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2. Trauma MCQs

Practice Set 375 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 7481

Topic: 2. Trauma

A 28-year-old man sustains a completely displaced, vertically oriented (Pauwels type III) femoral neck fracture. To maximize biomechanical stability and minimize the risk of shear-induced failure, which of the following fixation constructs is most appropriate?

. Three parallel cannulated cancellous screws in an inverted triangle configuration
. A sliding hip screw with a supplemental superior derotation screw
. Two parallel fully threaded cortical screws
. A cephalomedullary nail with a single lag screw
. Bipolar hemiarthroplasty

Correct Answer & Explanation

. Three parallel cannulated cancellous screws in an inverted triangle configuration

Explanation

Pauwels type III fractures exhibit high shear forces due to their vertical orientation. A fixed-angle device, such as a sliding hip screw with a supplemental derotation screw, provides superior biomechanical stability against vertical shear compared to multiple cancellous screws.

Question 7482

Topic: 2. Trauma

A 70-year-old woman sustains a reverse obliquity intertrochanteric hip fracture. Why is a cephalomedullary nail mechanically preferred over a sliding hip screw (SHS) for this specific fracture pattern?

. The SHS requires a larger surgical incision.
. The SHS is associated with a higher risk of nonunion due to biological stripping.
. A cephalomedullary nail prevents medial translation of the femoral shaft.
. A cephalomedullary nail allows for dynamic compression across the fracture site.
. The SHS causes excessive lateralization of the greater trochanter.

Correct Answer & Explanation

. The SHS requires a larger surgical incision.

Explanation

In reverse obliquity fractures, the lateral femoral cortex is disrupted, rendering a sliding hip screw biomechanically compromised as the shaft can translate medially. A cephalomedullary nail acts as an intramedullary buttress, preventing this medial displacement.

Question 7483

Topic: 2. Trauma

A 35-year-old man presents to the emergency department with a shortened, flexed, abducted, and externally rotated left lower extremity following a high-speed motorcycle accident. Which of the following is the most likely diagnosis?

. Posterior hip dislocation
. Anterior hip dislocation (inferior/obturator type)
. Anterior hip dislocation (superior/pubic type)
. Intertrochanteric femur fracture
. Subtrochanteric femur fracture

Correct Answer & Explanation

. Posterior hip dislocation

Explanation

Anterior hip dislocations of the inferior (obturator) type classically present with the hip in flexion, abduction, and external rotation. Posterior dislocations typically present with the hip flexed, adducted, and internally rotated.

Question 7484

Topic: 2. Trauma

A 75-year-old woman sustains a highly unstable intertrochanteric femur fracture and is treated with a cephalomedullary nail. To minimize the risk of lag screw cut-out, what is the maximum recommended tip-apex distance (TAD) as described by Baumgaertner?

. 10 mm
. 15 mm
. 25 mm
. 35 mm
. 45 mm

Correct Answer & Explanation

. 10 mm

Explanation

Baumgaertner et al. demonstrated that a tip-apex distance (TAD) of less than 25 mm significantly reduces the risk of lag screw cut-out in intertrochanteric fractures. The TAD is the sum of the distance from the tip of the screw to the apex of the femoral head on both AP and lateral radiographs.

Question 7485

Topic: 2. Trauma

A 32-year-old unrestrained driver is involved in a motor vehicle collision. Radiographs demonstrate a posterior hip dislocation associated with a femoral head fracture that involves the weight-bearing zone superior to the fovea capitis. According to the Pipkin classification, what is the grade of this injury?

. Type I
. Type II
. Type III
. Type IV
. Type V

Correct Answer & Explanation

. Type I

Explanation

The Pipkin classification describes femoral head fractures associated with posterior hip dislocations. Type I is below the fovea, Type II is above the fovea (involving the weight-bearing surface), Type III involves an associated femoral neck fracture, and Type IV involves an associated acetabular fracture.

Question 7486

Topic: 2. Trauma

A 28-year-old man sustains a completely displaced, vertically oriented (Pauwels type III) femoral neck fracture. Which of the following fixation constructs provides the greatest biomechanical stability against vertical shear forces for this specific fracture pattern?

. Three parallel cancellous lag screws in an inverted triangle
. Two parallel cancellous lag screws
. A sliding hip screw with a supplemental derotation screw
. A dynamic condylar screw
. A partially threaded cancellous screw combined with a fully threaded positioning screw

Correct Answer & Explanation

. Three parallel cancellous lag screws in an inverted triangle

Explanation

Pauwels type III (vertical) femoral neck fractures experience extraordinarily high shear forces, leading to a high failure rate if treated with parallel cancellous screws alone. A fixed-angle device, such as a sliding hip screw, provides superior biomechanical resistance to vertical shear, while a supplemental screw prevents rotational displacement.

Question 7487

Topic: 2. Trauma

A 45-year-old man reports severe discomfort following a twisting injury to his right ankle and foot. Plain radiographs are negative; however, the CT scans shown in Figures 39a and 39b reveal a fracture. Management should consist of

. open reduction and internal fixation.
. percutaneous pin fixation.
. excision of the fracture fragment.
. primary calcaneocuboid joint arthrodesis.
. a walking cast or removable cast boot.

Correct Answer & Explanation

. open reduction and internal fixation.

Explanation

The CT scans show a fracture of the anterior process of the calcaneus that involves less than 25% of the joint surface with minimal to no displacement. The preferred treatment is external immobilization in either a walking cast or, more typically, a removable cast boot. For larger fractures that involve more than 25% of the articular surface with joint incongruity, open reduction and internal fixation may be indicated. Primary calcaneocuboid joint arthrodesis is not warranted because symptoms are rare in most patients. Delayed excision of the fragment is a late reconstructive option if painful nonunion develops. Percutaneous pin fixation is not indicated beceause there tends to be inherent stability in this fracture. Heckman JD: Fractures and dislocations in the foot, in Rockwood CA Jr, Green DP, Bucholz RW, Heckman JD (eds): Rockwood and Green's Fractures in Adults, ed 4. Philadelphia, PA, Lippincott-Raven, 1996, pp 2267-2405.

Question 7488

Topic: 2. Trauma

A 40-year-old male presents after a high-energy motor vehicle collision with a closed Schatzker IV tibial plateau fracture. Which of the following associated injuries must be most highly suspected and systematically ruled out?

. Anterior cruciate ligament tear
. Superficial peroneal nerve injury
. Popliteal artery injury
. Patellar tendon rupture
. Lateral collateral ligament tear

Correct Answer & Explanation

. Anterior cruciate ligament tear

Explanation

Schatzker IV (medial plateau) fractures often result from a high-energy varus force, functioning similarly to a knee dislocation. Consequently, there is a high association with popliteal artery and common peroneal nerve injuries that must be carefully ruled out.

Question 7489

Topic: 2. Trauma

In the treatment of a complex pilon fracture, the surgeon identifies a large anterolateral articular fragment. Which of the following ligaments provides the primary soft-tissue attachment to this specific fragment?

. Anterior inferior tibiofibular ligament
. Posterior inferior tibiofibular ligament
. Deltoid ligament
. Interosseous membrane
. Calcaneofibular ligament

Correct Answer & Explanation

. Anterior inferior tibiofibular ligament

Explanation

The anterolateral articular fragment in a pilon fracture is often referred to as the Chaput fragment. It serves as the main tibial attachment site for the anterior inferior tibiofibular ligament (AITFL).

Question 7490

Topic: 2. Trauma

A 25-year-old polytrauma patient sustains bilateral femoral shaft fractures and severe pulmonary contusions. Initial labs reveal a pH of 7.21, base excess of -8, and core temperature of 34.5°C. What is the most appropriate initial management of the femoral fractures?

. Bilateral reamed antegrade intramedullary nailing
. Bilateral unreamed retrograde intramedullary nailing
. Spanning external fixation of both femurs
. Open reduction and internal fixation with plates
. Nonoperative management with skeletal traction

Correct Answer & Explanation

. Bilateral reamed antegrade intramedullary nailing

Explanation

This patient is in extremis based on acidosis (pH < 7.24) and hypothermia, meeting the criteria for Damage Control Orthopedics (DCO). The safest initial management is rapid temporary stabilization with spanning external fixators to minimize physiological hit.

Question 7491

Topic: 2. Trauma

When utilizing an anterolateral approach for open reduction and internal fixation of a distal tibia pilon fracture, which neurologic structure is at greatest risk of iatrogenic injury?

. Deep peroneal nerve
. Superficial peroneal nerve
. Sural nerve
. Saphenous nerve
. Tibial nerve

Correct Answer & Explanation

. Deep peroneal nerve

Explanation

The superficial peroneal nerve routinely crosses the operative field from lateral to medial over the distal third of the leg. It must be carefully identified and protected during the anterolateral approach to the distal tibia.

Question 7492

Topic: 2. Trauma

Following a high-energy Schatzker VI tibial plateau fracture treated with a spanning external fixator, the patient develops increasing leg pain out of proportion to the injury. Which of the following is the most sensitive early clinical finding for compartment syndrome?

. Loss of distal pulses
. Paresthesias in the first webspace
. Pain with passive stretch of the toes
. Paralysis of the extensor hallucis longus
. Pallor of the foot

Correct Answer & Explanation

. Loss of distal pulses

Explanation

Pain out of proportion to the injury and pain with passive stretch of the involved compartment's muscles are the earliest and most sensitive clinical indicators of acute compartment syndrome. Loss of pulses and pallor are late, unreliable signs.

Question 7493

Topic: 2. Trauma

A 45-year-old male sustains a closed, high-energy tibial pilon fracture initially managed with a spanning external fixator. What is the most reliable clinical indicator that the soft tissue envelope is ready for definitive open reduction and internal fixation?

. Resolution of fracture blisters within 48 hours
. Appearance of the wrinkle sign
. Normalization of inflammatory markers
. Formation of mature granulation tissue over fracture blisters
. Return of a palpable dorsalis pedis pulse

Correct Answer & Explanation

. Resolution of fracture blisters within 48 hours

Explanation

The "wrinkle sign" demonstrates that the initial massive soft tissue swelling has subsided, allowing the skin to wrinkle with joint motion or palpation. This typically occurs 10 to 21 days post-injury and indicates it is safe to proceed with surgical incisions.

Question 7494

Topic: 2. Trauma

During the initial resuscitation phase of a severely injured polytrauma patient, which of the following metabolic parameters is the most reliable prognostic indicator of adequate global tissue perfusion and resuscitation?

. Arterial oxygen saturation > 95%
. Mean arterial pressure > 65 mmHg
. Normalization of serum lactate
. Urine output of 0.5 mL/kg/hr
. Central venous pressure of 8-12 mmHg

Correct Answer & Explanation

. Arterial oxygen saturation > 95%

Explanation

Clearance of serum lactate and normalization of base deficit are the most reliable markers that oxygen debt has been repaid and global tissue perfusion is restored. Standard vital signs can often normalize before adequate resuscitation is achieved.

Question 7495

Topic: 2. Trauma

A 55-year-old female undergoes ORIF for a Schatzker II tibial plateau fracture. The depressed articular segment is elevated and supported with bone graft. Which fixation construct is most biomechanically critical to prevent secondary subsidence of the elevated articular fragment?

. A medially applied buttress plate
. Subchondral rafting screws placed parallel to the joint line
. A laterally applied locking plate with diaphyseal fixation only
. Interfragmentary lag screws directed from anterior to posterior
. An independent fibular head lag screw

Correct Answer & Explanation

. A medially applied buttress plate

Explanation

Subchondral rafting screws provide the crucial structural support directly beneath the elevated articular fragments. This acts as a mechanical floor, preventing secondary subsidence into the metaphyseal void during early rehabilitation.

Question 7496

Topic: 2. Trauma

A patient treated nonoperatively for a displaced pilon fracture develops a symptomatic varus malunion. Which of the following joint reactive force alterations is most likely to accelerate post-traumatic ankle arthrosis in this patient?

. Shift of forces to the lateral gutter
. Shift of forces to the medial talar dome
. Uniform increase in joint contact pressures
. Decrease in forces across the distal tibiofibular syndesmosis
. Shift of forces to the posterior malleolus

Correct Answer & Explanation

. Shift of forces to the lateral gutter

Explanation

A varus malunion shifts the mechanical axis of weight-bearing medially. This substantially increases contact pressures over the medial talar dome, leading to accelerated medial compartment post-traumatic arthritis.

Question 7497

Topic: 2. Trauma

A 28-year-old male polytrauma patient with bilateral femur fractures and a pelvic ring injury suddenly develops acute confusion, dyspnea, and a petechial rash over his axillae on hospital day 2. Which of the following is the most effective initial management?

. Administration of high-dose systemic corticosteroids
. Emergent surgical stabilization of all fractures
. Supportive care with supplemental oxygen and mechanical ventilation if necessary
. Immediate administration of therapeutic dose heparin
. Initiation of intravenous broad-spectrum antibiotics

Correct Answer & Explanation

. Administration of high-dose systemic corticosteroids

Explanation

This patient exhibits the classic triad of Fat Embolism Syndrome (FES): hypoxemia, neurologic abnormalities, and petechial rash. The mainstay of treatment is rigorous supportive care, primarily focusing on maintaining adequate oxygenation and ventilation.

Question 7498

Topic: 2. Trauma

When performing a direct posterolateral approach for a complex tibial plateau fracture, an osteotomy of the fibular head or neck is occasionally required for adequate visualization. Which of the following structures must be carefully identified and protected during this osteotomy?

. Popliteal artery
. Common peroneal nerve
. Tibial nerve
. Anterior tibial artery
. Lateral inferior genicular artery

Correct Answer & Explanation

. Popliteal artery

Explanation

The common peroneal nerve wraps directly around the fibular neck from posterior to anterior. It is at extremely high risk of injury during a posterolateral approach, especially if a fibular osteotomy is performed.

Question 7499

Topic: 2. Trauma

Which of the following radiographic patterns is most characteristic of a low-energy, rotational pilon fracture rather than a high-energy axial load pilon fracture?

. Severe metaphyseal comminution
. Severe articular impaction and central depression
. An associated transverse medial malleolus fracture
. A spiral fracture of the distal tibia extending into the joint
. Extensive diaphyseal extension with butterfly fragments

Correct Answer & Explanation

. Severe metaphyseal comminution

Explanation

Low-energy rotational mechanisms typically produce spiral fracture patterns of the distal tibia that extend into the plafond, with minimal comminution or articular impaction. High-energy injuries usually present with significant comminution and articular "die-punch" depression.

Question 7500

Topic: 2. Trauma

During the initial ATLS survey of a hemodynamically unstable polytrauma patient with an AP compression pelvic ring injury, a pelvic binder is indicated. To be maximally effective, the binder must be centered over which of the following anatomic landmarks?

. Anterior superior iliac spines
. Iliac crests
. Greater trochanters
. Pubic symphysis
. Umbilicus

Correct Answer & Explanation

. Anterior superior iliac spines

Explanation

Proper placement of a pelvic binder is centered directly over the greater trochanters. This allows the trochanters to act as levers, effectively internally rotating the hemipelvises and reducing the pelvic volume to tamponade bleeding.

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