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2. Trauma MCQs

Practice Set 500 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 9981

Topic: 2. Trauma

In a completely displaced subtrochanteric femur fracture, the proximal fracture fragment undergoes predictable multiplanar deformation. Which set of deforming forces accurately describes the position of the proximal fragment?

. Flexed, abducted, and externally rotated
. Flexed, adducted, and internally rotated
. Extended, abducted, and internally rotated
. Extended, adducted, and externally rotated
. Flexed, adducted, and externally rotated

Correct Answer & Explanation

. Flexed, abducted, and externally rotated

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. Recognizing these forces is critical for achieving an accurate reduction.

Question 9982

Topic: 2. Trauma

Following locked plate fixation of a proximal humerus fracture, what is the most common biomechanical cause of subsequent varus collapse and secondary screw cut-out?

. Inadequate restoration of medial calcar support
. Routine use of excessively short locking screws
. Unrecognized concomitant axillary nerve injury
. Initial over-reduction into excessive valgus
. Early aggressive passive range of motion therapy

Correct Answer & Explanation

. Inadequate restoration of medial calcar support

Explanation

Inadequate medial support, often due to a failure to restore the medial calcar hinge or failure to place an inferomedial calcar screw, is the primary biomechanical cause of varus collapse and hardware cut-out following locked plating of proximal humerus fractures.

Question 9983

Topic: 2. Trauma
A 28-year-old female presents with a Pipkin Type II femoral head fracture following trauma. Which of the following best describes this specific fracture pattern?
. Fracture of the femoral head inferior to the fovea capitis
. Fracture of the femoral head superior to the fovea capitis
. Femoral head fracture associated with a femoral neck fracture
. Femoral head fracture associated with an acetabular fracture
. Impaction fracture of the anterosuperior femoral head

Correct Answer & Explanation

. Fracture of the femoral head superior to the fovea capitis

Explanation

In the Pipkin classification, Type I is below the fovea, while Type II extends superior to the fovea capitis, involving the critical weight-bearing portion of the femoral head. Types III and IV involve associated neck or acetabular fractures, respectively.

Question 9984

Topic: 2. Trauma

A 40-year-old male sustains a closed spiral fracture of the distal third of the humerus. On initial exam, radial nerve function is intact. Following closed reduction and splinting, he develops a complete radial nerve palsy. What is the most appropriate next step in management?

. Immediate surgical exploration and nerve repair
. Observation and supportive care for 3-4 months
. EMG and nerve conduction studies immediately
. MRI of the humerus to visualize the nerve
. Skeletal traction via an olecranon pin

Correct Answer & Explanation

. Immediate surgical exploration and nerve repair

Explanation

A secondary radial nerve palsy that develops following closed reduction of a humeral shaft fracture (especially a Holstein-Lewis variant) is a classic indication for immediate surgical exploration. The nerve may be entrapped in the fracture site during the reduction maneuver.

Question 9985

Topic: Upper Extremity Trauma

Recent anatomical studies have redefined the primary blood supply to the proximal humerus. Which of the following vessels is now considered to supply the majority of the humeral head?

. Anterolateral branch of the anterior humeral circumflex artery
. Arcuate artery
. Posterior humeral circumflex artery
. Thoracoacromial artery
. Subscapular artery

Correct Answer & Explanation

. Posterior humeral circumflex artery

Explanation

Historically, the anterior humeral circumflex artery (via the arcuate artery) was thought to provide the main blood supply. However, recent quantitative studies demonstrate that the posterior humeral circumflex artery supplies up to 64% of the humeral head.

Question 9986

Topic: 2. Trauma

A 75-year-old female sustains a highly comminuted distal humerus fracture with severe osteopenia. Which of the following factors most strongly supports the use of Total Elbow Arthroplasty (TEA) over Open Reduction and Internal Fixation (ORIF)?

. Age greater than 65 alone
. Coronal shear fracture pattern
. Inability to achieve stable internal fixation to permit early range of motion
. Presence of a preoperative ulnar nerve palsy
. Closed fracture status

Correct Answer & Explanation

. Inability to achieve stable internal fixation to permit early range of motion

Explanation

The primary indication for TEA in elderly patients with distal humerus fractures is poor bone quality and comminution precluding stable ORIF. Stable fixation is absolutely essential for early range of motion to prevent profound elbow stiffness.

Question 9987

Topic: 2. Trauma

A 22-year-old male is evaluated for an intertrochanteric hip fracture. Preoperative radiographs reveal a significantly comminuted lateral wall. What is the biomechanical consequence of this finding if treated with a standard sliding hip screw (SHS)?

. Increased risk of femoral head osteonecrosis
. Increased risk of medialization of the femoral shaft and construct failure
. Decreased risk of lag screw cut-out
. Increased rotational stability of the head-neck fragment
. No difference in outcome compared to an intact lateral wall

Correct Answer & Explanation

. Increased risk of medialization of the femoral shaft and construct failure

Explanation

Loss of lateral wall integrity converts an intertrochanteric fracture into a highly unstable pattern. Using an SHS in this setting permits excessive medialization of the shaft, leading to high rates of construct failure and malunion.

Question 9988

Topic: 2. Trauma
A 30-year-old male falls from a height and sustains a vertical shear femoral neck fracture (Pauwels Type III). What is the predominant biomechanical force acting across the fracture site?
. Compression
. Tension
. Shear
. Torsion
. Bending

Correct Answer & Explanation

. Shear

Explanation

Pauwels Type III femoral neck fractures feature a fracture line angle greater than 50 degrees from the horizontal. This steep angle subjects the fracture site to incredibly high shear forces, increasing the risk of varus collapse and nonunion.

Question 9989

Topic: 2. Trauma

A patient with a comminuted proximal humerus fracture undergoes an open reduction internal fixation (ORIF). Disruption of the medial hinge (calcar) is noted intraoperatively. What is the primary complication associated with failure to restore the medial calcar?

. Axillary nerve palsy
. Varus collapse and screw cut-out
. Nonunion of the greater tuberosity
. Adhesive capsulitis
. Bicipital tendinitis

Correct Answer & Explanation

. Varus collapse and screw cut-out

Explanation

The medial calcar provides crucial structural support to the proximal humerus. Failure to restore medial cortical contact or utilize calcar screws leads to a high risk of varus collapse, resulting in hardware penetration into the glenohumeral joint.

Question 9990

Topic: 2. Trauma

An anteroposterior radiograph of a pelvis shows a "spur sign" on the obturator oblique view. This radiographic finding is pathognomonic for which type of acetabular fracture?

. Transverse
. T-type
. Both-column
. Anterior column / posterior hemitransverse
. Posterior column

Correct Answer & Explanation

. Both-column

Explanation

The "spur sign" is pathognomonic for a both-column acetabular fracture. It represents the intact strut of the ilium that remains attached to the axial skeleton, protruding posterosuperiorly relative to the medially displaced articular fragments.

Question 9991

Topic: 2. Trauma
A 25-year-old male sustains a high-energy Pauwels type III femoral neck fracture. To biomechanically resist the high shear forces associated with this fracture pattern, which of the following internal fixation constructs is most appropriate?
. Three parallel cancellous screws in an inverted triangle
. Dynamic hip screw with an anti-rotation screw
. Short cephalomedullary nail
. Unipolar hemiarthroplasty
. Multiple Knowles pins

Correct Answer & Explanation

. Dynamic hip screw with an anti-rotation screw

Explanation

Pauwels type III fractures are characterized by a vertical fracture line that is highly unstable due to significant shear forces. A fixed-angle device such as a dynamic hip screw (with an anti-rotation screw) provides superior biomechanical stability against shear compared to multiple parallel cancellous screws.

Question 9992

Topic: 2. Trauma

An 80-year-old female presents with a reverse oblique intertrochanteric femur fracture (OTA 31-A3). Biomechanically, why is a cephalomedullary nail preferred over a sliding hip screw (SHS) for this specific fracture pattern?

. An SHS allows excessive medialization of the femoral shaft
. An SHS increases the risk of avascular necrosis
. Cephalomedullary nails provide dynamic compression along the fracture line
. Cephalomedullary nails require a smaller incision
. An SHS prevents proper abductor tensioning

Correct Answer & Explanation

. An SHS allows excessive medialization of the femoral shaft

Explanation

Reverse oblique intertrochanteric fractures lack a competent lateral wall to buttress the proximal fragment. If an SHS is used, the proximal fragment tends to slide laterally while the shaft medializes, leading to fixation failure, making a cephalomedullary nail the implant of choice.

Question 9993

Topic: 2. Trauma

According to Hertel's criteria, which of the following radiographic findings is a strong predictor of humeral head ischemia following a proximal humerus fracture?

. Greater tuberosity displacement greater than 5 mm
. Varus angulation greater than 20 degrees
. Calcar length less than 8 mm attached to the articular segment
. Medial hinge disruption less than 2 mm
. Head-split fracture pattern involving less than 10 percent of the surface

Correct Answer & Explanation

. Calcar length less than 8 mm attached to the articular segment

Explanation

Hertel described several predictors for humeral head ischemia, including a metaphyseal head extension (calcar length) of less than 8 mm, disruption of the medial hinge greater than 2 mm, and an anatomic neck fracture pattern. These factors indicate severe disruption of the vascular supply.

Question 9994

Topic: 2. Trauma

When performing a transolecranon approach for a complex distal humerus fracture, an apex-distal chevron osteotomy is often preferred over a simple transverse osteotomy primarily to:

. Preserve the triceps insertion on the tip of the olecranon
. Increase the articular surface area exposed in the trochlear notch
. Provide a larger cancellous bone bed for healing
. Enhance rotational stability upon subsequent repair
. Protect the ulnar nerve during the osteotomy cut

Correct Answer & Explanation

. Enhance rotational stability upon subsequent repair

Explanation

An apex-distal chevron osteotomy provides a larger surface area for bone healing and confers inherent rotational and translational stability compared to a transverse osteotomy. This interlocking geometry aids in accurate anatomic reduction when repairing the olecranon.

Question 9995

Topic: 2. Trauma

In a classical subtrochanteric femur fracture, the proximal fragment assumes a predictable deformed position. Which combination of muscles is primarily responsible for the flexion, abduction, and external rotation of the proximal fragment?

. Iliopsoas, adductor longus, and piriformis
. Rectus femoris, gluteus maximus, and obturator internus
. Iliopsoas, gluteus medius, and short external rotators
. Sartorius, gluteus minimus, and superior gemellus
. Hamstrings, tensor fasciae latae, and quadratus femoris

Correct Answer & Explanation

. Iliopsoas, gluteus medius, and short external rotators

Explanation

The iliopsoas flexes the proximal fragment, the gluteus medius and minimus abduct it, and the short external rotators externally rotate it. Overcoming these deforming forces is critical for achieving anatomic reduction during intramedullary nailing.

Question 9996

Topic: 2. Trauma

A 45-year-old female presents with an atrophic nonunion 8 months after sustaining a transverse middle-third humeral shaft fracture treated initially with functional bracing. She has no nerve deficits. What is the most reliable definitive surgical management?

. Exchange functional bracing and bone stimulator
. Open reduction and internal fixation with compression plating and autologous bone grafting
. Closed intramedullary nailing with reaming
. External fixation with distraction osteogenesis
. Vascularized fibular graft

Correct Answer & Explanation

. Open reduction and internal fixation with compression plating and autologous bone grafting

Explanation

The gold standard for an atrophic humeral shaft nonunion is open reduction and internal fixation using rigid compression plating coupled with autologous bone grafting. This addresses both the mechanical instability and the biological deficiency characteristic of atrophic nonunions.

Question 9997

Topic: 2. Trauma

A 72-year-old female sustains a 4-part proximal humerus fracture. According to the Hertel criteria, 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
. Medial hinge displacement of 1 mm
. Comminution of the greater tuberosity
. An intact lesser tuberosity
. Extension of the fracture into the diaphyseal shaft

Correct Answer & Explanation

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

Explanation

The Hertel criteria identify predictors of humeral head ischemia, most notably a metaphyseal head extension (calcar length) of less than 8 mm and a medial hinge disruption of greater than 2 mm. These findings suggest severe disruption of the critical medial periosteal blood supply.

Question 9998

Topic: Upper Extremity Trauma

During a deltopectoral approach for proximal humerus plating, the cephalic vein is identified. To preserve the primary venous drainage of the deltoid muscle and minimize bleeding, the vein is typically retracted in which direction, and which artery's branch travels in this same interval?

. Medially; acromial branch of the thoracoacromial artery
. Laterally; deltoid branch of the thoracoacromial artery
. Medially; deltoid branch of the thoracoacromial artery
. Laterally; acromial branch of the thoracoacromial artery
. Laterally; anterior circumflex humeral artery

Correct Answer & Explanation

. Laterally; deltoid branch of the thoracoacromial artery

Explanation

The cephalic vein receives numerous small tributaries from the deltoid muscle. Therefore, it is typically retracted laterally with the deltoid to prevent avulsing these branches, taking care to preserve the deltoid branch of the thoracoacromial artery.

Question 9999

Topic: 2. Trauma

A patient undergoes selective embolization for an actively bleeding subtrochanteric fracture. The interventional radiologist notes robust collateral flow through the cruciate anastomosis of the thigh. Which of the following arteries is NOT a direct contributor to this anastomotic network?

. Inferior gluteal artery
. First perforating branch of the profunda femoris
. Medial femoral circumflex artery
. Lateral femoral circumflex artery
. Superior gluteal artery

Correct Answer & Explanation

. Superior gluteal artery

Explanation

The cruciate anastomosis of the proximal thigh is formed by the inferior gluteal artery, the transverse branches of the medial and lateral femoral circumflex arteries, and the first perforating branch of the profunda femoris. The superior gluteal artery does not participate.

Question 10000

Topic: 2. Trauma

A 35-year-old sustains a comminuted subtrochanteric femur fracture. Biological plating is planned. The surgeon must be cautious of the perforating branches of the profunda femoris. Between which two muscular structures do these perforators typically pass to reach the posterior compartment of the thigh?

. Adductor longus and adductor brevis
. Pectineus and adductor longus
. Adductor magnus and vastus lateralis
. Adductor brevis and adductor magnus
. Vastus medialis and adductor longus

Correct Answer & Explanation

. Adductor magnus and vastus lateralis

Explanation

The perforating branches of the profunda femoris artery travel posterolaterally by piercing the tendinous insertions of the adductor magnus and the vastus lateralis near the linea aspera.

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