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2. Trauma MCQs

Practice Set 365 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 7281

Topic: 2. Trauma

A 25-year-old man sustains a basicervical femoral neck fracture. Which of the following fixation constructs provides the most biomechanical stability for this specific fracture pattern?

. Three parallel cannulated screws
. A sliding hip screw with a derotation screw
. A cephalomedullary nail
. Two crossed cannulated screws
. A dynamic condylar screw

Correct Answer & Explanation

. Three parallel cannulated screws

Explanation

Basicervical fractures are mechanically unstable and behave more like extracapsular fractures. A sliding hip screw, often supplemented with a derotation screw, provides superior biomechanical stability.

Question 7282

Topic: 2. Trauma



Based on Figure 9 showing an intertrochanteric fracture with posteromedial comminution, what is the primary advantage of a cephalomedullary nail over a sliding hip screw?

. Shorter operative time
. Decreased blood loss
. Shorter lever arm reducing implant strain
. Lower risk of hardware infection
. Better restoration of abductor offset

Correct Answer & Explanation

. Shorter operative time

Explanation

Intramedullary devices have a shorter lever arm because their intramedullary position is closer to the mechanical axis of the femur, making them mechanically advantageous for unstable fracture patterns.

Question 7283

Topic: 2. Trauma



A 45-year-old man sustains a subtrochanteric femur fracture. Which muscle group is primarily responsible for the flexion and external rotation deformity of the proximal fragment?

. Adductors and gluteus maximus
. Iliopsoas and short external rotators
. Gluteus medius and minimus
. Tensor fascia latae
. Hamstrings

Correct Answer & Explanation

. Adductors and gluteus maximus

Explanation

The proximal fragment in a subtrochanteric fracture is characteristically flexed by the iliopsoas, abducted by the gluteus medius and minimus, and externally rotated by the short external rotators.

Question 7284

Topic: 2. Trauma

When utilizing a sliding hip screw for an intertrochanteric femur fracture, maintaining a tip-apex distance (TAD) of less than 25 mm is primarily associated with a decreased risk of:

. Nonunion
. Avascular necrosis
. Cutout of the lag screw
. Deep vein thrombosis
. Hardware infection

Correct Answer & Explanation

. Nonunion

Explanation

Baumgaertner et al. demonstrated that achieving a tip-apex distance (TAD) of less than 25 mm on AP and lateral radiographs significantly minimizes the risk of lag screw cutout in intertrochanteric fractures.

Question 7285

Topic: 2. Trauma

A 30-year-old man sustains a Pauwels type III femoral neck fracture. To maximize biomechanical stability and prevent shear failure, the optimal construct should include:

. Two parallel cannulated screws placed superiorly
. Three parallel screws placed in an inverted triangle
. Three divergent cancellous screws
. A sliding hip screw with a derotational screw
. Three parallel screws placed in a standard triangle

Correct Answer & Explanation

. Two parallel cannulated screws placed superiorly

Explanation

Pauwels type III fractures are highly vertically oriented, exposing the fracture to high shear forces. A fixed-angle device such as a sliding hip screw, often supplemented with a derotational screw, provides superior biomechanical stability against shear compared to multiple cancellous screws.

Question 7286

Topic: 2. Trauma

Which of the following vessels provides the primary blood supply to the adult femoral head and is at highest risk of injury during a displaced femoral neck fracture?

. Medial femoral circumflex artery
. Lateral femoral circumflex artery
. Artery of the ligamentum teres
. Inferior gluteal artery
. Superior gluteal artery

Correct Answer & Explanation

. Medial femoral circumflex artery

Explanation

The medial femoral circumflex artery (MFCA) provides the predominant blood supply to the adult femoral head via its lateral epiphyseal branches. Disruption of this supply in displaced femoral neck fractures leads to a high risk of avascular necrosis.

Question 7287

Topic: 2. Trauma

Which of the following radiographic fracture patterns makes an intertrochanteric femur fracture inherently unstable and prone to collapse with a sliding hip screw?

. Fracture line extending through the greater trochanter
. Loss of the posteromedial cortex
. Two-part fracture pattern
. Intact lesser trochanter
. Non-displaced fracture of the lateral wall

Correct Answer & Explanation

. Fracture line extending through the greater trochanter

Explanation

Unstable intertrochanteric fractures are characterized by a loss of the posteromedial calcar support, a reverse obliquity pattern, or a deficient lateral wall. These patterns are typically better treated with an intramedullary device.

Question 7288

Topic: 2. Trauma

A 72-year-old woman on long-term bisphosphonate therapy presents with atraumatic thigh pain. Radiographs reveal a transverse, non-comminuted subtrochanteric fracture with a medial spike and lateral cortical thickening. What is the most appropriate surgical treatment?

. Lateral locking plate and screw construct
. Cephalomedullary nailing
. Cancellous lag screws alone
. Total hip arthroplasty
. Conservative management in a spica cast

Correct Answer & Explanation

. Lateral locking plate and screw construct

Explanation

Atypical femur fractures associated with prolonged bisphosphonate use are best treated with intramedullary nailing (such as a cephalomedullary nail). This optimally addresses the diaphyseal stress riser and biomechanically supports healing.

Question 7289

Topic: 2. Trauma

A 35-year-old man sustains a completely displaced, vertically oriented (Pauwels Type III) femoral neck fracture after a motor vehicle collision. Which of the following fixation constructs provides the most biomechanically stable fixation for this specific fracture pattern?

. Three parallel cannulated cancellous screws
. A sliding hip screw with a derotational cancellous screw
. A cephalomedullary nail
. A dynamic condylar screw
. Bipolar hemiarthroplasty

Correct Answer & Explanation

. Three parallel cannulated cancellous screws

Explanation

Vertically oriented (Pauwels Type III) femoral neck fractures experience high shear forces. A sliding hip screw (often with a derotational screw) provides superior biomechanical stability against shear stress compared to parallel cannulated screws.

Question 7290

Topic: 2. Trauma



Figure 4 illustrates a radiograph of an 82-year-old woman who sustained a low-energy fall resulting in a reverse obliquity intertrochanteric femur fracture. Based on the fracture morphology, what is the most biomechanically stable surgical intervention?

. Sliding hip screw with a 135-degree side plate
. Sliding hip screw with a 150-degree side plate
. Intramedullary cephalomedullary nail
. Multiple parallel cancellous lag screws
. Bipolar hemiarthroplasty

Correct Answer & Explanation

. Sliding hip screw with a 135-degree side plate

Explanation

Reverse obliquity intertrochanteric fractures are inherently unstable and prone to medial displacement of the distal fragment when fixed with a sliding hip screw. An intramedullary nail provides an internal medial buttress, making it the most biomechanically superior construct for this specific fracture pattern.

Question 7291

Topic: 2. Trauma



A 35-year-old patient presents with a vertically oriented, displaced femoral neck fracture (Pauwels Type III) after a motor vehicle collision. To minimize the risk of varus collapse, which of the following internal fixation strategies provides the greatest biomechanical stability?

. Three parallel partially threaded cancellous screws in an inverted triangle
. A sliding hip screw with a supplemental derotation screw
. A cephalomedullary nail with a single proximal interlocking screw
. Non-vascularized fibular strut graft with two lag screws
. Two large-diameter fully threaded cortical screws

Correct Answer & Explanation

. Three parallel partially threaded cancellous screws in an inverted triangle

Explanation

Pauwels Type III (vertical) femoral neck fractures are subjected to high vertical shear forces that frequently lead to varus collapse and fixation failure. A fixed-angle device, such as a sliding hip screw, combined with a supplemental anti-rotation screw is biomechanically superior to multiple cancellous screws in resisting these extreme shear forces.

Question 7292

Topic: 2. Trauma

A 65-year-old woman sustains a 3-part proximal humerus fracture. It is treated with open reduction and internal fixation using a locking plate. During follow-up, she complains of new, progressive shoulder pain and mechanical catching. Radiographs show varus collapse of the fracture. What is the most common hardware-related complication associated with this failure pattern?

. Plate breakage
. Intra-articular screw penetration (cutout)
. Subacromial impingement by the plate
. Axillary nerve entrapment under the plate
. Coracoid impingement

Correct Answer & Explanation

. Plate breakage

Explanation

Varus collapse of a proximal humerus fracture treated with a locking plate frequently leads to relative intra-articular screw penetration (cutout). Placement of calcar screws during initial surgery is critical to support the inferomedial neck and prevent this varus collapse.

Question 7293

Topic: 2. Trauma

A 68-year-old female presents with a 4-part proximal humerus fracture. Radiographs demonstrate a valgus-impacted fracture pattern. Which of the following features makes this specific fracture pattern more amenable to joint-preserving fixation compared to a classic displaced 4-part fracture?

. The anterior circumflex humeral artery remains completely undisrupted
. The medial periosteal hinge is typically intact, preserving blood supply
. The tuberosities are widely displaced from the head
. There is a lower incidence of associated axillary nerve injury
. The fracture exclusively occurs through the anatomic neck

Correct Answer & Explanation

. The anterior circumflex humeral artery remains completely undisrupted

Explanation

Valgus-impacted 4-part proximal humerus fractures have a significantly lower rate of avascular necrosis than displaced 4-part fractures because the medial periosteal hinge remains intact, preserving the critical blood supply from the posterior circumflex humeral artery.

Question 7294

Topic: 2. Trauma

During hemiarthroplasty for a complex 4-part proximal humerus fracture, restoring precise humeral length is critical for soft-tissue balancing. The surgeon should measure the distance from the superior margin of the pectoralis major tendon insertion to the top of the prosthetic humeral head. This distance should be approximately:

. 2.6 cm
. 5.6 cm
. 8.0 cm
. 10.5 cm
. 1.0 cm

Correct Answer & Explanation

. 2.6 cm

Explanation

The superior border of the pectoralis major tendon is a reliable landmark. The average distance from this border to the superior aspect of the articular surface of the humeral head is approximately 5.6 cm. Restoring this height prevents overstuffing or profound weakness.

Question 7295

Topic: 2. Trauma

A 65-year-old woman sustains a 4-part proximal humerus fracture. Which of the following radiographic findings is the most reliable predictor of subsequent humeral head ischemia?

. Metaphyseal head extension (calcar length) less than 8 mm
. Varus angulation greater than 20 degrees
. Displacement of the greater tuberosity by 5 mm
. Intact medial periosteal hinge
. Head-shaft displacement of 5 mm

Correct Answer & Explanation

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

Explanation

According to Hertel's criteria, the most reliable predictors of humeral head ischemia are a metaphyseal head extension (calcar length) of less than 8 mm and disruption of the medial periosteal hinge. These findings indicate significant disruption of the blood supply to the humeral head.

Question 7296

Topic: 2. Trauma

A 75-year-old woman sustains a minimally displaced 3-part proximal humerus fracture. She is treated nonoperatively with a sling and early passive range of motion. What is the most commonly reported complication or outcome of this management strategy?

. Adhesive capsulitis
. Axillary nerve palsy
. Avascular necrosis of the humeral head
. Nonunion
. Varus malunion with restricted motion

Correct Answer & Explanation

. Adhesive capsulitis

Explanation

Nonoperative management of 3-part proximal humerus fractures frequently results in healing with a varus malunion. This predictably leads to restricted range of motion, particularly in forward elevation and abduction, though many elderly patients tolerate this well functionally.

Question 7297

Topic: 2. Trauma

A 35-year-old man arrives at the emergency department after a seizure. He complains of shoulder pain and an inability to externally rotate his arm. An AP radiograph demonstrates a "light bulb" sign. Which associated bony defect is most likely present?

. Anteromedial humeral head impaction fracture
. Posterolateral humeral head impaction fracture
. Avulsion of the greater tuberosity
. Anterior glenoid rim fracture
. Coracoid process fracture

Correct Answer & Explanation

. Anteromedial humeral head impaction fracture

Explanation

The clinical presentation and "light bulb" sign are classic for a posterior shoulder dislocation. This injury is highly associated with a reverse Hill-Sachs lesion, which is an impaction fracture of the anteromedial aspect of the humeral head.

Question 7298

Topic: 2. Trauma

A 68-year-old woman sustains a 4-part proximal humerus fracture after a mechanical fall. She has significant medical comorbidities and severe osteoporosis. What is the most common complication if she is treated with open reduction and internal fixation (ORIF) using a locking plate?

. Avascular necrosis of the humeral head
. Nonunion
. Intra-articular screw penetration
. Axillary nerve palsy
. Deep infection

Correct Answer & Explanation

. Avascular necrosis of the humeral head

Explanation

Intra-articular screw penetration is the most common complication following locking plate fixation of proximal humerus fractures, often due to osteoporotic settling and head collapse. Avascular necrosis is also a risk, but screw cutout is the most frequent reason for reoperation.

Question 7299

Topic: 2. Trauma

A 45-year-old construction worker fell from a ladder, sustaining an anterior shoulder dislocation. The dislocation was reduced, but post-reduction radiographs show a residual 1.5 cm superior displacement of a greater tuberosity fracture fragment. What is the most appropriate management?

. Sling immobilization for 6 weeks
. Open or arthroscopic reduction and internal fixation
. Proximal humerus hemiarthroplasty
. Closed reduction under general anesthesia
. Corticosteroid injection

Correct Answer & Explanation

. Sling immobilization for 6 weeks

Explanation

Greater tuberosity fractures displaced more than 5 mm in the general population, or >3 mm in active/overhead workers, require surgical fixation (ORIF). Leaving it displaced can lead to severe subacromial impingement and loss of rotator cuff function.

Question 7300

Topic: 2. Trauma

When evaluating a proximal humerus fracture for the risk of avascular necrosis (AVN), which of the following radiographic findings is the most reliable predictor of humeral head ischemia according to Hertel's criteria?

. Greater tuberosity displacement > 5 mm
. Metaphyseal head extension (calcar length) < 8 mm
. Shaft displacement > 1 cm
. Valgus impaction of the head
. Disruption of the lateral hinge

Correct Answer & Explanation

. Greater tuberosity displacement > 5 mm

Explanation

Hertel described several predictors of humeral head ischemia. The most reliable indicator is a metaphyseal head extension (calcar length) of less than 8 mm combined with disruption of the medial hinge, as these compromise the posteromedial vessel supply.

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