Menu

2. Trauma MCQs

Practice Set 558 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 11141

Topic: 2. Trauma

A 25-year-old mechanic sustains a displaced fracture of the proximal pole of the scaphoid. Nonunion and avascular necrosis are significant concerns for this fracture pattern. Which of the following best describes the predominant arterial supply to the proximal pole of the scaphoid?

. Palmar carpal branch of the radial artery via volar entry
. Dorsal carpal branch of the radial artery via retrograde flow
. Deep palmar arch via distal pole entry
. Anterior interosseous artery via proximal entry
. Ulnar artery branches to the dorsal ridge

Correct Answer & Explanation

. Palmar carpal branch of the radial artery via volar entry

Explanation

The major blood supply to the scaphoid comes from the dorsal carpal branch of the radial artery, which enters at the dorsal ridge near the waist and provides retrograde blood flow to the proximal pole. Fractures at the waist or proximal pole disrupt this retrograde supply, leading to a high risk of avascular necrosis and nonunion.

Question 11142

Topic: 2. Trauma
A 32-year-old male undergoes intramedullary nailing for a closed tibial shaft fracture. Twelve hours postoperatively, he complains of severe leg pain out of proportion to the injury, unrelieved by opioids. Passive stretch of his toes elicits excruciating pain. To confirm acute compartment syndrome using intracompartmental pressure monitoring, which criterion is the most accurate indicator for emergency fasciotomy?
. Absolute compartment pressure > 20 mmHg
. Absolute compartment pressure > 45 mmHg
. Mean arterial pressure minus compartment pressure < 40 mmHg
. Diastolic blood pressure minus compartment pressure < 30 mmHg
. Systolic blood pressure minus compartment pressure < 50 mmHg

Correct Answer & Explanation

. Diastolic blood pressure minus compartment pressure < 30 mmHg

Explanation

The delta pressure (ฮ”P) is the most reliable threshold for diagnosing acute compartment syndrome, particularly in hypotensive patients. A ฮ”P (diastolic blood pressure minus compartment pressure) of less than 30 mmHg is an absolute indication for emergency fasciotomy to prevent irreversible muscle and nerve ischemia.

Question 11143

Topic: 2. Trauma
A 29-year-old male sustains a high-energy Pauwels type III (vertical) femoral neck fracture. He undergoes closed reduction and internal fixation with three cannulated screws. Despite an anatomic reduction, there is a significantly elevated risk of nonunion compared to less vertical fractures. What biomechanical factor primarily accounts for this increased risk?
. Excessive compressive forces at the fracture line
. Disruption of the ligamentum teres blood supply
. High shear stress across the vertically oriented fracture site
. Lack of periosteal callus formation in intracapsular fractures
. Interposition of the iliopsoas tendon

Correct Answer & Explanation

. High shear stress across the vertically oriented fracture site

Explanation

Pauwels type III femoral neck fractures have a high fracture angle (>50 degrees) relative to the horizontal. This vertical orientation translates axial physiological loads into high shear stresses across the fracture line, significantly increasing the risk of loss of fixation, varus collapse, and nonunion.

Question 11144

Topic: 2. Trauma
A 25-year-old male sustains a vertically oriented, displaced femoral neck fracture (Pauwels type III) after a fall from a height. Open reduction and internal fixation is planned. What biomechanical construct provides the most stable fixation for this specific fracture pattern?
. Three parallel cancellous screws placed in an inverted triangle pattern
. A single dynamic hip screw (DHS) alone
. A dynamic hip screw (DHS) supplemented with a derotational cancellous screw
. Cephalomedullary nail with a single head screw
. Two parallel cancellous screws

Correct Answer & Explanation

. A dynamic hip screw (DHS) supplemented with a derotational cancellous screw

Explanation

Pauwels type III fractures are highly unstable due to significant vertical shear forces. A fixed-angle device such as a DHS supplemented with an anti-rotation screw provides superior biomechanical stability against shear compared to parallel cancellous screws.

Question 11145

Topic: 2. Trauma

A 40-year-old male sustains a closed posterior wall acetabular fracture with a concomitant posterior hip dislocation. Post-reduction CT scan reveals a 25% posterior wall fracture, a congruent joint, and a 2 mm intra-articular fragment. What is the most appropriate definitive management?

. Skeletal traction for 6 weeks
. Immediate weight-bearing as tolerated
. Surgical excision of the intra-articular fragment and fixation of the posterior wall
. Observation with touch-down weight-bearing
. Total hip arthroplasty

Correct Answer & Explanation

. Skeletal traction for 6 weeks

Explanation

Intra-articular incarcerated fragments following hip reduction are an absolute indication for operative intervention. The posterior wall should also be fixed simultaneously, as the approach is already necessary to clear the joint.

Question 11146

Topic: 2. Trauma

A 32-year-old female sustains a closed midshaft tibia fracture and undergoes intramedullary nailing. Six hours post-operatively, she complains of severe pain out of proportion to the injury. Passive stretch of her toes exacerbates the pain. Compartment pressures measure 45 mmHg. What is the immediate indicated treatment?

. Elevation of the limb above the heart and observation
. Administration of intravenous mannitol
. Emergent four-compartment fasciotomy of the leg
. Removal of the intramedullary nail
. Epidural analgesia

Correct Answer & Explanation

. Elevation of the limb above the heart and observation

Explanation

The clinical scenario strongly suggests acute compartment syndrome. Intracompartmental pressures above 30 mmHg (or within 30 mmHg of diastolic blood pressure) in conjunction with classic clinical signs necessitate emergent fasciotomy.

Question 11147

Topic: 2. Trauma

A 28-year-old female presents with a closed tibial shaft fracture. She complains of severe pain out of proportion to the injury. Which of the following compartment pressure measurements is the most accepted threshold for diagnosing acute compartment syndrome and indicating the need for fasciotomy?

. Absolute compartment pressure greater than 15 mmHg
. Absolute compartment pressure greater than 20 mmHg
. Delta pressure (Diastolic blood pressure minus compartment pressure) less than 30 mmHg
. Delta pressure (Mean arterial pressure minus compartment pressure) less than 45 mmHg
. Delta pressure (Systolic blood pressure minus compartment pressure) less than 30 mmHg

Correct Answer & Explanation

. Absolute compartment pressure greater than 15 mmHg

Explanation

Acute compartment syndrome is a clinical diagnosis, but pressure monitoring can be utilized in obtunded patients. A delta pressure (diastolic blood pressure minus compartment pressure) of less than 30 mmHg is the most widely accepted threshold for performing a fasciotomy.

Question 11148

Topic: 2. Trauma
A 40-year-old male sustains a Gustilo-Anderson Type IIIB open tibial shaft fracture. According to classic principles established by Godina, within what timeframe should definitive free soft tissue coverage ideally be performed to significantly decrease the risk of flap failure and deep infection?
. Within 24 hours
. Within 72 hours
. Between 5 and 7 days
. Between 2 and 3 weeks
. After 4 weeks

Correct Answer & Explanation

. Within 72 hours

Explanation

In Gustilo IIIB open fractures, timing of soft tissue coverage is critical. Godina's classic studies demonstrated that definitive free tissue transfer within 72 hours significantly decreases the rates of deep infection, flap failure, and nonunion compared to delayed coverage.

Question 11149

Topic: 2. Trauma

A 59-year-old woman with a history of osteoporosis is involved in a high-speed motor vehicle accident,

resulting in left hip pain and deformity. The initial radiograph from the trauma bay is shown in Figure

. Postreduction CT is shown in Figures 2 through
. What is the most appropriate definitive surgical treatment?
. Open reduction and internal fixation (ORIF) of the acetabular fracture with concomitant acute total hip arthroplasty
. ORIF of the acetabular fracture and ORIF of the femoral head fracture fragments
. ORIF of the acetabular fracture and hemiarthroplasty

Correct Answer & Explanation

. Postreduction CT is shown in Figures 2 through

Explanation

The radiograph shows a posterior wall acetabular fracture-dislocation. Post reduction CT indicates a large comminuted posterior wall fracture with marginal impaction of the articular surface. A comminuted femoral head fracture also is seen extending to the superior weight-bearing surface. Given the marginalimpaction of the acetabulum and the considerable comminution of the femoral head (which is likely unreconstructible), this injury would have a high risk of causing posttraumatic arthritis if treated with ORIF of the fractures alone. Considering this fact and the patientโ€™s age, ORIF of the posterior wall and acute total hip arthroplasty would likely have the best functional result and the lowest risk of reoperation. Hemiarthroplasty is inappropriate for this injury considering the acetabular fracture. Skeletal traction currently plays a limited role in the definitive treatment of acetabular fractures.

Question 11150

Topic: 2. Trauma

A healthy, active 72-year-old man trips and falls, landing on his left hip 10 weeks after an uncomplicated

left primary uncemented total hip replacement. A radiograph taken 6 weeks after surgery and before the fall is shown in Figure

. A radiograph taken after the fall is shown in Figure
. He is unable to bear weight and is brought to the emergency department. Examination reveals a slightly shortened left lower extremity and some mild ecchymosis just distal to the left greater trochanteric region, but his skin is intact, without abrasions or lacerations. What is the most appropriate treatment?
. Open reduction and cerclage fixation of the fracture
. Open reduction and revision of the femoral implant to a long cemented stem
. Open reduction and revision of the femoral implant to a long fluted and tapered uncemented stem

Correct Answer & Explanation

. A radiograph taken after the fall is shown in Figure

Explanation

This patient has a periprosthetic femoral fracture with a loose femoral stem and normal femoral bone stock, representing a Vancouver type B2 fracture. The most appropriate treatment is fixation of the fracture, along with revision of the stem. Considering his age, bone quality, and activity level, a longer uncemented stem is most predictable. Although a cylindrical stem may also be used, the fluted stem option is the only uncemented choice listed and is the most appropriate option. A cemented stem is a poorer choice because it is difficult to keep the cement out of the fracture site, which would pose a risk for nonunion at the fracture. Also, overall poorer results have been associated with long cemented stems in healthy, active people. Surgery does not need to be delayed to allow the ecchymosis to resolve, and simple open reduction and fixation does not address the loose stem.

Question 11151

Topic: 2. Trauma

Figure below shows the radiograph obtained from a 68-year-old man who fell 3 weeks after undergoing a

successful left primary total hip arthroplasty. He is experiencing a substantial increase in pain and an inability to bear weight. What is an appropriate treatment plan?

. Open reduction and internal fixation (ORIF) of the fracture
. Removal of the current stem, femur ORIF, and insertion of a longer revision stem
. Femur ORIF with cables and strut graft, leaving the current stem in situ
. Femur ORIF combined with reimplantation of the primary component

Correct Answer & Explanation

. Open reduction and internal fixation (ORIF) of the fracture

Explanation

The fracture has occurred around the stem, representing a Vancouver type B fracture, and the stem is clearly loose, making it a type B2 fracture. The appropriate treatment is removal of the loose in situ stem; ORIF of the femur using cerclage wires, cables, or a plate; and insertion of a longer revision stem such as a tapered fluted modular titanium or fully porous coated cylindrical stem to bypass the fracture. All of the other options are incorrect, because they represent inappropriate treatment options for a Vancouver type B2 fracture.

Question 11152

Topic: Pelvic & Acetabular Trauma
In patients with Crowe types III and IV developmental dysplasia of the hip with high hip centers, acetabular reconstruction often requires lowering the acetabular component into the native acetabulum. In doing so, considerable risk for limb lengthening beyond 4 cm exists, making the hip difficult to reduce and raising the risk for nerve injury. Which technique is used to overcome this problem?
. Subtrochanteric osteotomy with femoral shortening
. An offset femoral component
. A lateralized liner
. Extended trochanteric osteotomy

Correct Answer & Explanation

. Subtrochanteric osteotomy with femoral shortening

Explanation

When substantial lengthening of a dysplastic hip will occur because a high dislocation is relocated into a considerably lower acetabulum, a femoral shortening may be necessary to reduce the hip and avoid a stretch injury to the sciatic nerve. No other choice specifically addresses the need for femoral shortening, and high offset stems and lateralized liners may exacerbate the problem if used alone and without femoral shortening.

Question 11153

Topic: Pelvic & Acetabular Trauma
In patients with Crowe types III and IV developmental dysplasia of the hip with high hip centers, acetabular reconstruction often requires lowering the acetabular component into the native acetabulum. In doing so, considerable risk for limb lengthening beyond 4 cm exists, making the hip difficult to reduce and raising the risk for nerve injury. Which technique is used to overcome this problem?
. Subtrochanteric osteotomy with femoral shortening
. An offset femoral component
. A lateralized liner
. Extended trochanteric osteotomy

Correct Answer & Explanation

. Subtrochanteric osteotomy with femoral shortening

Explanation

When substantial lengthening of a dysplastic hip will occur because a high dislocation is relocated into a considerably lower acetabulum, a femoral shortening may be necessary to reduce the hip and avoid a stretch injury to the sciatic nerve. No other choice specifically addresses the need for femoral shortening, and high offset stems and lateralized liners may exacerbate the problem if used alone and without femoral shortening.

Question 11154

Topic: 2. Trauma

A 32-year-old male sustains a high-energy closed tibia fracture. In the emergency department, his blood pressure is 130/80 mmHg. He is intubated for associated head trauma, making clinical assessment of compartment syndrome difficult. Intracompartmental pressure monitoring is utilized. What is the most widely accepted absolute tissue pressure and Delta P criteria for performing a four-compartment fasciotomy?

. Absolute pressure > 30 mmHg and Delta P < 30 mmHg relative to systolic pressure
. Absolute pressure > 45 mmHg and Delta P < 30 mmHg relative to diastolic pressure
. Absolute pressure > 30 mmHg and Delta P < 30 mmHg relative to diastolic pressure
. Absolute pressure > 20 mmHg and Delta P < 40 mmHg relative to mean arterial pressure
. Absolute pressure > 40 mmHg and Delta P < 40 mmHg relative to systolic pressure

Correct Answer & Explanation

. Absolute pressure > 30 mmHg and Delta P < 30 mmHg relative to systolic pressure

Explanation

Compartment syndrome is a surgical emergency diagnosed clinically or via compartment pressure measurements, particularly in obtunded patients. The classic absolute tissue pressure threshold for fasciotomy is > 30 mmHg. However, absolute pressure alone can be misleading depending on systemic hemodynamics. The Delta P, defined as the Diastolic Blood Pressure minus the Intracompartmental Pressure, is a more accurate indicator of tissue perfusion. A Delta P of less than 30 mmHg (meaning the compartment pressure is within 30 mmHg of the diastolic pressure) is an absolute indication for emergency fasciotomy.

Question 11155

Topic: 2. Trauma

When inserting a cortical bone screw during fracture fixation, maximizing pull-out strength is essential for construct stability. Biomechanically, the pull-out strength of a bone screw is directly proportional to which of the following variables?

. Inner core diameter
. Thread pitch
. Outer thread diameter
. The density of the cancellous bone
. Core diameter minus thread depth

Correct Answer & Explanation

. Inner core diameter

Explanation

The pull-out strength of a bone screw is mathematically proportional to the volume of bone caught between the threads. The formula for pull-out strength is: S = L x D x T x F, where L is the length of thread engagement, D is the OUTER thread diameter, T is the thread shape factor, and F is the shear strength of the bone material. Increasing the outer diameter of the screw, increasing the length of engagement (e.g., utilizing bicortical purchase instead of unicortical), and increasing the sheer strength of the surrounding bone (cortical vs cancellous) all directly increase pull-out strength. Conversely, increasing inner root (core) diameter improves the screw's bending or breaking strength, but does not increase pull-out strength unless the outer diameter also increases.

Question 11156

Topic: 2. Trauma
A 35-year-old male sustains a vertically oriented femoral neck fracture after a high-energy motor vehicle accident. The fracture line measures 75 degrees relative to the horizontal (Pauwels Type III). Which of the following internal fixation constructs provides the most biomechanical stability against the exceedingly high shear forces present in this specific fracture pattern?
. Three parallel cannulated screws placed in an inverted triangle configuration
. Two parallel cannulated screws supplemented with an independent derotational screw
. A fixed-angle sliding hip screw (SHS) with an independent anti-rotation screw
. Three parallel screws placed entirely within the anterior half of the femoral neck
. A single large-diameter cancellous lag screw with a washer

Correct Answer & Explanation

. A fixed-angle sliding hip screw (SHS) with an independent anti-rotation screw

Explanation

Pauwels classification of femoral neck fractures is based on the angle of the fracture relative to the horizontal. Type I is <30 degrees, Type II is 30-50 degrees, and Type III is >50 degrees. The more vertical the fracture (Type III), the higher the shear forces across the fracture site, predisposing it to displacement, varus collapse, and nonunion. Biomechanical studies have consistently shown that a fixed-angle device, such as a Sliding Hip Screw (SHS, also known as a dynamic hip screw) supplemented with a derotational screw, provides significantly superior resistance to shear stress and vertical displacement in Pauwels III fractures compared to multiple parallel cancellous screws.

Question 11157

Topic: Pelvic & Acetabular Trauma
A 42-year-old male sustains a severe pelvic ring injury from a crush mechanism. Radiographs show complete disruption of the pubic symphysis, bilateral rami fractures, and significant widening of the left sacroiliac joint. Despite the application of a pelvic binder and massive transfusion protocol, he remains hemodynamically unstable. An urgent angiogram is performed. In the context of major posterior pelvic ring disruptions, which branch of the internal iliac artery is statistically the most frequently injured, leading to life-threatening retroperitoneal hemorrhage?
. Superior gluteal artery
. Inferior gluteal artery
. Obturator artery
. Internal pudendal artery
. Iliolumbar artery

Correct Answer & Explanation

. Superior gluteal artery

Explanation

Pelvic ring fractures are associated with massive, life-threatening hemorrhage. The source is venous (presacral plexus) in approximately 80-90% of cases, and arterial in 10-20%. When arterial bleeding is present and requires embolization, the superior gluteal artery is historically the most frequently injured artery overall, specifically owing to its intimate anatomic relationship with the posterior pelvic ring and greater sciatic notch, which are often severely disrupted in high-energy trauma (such as APC-III or vertical shear injuries). The obturator and internal pudendal arteries are more commonly injured in isolated anterior ring fractures.

Question 11158

Topic: 2. Trauma

According to the principles of Damage Control Orthopedics (DCO) in polytraumatized patients, which of the following systemic inflammatory markers is most strongly associated with the magnitude of the "second hit" and is frequently utilized to guide the safe timing of definitive fracture fixation?

. Interleukin-1 (IL-1)
. Interleukin-6 (IL-6)
. Tumor Necrosis Factor-alpha (TNF-a)
. C-reactive protein (CRP)
. Procalcitonin

Correct Answer & Explanation

. Interleukin-1 (IL-1)

Explanation

Interleukin-6 (IL-6) is the primary cytokine responsible for the systemic inflammatory response following major trauma. Its levels peak 12-24 hours post-injury and directly correlate with the severity of the trauma and the magnitude of the systemic inflammatory response syndrome (SIRS). A persistent elevation suggests the patient is not yet physiologically optimized for the "second hit" of definitive surgery.

Question 11159

Topic: 2. Trauma

In the context of lower extremity amputations, an increase in the proximal level of amputation and the specific etiology of limb loss directly correlate with increased metabolic energy expenditure during gait. Which of the following scenarios results in the highest increase in metabolic demand compared to normal baseline walking?

. Unilateral traumatic transtibial amputation
. Bilateral traumatic transtibial amputations
. Unilateral vascular transfemoral amputation
. Unilateral traumatic transfemoral amputation
. Unilateral Syme amputation

Correct Answer & Explanation

. Unilateral traumatic transtibial amputation

Explanation

Energy expenditure during gait increases significantly with more proximal amputations and in patients with vascular disease compared to trauma. Approximate increases in energy expenditure are: Unilateral traumatic BKA (~25%), Bilateral traumatic BKA (~40%), Unilateral traumatic AKA (~60%), and Unilateral vascular AKA (~65-100%). Thus, the unilateral vascular transfemoral (AKA) amputation has the highest metabolic demand.

Question 11160

Topic: 2. Trauma
A 35-year-old obtunded polytrauma patient sustains a severe closed tibial shaft fracture. You suspect acute compartment syndrome and decide to measure intracompartmental pressures. The "delta P" is widely considered the most reliable threshold for diagnosing compartment syndrome. Which formula correctly defines the delta P?
. Mean Arterial Pressure minus Compartment Pressure
. Systolic Blood Pressure minus Compartment Pressure
. Diastolic Blood Pressure minus Compartment Pressure
. Pulse Pressure minus Compartment Pressure
. Compartment Pressure minus Central Venous Pressure

Correct Answer & Explanation

. Diastolic Blood Pressure minus Compartment Pressure

Explanation

The delta P (ฮ”P) is calculated as the patient's Diastolic Blood Pressure (DBP) minus the absolute Intracompartmental Pressure (ICP). A delta P of less than 30 mm Hg indicates inadequate tissue perfusion and is the standard threshold indicating the need for emergent fasciotomy.

Test Yourself

Switch to an interactive, timed exam simulation to truly master this topic.

On this Page