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2. Trauma MCQs

Practice Set 373 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 7441

Topic: 2. Trauma

A 32-year-old male sustains a displaced, vertically oriented (Pauwels type III) femoral neck fracture in a motor vehicle collision. Which of the following fixation constructs provides the most biomechanically stable fixation for this specific fracture pattern?

. Three parallel cancellous lag screws
. Sliding hip screw with an anti-rotation screw
. Two parallel fully threaded cortical screws
. Cephalomedullary nail with a single lag screw
. Dynamic condylar screw

Correct Answer & Explanation

. Three parallel cancellous lag screws

Explanation

Pauwels type III femoral neck fractures are highly unstable due to high vertical shear forces across the fracture site. A sliding hip screw (a fixed-angle device) combined with an anti-rotation screw provides superior biomechanical stability against these shear stresses compared to multiple cancellous lag screws.

Question 7442

Topic: 2. Trauma

In a highly comminuted subtrochanteric femur fracture, the proximal fragment typically assumes a predictable deformed position due to un-opposed muscular forces. What is the classic position of this proximal fragment?

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

Correct Answer & Explanation

. Extended, adducted, and internally rotated

Explanation

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

Question 7443

Topic: 2. Trauma

When evaluating an intertrochanteric femur fracture for stability and implant choice, which of the following characteristics most strongly indicates the need for an intramedullary nail over a sliding hip screw?

. A two-part fracture pattern
. Intact posteromedial cortex
. Tip-apex distance greater than 25 mm
. Lateral wall thickness less than 20.5 mm
. Increased femoral neck-shaft angle

Correct Answer & Explanation

. A two-part fracture pattern

Explanation

A lateral wall thickness of less than 20.5 mm in an intertrochanteric fracture is a major predictor of postoperative lateral wall fracture and subsequent failure if treated with a sliding hip screw. Intramedullary nailing is indicated for these unstable patterns.

Question 7444

Topic: 2. Trauma

On a Judet obturator oblique radiograph of the pelvis, the 'spur sign' is a pathognomonic finding for which specific type of acetabular fracture?

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

Correct Answer & Explanation

. Transverse fracture

Explanation

The spur sign, seen on the obturator oblique radiograph, represents the intact portion of the ilium protruding superior to the displaced acetabular columns. It is the hallmark radiographic feature of a both-column acetabular fracture.

Question 7445

Topic: 2. Trauma

A Pauwels type III femoral neck fracture is characterized by a high angle relative to the horizontal plane. Why do these fractures have a significantly higher rate of nonunion compared to Pauwels type I fractures?

. They occur exclusively in elderly, osteoporotic patients
. They have minimal cortical contact due to associated greater trochanteric involvement
. They interrupt the ligamentum teres arterial supply
. They predominantly experience compressive forces across the fracture line
. They are subjected to high vertical shear forces that destabilize fixation

Correct Answer & Explanation

. They occur exclusively in elderly, osteoporotic patients

Explanation

Pauwels type III fractures are highly vertical (angle > 50 degrees). This orientation converts joint reactive forces into substantial shear forces across the fracture site, drastically increasing the risk of fixation failure and nonunion.

Question 7446

Topic: 2. Trauma

A patient presents with a traumatic hip dislocation and is diagnosed with a Pipkin type IV fracture.

By definition, this injury includes a fracture of the femoral head combined with which of the following?

. Femoral neck fracture
. Intertrochanteric femur fracture
. Acetabular rim fracture
. Ipsilateral knee ligament injury
. Pelvic ring disruption

Correct Answer & Explanation

. Femoral neck fracture

Explanation

The Pipkin classification describes femoral head fractures associated with hip dislocations. A Pipkin type IV fracture is defined as a femoral head fracture combined with an associated fracture of the acetabular rim.

Question 7447

Topic: 2. Trauma

A 45-year-old male with a history of alcohol abuse presents with severe groin pain. AP pelvis and frog-leg lateral radiographs reveal a 'crescent sign' in the anterosuperior aspect of the femoral head. According to the Ficat classification, what does this sign represent?

. Ficat Stage I - Pre-radiographic disease
. Ficat Stage II - Cystic and sclerotic changes without collapse
. Ficat Stage III - Advanced osteoarthritis with joint space narrowing
. Ficat Stage III - Subchondral fracture and early segmental collapse
. Ficat Stage IV - Joint space narrowing with acetabular involvement

Correct Answer & Explanation

. Ficat Stage I - Pre-radiographic disease

Explanation

The 'crescent sign' represents a subchondral fracture signaling impending or early structural collapse of the femoral head. In the Ficat system, this subchondral collapse characterizes Stage III avascular necrosis.

Question 7448

Topic: 2. Trauma

A 35-year-old man sustains a vertically oriented femoral neck fracture (Pauwels type III). Biomechanical studies suggest that which of the following fixation constructs provides the highest resistance to shear forces for this fracture pattern?

. Three parallel cancellous screws
. Sliding hip screw with a derotational screw
. Two parallel cancellous screws
. Proximal femoral nail
. Dynamic condylar screw

Correct Answer & Explanation

. Three parallel cancellous screws

Explanation

Pauwels type III fractures are highly unstable and subjected to significant shear forces. A sliding hip screw (fixed-angle device) combined with a derotational screw provides superior biomechanical stability compared to multiple parallel cancellous screws.

Question 7449

Topic: 2. Trauma

In a subtrochanteric femur fracture, the proximal fragment is typically deformed into flexion, abduction, and external rotation. Which muscle group is primarily responsible for the external rotation deformity?

. Iliopsoas
. Gluteus medius
. Adductor longus
. Short external rotators
. Gluteus maximus

Correct Answer & Explanation

. Iliopsoas

Explanation

The short external rotators (piriformis, gemelli, obturator internus) pull the proximal fragment into external rotation. The iliopsoas flexes the fragment, while the gluteus medius and minimus abduct it.

Question 7450

Topic: 2. Trauma

A 30-year-old man is involved in a motor vehicle collision and sustains a pelvic injury.

Imaging reveals an acetabular fracture. The 'spur sign' on an obturator oblique plain radiograph is pathognomonic for which fracture pattern?

. Transverse fracture
. T-type fracture
. Anterior column fracture
. Posterior column fracture
. Both-column fracture

Correct Answer & Explanation

. Transverse fracture

Explanation

The 'spur sign' represents the intact portion of the ilium that remains attached to the axial skeleton while the articular acetabulum is completely dissociated. It is pathognomonic for a both-column acetabular fracture.

Question 7451

Topic: 2. Trauma

A 35-year-old man undergoes an open reduction and internal fixation for a displaced femoral neck fracture. To preserve the remaining blood supply to the femoral head, the surgeon must be mindful of the primary arterial supply. Which of the following vessels provides the primary blood supply to the adult femoral head?

. Deep branch of the medial femoral circumflex artery
. Descending branch of the lateral femoral circumflex artery
. Ascending branch of the lateral femoral circumflex artery
. Obturator artery via the ligamentum teres
. Inferior gluteal artery

Correct Answer & Explanation

. Deep branch of the medial femoral circumflex artery

Explanation

The deep branch of the medial femoral circumflex artery (MFCA) provides the primary blood supply to the weight-bearing dome of the femoral head in adults. The artery of the ligamentum teres (from the obturator artery) provides a negligible supply in adults.

Question 7452

Topic: Pelvic & Acetabular Trauma

When stabilizing an acute anteroposterior compression (APC) type pelvic ring injury in a hemodynamically unstable patient, a pelvic binder should be centered over which of the following anatomic landmarks?

. Anterior superior iliac spines
. Greater trochanters
. Iliac crests
. Umbilicus
. Symphysis pubis

Correct Answer & Explanation

. Anterior superior iliac spines

Explanation

To effectively reduce pelvic volume and stabilize the fracture, a pelvic binder must be applied and centered directly over the greater trochanters. Placement over the iliac crests may inadvertently widen the pelvic floor and worsen the deformity.

Question 7453

Topic: 2. Trauma

A 78-year-old man sustains a reverse obliquity intertrochanteric femur fracture. Why is a cephalomedullary nail mechanically preferred over a sliding hip screw (SHS) for this fracture pattern?

. It prevents lateral wall blowout and medial shaft displacement
. It provides superior compression along the fracture line
. It requires a smaller incision and less blood loss
. It allows for dynamic dynamization of the femoral neck
. It decreases the risk of postoperative deep vein thrombosis

Correct Answer & Explanation

. It prevents lateral wall blowout and medial shaft displacement

Explanation

Reverse obliquity fractures lack an intact lateral wall to buttress the proximal fragment. A sliding hip screw would allow the femoral shaft to displace medially, leading to failure, whereas a cephalomedullary nail effectively stabilizes the lateral wall.

Question 7454

Topic: 2. Trauma

Which of the following radiographic findings is pathognomonic for a both-column acetabular fracture?

. Disruption of the iliopectineal line only
. Disruption of the ilioischial line only
. Presence of the spur sign on the obturator oblique view
. Presence of the spur sign on the iliac oblique view
. Fracture extending through the obturator ring without involving the superior dome

Correct Answer & Explanation

. Disruption of the iliopectineal line only

Explanation

The spur sign represents the intact portion of the ilium that remains attached to the axial skeleton while the articular fragments are medially displaced. It is pathognomonic for a both-column acetabular fracture and is best visualized on the obturator oblique view.

Question 7455

Topic: 2. Trauma

A 75-year-old woman presents with a reverse obliquity intertrochanteric femur fracture. Which of the following implants offers the most biomechanically stable fixation for this specific fracture pattern?

. Multiple cancellous lag screws
. Dynamic hip screw (sliding hip screw) with a 2-hole side plate
. Dynamic hip screw with a 4-hole side plate
. Cephalomedullary nail
. Proximal femoral locking plate

Correct Answer & Explanation

. Multiple cancellous lag screws

Explanation

Reverse obliquity intertrochanteric fractures are inherently unstable because the fracture geometry allows medial and distal displacement of the femoral shaft. A cephalomedullary nail acts as an intramedullary buttress, providing superior biomechanical stability and preventing excessive medial translation.

Question 7456

Topic: 2. Trauma

A 32-year-old man sustains a displaced, vertical (Pauwels type III) femoral neck fracture. Which of the following fixation constructs offers the highest biomechanical stability against shear forces for this specific fracture pattern?

. Three parallel cancellous screws
. Sliding hip screw with a derotation screw
. Cephalomedullary nail
. Multiple partially threaded screws in a diamond pattern
. Proximal femoral locking plate

Correct Answer & Explanation

. Three parallel cancellous screws

Explanation

A sliding hip screw (SHS) with a derotation screw provides superior biomechanical stability against vertical shear forces seen in Pauwels type III fractures compared to parallel cancellous screws. This fixed-angle construct allows controlled impaction and significantly minimizes the risk of varus collapse.

Question 7457

Topic: 2. Trauma

A 28-year-old man presents following a high-speed motor vehicle collision with a posterior hip dislocation and an associated fracture of the femoral head.

A computed tomography (CT) scan reveals that the femoral head fracture fragment is located caudad (inferior) to the fovea centralis. According to the Pipkin classification, this injury is classified as:

. Pipkin type I
. Pipkin type II
. Pipkin type III
. Pipkin type IV
. Pipkin type V

Correct Answer & Explanation

. Pipkin type I

Explanation

A Pipkin type I fracture involves a femoral head fracture caudad to the fovea centralis, thus sparing the primary weight-bearing surface. Pipkin type II is cephalad to the fovea, type III involves a concurrent femoral neck fracture, and type IV includes an associated acetabular fracture.

Question 7458

Topic: 2. Trauma

A 72-year-old patient sustains a reverse obliquity intertrochanteric fracture of the proximal femur (AO/OTA 31-A3). Which of the following fixation constructs is considered biomechanically superior for this specific fracture pattern?

. Sliding hip screw (dynamic hip screw)
. Long cephalomedullary nail
. Multiple parallel cannulated screws
. Dynamic condylar screw
. Cemented unipolar hemiarthroplasty

Correct Answer & Explanation

. Sliding hip screw (dynamic hip screw)

Explanation

Reverse obliquity fractures are highly unstable and prone to medial displacement of the femoral shaft. A cephalomedullary nail provides superior biomechanical stability by medially translating the weight-bearing axis and preventing excessive lateral translation, unlike a sliding hip screw which has a high failure rate in this pattern.

Question 7459

Topic: 2. Trauma

A 28-year-old man sustains a completely displaced, vertically oriented femoral neck fracture (Pauwels type III). Assuming anatomical closed or open reduction is achieved, which internal fixation construct provides the greatest biomechanical stability to counteract the high shear forces in this injury?

. Three parallel cancellous screws placed in an inverted triangle
. A sliding hip screw with a supplemental derotation screw
. Two divergent fully threaded cortical screws
. A cephalomedullary nail with a single head screw
. A hook plate with cerclage wiring

Correct Answer & Explanation

. Three parallel cancellous screws placed in an inverted triangle

Explanation

Pauwels type III fractures are inherently unstable due to their vertical orientation, which subjects the fracture site to high shear forces. Biomechanical studies have demonstrated that a fixed-angle device, such as a sliding hip screw combined with an anti-rotation screw, provides superior resistance to shear compared to multiple cancellous screws.

Question 7460

Topic: 2. Trauma

A 32-year-old man sustains a completely displaced, vertically oriented femoral neck fracture (Pauwels Type III). What is the most biomechanically sound fixation method to prevent shear-induced displacement?

. Three parallel cancellous screws placed in an inverted triangle
. A sliding hip screw construct with an anti-rotation screw
. Unipolar hemiarthroplasty
. Total hip arthroplasty
. Two divergent cannulated screws

Correct Answer & Explanation

. Three parallel cancellous screws placed in an inverted triangle

Explanation

Vertical shear fractures (Pauwels III) experience high destabilizing forces. A sliding hip screw coupled with a derotation screw provides superior biomechanical stability against shear forces compared to multiple cancellous screws.

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