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2. Trauma MCQs

Practice Set 423 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 8441

Topic: 2. Trauma
A 45-year-old male sustains a transverse posterior wall acetabular fracture after being struck by a car as a pedestrian. On examination, there is a large, fluctuant swelling over the greater trochanter with overlying skin ecchymosis and decreased sensation. Which of the following statements regarding this soft tissue lesion is true?
. It is a closed degloving injury that significantly decreases the risk of postoperative infection.
. It is best managed by immediate primary closure and skin grafting.
. It contains a collection of blood and necrotic fat resulting from the separation of the subcutaneous tissue from the underlying fascia.
. Aspiration of the lesion is contraindicated due to the high risk of introducing bacterial flora.
. The presence of this lesion has no bearing on the surgical timing of the acetabular fracture.

Correct Answer & Explanation

. It contains a collection of blood and necrotic fat resulting from the separation of the subcutaneous tissue from the underlying fascia.

Explanation

This clinical description represents a Morel-Lavallée lesion, which is a closed degloving injury where the skin and subcutaneous tissue are violently separated from the underlying fascia. This creates a potential space filled with blood, lymph, and necrotic fat. It is associated with a significantly increased risk of infection if an incision is made through it for internal fixation. Management often involves early percutaneous drainage, debridement, or delaying internal fixation until the soft tissue envelope recovers.

Question 8442

Topic: 2. Trauma
A 35-year-old male is brought to the trauma bay in hemorrhagic shock after a heavy crush injury. Pelvic radiographs reveal an anterior posterior compression (APC-III) pelvic ring injury. Despite the application of a pelvic binder and initiation of a massive transfusion protocol, he remains persistently hypotensive. FAST exam is negative. He is taken emergently to the operating room for preperitoneal pelvic packing. Through which anatomic space are the laparotomy sponges primarily placed to tamponade the most common source of bleeding?
. Posterior to the sacrum in the epidural space
. Anterior to the rectus abdominis muscle
. Within the intraperitoneal cavity
. In the retropubic space of Retzius extending posteriorly along the pelvic brim
. Through the greater sciatic notch into the gluteal region

Correct Answer & Explanation

. In the retropubic space of Retzius extending posteriorly along the pelvic brim

Explanation

Preperitoneal pelvic packing is an effective method for controlling venous and small arterial hemorrhage in hemodynamically unstable pelvic ring injuries. The packing is performed via a midline incision, entering the preperitoneal retropubic space (Space of Retzius), and bluntly dissecting along the pelvic brim toward the sacroiliac joints. Three laparotomy sponges are typically packed sequentially on each side to tamponade the presacral and paravesical venous plexuses, which are the most common sources of bleeding in pelvic fractures.

Question 8443

Topic: 2. Trauma
A 32-year-old male sustains a vertically oriented, displaced femoral neck fracture (Pauwels type III, angle > 50 degrees). Open reduction and internal fixation is planned. Which of the following fixation constructs provides the greatest biomechanical stability for this specific fracture pattern in a young adult?
. Three parallel cancellous screws in an inverted triangle configuration
. A sliding hip screw (fixed-angle device) with a supplemental derotation screw
. Three parallel cancellous screws in a standard triangle configuration
. Two parallel cancellous screws placed centrally
. A dynamic condylar screw

Correct Answer & Explanation

. A sliding hip screw (fixed-angle device) with a supplemental derotation screw

Explanation

Pauwels III fractures are vertically oriented and subjected to high vertical shear forces during weight-bearing, which leads to a high rate of varus collapse, nonunion, and failure if fixed with standard cancellous screws alone. Biomechanical studies have consistently shown that a fixed-angle construct, such as a sliding hip screw (SHS), provides superior resistance to vertical shear. A supplemental derotation screw is typically added to prevent rotation of the femoral head during insertion of the lag screw and to provide additional rotational stability.

Question 8444

Topic: 2. Trauma

A 45-year-old male presents with a closed, highly comminuted tibial pilon fracture. There is severe soft tissue swelling, pitting edema, and hemorrhagic fracture blisters over the medial ankle. A standard staged protocol using a spanning external fixator is initiated. What is the most appropriate clinical indicator that the soft tissue envelope is ready for definitive open reduction and internal fixation?

. Resolution of all fracture blisters and complete re-epithelialization
. Appearance of skin wrinkling (the 'wrinkle sign')
. Return of normal capillary refill to the toes
. Exactly 14 days from the time of external fixator application
. Decrease in intracompartmental pressures to less than 30 mmHg

Correct Answer & Explanation

. Appearance of skin wrinkling (the 'wrinkle sign')

Explanation

The timing of definitive fixation for tibial pilon fractures is dictated by the condition of the soft tissues rather than a specific time frame. The appearance of the 'wrinkle sign' indicates a significant reduction in interstitial edema and suggests that the soft tissue envelope can tolerate surgical incisions with a minimized risk of wound dehiscence and deep infection. Capillary refill evaluates perfusion but not edema, and while 10-14 days is a typical timeframe, the clinical wrinkle sign is the definitive metric.

Question 8445

Topic: 2. Trauma

A 25-year-old male sustains a low-velocity gunshot wound to the right thigh, resulting in a comminuted midshaft femur fracture. He is hemodynamically stable. There is no expanding hematoma, distal pulses are normal, and he has an intact neurologic examination. What is the most appropriate initial management of the wound and fracture?

. Immediate open debridement of the entire bullet track followed by external fixation
. Local wound care, tetanus prophylaxis, IV antibiotics, and reamed intramedullary nailing
. Emergent conventional arteriography to rule out occult vascular injury
. Open reduction and internal fixation with a dynamic compression plate
. Intravenous antibiotics and skeletal traction for 6 weeks

Correct Answer & Explanation

. Local wound care, tetanus prophylaxis, IV antibiotics, and reamed intramedullary nailing

Explanation

Low-velocity gunshot wounds resulting in long bone fractures without evidence of neurovascular compromise or massive contamination are generally treated similarly to closed fractures. Aggressive operative debridement of the bullet track is unnecessary and increases morbidity. The standard of care involves superficial local wound care, tetanus prophylaxis, short-course intravenous antibiotics, and stabilization with reamed intramedullary nailing.

Question 8446

Topic: 2. Trauma

A 28-year-old man sustains a closed tibial shaft fracture and undergoes uncomplicated reamed intramedullary nailing. In the recovery room, he complains of severe, unrelenting leg pain that is out of proportion to the injury and not relieved by intravenous opioids. Passive stretch of his toes elicits excruciating pain. The leg feels tense to palpation, but dorsalis pedis and posterior tibial pulses are full and symmetric to the contralateral side. What is the most appropriate next step?

. Perform intracompartmental pressure measurements to confirm the diagnosis
. Proceed directly to immediate four-compartment fasciotomy of the leg
. Administer additional IV opioids, elevate the leg, and re-evaluate in 1 hour
. Obtain a venous duplex ultrasound to rule out deep vein thrombosis
. Apply a compressive dressing and ice packs to reduce swelling

Correct Answer & Explanation

. Proceed directly to immediate four-compartment fasciotomy of the leg

Explanation

The patient is presenting with classic signs of acute compartment syndrome (ACS): pain out of proportion to the injury, intense pain with passive stretch of the involved muscles, and a tense compartment. Distal pulses are typically maintained in ACS until very late in the clinical course, so their presence does not rule out the condition. In a conscious, alert patient with unequivocal clinical signs of ACS, the diagnosis is clinical, and time should not be wasted measuring compartment pressures. The definitive treatment is immediate surgical release via a four-compartment fasciotomy.

Question 8447

Topic: Upper Extremity Trauma

A 22-year-old male motorcyclist is struck by a car and presents with massive swelling over his left shoulder girdle and a completely flail, pulseless left upper extremity. A chest radiograph demonstrates a laterally displaced scapula, a widened acromioclavicular joint, and an intact clavicle. What is the most critical immediate priority in the management of this specific injury?

. Emergent open reduction and internal fixation of the scapula
. MRI of the brachial plexus to assess for nerve root avulsions
. CT angiography of the upper extremity and vascular surgery consultation
. Immediate forequarter amputation to prevent crush syndrome
. Application of a shoulder spica cast and strict elevation

Correct Answer & Explanation

. CT angiography of the upper extremity and vascular surgery consultation

Explanation

The clinical and radiographic presentation describes a scapulothoracic dissociation, a severe, high-energy injury characterized by complete disruption of the scapulothoracic articulation. It is often likened to a 'closed forequarter amputation'. It is highly associated with massive, potentially life-threatening hemorrhage from subclavian or axillary artery disruption, as well as severe brachial plexus avulsions. Because of the immediate threat to life and limb from vascular injury, CT angiography and vascular surgery evaluation are the most critical immediate priorities.

Question 8448

Topic: Pelvic & Acetabular Trauma
A 45-year-old male presents in hemorrhagic shock following a high-speed motor vehicle collision. Primary survey reveals an unstable pelvis. Anteroposterior pelvic radiograph demonstrates an anteroposterior compression type III (APC III) injury. A pelvic binder is to be applied. What is the anatomically correct landmark for the placement of the pelvic binder to optimally reduce pelvic volume?
. Centered over the iliac crests
. Centered over the greater trochanters
. Centered over the anterior superior iliac spines
. Transversely at the level of the umbilicus
. Circumferentially bridging the costal margin to the iliac wings

Correct Answer & Explanation

. Centered over the greater trochanters

Explanation

The optimal placement for a pelvic binder is centered over the greater trochanters. This allows the forces to be transmitted directly through the femurs to the pubic symphysis, effectively closing the pelvic ring and reducing pelvic volume in "open book" (APC) injuries. Placement over the iliac crests is a common error; it is less effective and can paradoxically open the true pelvis further or cause skin necrosis over bony prominences.

Question 8449

Topic: 2. Trauma

A 28-year-old construction worker sustains an isolated, severe open midshaft tibia fracture. The wound is 12 cm long with significant periosteal stripping, but there is adequate soft tissue for coverage. The patient arrives at the emergency department 45 minutes after the injury. What single intervention has been shown in the literature to be the most critical for reducing the patient's risk of deep infection?

. Surgical debridement within 6 hours of injury
. Intravenous antibiotic administration within 1 hour of injury
. Primary closure of the soft tissue wound in the emergency department
. High-pressure pulsatile lavage prior to definitive debridement
. Placement of local antibiotic-impregnated beads during initial fixation

Correct Answer & Explanation

. Intravenous antibiotic administration within 1 hour of injury

Explanation

Early administration of systemic intravenous antibiotics (ideally within 1 hour of injury) is the most heavily supported, single most critical factor in reducing infection rates in open fractures. While prompt surgical debridement is standard of care, the rigid "6-hour rule" has not been definitively supported by recent literature. High-pressure pulsatile lavage has been shown to potentially drive debris deeper into tissues and damage bone, making low-pressure gravity lavage preferable.

Question 8450

Topic: 2. Trauma

A 40-year-old female presents with a severely comminuted intra-articular distal femur fracture (OTA/AO 33C3). Computed tomography reveals a coronal plane fracture of the lateral femoral condyle. During open reduction and internal fixation, what is the most appropriate biomechanical fixation strategy for this specific coronal plane fragment before applying a lateral locking plate?

. Anterior-to-posterior partially threaded lag screws
. Posterior-to-anterior partially threaded lag screws
. Medial-to-lateral fully threaded screws
. Lateral-to-medial fully threaded screws
. Capture with distal locking screws from the lateral plate without independent fixation

Correct Answer & Explanation

. Anterior-to-posterior partially threaded lag screws

Explanation

A coronal plane fracture of the femoral condyle is known as a Hoffa fracture, which most commonly affects the lateral condyle. The standard and biomechanically most practical approach to fixing a Hoffa fragment is using anterior-to-posterior (A-P) lag screws, placed perpendicular to the fracture line to achieve compression. While P-A screws are biomechanically stronger, they are technically difficult to place due to the posterior neurovascular structures and required exposure. A lateral locking plate alone cannot provide the necessary interfragmentary compression for this articular shear injury.

Question 8451

Topic: 2. Trauma
A 24-year-old man sustains a displaced, highly vertical femoral neck fracture (Pauwels type III) after falling from a height. Which of the following surgical constructs provides the greatest biomechanical stability to counteract the significant shear forces associated with this fracture pattern?
. Three parallel cancellous lag screws in an inverted triangle configuration
. A sliding hip screw (SHS) with an anti-rotation screw
. A short cephalomedullary nail
. Two parallel fully threaded screws
. Bipolar hemiarthroplasty

Correct Answer & Explanation

. A sliding hip screw (SHS) with an anti-rotation screw

Explanation

Pauwels type III fractures have a fracture angle greater than 50 degrees from the horizontal, leading to high shear forces and a propensity for varus collapse and nonunion. Biomechanical studies have demonstrated that a fixed-angle device, such as a sliding hip screw (SHS) augmented with an anti-rotation screw, provides superior biomechanical stability against shear forces compared to multiple cancellous screws in young adults with vertical femoral neck fractures.

Question 8452

Topic: 2. Trauma

A 32-year-old male is admitted with a closed midshaft tibia fracture. Ten hours later, he complains of extreme leg pain unrelieved by intravenous opioids. On examination, his leg is tight, and he has severe pain with passive extension of his toes. Dorsalis pedis pulses are 2+. Intracompartmental pressure testing reveals an anterior compartment pressure of 35 mmHg. His systemic blood pressure is 110/65 mmHg. What is the most appropriate next step in management?

. Elevate the leg above heart level to decrease swelling
. Perform a CT angiogram to rule out vascular injury
. Immediate four-compartment fasciotomy of the leg
. Observation and repeat intracompartmental pressures in 4 hours
. Application of a bivalved long leg cast

Correct Answer & Explanation

. Immediate four-compartment fasciotomy of the leg

Explanation

The patient has clinical acute compartment syndrome (ACS) supported by pressure measurements. The "delta pressure" (diastolic blood pressure minus compartment pressure) is 65 - 35 = 30 mmHg. A delta pressure of 30 mmHg or less, combined with classical clinical signs (pain out of proportion, pain on passive stretch), is a definitive indication for urgent surgical decompression via four-compartment fasciotomy. Palpable pulses do not rule out ACS, as arterial flow is maintained until late in the process. Elevation above the heart decreases arterial inflow, exacerbating ischemia, and is contraindicated.

Question 8453

Topic: 2. Trauma

A 50-year-old male is involved in a high-speed MVC. Anteroposterior pelvic radiograph demonstrates disruption of both the iliopectineal and ilioischial lines on the right side. The radiographic teardrop is displaced medially, but the obturator ring is completely intact without any fracture lines. Based on the Letournel and Judet classification, what type of acetabular fracture does this patient have?

. Both-column fracture
. Transverse fracture
. T-type fracture
. Anterior column with posterior hemitransverse fracture
. Isolated anterior column fracture

Correct Answer & Explanation

. Transverse fracture

Explanation

A transverse fracture of the acetabulum uniquely disrupts both the anterior column (iliopectineal line) and posterior column (ilioischial line) while leaving the obturator ring intact. A both-column fracture typically involves the obturator ring and demonstrates a "spur sign." A T-type fracture is essentially a transverse fracture with an inferior vertical split that breaks the obturator ring. Thus, disruption of both lines with an intact obturator ring is pathognomonic for a transverse fracture.

Question 8454

Topic: 2. Trauma

A 21-year-old male cyclist falls directly onto his left shoulder. Radiographs show a displaced, comminuted midshaft clavicle fracture. Which of the following scenarios represents an absolute indication for immediate open reduction and internal fixation of this fracture?

. 2 cm of shortening
. 100% superior displacement without bony apposition
. Presence of a Z-type comminuted "butterfly" fragment
. Concomitant ipsilateral scapular neck fracture (floating shoulder)
. Open fracture with a 1 cm wound directly over the fracture site

Correct Answer & Explanation

. Open fracture with a 1 cm wound directly over the fracture site

Explanation

Absolute indications for surgical fixation of clavicle fractures are open fractures, skin tenting leading to impending skin necrosis, and associated neurovascular injuries (e.g., subclavian artery disruption). While >2cm shortening, 100% displacement, and floating shoulders are highly regarded relative indications that often lead to surgery (especially in active patients to minimize nonunion and malunion), an open fracture necessitates urgent surgical irrigation, debridement, and internal fixation.

Question 8455

Topic: Pelvic & Acetabular Trauma

A 42-year-old male presents hypotensive (BP 75/40 mmHg) after a severe crush injury. AP pelvis radiograph demonstrates a 4-cm pubic symphysis diastasis and disruption of the bilateral sacroiliac joints. A pelvic binder is applied in the trauma bay, but his blood pressure remains 80/40 mmHg despite balanced crystalloid and blood product resuscitation. A FAST exam is negative. What is the most appropriate next step in management?

. Retrograde urethrogram
. Pelvic angiography with possible embolization
. Immediate anterior plate fixation of the symphysis pubis
. Percutaneous sacroiliac joint screw fixation
. Exploratory laparotomy

Correct Answer & Explanation

. Pelvic angiography with possible embolization

Explanation

In a hemodynamically unstable patient with a pelvic ring injury and a negative FAST exam, retroperitoneal hemorrhage is the most likely source of bleeding. When mechanical stabilization (e.g., pelvic binder) fails to restore hemodynamics, pelvic angiography is indicated to identify and embolize arterial bleeders. The most commonly injured arteries are branches of the internal iliac artery, such as the superior gluteal or internal pudendal arteries.

Question 8456

Topic: 2. Trauma
A 28-year-old healthy male sustains a completely displaced, vertically oriented (Pauwels type III) femoral neck fracture in a motor vehicle collision. Which of the following fixation constructs offers the highest biomechanical stability for this specific fracture pattern?
. Three parallel partially threaded cancellous screws
. Sliding hip screw with a derotational screw
. Proximal femoral nail
. Cannulated screws placed in an inverted triangle configuration
. Hemiarthroplasty

Correct Answer & Explanation

. Sliding hip screw with a derotational screw

Explanation

Pauwels type III femoral neck fractures in young adults are characterized by a steep, vertical fracture line (angle > 50 degrees) subjected to extremely high shear forces. Biomechanical studies demonstrate that fixed-angle devices, such as a sliding hip screw (often supplemented with an anti-rotation screw), provide superior biomechanical stability and increased resistance to shear forces compared to multiple cancellous screws.

Question 8457

Topic: 2. Trauma

A 40-year-old male sustains an isolated, displaced coronal plane fracture of the lateral femoral condyle following a direct blow to the flexed knee. What is the most appropriate surgical management for this specific fracture pattern?

. Closed reduction and long leg cast
. Retrograde intramedullary nailing
. Anterior-to-posterior directed lag screws
. Posterior-to-anterior directed lag screws with or without an anti-glide plate
. Lateral locked plating with screws directed laterally to medially

Correct Answer & Explanation

. Posterior-to-anterior directed lag screws with or without an anti-glide plate

Explanation

A coronal plane fracture of the femoral condyle is known as a Hoffa fracture. It is intrinsically unstable due to the pull of the gastrocnemius and popliteus muscles (for the lateral condyle). Fixation requires lag screws, ideally placed from posterior to anterior to sit perfectly perpendicular to the fracture plane. This is often supplemented with a posterior anti-glide plate to resist the shear forces generated during knee flexion.

Question 8458

Topic: 2. Trauma

A 30-year-old male sustains a Type II open fracture of the tibial shaft. Based on recent evidence and consensus guidelines regarding open fracture management, which of the following statements concerning antibiotic administration is true?

. Antibiotics should be continued until the wound is definitively closed or for a maximum of 7 days
. The use of systemic aminoglycosides significantly decreases the rate of nonunion
. Prophylactic systemic antibiotics should be administered within 1 hour of injury for maximum efficacy
. Topical antibiotic powder at the time of closure has been shown to completely eliminate deep infection risk
. Gram-negative coverage is mandatory for all Type I and II open fractures

Correct Answer & Explanation

. Prophylactic systemic antibiotics should be administered within 1 hour of injury for maximum efficacy

Explanation

The most critical factor in preventing infection in open fractures is the early administration of systemic antibiotics, ideally within 1 hour of injury. Current guidelines recommend 24-48 hours of systemic antibiotics; prolonged courses do not decrease infection rates and increase the risk of resistance. The standard prophylactic agent for Type I and II open fractures is a first-generation cephalosporin.

Question 8459

Topic: 2. Trauma

A 27-year-old male undergoes intramedullary nailing for a closed tibial shaft fracture. Twelve hours postoperatively, he complains of severe leg pain out of proportion to the injury, unrelieved by opioids. On examination, he has pain with passive stretch of the hallux and diminished two-point discrimination in the first web space. Intracompartmental pressure monitoring is performed. A fasciotomy is strictly indicated when the difference between the diastolic blood pressure and the compartment pressure (Delta P) is less than:

. 10 mmHg
. 20 mmHg
. 30 mmHg
. 40 mmHg
. 50 mmHg

Correct Answer & Explanation

. 30 mmHg

Explanation

Compartment syndrome is primarily a clinical diagnosis, but when continuous or intermittent pressure monitoring is utilized, a Delta P (diastolic blood pressure minus compartment pressure) of less than 30 mmHg is an absolute indication for emergency fasciotomy to prevent irreversible ischemic necrosis of muscles and nerves.

Question 8460

Topic: 2. Trauma

A 68-year-old female with a 10-year history of alendronate use presents with right thigh pain for the past 3 months. Radiographs demonstrate focal lateral cortical thickening and a transverse radiolucent line in the subtrochanteric region of the right femur. The patient is ambulating with a limp. What is the recommended orthopedic management?

. Immediate discontinuation of alendronate and strict bed rest
. Prophylactic cephalomedullary nailing of the right femur
. Core decompression of the subtrochanteric region
. Application of an external bone stimulator and protected weight-bearing
. Open biopsy to rule out a neoplastic process

Correct Answer & Explanation

. Prophylactic cephalomedullary nailing of the right femur

Explanation

Atypical femur fractures (AFFs) are a recognized complication of long-term bisphosphonate therapy. They typically present with prodromal thigh pain and distinct radiographic features (lateral cortical thickening, transverse 'beaking'). Given the presence of a radiolucent line (incomplete fracture) and mechanical pain (limp), prophylactic intramedullary nailing is highly recommended to prevent catastrophic completion of the fracture, which is associated with a high rate of nonunion.

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