correlates with improved short musculoskeletal functional assessment scores
. Brake travel time is significantly reduced until 8 weeks after patient begins weight bearing
. Brake travel time returns to normal when weight bearing begins

Correct Answer & Explanation

. Brake travel time is significantly reduced until 6 weeks after patient begins weight bearing

Explanation

DISCUSSION: Brake travel time (BTT) has been shown to be significantly reduced until 6 weeks after initiation of weight bearing in both long bone and articular fractures of the right lower extremity. Egol et al used a computerized driving simulator to compare BTT in three groups of patients: 1) control group, 2) long bone lower extremity fracture group, 3) lower extremity articular fracture group. They concluded that BTT was significantly reduced until 6 weeks after initiation of weight bearing in both long bone and articular fractures of the right lower extremity, and that short musculoskeletal functional assessment scores improved with respect to function and other indexes, but did not correlate with improvement in BTT. An earlier study by Egol et al looked at total brake time as it related to distance traveled by the automobile before braking at 6, 9, and 12 weeks after operative fixation of a right ankle fracture. When compared with controls, braking time was shown to return to normal by 9 weeks post-operatively, and no significant association was found between the functional scores and this normalization. Giddins et al provide a review of the literature, the law, and the views of the major motor insurers related to driving after injury or operations.

Question 5228

Topic: 2. Trauma

According to the 2013 revised American Society for Bone and Mineral Research (ASBMR) Task Force criteria, which of the following is considered a 'major' diagnostic criterion for an atypical femoral fracture (AFF)?

. Comminuted fracture pattern at the diaphysis
. Fracture location proximal to the lesser trochanter
. Bilateral incomplete femoral radiolucent lines
. Fracture line originates at the lateral cortex and is strictly transverse or short oblique
. Delayed union or nonunion following surgical fixation

Correct Answer & Explanation

. Fracture line originates at the lateral cortex and is strictly transverse or short oblique

Explanation

The 2013 ASBMR revised major criteria for AFF require all of the following: location anywhere from just distal to the lesser trochanter to just proximal to the supracondylar flare; associated with minimal or no trauma; a transverse or short oblique line originating at the lateral cortex; noncomminuted or minimally comminuted; and localized periosteal or endosteal thickening of the lateral cortex (beaking). Bilateral fractures and delayed union are considered minor criteria.

Question 5229

Topic: 2. Trauma

A 45-year-old trauma patient sustains a highly comminuted extra-articular scapula neck fracture. Which of the following radiographic parameters is generally considered an absolute indication for operative fixation to prevent altered shoulder biomechanics?

. Glenopolar angle (GPA) of 15 degrees
. Medial displacement of the glenoid fragment of 5 mm
. Angular deformity of 15 degrees in the sagittal plane
. Concomitant non-displaced clavicle fracture
. Superior displacement of the lateral fragment by 3 mm

Correct Answer & Explanation

. Glenopolar angle (GPA) of 15 degrees

Explanation

Operative indications for extra-articular scapular neck fractures include severe medialization (e.g., >20 mm), severe angulation (e.g., >45 degrees), and a significantly decreased glenopolar angle (GPA). A normal GPA is between 30 and 45 degrees. A GPA <22 degrees alters the relationship of the glenoid to the rotator cuff line of pull, leading to poor functional outcomes and rotator cuff dysfunction, making it a strong indication for surgery.

Question 5230

Topic: 2. Trauma

A 38-year-old male sustains a severe hyperflexion injury to the knee, resulting in a tibial plateau fracture. CT imaging demonstrates a coronal primary fracture line with a large, displaced posteromedial shear fragment. According to Luo's three-column concept, which surgical approach and fixation strategy is biomechanically optimal for this specific fragment?

. Anterolateral approach with a laterally applied locking plate
. Anteromedial approach with an anteriorly applied buttress plate
. Posteromedial approach with a posteriorly applied anti-glide plate
. Direct posterior approach with a single lag screw placed from anterior to posterior
. Dual anterolateral and anteromedial incisions with anteriorly placed plates

Correct Answer & Explanation

. Posteromedial approach with a posteriorly applied anti-glide plate

Explanation

A posteromedial shear fragment of the tibial plateau is notoriously difficult to reduce and stabilize from an anterior approach. Luo's three-column concept emphasizes direct mechanical support for the involved posterior column. A posteromedial approach with a posteriorly applied buttress or anti-glide plate provides the optimal biomechanical stability to counteract the vertical shear forces during knee flexion.

Question 5231

Topic: 2. Trauma
Six weeks following open reduction and internal fixation of a Hawkins Type III talar neck fracture, a follow-up anteroposterior radiograph of the ankle demonstrates a subchondral radiolucent band in the talar dome. What does this specific radiographic finding indicate?
. Imminent avascular necrosis of the talar body
. Nonunion of the talar neck fracture
. Subchondral collapse and early post-traumatic arthritis
. Intact vascular supply to the talar body
. Deep bone infection of the talar dome

Correct Answer & Explanation

. Intact vascular supply to the talar body

Explanation

The Hawkins sign is a subchondral radiolucent band that appears typically 6 to 8 weeks post-injury in the talar dome. It represents subchondral osteopenia secondary to disuse atrophy and active bone resorption. Because bone resorption requires an intact, active blood supply, the presence of the Hawkins sign is a highly reliable indicator that the talar body remains vascularized and avascular necrosis (AVN) is unlikely.

Question 5232

Topic: 2. Trauma

After intramedullary nailing of a femoral shaft fracture, a patient reports anterior knee pain. Lateral knee radiographs are obtained to assess for patellar height changes (patella baja/alta). Which of the following radiographic indices is most independent of the degree of knee flexion at the time the radiograph was taken?

. Insall-Salvati ratio
. Blackburne-Peel ratio
. Caton-Deschamps index
. Blumensaat line alignment
. Merchant angle

Correct Answer & Explanation

. Insall-Salvati ratio

Explanation

The Insall-Salvati ratio measures the length of the patellar tendon (from the lower pole of the patella to the tibial tubercle) divided by the longest diagonal length of the patella. Because both measurements are based solely on fixed anatomical landmarks of the extensor mechanism and do not rely on the articulation with the femur or the joint line, the ratio is relatively independent of the knee flexion angle compared to the Blackburne-Peel or Caton-Deschamps indices.

Question 5233

Topic: Lower Extremity Trauma

A surgeon performs a medial opening-wedge high tibial osteotomy (HTO) to correct varus deformity in a patient with medial compartment osteoarthritis. The surgeon fails to release the distal superficial medial collateral ligament (sMCL) and inadvertently opens the osteotomy gap predominantly at the anterior cortex. What unintended sagittal plane deformity is most likely to result?

. Increased posterior tibial slope
. Decreased posterior tibial slope
. Increased anterior tibial slope
. Tibial recurvatum deformity
. Complete loss of normal tibial rotation

Correct Answer & Explanation

. Increased posterior tibial slope

Explanation

In a medial opening-wedge HTO, the tight posteromedial structures (specifically the sMCL) can act as a hinge. If the sMCL is not released, the osteotomy gap will preferentially open anteriorly. This anterior opening elevates the anterior tibial plateau relative to the posterior plateau, leading to an unintended increase in the posterior tibial slope. Releasing the sMCL and ensuring the gap is opened evenly (or slightly more posteromedially) prevents this.

Question 5234

Topic: 2. Trauma
A 32-year-old male sustains a Hawkins Type III talar neck fracture and undergoes open reduction and internal fixation. At the 6-week postoperative visit, a well-defined subchondral radiolucent band is visible across the talar dome on the AP mortise radiograph. What is the clinical significance of this finding?
. It represents the early onset of avascular necrosis (AVN) of the talar body
. It represents resorption of the subchondral bone secondary to hyperemia and intact vascular supply
. It is an early radiographic sign of pyogenic infection of the talus
. It indicates impending nonunion of the fracture site
. It reflects rapidly progressive post-traumatic osteoarthritis

Correct Answer & Explanation

. It represents resorption of the subchondral bone secondary to hyperemia and intact vascular supply

Explanation

This finding is the 'Hawkins sign'. The radiolucent band represents subchondral osteopenia, which occurs as a result of active hyperemia following the fracture. The presence of hyperemia definitively proves that the vascular supply to the talar body is intact, thereby serving as an excellent prognostic indicator that avascular necrosis (AVN) will not occur.

Question 5235

Topic: 2. Trauma
In the surgical management of a high-angle, vertical femoral neck fracture (Pauwels type III) in a 30-year-old patient, construct choice is critical due to distinct deforming forces. Biomechanical studies comparing the use of a dynamic hip screw (DHS) with an anti-rotation screw versus three parallel cancellous screws suggest which primary advantage for the DHS construct?
. Superior resistance to vertical shear forces
. Greater preservation of the lateral epiphyseal artery
. Prevention of post-traumatic cam-type femoroacetabular impingement
. Elimination of fracture site sliding to promote primary bone healing
. Lower theoretical risk of hardware-related osteonecrosis

Correct Answer & Explanation

. Superior resistance to vertical shear forces

Explanation

Pauwels type III fractures are highly vertical and experience significant vertical shear forces rather than compressive forces. Biomechanical studies have demonstrated that a fixed-angle construct, such as a dynamic hip screw (DHS), provides superior resistance to these vertical shear forces compared to three parallel cancellous lag screws, reducing the risk of varus collapse and nonunion.

Question 5236

Topic: 2. Trauma

A 35-year-old male sustains a high-energy trauma resulting in an isolated coronal plane fracture of the posterior aspect of the lateral femoral condyle (Hoffa fracture). Which of the following muscle combinations represents the primary deforming forces that pull the fracture fragment posteriorly and distally?

. Biceps femoris and plantaris
. Gastrocnemius and popliteus
. Semimembranosus and soleus
. Quadriceps and iliotibial band
. Adductor magnus and gracilis

Correct Answer & Explanation

. Gastrocnemius and popliteus

Explanation

A Hoffa fracture of the lateral femoral condyle creates a free posterior osteochondral fragment. The lateral head of the gastrocnemius originates from the posterior surface of the lateral condyle, and the popliteus originates from the lateral epicondyle. These muscles act as the primary deforming forces, displacing the free coronal fragment posteriorly and distally.

Question 5237

Topic: 2. Trauma

A 35-year-old male involved in a motorcycle collision sustains a coronal plane fracture of the lateral femoral condyle (Hoffa fracture). Which surgical approach and fixation strategy is historically and biomechanically most appropriate for rigid fixation of this fracture?

. Medial parapatellar approach; anterior-to-posterior lag screws
. Lateral parapatellar approach; posterior-to-anterior lag screws
. Lateral approach (parapatellar or direct); anterior-to-posterior lag screws
. Subvastus approach; lateral plating alone without lag screws
. Medial subvastus approach; posterior-to-anterior lag screws

Correct Answer & Explanation

. Lateral approach (parapatellar or direct); anterior-to-posterior lag screws

Explanation

A Hoffa fracture (OTA 33-B3) of the lateral condyle is best addressed via a lateral approach (such as lateral parapatellar). Biomechanical studies show that anterior-to-posterior placed lag screws (often countersunk to avoid articular damage) are significantly stronger than posterior-to-anterior screws in resisting the shear forces at this fracture site.

Question 5238

Topic: 2. Trauma

A 40-year-old skier sustains a Schatzker II tibial plateau fracture. Which specific soft tissue injury is most frequently associated with this fracture pattern?

. Medial collateral ligament complete rupture
. Anterior cruciate ligament mid-substance tear
. Lateral meniscus tear (peripheral/meniscocapsular)
. Medial meniscus root tear
. Patellar tendon rupture

Correct Answer & Explanation

. Lateral meniscus tear (peripheral/meniscocapsular)

Explanation

A Schatzker II fracture is a split-depression of the lateral tibial plateau. It is highly associated with lateral meniscus tears, particularly peripheral or meniscocapsular separations, occurring in up to 50% of these injuries as the meniscus is trapped or damaged by the depressed articular fragment.

Question 5239

Topic: Lower Extremity Trauma

A 6-year-old child is evaluated for a painless 'snapping' and 'popping' of the lateral knee during flexion and extension. MRI reveals a complete Wrisberg variant of a discoid lateral meniscus. What is the primary anatomical deficiency in this specific variant?

. Absence of the meniscofemoral ligament of Wrisberg
. Absence of the posterior coronary (meniscotibial) ligaments
. Absence of the anterior horn attachment to the tibia
. Hypertrophy of the transverse meniscal ligament
. Anomalous insertion of the popliteus tendon into the meniscus

Correct Answer & Explanation

. Absence of the posterior coronary (meniscotibial) ligaments

Explanation

The Wrisberg variant of the discoid lateral meniscus lacks the normal posterior coronary ligament (meniscotibial) attachments to the tibial plateau. The posterior horn is only stabilized by the meniscofemoral ligament of Wrisberg, allowing hypermobility and resulting in the classic 'snapping knee' syndrome.

Question 5240

Topic: 2. Trauma

When assessing a displaced 4-part proximal humerus fracture, which of the following specific radiographic criteria (Hertel's criteria) is the most reliable predictor of subsequent humeral head ischemia?

. Medial hinge displacement greater than 2 mm
. Metaphyseal head extension (calcar length) less than 8 mm
. Angulation of the humeral head greater than 45 degrees
. Greater tuberosity superior displacement greater than 1 cm
. Comminution of the bicipital groove

Correct Answer & Explanation

. Metaphyseal head extension (calcar length) less than 8 mm

Explanation

Hertel described predictors of ischemia for proximal humerus fractures. The most significant predictors include a metaphyseal head extension (calcar length attached to the articular segment) of < 8 mm, disruption of the medial hinge (> 2 mm displacement), and an anatomic neck fracture pattern.

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