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2. Trauma MCQs

Practice Set 255 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 5081

Topic: 2. Trauma

A surgeon is considering the use of a synthetic bone graft substitute to fill a metaphyseal void following elevation of a depressed tibial plateau fracture. Which of the following best describes the properties of calcium phosphate cement compared to calcium sulfate?

. Higher compressive strength and slower resorption rate
. Lower compressive strength and faster resorption rate
. Greater osteoinductive capability
. Exothermic setting reaction that causes tissue necrosis
. Provides both osteoconductive and osteogenic properties

Correct Answer & Explanation

. Higher compressive strength and slower resorption rate

Explanation

Calcium phosphate cements have high compressive strength (often exceeding that of cancellous bone) and are resorbed very slowly, sometimes remaining visible on radiographs for years. They set via an isothermal or mildly exothermic reaction (unlike PMMA which is highly exothermic). In contrast, calcium sulfate has lower compressive strength and resorbs very rapidly (typically within 4 to 8 weeks), which can occasionally result in sterile serous drainage. Neither material is osteoinductive or osteogenic; both are strictly osteoconductive.

Question 5082

Topic: 2. Trauma

A 21-year-old man sustains a fracture through the proximal pole of the scaphoid. The vulnerability of this specific fracture to avascular necrosis and nonunion is primarily determined by the unique intraosseous retrograde blood supply of the scaphoid. The major blood supply to the scaphoid enters the bone predominantly at the dorsal ridge and is derived from a branch of which artery?

. Ulnar artery
. Anterior interosseous artery
. Volar carpal branch of the radial artery
. Dorsal carpal branch of the radial artery
. Princeps pollicis artery

Correct Answer & Explanation

. Dorsal carpal branch of the radial artery

Explanation

The scaphoid has a tenuous retrograde blood supply. The major blood supply (accounting for 70-80% of the bone, including the entire proximal pole) enters via foramina along the dorsal ridge at the waist of the scaphoid. These vessels are branches of the dorsal carpal branch of the radial artery. Because the intraosseous blood flow is from distal to proximal, fractures at the waist or proximal pole disrupt the blood supply to the proximal fragment, leading to high rates of avascular necrosis and nonunion.

Question 5083

Topic: 2. Trauma

In the treatment of severe scaphoid nonunions with avascular necrosis of the proximal pole, a free vascularized bone graft from the medial femoral condyle (MFC) is frequently utilized. Which of the following vessels provides the primary arterial supply to the standard MFC vascularized bone graft?

. Superior medial genicular artery
. Descending genicular artery
. Inferior medial genicular artery
. Medial sural artery
. Popliteal artery directly

Correct Answer & Explanation

. Descending genicular artery

Explanation

The descending genicular artery, along with its articular and saphenous branches, is the primary vascular supply to the medial femoral condyle corticocancellous bone graft.

Question 5084

Topic: 2. Trauma

Compact bone, titanium, stainless steel, cobalt-chrome Modulus of elasticities are as follows in Gpa (psi 3 10 6 ):

. Compact bone: 21 (3)
. Titanium: 96 (14)
. Stainless steel: 193 (28)
. Cobalt-chrome: 235 (34)

Correct Answer & Explanation

. Compact bone: 21 (3)

Explanation

(1790) Q1-2189:Which of the following precautionary measures should be taken to prevent a periprosthetic fracture when removing components from a patient with a previous compression hip screw:

Question 5085

Topic: 2. Trauma

A 9-year-old boy sustains a minor fall and presents with arm pain. Radiographs reveal a pathologic fracture through a centrally located, cystic lesion in the proximal humerus with a "fallen leaf" sign. After the fracture heals, what is the initial preferred management to prevent recurrence?

. Wide en bloc resection
. Curettage and polymethylmethacrylate (PMMA) packing
. Corticosteroid or bone marrow aspirate injection
. Radiation therapy
. Intravenous bisphosphonates

Correct Answer & Explanation

. Corticosteroid or bone marrow aspirate injection

Explanation

The presentation and "fallen leaf" sign are pathognomonic for a unicameral bone cyst (UBC). The initial treatment of choice after fracture healing is typically minimally invasive, utilizing corticosteroid or autologous bone marrow injections.

Question 5086

Topic: 2. Trauma
A 28-year-old high-speed trauma patient presents with a vertically oriented Pauwels type III femoral neck fracture. To provide the best biomechanical stability against vertical shear forces, which fixation construct is most appropriate?
. Three parallel cancellous screws
. Sliding hip screw with an anti-rotation screw
. Short cephalomedullary nail
. Bipolar hemiarthroplasty
. Total hip arthroplasty

Correct Answer & Explanation

. Sliding hip screw with an anti-rotation screw

Explanation

Pauwels type III femoral neck fractures are highly vertical and experience massive shear forces, leading to high rates of nonunion and varus collapse. A fixed-angle device like a sliding hip screw with a derotational screw provides superior biomechanical resistance to these shear forces compared to multiple cancellous screws.

Question 5087

Topic: 2. Trauma

A 45-year-old heavy smoker underwent intramedullary nailing for a tibial shaft fracture 8 months ago. Radiographs now show an 'elephant foot' hypertrophic nonunion. What is the primary underlying cause of this specific type of nonunion?

. Inadequate biological healing potential
. Inadequate mechanical stability
. Subclinical indolent infection
. Poor nutritional status
. Smoking-induced local ischemia

Correct Answer & Explanation

. Inadequate mechanical stability

Explanation

Hypertrophic nonunions (characterized by abundant callus formation or an 'elephant foot' appearance) possess adequate biological healing capacity and blood supply but lack sufficient mechanical stability. Treatment typically involves augmenting mechanical stability, such as exchanging the nail for a larger diameter.

Question 5088

Topic: Pelvic & Acetabular Trauma

A 25-year-old male sustains a vertical shear pelvic ring injury. He is hypotensive in the ED. A pelvic binder is applied, but his blood pressure remains 70/40 mmHg despite 2 units of PRBCs. The FAST exam is negative. What is the most appropriate next step in management?

. Diagnostic peritoneal lavage
. Exploratory laparotomy
. Preperitoneal pelvic packing
. Bilateral internal iliac artery ligation
. Application of a halo-femoral traction pin

Correct Answer & Explanation

. Preperitoneal pelvic packing

Explanation

In a hemodynamically unstable patient with a pelvic ring injury and a negative FAST (ruling out intra-abdominal hemorrhage), preperitoneal pelvic packing or emergent angiography is indicated. Packing is rapid, can be done immediately in the OR, and controls the venous bleeding that is the most common source of hemorrhage.

Question 5089

Topic: 2. Trauma

During a minimally invasive percutaneous plate osteosynthesis (MIPPO) of a distal tibia fracture via an anteromedial approach, which neurovascular structure is at highest risk of iatrogenic injury at the distal insertion site?

. Sural nerve
. Deep peroneal nerve
. Anterior tibial artery
. Great saphenous vein and saphenous nerve
. Posterior tibial artery

Correct Answer & Explanation

. Great saphenous vein and saphenous nerve

Explanation

The great saphenous vein and saphenous nerve course superficially along the anteromedial aspect of the distal tibia. They are at significant risk of iatrogenic injury during the insertion and distal screw fixation of medial tibial plates.

Question 5090

Topic: 2. Trauma

A 22-year-old male sustains a mid-shaft clavicle fracture with 2.5 cm of shortening and significant displacement. He is highly active. What is the primary indication for open reduction and internal fixation in this specific patient scenario?

. Prevention of glenohumeral stiffness
. Decreased risk of symptomatic non-union and improved functional outcomes
. Prevention of immediate skin necrosis
. Risk of subclavian artery pseudoaneurysm
. Cosmetic correction of the deformity

Correct Answer & Explanation

. Decreased risk of symptomatic non-union and improved functional outcomes

Explanation

Significant shortening (> 2 cm) or severe displacement of mid-shaft clavicle fractures in active adults is associated with a higher rate of symptomatic non-union, loss of shoulder strength, and altered shoulder biomechanics. ORIF significantly decreases the non-union rate and improves functional return.

Question 5091

Topic: 2. Trauma

A 72-year-old woman on long-term alendronate therapy sustains an atypical subtrochanteric femur fracture. Prophylactic fixation of the contralateral femur is being considered. Which of the following radiographic findings in the contralateral femur is the strongest indication for prophylactic surgical fixation?

. Diffuse cortical thickening
. A radiolucent line in the lateral cortex
. Medial cortical spiking
. Narrowing of the medullary canal
. Bowing of the femoral shaft without cortical lucency

Correct Answer & Explanation

. A radiolucent line in the lateral cortex

Explanation

A radiolucent line (dreaded black line) in the thickened lateral cortex of a bowed femur signifies an impending atypical femur fracture in a patient on bisphosphonates. This finding is a strong indication for prophylactic intramedullary nailing to prevent catastrophic completion of the fracture.

Question 5092

Topic: Pelvic & Acetabular Trauma

A 35-year-old man is brought to the trauma bay after a motorcycle accident. He remains hemodynamically unstable despite aggressive initial fluid resuscitation. Radiographs show a 4 cm pubic symphysis diastasis with intact posterior sacroiliac ligaments. A pelvic binder is applied but he remains hypotensive. What is the next most appropriate step in management?

. Immediate open reduction and internal fixation of the symphysis
. Retrograde urethrogram
. Preperitoneal pelvic packing or angioembolization
. Application of an anterior external fixator
. CT scan of the abdomen and pelvis

Correct Answer & Explanation

. Preperitoneal pelvic packing or angioembolization

Explanation

The patient has an APC-II pelvic ring injury and is in hemorrhagic shock. Following mechanical stabilization with a pelvic binder, persistent hemodynamic instability dictates immediate intervention for hemorrhage control via preperitoneal pelvic packing or angiography with embolization.

Question 5093

Topic: 2. Trauma

A 45-year-old man sustains a closed, displaced, intra-articular calcaneus fracture after a fall. Surgery via an extensile lateral approach is planned. Which of the following patient factors is the strongest predictor of postoperative wound complications?

. Diabetes mellitus
. Cigarette smoking
. Body Mass Index greater than 30
. Age over 40
. High-energy mechanism of injury

Correct Answer & Explanation

. Cigarette smoking

Explanation

Cigarette smoking is the single most significant modifiable risk factor for wound complications following the extensile lateral approach for calcaneus fractures. Smokers have a substantially increased risk of edge necrosis, deep infection, and the subsequent need for soft tissue coverage.

Question 5094

Topic: 2. Trauma

A 25-year-old male presents with a persistent scaphoid nonunion 18 months after a cast-treated fracture. Imaging reveals a humpback deformity, an intrascaphoid angle of 65 degrees, and sclerosis with fragmentation of the proximal pole consistent with avascular necrosis (AVN). Which of the following is the most appropriate surgical treatment to achieve both structural restoration and biological healing?

. Non-vascularized iliac crest bone graft with K-wire fixation
. 1,2-Intercompartmental supraretinacular artery (1,2-ICSRA) vascularized bone graft
. Free vascularized medial femoral condyle (MFC) corticocancellous bone graft
. Proximal row carpectomy (PRC)
. Scaphoid excision and 4-corner fusion

Correct Answer & Explanation

. Free vascularized medial femoral condyle (MFC) corticocancellous bone graft

Explanation

In cases of scaphoid nonunion with both proximal pole AVN and a humpback deformity, a free vascularized medial femoral condyle (MFC) corticocancellous bone graft is indicated. The MFC graft provides robust, independent blood supply necessary for a necrotic proximal pole and offers structural corticocancellous bone to correct the volar carpal collapse (humpback deformity). The 1,2-ICSRA graft often lacks sufficient structural integrity to reliably correct a humpback deformity and has a lower union rate in the presence of proximal pole fragmentation and AVN compared to the MFC graft.

Question 5095

Topic: 2. Trauma

A 28-year-old man presents with a symptomatic proximal pole scaphoid nonunion with avascular necrosis, 2 years post-injury. You plan a vascularized medial femoral condyle (MFC) bone graft. What is the primary arterial supply to this corticocancellous graft?

. Descending genicular artery
. Medial superior genicular artery
. Inferior medial genicular artery
. Popliteal artery
. Deep femoral artery

Correct Answer & Explanation

. Descending genicular artery

Explanation

The medial femoral condyle (MFC) vascularized bone graft is primarily supplied by the descending genicular artery (DGA), which arises from the superficial femoral artery just proximal to the adductor hiatus. If the DGA is absent or unsuitable, the medial superior genicular artery (MSGA) provides a reliable secondary source of blood supply to the periosteum of the MFC.

Question 5096

Topic: 2. Trauma

A 25-year-old man presents with a symptomatic proximal pole scaphoid nonunion. MRI demonstrates avascular necrosis (AVN) of the proximal pole. The surgeon plans to perform a free vascularized bone graft using the medial femoral condyle. What is the primary arterial supply to this specific bone graft?

. Descending genicular artery
. Superior medial genicular artery
. Inferior medial genicular artery
. Popliteal artery direct branches
. Sural artery

Correct Answer & Explanation

. Descending genicular artery

Explanation

The free vascularized medial femoral condyle (MFC) bone graft is commonly utilized for recalcitrant nonunions with AVN, such as proximal pole scaphoid nonunions. Its primary pedicle is the descending genicular artery (specifically the articular branch). The superior medial genicular artery can serve as an alternative if the descending genicular artery is absent or unsuitable.

Question 5097

Topic: 2. Trauma

A hand surgeon plans a 1,2 intercompartmental supraretinacular artery (1,2 ICSRA) vascularized bone graft for a scaphoid waist nonunion. Topographically, the vascular pedicle for this graft is located between which two extensor compartments?

. First and Second
. Second and Third
. Third and Fourth
. Fourth and Fifth
. Fifth and Sixth

Correct Answer & Explanation

. First and Second

Explanation

The 1,2 ICSRA vascularized bone graft is based on the 1,2 intercompartmental supraretinacular artery. This pedicle runs superficially in the fascia between the first dorsal extensor compartment (abductor pollicis longus, extensor pollicis brevis) and the second dorsal extensor compartment (extensor carpi radialis longus, extensor carpi radialis brevis).

Question 5098

Topic: 2. Trauma

When performing a volar wedge bone graft (Russe technique) for a humpback scaphoid nonunion, it is critical to understand the scaphoid's blood supply. The primary intraosseous blood supply to the proximal 80% of the scaphoid enters the bone at which anatomical location?

. Volar proximal pole
. Volar distal pole
. Dorsal ridge
. Proximal articular surface
. Scaphotrapeziotrapezoid joint capsule

Correct Answer & Explanation

. Dorsal ridge

Explanation

The scaphoid receives its primary blood supply (about 80%) from the dorsal carpal branch of the radial artery, which enters the bone at the dorsal ridge and flows retrogradely to supply the waist and proximal pole. The volar carpal branch supplies the remaining 20% (the distal pole) entering volar-distally. This retrograde flow is why proximal pole fractures have a high rate of AVN.

Question 5099

Topic: 2. Trauma

A 35-year-old male presents with a pelvic injury following a motor vehicle collision. Plain radiographs of the pelvis show disruption of both the iliopectineal and ilioischial lines, but the obturator ring remains completely intact. According to the Letournel and Judet classification, what is the diagnosis?

. T-type fracture
. Both column fracture
. Transverse fracture
. Anterior column, posterior hemitransverse fracture
. Isolated posterior column fracture

Correct Answer & Explanation

. Transverse fracture

Explanation

A transverse acetabular fracture separates the innominate bone into upper (iliac) and lower (ischiopubic) segments. It crosses both the anterior column (disrupting the iliopectineal line) and the posterior column (disrupting the ilioischial line) but distinctly leaves the obturator ring intact. T-type and both column fractures also involve both columns but extend into and disrupt the obturator ring.

Question 5100

Topic: 2. Trauma
A 28-year-old female sustains a knee injury. Imaging reveals a fracture involving the medial tibial plateau with a coronal plane fracture line separating the posteromedial aspect of the condyle. According to the Moore classification of fracture-dislocations of the knee, which type is this?
. Type I
. Type II
. Type III
. Type IV
. Type V

Correct Answer & Explanation

. Type I

Explanation

The Moore classification describes fracture-dislocations of the proximal tibia. Type I is a split fracture of the medial plateau in the coronal plane (posteromedial fragment). Type II is an entire medial condyle fracture with the fracture line extending into the opposite compartment. Type III is a rim avulsion (often associated with lateral capsular avulsion/Segond fracture). Type IV is a rim compression. Type V is a four-part fracture.

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