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2. Trauma MCQs

Practice Set 239 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 4761

Topic: 2. Trauma

A 40-year-old pedestrian is struck by a vehicle and sustains a Schatzker Type IV tibial plateau fracture. Which of the following best describes the typical pathomechanics of this specific fracture pattern and its most feared associated complication?

. Low-energy valgus force in an osteoporotic patient; high risk of peroneal nerve injury
. High-energy valgus force with lateral plateau depression; high risk of anterior tibial artery injury
. High-energy varus force with medial plateau involvement; high risk of popliteal artery injury
. Low-energy varus force; high risk of common peroneal nerve injury
. Direct axial loading; high risk of deep vein thrombosis

Correct Answer & Explanation

. High-energy varus force with medial plateau involvement; high risk of popliteal artery injury

Explanation

A Schatzker Type IV fracture involves the medial tibial plateau. It typically results from a high-energy varus force combined with axial loading. Because the medial plateau is anatomically robust, fracturing it requires significant energy, which frequently disrupts the knee's ligamentous stability (often a fracture-dislocation) and carries a uniquely high risk of injury to the popliteal artery and common peroneal nerve due to stretching.

Question 4762

Topic: 2. Trauma

A 29-year-old male sustains a subtrochanteric femur fracture. On an anteroposterior radiograph, the proximal fragment exhibits a characteristic deformity consisting of flexion, abduction, and external rotation. Which muscle group is primarily responsible for the external rotation component of this deformity?

. Iliopsoas
. Gluteus medius and minimus
. Gluteus maximus
. Short external rotators (e.g., piriformis, obturator internus)
. Adductor magnus

Correct Answer & Explanation

. Iliopsoas

Explanation

In a subtrochanteric fracture, the proximal fragment is aggressively deformed by the muscles attaching to the greater and lesser trochanters. Flexion is driven by the iliopsoas (lesser trochanter), abduction is driven by the gluteus medius and minimus (greater trochanter), and external rotation is driven by the short external rotators (piriformis, gemelli, obturator internus/externus, quadratus femoris).

Question 4763

Topic: Upper Extremity Trauma
A 25-year-old male falls directly onto his right shoulder during a cycling accident. Radiographs reveal an acromioclavicular (AC) joint injury. According to the Rockwood classification, which of the following specific radiographic and anatomic findings distinguishes a Type V injury from a Type III injury?
. Complete disruption of the AC ligaments with intact coracoclavicular (CC) ligaments
. Superior displacement of the clavicle by 25% to 100% of the normal joint space
. Posterior displacement of the distal clavicle into the trapezius muscle
. Superior translation of the distal clavicle by 100% to 300% with extensive stripping of the deltotrapezial fascia
. Inferior displacement of the clavicle under the coracoid process

Correct Answer & Explanation

. Superior translation of the distal clavicle by 100% to 300% with extensive stripping of the deltotrapezial fascia

Explanation

In the Rockwood classification of AC joint separations, a Type III injury involves disruption of both the AC and CC ligaments, resulting in up to 100% superior displacement of the clavicle relative to the acromion. A Type V injury is a much more severe form of Type III, characterized by 100% to 300% superior displacement, along with severe disruption/stripping of the deltotrapezial fascia, resulting in a dramatic clinical deformity.

Question 4764

Topic: 2. Trauma

A 38-year-old male sustains a Hawkins Type II talar neck fracture and undergoes open reduction internal fixation (ORIF). At his 8-week postoperative visit, an AP radiograph of the ankle reveals a subchondral radiolucent band in the dome of the talus (Hawkins sign). What does this specific radiographic finding indicate?

. Nonunion of the talar neck fracture
. Imminent collapse of the talar dome due to osteonecrosis
. Revascularization and intact blood supply to the talar body
. Septic arthritis of the tibiotalar joint
. Post-traumatic osteoarthritis of the subtalar joint

Correct Answer & Explanation

. Revascularization and intact blood supply to the talar body

Explanation

The Hawkins sign is a subchondral radiolucent band visible in the talar dome on an AP or mortise radiograph, typically seen 6 to 8 weeks after a talus fracture. It represents subchondral osteopenia secondary to bone resorption. Because this resorptive process requires an active blood supply, a positive Hawkins sign is a highly reassuring indicator that the talar body has sufficient vascularity and that clinically significant avascular necrosis (AVN) is unlikely.

Question 4765

Topic: 2. Trauma

According to the criteria for borderline polytrauma patients, which of the following physiologic parameters most strongly favors the use of Damage Control Orthopedics (DCO) over Early Total Care (ETC) for the fixation of a bilateral femoral shaft fracture?

. Base deficit of 4.0 mmol/L
. Serum lactate of 1.5 mmol/L
. Platelet count of 120,000/uL
. Core temperature of 33.5°C
. Injury Severity Score (ISS) of 18

Correct Answer & Explanation

. Core temperature of 33.5°C

Explanation

Damage Control Orthopedics (DCO), which involves temporary external fixation prior to definitive internal fixation, is indicated in 'in extremis' or unstable polytrauma patients. Parameters favoring DCO include hypothermia (core temperature < 35°C), significant acidosis (pH < 7.24, base deficit > 6 mmol/L, lactate > 2.5 mmol/L), and coagulopathy (platelet count < 90,000/uL). A core temperature of 33.5°C reflects severe hypothermia, making the patient a poor candidate for the physiologic hit of prolonged early total care (ETC).

Question 4766

Topic: 2. Trauma
When treating a highly vertical (Pauwels type III) femoral neck fracture in a young adult, what is the primary biomechanical rationale for adding a fully threaded transverse 'position' screw to a standard construct of three parallel partially threaded cannulated screws?
. To prevent varus collapse and inferior translation by resisting shear forces
. To provide dynamic interfragmentary compression across the fracture site
. To decrease the risk of avascular necrosis by preserving the retinacular vessels
. To increase femoral neck offset and abductor lever arm
. To act as a lag screw for the superior cortical fragments

Correct Answer & Explanation

. To prevent varus collapse and inferior translation by resisting shear forces

Explanation

Vertically oriented (Pauwels type III) femoral neck fractures in young adults experience exceptionally high shear forces, predisposing them to varus collapse, nonunion, and failure. The addition of a fully threaded transverse 'position' screw (often placed inferiorly or centrally) crosses the fracture perpendicularly to the vertical shear plane. Unlike partially threaded lag screws, which can allow the fracture to slide excessively and shorten in vertical patterns, the fully threaded screw acts as a rigid dowel to resist inferior translation and varus collapse.

Question 4767

Topic: 2. Trauma

A 35-year-old female sustains a high-energy Schatzker type IV tibial plateau fracture extending into the medial metaphyseal-diaphyseal junction. Which of the following anatomical structures is at highest risk of severe injury due to this specific fracture pattern?

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

Correct Answer & Explanation

. Popliteal artery

Explanation

Schatzker IV (medial plateau) fractures, especially those caused by high-energy trauma (e.g., varus force with axial load), are frequently associated with occult knee subluxation or dislocation. Because of the tethering of the popliteal artery at the adductor hiatus proximally and the soleal arch distally, it is at very high risk of stretch, intimal tear, or transection in medial plateau fractures. Thorough vascular evaluation (ABI, CTA if indicated) is mandatory.

Question 4768

Topic: 2. Trauma

During open reduction and internal fixation (ORIF) of a displaced 3-part proximal humerus fracture using a locking plate, failure to achieve which of the following technical goals most strongly predicts secondary varus collapse?

. Repair of the lesser tuberosity with heavy non-absorbable suture
. Restoration of medial calcar support
. Placement of a minimum of six locking screws into the humeral head
. Tension band wiring of the greater tuberosity to the diaphysis
. Anatomic reduction of the bicipital groove

Correct Answer & Explanation

. Restoration of medial calcar support

Explanation

Restoration of the medial hinge (calcar) is critical to the biomechanical stability of a proximal humerus fracture fixed with a locking plate. Failure to restore medial support—whether via direct cortical contact, placement of calcar screws in the inferomedial quadrant of the humeral head, or the use of an endosteal fibular strut allograft—is the strongest independent predictor of secondary varus collapse and subsequent screw cut-out into the joint.

Question 4769

Topic: 2. Trauma

A 19-year-old male is brought to the trauma bay following a high-speed motor vehicle collision with a diagnosed posterior sternoclavicular (SC) joint dislocation. He exhibits dyspnea, venous engorgement of the left arm, and dysphagia. Which specific anatomical structure is at greatest risk of direct compression by the displaced medial clavicle?

. Medial cord of the brachial plexus
. Axillary artery
. Subclavian/Brachiocephalic vein
. Left recurrent laryngeal nerve
. Phrenic nerve

Correct Answer & Explanation

. Subclavian/Brachiocephalic vein

Explanation

Posterior sternoclavicular joint dislocations are orthopedic emergencies due to the proximity of the medial clavicle to critical mediastinal and superior thoracic outlet structures. The great vessels, particularly the brachiocephalic (innominate) and subclavian veins, lie immediately posterior to the SC joint. The subclavian vein is at highest risk for direct compression or laceration, which can present with venous engorgement of the ipsilateral upper extremity. The trachea and esophagus are also at risk, causing dyspnea and dysphagia.

Question 4770

Topic: 2. Trauma
A 32-year-old male with a closed midshaft tibia fracture is suspected of developing acute compartment syndrome. His blood pressure is 110/70 mmHg. Intracompartmental pressure (ICP) monitoring is performed. According to the Delta P (ΔP) concept, at what threshold is emergent fasciotomy definitively indicated?
. Absolute ICP > 20 mmHg
. Absolute ICP > 25 mmHg
. Diastolic BP minus ICP < 30 mmHg
. Mean Arterial Pressure minus ICP < 40 mmHg
. Systolic BP minus ICP < 30 mmHg

Correct Answer & Explanation

. Diastolic BP minus ICP < 30 mmHg

Explanation

The Delta P (ΔP) is defined as the difference between the diastolic blood pressure and the measured intracompartmental pressure (ΔP = Diastolic BP - ICP). A ΔP of less than 30 mmHg is the gold standard objective threshold indicating inadequate tissue perfusion, necessitating emergent fasciotomy. Absolute ICP values are less reliable due to variations in patient hemodynamics.

Question 4771

Topic: 2. Trauma
You are evaluating a 45-year-old polytrauma patient with a displaced extra-articular fracture of the scapular body and neck. Which of the following radiographic parameters is widely accepted as a standard indication for operative fixation of this scapula fracture?
. Scapular body medial displacement of 5 mm
. Glenopolar angle (GPA) of 35 degrees
. Medial/lateral translation of the glenoid fragment greater than 20 mm
. Angulation of the scapular neck of 15 degrees
. Isolated fracture of the coracoid process distal to the coracoclavicular ligaments

Correct Answer & Explanation

. Medial/lateral translation of the glenoid fragment greater than 20 mm

Explanation

Operative indications for extra-articular scapular neck and body fractures include significant displacement that alters glenohumeral mechanics. Standard indications include medial/lateral displacement (translation) >20 mm, angular deformity >45 degrees, a glenopolar angle (GPA) of < 22 degrees (normal is 30-45 degrees), or a double disruption of the superior shoulder suspensory complex (SSSC).

Question 4772

Topic: 2. Trauma

A 65-year-old female on long-term alendronate therapy sustains a low-energy subtrochanteric femur fracture. Radiographs show a transverse fracture with a medial cortical spike and lateral cortical thickening. During intramedullary nailing of this atypical femur fracture, what technical challenge must be anticipated compared to typical femur fractures?

. Higher likelihood of excessive anterolateral femoral bow leading to anterior cortical perforation during nail insertion
. Difficulty achieving a rigid interlock due to a thin, severely osteoporotic lateral cortex
. Over-reaming is strictly contraindicated due to an increased risk of thermal necrosis in atypical fractures
. The medullary canal is exceptionally wide, routinely requiring a custom large-diameter nail
. Routine requirement of autologous bone grafting at the time of initial fixation to ensure union

Correct Answer & Explanation

. Higher likelihood of excessive anterolateral femoral bow leading to anterior cortical perforation during nail insertion

Explanation

Atypical femur fractures (AFFs) associated with prolonged bisphosphonate use frequently occur in femurs with an increased anterolateral bow. Using standard, relatively straight intramedullary nails can result in an apex-anterior mismatch, leading to anterior cortical perforation or straightening of the fracture with lateral gap formation. Technical considerations include using a smaller radius of curvature (more bowed) nail, altering the starting point, or over-reaming to accommodate the anatomical mismatch.

Question 4773

Topic: 2. Trauma
A 28-year-old male sustains a vertically oriented femoral neck fracture (Pauwels Type III) after a fall from a height. Which of the following fixation constructs provides the greatest biomechanical stability against vertical shear forces for this fracture pattern?
. Three parallel cannulated screws
. Sliding hip screw with a derotational cancellous screw
. Dynamic condylar screw
. Proximal femoral nail
. Two parallel cannulated screws

Correct Answer & Explanation

. Sliding hip screw with a derotational cancellous screw

Explanation

A sliding hip screw (SHS) with a derotational screw provides superior biomechanical stability compared to multiple cannulated screws for high-shear, vertically oriented (Pauwels Type III) femoral neck fractures. This construct better resists the vertical shearing forces that commonly lead to failure and varus collapse in young patients.

Question 4774

Topic: 2. Trauma
A 45-year-old polytrauma patient arrives with a hemodynamically unstable anteroposterior compression (APC) Type III pelvic ring injury. In the trauma bay, a circumferential pelvic binder is applied. What is the optimal anatomic landmark for centering the pelvic binder to effectively reduce the pelvic volume?
. Over the anterior superior iliac spines (ASIS)
. Over the iliac crests
. Over the greater trochanters
. Over the pubic symphysis only
. Between the umbilicus and the pubic symphysis

Correct Answer & Explanation

. Over the greater trochanters

Explanation

Circumferential pelvic binders should be centered over the greater trochanters to effectively close the pelvic ring and reduce pelvic volume. Placing the binder higher over the iliac crests is less effective and can paradoxically open the pelvis further or cause detrimental abdominal compression.

Question 4775

Topic: 2. Trauma
A 28-year-old male sustains a vertical, Pauwels type III femoral neck fracture. To biomechanically optimize fixation and reduce the risk of shear-induced varus collapse, which construct is most appropriate?
. Three parallel cancellous screws
. Sliding hip screw with an anti-rotation screw
. Cephalomedullary nail
. Fully threaded cortical screws
. Dynamic condylar screw

Correct Answer & Explanation

. Sliding hip screw with an anti-rotation screw

Explanation

Pauwels type III fractures have high vertical shear forces. A fixed-angle device like a sliding hip screw, supplemented with a derotation screw, provides superior biomechanical resistance to varus collapse compared to parallel cancellous screws.

Question 4776

Topic: 2. Trauma

During open reduction and internal fixation of a posterior wall acetabular fracture via a Kocher-Langenbeck approach, the surgeon utilizes the "safe zone" for hardware placement to avoid intra-articular screw penetration. What defines the borders of this safe zone?

. A line from the ASIS to the ischial tuberosity
. The greater sciatic notch to the obturator foramen
. The gluteus medius pillar to the ischial spine
. The quadrant superior to the fovea
. A line connecting the PSIS to the greater trochanter

Correct Answer & Explanation

. The gluteus medius pillar to the ischial spine

Explanation

The safe zone for screw placement in the posterior acetabulum extends from the gluteus medius pillar cranially to the ischial spine caudally. Placing screws parallel to the quadrilateral plate within this zone avoids articular penetration.

Question 4777

Topic: 2. Trauma

A 78-year-old female sustains an unstable intertrochanteric fracture with a large posteromedial fragment and loss of the lateral wall. Which of the following fixation devices is most appropriate to prevent excessive sliding and medialization of the femoral shaft?

. Sliding hip screw with a 2-hole sideplate
. Multiple cancellous lag screws
. Cephalomedullary nail
. Proximal femoral locking plate
. Dynamic condylar screw

Correct Answer & Explanation

. Cephalomedullary nail

Explanation

In unstable intertrochanteric fractures with lateral wall incompetence, a sliding hip screw allows excessive sliding and medial displacement of the shaft. A cephalomedullary nail acts as an intact lateral buttress, preventing this mechanical failure.

Question 4778

Topic: 2. Trauma

A 30-year-old polytrauma patient presents with a severe closed midshaft femur fracture, bilateral rib fractures, and a pulmonary contusion. Serum lactate is 4.5 mmol/L and base deficit is -8. What is the most appropriate initial management of the femur fracture?

. Reamed antegrade intramedullary nailing
. Unreamed antegrade intramedullary nailing
. Open reduction and internal fixation with a compression plate
. External fixation
. Retrograde intramedullary nailing

Correct Answer & Explanation

. External fixation

Explanation

This patient is in physiological extremis (high lactate, high base deficit) with significant chest trauma. Damage control orthopedics utilizing rapid external fixation is indicated to minimize the inflammatory "second hit" from intramedullary nailing.

Question 4779

Topic: 2. Trauma

A 45-year-old male sustains a Schatzker type VI tibial plateau fracture. He is scheduled for dual-plate fixation. Which principle is most critical to minimize the risk of wound complications and deep infection?

. Immediate internal fixation regardless of soft tissue swelling
. Utilizing a single midline longitudinal incision
. Delaying fixation until resolution of soft tissue edema and fracture blisters
. Minimizing the use of locking screws
. Using exclusively medial-based external fixation

Correct Answer & Explanation

. Delaying fixation until resolution of soft tissue edema and fracture blisters

Explanation

High-energy tibial plateau fractures (Schatzker VI) cause severe soft-tissue compromise. Delaying definitive open reduction until the "wrinkle sign" appears significantly reduces the incidence of wound dehiscence and deep infection.

Question 4780

Topic: 2. Trauma

A 25-year-old cyclist falls directly onto his shoulder and sustains a completely displaced midshaft clavicle fracture with 2.5 cm of shortening. Compared to operative fixation, nonoperative management of this specific fracture pattern is associated with which outcome?

. Higher rates of symptomatic nonunion
. Lower rates of brachial plexus irritation
. Improved ultimate shoulder strength
. Faster time to radiographic union
. Decreased incidence of cosmetic deformity

Correct Answer & Explanation

. Higher rates of symptomatic nonunion

Explanation

Completely displaced midshaft clavicle fractures with significant shortening (>2 cm) have significantly higher rates of symptomatic nonunion and delayed union when managed nonoperatively compared to primary open reduction and internal fixation.

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