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2. Trauma MCQs

Practice Set 372 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 7421

Topic: 2. Trauma

A 30-month-old girl presents with a painless limp. Examination reveals a positive Galeazzi sign and limited abduction of the left hip. Radiographs demonstrate a high dislocation of the left hip with a false acetabulum. She has had no prior treatment. What is the most appropriate definitive management?

. Pavlik harness application
. Closed reduction and spica casting
. Open reduction with a femoral shortening osteotomy
. Gallows traction for 3 weeks followed by spica casting
. Observation until skeletal maturity

Correct Answer & Explanation

. Pavlik harness application

Explanation

In a child older than 2 years with a high untreated hip dislocation, soft tissue contractures make closed reduction unsafe and unlikely to succeed. Open reduction with a femoral shortening osteotomy is typically required to reduce joint pressure and minimize the risk of avascular necrosis.

Question 7422

Topic: 2. Trauma

A 35-year-old male sustains a vertically oriented (Pauwels type III) displaced femoral neck fracture. What is the most biomechanically stable construct for internal fixation?

. Three parallel cannulated screws
. Sliding hip screw with a derotational screw
. Cephalomedullary nail
. Multiple partially threaded pins
. Dynamic condylar screw

Correct Answer & Explanation

. Three parallel cannulated screws

Explanation

Pauwels type III fractures have high shear forces. A sliding hip screw with a derotational screw provides superior biomechanical stability compared to multiple cannulated screws for vertically oriented femoral neck fractures.

Question 7423

Topic: 2. Trauma

A 42-year-old female presents 9 months after internal fixation of a displaced femoral neck fracture. She complains of persistent groin pain with weight-bearing. Radiographs show a prominent screw backing out and a visible radiolucent line across the fracture site. What is the most appropriate surgical treatment?

. Valgus intertrochanteric osteotomy
. Total hip arthroplasty
. Removal of hardware alone
. Revision internal fixation with bone grafting
. Bipolar hemiarthroplasty

Correct Answer & Explanation

. Valgus intertrochanteric osteotomy

Explanation

In a young patient with a femoral neck nonunion and a viable femoral head, a valgus intertrochanteric osteotomy converts shear forces into compressive forces, promoting fracture healing.

Question 7424

Topic: Pelvic & Acetabular Trauma

A 25-year-old male presents with deep groin pain worsened by hip flexion and internal rotation. Radiographs show a pistol grip deformity. What is the primary mechanism of cartilage damage in this condition?

. Linear impaction of the femoral head against the labrum
. Delamination of the acetabular cartilage primarily at the chondrolabral junction
. Global pincer-type overcoverage causing contrecoup lesions
. Avascular necrosis of the anterosuperior femoral head
. Ligamentum teres hypertrophy

Correct Answer & Explanation

. Linear impaction of the femoral head against the labrum

Explanation

Cam impingement is caused by an aspherical femoral head (pistol grip) squeezing into the acetabulum during flexion. This causes shear forces that lead to delamination of the anterosuperior acetabular cartilage at the chondrolabral junction.

Question 7425

Topic: 2. Trauma

A 32-year-old female sustains a displaced, completely off-ended, Pauwels type III femoral neck fracture. What is the most appropriate definitive management to minimize the risk of nonunion while maximizing biomechanical stability?

. Closed reduction and percutaneous pinning with three cancellous screws
. Open reduction and internal fixation with a dynamic hip screw and derotational screw
. Hemiarthroplasty
. Total hip arthroplasty
. Core decompression and fibular strut grafting

Correct Answer & Explanation

. Closed reduction and percutaneous pinning with three cancellous screws

Explanation

In young adults with a vertical (Pauwels III) displaced femoral neck fracture, a fixed-angle device such as a dynamic hip screw with a derotational screw provides superior biomechanical stability against shear forces compared to cancellous lag screws.

Question 7426

Topic: 2. Trauma

Which of the following arteries provides the primary blood supply to the femoral head in an adult, making it highly vulnerable to injury in displaced femoral neck fractures?

. Inferior gluteal artery
. Lateral epiphyseal artery (branch of MFCA)
. Artery of the ligamentum teres
. Medial epiphyseal artery (branch of LFCA)
. Ascending branch of the lateral femoral circumflex artery

Correct Answer & Explanation

. Inferior gluteal artery

Explanation

The lateral epiphyseal artery, a terminal branch of the medial femoral circumflex artery (MFCA), supplies the majority of the adult femoral head. It is frequently disrupted in displaced femoral neck fractures, leading to osteonecrosis.

Question 7427

Topic: 2. Trauma

A 28-year-old athlete undergoes evaluation for hip pain. The alpha angle is measured on a Dunn lateral view. What anatomical landmarks define the alpha angle?

. A line through the center of the femoral neck and a line to the point where the head exceeds the radius of the best-fit circle
. A line from the center of the femoral head to the anterior superior iliac spine and a line along the femoral shaft
. The angle between the acetabular inclination line and the femoral neck axis
. A line from the center of the femoral head to the edge of the acetabulum and the horizontal pelvis line
. A line connecting the teardrops and a line perpendicular to the femoral shaft

Correct Answer & Explanation

. A line through the center of the femoral neck and a line to the point where the head exceeds the radius of the best-fit circle

Explanation

The alpha angle is measured between the axis of the femoral neck and a line connecting the center of the femoral head to the point where the anterior femoral head-neck junction extends beyond the margin of a best-fit circle. An angle >55 degrees indicates cam morphology.

Question 7428

Topic: 2. Trauma

Which of the following best describes a Garden Type II femoral neck fracture?

. Incomplete fracture with valgus impaction
. Complete fracture, nondisplaced
. Complete fracture, partially displaced (<50%)
. Complete fracture, completely displaced (>50%)
. Stress fracture involving the tension side of the femoral neck

Correct Answer & Explanation

. Incomplete fracture with valgus impaction

Explanation

The Garden classification for femoral neck fractures categorizes Type II as a complete fracture across the femoral neck without any displacement.

Question 7429

Topic: 2. Trauma

When utilizing three parallel cancellous lag screws for fixation of a nondisplaced femoral neck fracture, where should the inferior (calcar) screw be positioned to provide the most optimal biomechanical construct?

. Anterior and superior in the femoral head
. Central within the femoral neck
. Resting directly on or immediately adjacent to the inferior cortex (calcar)
. Posterior and superior in the femoral neck
. Along the anterior cortex of the femoral neck

Correct Answer & Explanation

. Anterior and superior in the femoral head

Explanation

For maximum stability, an inverted triangle configuration is commonly used. The inferior screw must be positioned along the dense bone of the calcar (inferior cortex) to provide cortical support and resist inferior displacement forces.

Question 7430

Topic: Pelvic & Acetabular Trauma

A 28-year-old male athlete presents with groin pain exacerbated by hip flexion and internal rotation. Radiographs reveal an alpha angle of 70 degrees. Which of the following is the most likely primary mechanism of cartilage damage in this condition?

. Outside-in delamination of the anterosuperior acetabular cartilage
. Global full-thickness degeneration of the femoral head cartilage
. Chondromalacia of the posteroinferior acetabulum due to contrecoup forces
. Degenerative tearing of the ligamentum teres
. Hypertrophy of the pulvinar leading to central acetabular wear

Correct Answer & Explanation

. Outside-in delamination of the anterosuperior acetabular cartilage

Explanation

Cam impingement (alpha angle > 55 degrees) involves a non-spherical femoral head engaging the acetabulum during flexion. The resulting shear forces characteristically cause outside-in delamination of the anterosuperior acetabular cartilage and subsequent labral separation.

Question 7431

Topic: 2. Trauma

A 28-year-old male sustains a vertically oriented, Pauwels type III femoral neck fracture after a high-energy motor vehicle collision. Which of the following internal fixation constructs provides the highest biomechanical stability for this specific fracture pattern?

. Three parallel cancellous screws
. Sliding hip screw with an anti-rotation screw
. Cephalomedullary nail
. Non-sliding short blade plate
. Two parallel cancellous screws

Correct Answer & Explanation

. Three parallel cancellous screws

Explanation

A sliding hip screw combined with a derotation screw provides superior biomechanical stability compared to multiple parallel cancellous screws for vertically oriented (Pauwels type III) femoral neck fractures, as it better resists vertical shear forces.

Question 7432

Topic: Pelvic & Acetabular Trauma

A 32-year-old female presents with chronic anterior groin pain exacerbated by hip flexion and internal rotation. An anteroposterior (AP) radiograph of the pelvis demonstrates a 'crossover sign.' This radiographic finding is most indicative of which of the following?

. A prominent anterior femoral head-neck junction
. A retroverted acetabulum
. A retroverted femoral neck
. Coxa valga
. An excessively anteverted acetabulum

Correct Answer & Explanation

. A prominent anterior femoral head-neck junction

Explanation

The crossover sign occurs when the anterior wall of the acetabulum projects laterally to the posterior wall on an AP pelvis radiograph. It is a classic radiographic indicator of acetabular retroversion, a primary cause of pincer-type femoroacetabular impingement.

Question 7433

Topic: 2. Trauma

A 75-year-old patient sustains a periprosthetic femur fracture around a total hip arthroplasty placed 10 years ago. Radiographs show a fracture at the tip of the stem. The stem is clinically and radiographically loose, but the proximal femoral bone stock remains adequate. What is the most appropriate surgical management?

. Open reduction and internal fixation with locking plates and cables
. Revision of the acetabular component only
. Revision to a long, diaphyseal-fitting uncemented stem
. Cortical strut allografting alone
. Revision to a short cemented stem

Correct Answer & Explanation

. Open reduction and internal fixation with locking plates and cables

Explanation

This describes a Vancouver B2 periprosthetic fracture (fracture around a loose stem with good bone stock). The gold standard of treatment is revision to a long, diaphyseal-fitting (often fluted and tapered) uncemented stem to bypass the fracture and achieve stable distal fixation.

Question 7434

Topic: 2. Trauma

When evaluating a patient with a femoral neck fracture, which of the following is the most significant prognostic factor for the subsequent development of avascular necrosis of the femoral head after internal fixation?

. Time from injury to surgery (> 24 hours)
. Initial degree of fracture displacement
. Patient age at the time of injury
. Use of a sliding hip screw instead of parallel screws
. Preoperative medical comorbidities

Correct Answer & Explanation

. Time from injury to surgery (> 24 hours)

Explanation

The initial degree of fracture displacement (e.g., Garden classification) is the single most important predictor of avascular necrosis after a femoral neck fracture, as greater displacement correlates directly with more severe disruption of the retinacular blood supply.

Question 7435

Topic: 2. Trauma

A 25-year-old male sustains a vertically oriented femoral neck fracture (Pauwels type III). What fixation construct provides the greatest biomechanical stability for this specific pattern?

. Three parallel cannulated screws
. Sliding hip screw with a derotational screw
. Two parallel cannulated screws
. Dynamic condylar screw
. Proximal femoral locking plate

Correct Answer & Explanation

. Three parallel cannulated screws

Explanation

A sliding hip screw with a derotational screw provides superior biomechanical stability for highly unstable, vertically oriented (Pauwels III) femoral neck fractures compared to parallel cannulated screws by resisting shear forces.

Question 7436

Topic: 2. Trauma

In the treatment of displaced femoral neck fractures in young adults, which of the following is the most reliable predictor of developing avascular necrosis (AVN)?

. Time to surgery greater than 6 hours
. Use of a sliding hip screw instead of cannulated screws
. Degree of initial fracture displacement
. Performance of a capsulotomy
. Use of an open rather than closed reduction

Correct Answer & Explanation

. Time to surgery greater than 6 hours

Explanation

The degree of initial fracture displacement is the most significant and reliable predictor of AVN and nonunion in young patients with femoral neck fractures. The role of timing and capsulotomy remains controversial in recent literature.

Question 7437

Topic: 2. Trauma

A 70-year-old female sustains a basicervical femoral neck fracture. Which of the following statements regarding this fracture pattern is true?

. It is strictly an intracapsular fracture
. It has a higher rate of nonunion than subcapital fractures
. It is best treated with parallel cannulated screws alone
. It is biomechanically unstable and acts like an intertrochanteric fracture
. Avascular necrosis occurs in nearly 100% of cases

Correct Answer & Explanation

. It is strictly an intracapsular fracture

Explanation

Basicervical fractures are at the extracapsular base of the neck and are biomechanically unstable. They behave like intertrochanteric fractures and typically require a sliding hip screw or cephalomedullary nail rather than multiple parallel screws.

Question 7438

Topic: 2. Trauma

A 35-year-old female presents with persistent groin pain 8 months after internal fixation of a femoral neck fracture. Radiographs reveal varus collapse with a visible fracture line. MRI demonstrates a viable femoral head. What is the most appropriate management?

. Total hip arthroplasty
. Hemiarthroplasty
. Valgus intertrochanteric osteotomy
. Removal of hardware and immediate weight bearing
. Core decompression

Correct Answer & Explanation

. Total hip arthroplasty

Explanation

In a young patient with a femoral neck nonunion and a viable femoral head, a valgus intertrochanteric osteotomy is indicated. This procedure converts detrimental shear forces into compressive forces to promote fracture healing.

Question 7439

Topic: Pelvic & Acetabular Trauma

A 40-year-old female runner complains of deep gluteal pain radiating down the posterior thigh. MRI reveals narrowing of the space between the lesser trochanter and the ischium, with edema within the intervening muscle. What is the diagnosis?

. Piriformis syndrome
. Ischiofemoral impingement
. Hamstring syndrome
. Sacroiliac joint dysfunction
. Pudendal neuralgia

Correct Answer & Explanation

. Piriformis syndrome

Explanation

Ischiofemoral impingement occurs due to a narrowed space between the lesser trochanter and the ischial tuberosity. It classically presents with deep posterior pain and MRI findings of quadratus femoris muscle edema.

Question 7440

Topic: 2. Trauma



A patient presents with an intracapsular femoral neck fracture that extends distally to the level of the lesser trochanter. If internal fixation is planned, what is the most biomechanically sound implant choice?

. Three parallel cannulated screws
. A standard sliding hip screw with a 2-hole side plate
. A cephalomedullary nail
. Cancellous lag screws with washers
. Hook pin fixation

Correct Answer & Explanation

. Three parallel cannulated screws

Explanation

Femoral neck fractures with basicervical or subtrochanteric extension are highly unstable. A cephalomedullary nail or a long sliding hip screw is required to bypass the subtrochanteric region and prevent catastrophic hardware failure.

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