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2. Trauma MCQs

Practice Set 502 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 10021

Topic: 2. Trauma

Which of the following is considered the gold standard for diagnosing a nonunion of a long bone fracture?

. Plain radiographs
. CT scan
. MRI
. Bone scan
. Clinical examination with pain and motion at fracture site

Correct Answer & Explanation

. CT scan

Explanation

While plain radiographs are the initial imaging modality for fracture assessment, a CT scan is considered the gold standard for diagnosing a nonunion. It provides detailed cross-sectional images, allowing for precise assessment of fracture callus formation, the presence of a fracture gap, bone remodeling, and the extent of any sclerotic bone, which are crucial for determining if healing is truly stalled. Plain radiographs can be suggestive but may be difficult to interpret definitively. MRI is excellent for soft tissue and bone marrow edema but less precise for cortical bone healing. Bone scans show metabolic activity but are not specific for nonunion. Clinical examination is essential but needs imaging confirmation.

Question 10022

Topic: 2. Trauma

A 45-year-old male presents to the emergency department after a high-speed motor vehicle collision. He is hypotensive (BP 80/40 mmHg), tachycardic (HR 130 bpm), and has gross hematuria. Physical examination reveals an unstable open-book pelvic fracture. Initial resuscitation with crystalloids is ongoing. What is the MOST appropriate next step in his management AFTER initial ATLS protocol?

. External fixation of the pelvis
. Angiography with embolization
. Pelvic binder application
. Laparotomy
. CT scan of the pelvis

Correct Answer & Explanation

. Pelvic binder application

Explanation

In an unstable open-book pelvic fracture, immediate pelvic stabilization with a binder or sheet is crucial to reduce pelvic volume, tamponade venous bleeding, and improve hemodynamic stability. While external fixation is definitive, it takes time. Angiography is typically performed after mechanical stabilization if bleeding persists. Laparotomy is for intra-abdominal organ injury, not primary pelvic hemorrhage control. CT scan should be performed once hemodynamically stable or after initial stabilization.

Question 10023

Topic: 2. Trauma
A 35-year-old construction worker sustains an open tibia fracture (Gustilo-Anderson Type IIIB) after a fall. He presents to the ER within 1 hour of injury. What is the most appropriate initial surgical management within the first 6-8 hours?
. Extensive surgical debridement and delayed primary closure
. External fixation, extensive surgical debridement, and intravenous antibiotics
. Immediate open reduction and internal fixation with plates and screws
. Vacuum-assisted closure (VAC) therapy after minimal debridement
. Amputation below the knee due to severe soft tissue injury

Correct Answer & Explanation

. External fixation, extensive surgical debridement, and intravenous antibiotics

Explanation

For Gustilo-Anderson Type IIIB open tibia fractures, the cornerstone of management is urgent, thorough surgical debridement of all contaminated and non-viable tissue, followed by external fixation for skeletal stabilization, and appropriate broad-spectrum intravenous antibiotics. Delayed primary closure or staged soft tissue reconstruction is then planned. Immediate ORIF is contraindicated due to high infection risk. VAC therapy is a dressing, not a primary surgical debridement. Amputation is typically reserved for unsalvageable limbs (e.g., mangled extremity score, failed reconstruction attempts).

Question 10024

Topic: 2. Trauma
A 25-year-old male is involved in a high-speed frontal motor vehicle collision. He complains of severe right hip pain. On examination, his right leg is shortened, internally rotated, and adducted. What is the most likely diagnosis, and what is the immediate management priority?
. Femoral neck fracture; urgent MRI
. Acetabular fracture; CT scan of the pelvis
. Posterior hip dislocation; urgent closed reduction
. Anterior hip dislocation; urgent open reduction
. Intertrochanteric fracture; traction

Correct Answer & Explanation

. Posterior hip dislocation; urgent closed reduction

Explanation

The classic presentation of a posterior hip dislocation involves a shortened, internally rotated, and adducted lower extremity, often following a dashboard injury in an MVC. The immediate management priority is urgent closed reduction of the hip, ideally within 6 hours, to minimize the risk of avascular necrosis (AVN) of the femoral head. While associated fractures (femoral head, acetabulum) are common and require further imaging (CT post-reduction), the dislocation itself is the immediate limb-threatening concern due to vascular compromise.

Question 10025

Topic: 2. Trauma

A 60-year-old female with osteoporosis falls onto an outstretched hand, sustaining a dorsally displaced and angulated distal radius fracture (Colles fracture). Which of the following is the MOST important factor to consider when determining the need for surgical fixation versus closed reduction and casting?

. Patient's dominant hand
. Associated ulnar styloid fracture
. Age of the patient
. Degree of comminution and intra-articular involvement
. Mechanism of injury

Correct Answer & Explanation

. Degree of comminution and intra-articular involvement

Explanation

The most important factor determining the need for surgical fixation versus closed reduction and casting for a distal radius fracture, especially in osteoporotic patients, is the degree of comminution and intra-articular involvement, and the stability of the reduction. Fractures with significant comminution, intra-articular displacement/gapping, or instability after reduction are more prone to malunion and functional impairment, thus often requiring surgical fixation. While age and dominance are considered, they are secondary to fracture characteristics impacting stability and long-term function.

Question 10026

Topic: 2. Trauma
A 40-year-old male sustains a severe open tibia fracture with a >10 cm laceration, extensive muscle devitalization, and significant periosteal stripping. There is adequate soft tissue coverage for bony fixation but extensive contamination. According to the Gustilo-Anderson classification, what type of open fracture is this?
. Type I
. Type II
. Type IIIA
. Type IIIB
. Type IIIC

Correct Answer & Explanation

. Type IIIB

Explanation

This description fits a Gustilo-Anderson Type IIIB open fracture. Type IIIB involves extensive soft tissue damage, periosteal stripping, and massive contamination, with associated significant comminution, and typically requires local or free flap coverage. Type IIIA has extensive soft tissue damage but usually allows for primary closure. Type I and II have smaller wounds and less severe soft tissue injury. Type IIIC includes an associated arterial injury requiring repair.

Question 10027

Topic: 2. Trauma
A 48-year-old male sustains a high-energy Schatzker Type VI tibial plateau fracture. He has an open wound over the medial aspect of the knee and a tense calf compartment with diminished distal pulses. What is the immediate priority in management?
. Application of an external fixator to the tibia
. Urgent surgical debridement and fasciotomy
. CT angiogram to assess vascular injury
. Closed reduction and long-leg casting
. Delayed open reduction and internal fixation

Correct Answer & Explanation

. Urgent surgical debridement and fasciotomy

Explanation

This scenario describes a severe tibial plateau fracture with signs of both an open injury and impending compartment syndrome. The immediate priority is an urgent surgical debridement of the open wound to prevent infection, and fasciotomy of the calf compartments to relieve pressure and restore perfusion, given the tense calf and diminished pulses. External fixation provides temporary stability but does not address the acute soft tissue/vascular emergency. A CT angiogram may be needed but follows fasciotomy if pulses do not improve. Delayed ORIF is appropriate for definitive fixation, but not initially.

Question 10028

Topic: 2. Trauma

A 22-year-old long-distance runner complains of bilateral lower leg pain, tightness, and cramping that consistently develops at the same point during his runs, forcing him to stop. The pain resolves with rest. Physical examination is normal at rest. What is the MOST appropriate diagnostic test?

. Plain radiographs of the tibia and fibula
. MRI of the lower leg
. Ultrasound with Doppler to rule out DVT
. Intracompartmental pressure measurements before and after exercise
. Nerve conduction studies

Correct Answer & Explanation

. Intracompartmental pressure measurements before and after exercise

Explanation

This presentation is classic for chronic exertional compartment syndrome (CECS). The definitive diagnostic test for CECS is intracompartmental pressure measurement performed before and after exercise. A significant elevation in pressure after exercise, which fails to normalize within a few minutes, confirms the diagnosis. Imaging (X-rays, MRI) is typically normal and is used to rule out other pathology but not to diagnose CECS directly.

Question 10029

Topic: 2. Trauma

A 85-year-old female sustains an intertrochanteric hip fracture after a fall. She has multiple comorbidities. Which surgical implant is generally preferred for stable intertrochanteric fractures, offering good stability and allowing early weight-bearing?

. Dynamic hip screw (DHS)
. Cephalomedullary nail
. Total hip arthroplasty
. Hemiarthroplasty
. Cannulated screws

Correct Answer & Explanation

. Dynamic hip screw (DHS)

Explanation

For stable intertrochanteric fractures, the Dynamic Hip Screw (DHS) is a widely used and effective implant, providing compression across the fracture site and allowing controlled collapse, which promotes union and permits early weight-bearing. Cephalomedullary nails are often preferred for unstable intertrochanteric and subtrochanteric fractures. Arthroplasty is typically for femoral neck fractures. Cannulated screws are usually for non-displaced femoral neck fractures or certain acetabular fractures.

Question 10030

Topic: 2. Trauma

Which of the following describes the mechanism of injury for a 'dashboard injury' that commonly results in a posterior hip dislocation?

. Axial load on an extended knee with the hip abducted
. Axial load on a flexed knee with the hip adducted
. Direct blow to the greater trochanter with the hip extended
. Rotation of the femur with a fixed foot
. Fall onto an outstretched hand

Correct Answer & Explanation

. Axial load on a flexed knee with the hip adducted

Explanation

A 'dashboard injury' typically involves an axial load on a flexed knee with the hip adducted. This forces the femoral head posteriorly out of the acetabulum, resulting in a posterior hip dislocation, which is the most common type of hip dislocation. A direct blow to the greater trochanter usually results in a trochanteric fracture. Other mechanisms are for different injuries.

Question 10031

Topic: 2. Trauma

A 10-year-old boy presents with a painful right wrist and limited pronation/supination after a fall. Radiographs show a fracture of the distal radius with intact ulna but significant widening of the distal radioulnar joint (DRUJ) and disruption of the interosseous membrane proximally. What is the MOST likely diagnosis?

. Colles fracture
. Smith fracture
. Monteggia fracture-dislocation
. Galeazzi fracture-dislocation
. Essex-Lopresti injury

Correct Answer & Explanation

. Essex-Lopresti injury

Explanation

This describes an Essex-Lopresti injury, which is a rare but severe injury involving a comminuted radial head fracture, disruption of the interosseous membrane, and dislocation of the distal radioulnar joint (DRUJ). The key is the radial head involvement with distal radioulnar joint instability. Galeazzi fracture-dislocation involves a distal radius fracture with DRUJ dislocation. Monteggia involves a proximal ulna fracture with radial head dislocation. Colles and Smith are distal radius fractures without such extensive DRUJ/interosseous membrane involvement.

Question 10032

Topic: 2. Trauma

A 30-year-old male sustains a high-energy Pilon fracture of the tibia (distal tibia intra-articular fracture). He has significant soft tissue swelling. What is the MOST appropriate initial approach to definitive surgical management?

. Immediate open reduction and internal fixation with plates and screws
. Closed reduction and long-leg casting
. External fixation followed by staged ORIF once soft tissues improve
. Primary ankle arthrodesis
. Amputation due to complex injury

Correct Answer & Explanation

. External fixation followed by staged ORIF once soft tissues improve

Explanation

Pilon fractures are high-energy intra-articular distal tibia fractures often associated with severe soft tissue swelling. The MOST appropriate initial approach to definitive surgical management is usually a staged protocol: initial management with external fixation to restore length and alignment and allow the soft tissues to recover, followed by delayed (typically 7-14 days) open reduction and internal fixation once the soft tissue envelope has improved and the 'wrinkle sign' is present. Immediate ORIF risks wound complications and infection. Casting is inadequate for these unstable, articular fractures. Arthrodesis and amputation are salvage procedures.

Question 10033

Topic: 2. Trauma

In the management of open fractures, what is the MOST critical factor influencing the risk of infection and overall outcome?

. Timing of prophylactic antibiotics
. Type of fixation used (internal vs. external)
. Patient's age and comorbidities
. Adequacy of debridement
. Location of the fracture

Correct Answer & Explanation

. Adequacy of debridement

Explanation

The adequacy and timeliness of surgical debridement are paramount in preventing infection and improving outcomes in open fractures. Debridement involves removing all non-viable tissue, foreign material, and contaminated bone, reducing the bacterial load. While prophylactic antibiotics are crucial, their effectiveness is greatly diminished if debridement is incomplete. Fixation type, patient age, comorbidities, and fracture location are important considerations but are secondary to thorough debridement in preventing infection.

Question 10034

Topic: 2. Trauma

A 10-year-old male falls onto an outstretched hand. Radiographs show a fracture of the distal radius with dorsal displacement and angulation. There is an intact volar cortex. What type of fracture is this, based on pediatric classification?

. Greenstick fracture
. Torus fracture
. Salter-Harris Type I
. Galeazzi fracture
. Monteggia fracture

Correct Answer & Explanation

. Greenstick fracture

Explanation

A greenstick fracture is an incomplete fracture of a long bone in children, characterized by a break in one side of the cortex while the opposite cortex remains intact and bent. This description of a distal radius fracture with dorsal displacement and angulation, but an intact volar cortex, perfectly fits a greenstick fracture. A torus (buckle) fracture is an incomplete fracture characterized by buckling of the cortex. Salter-Harris Type I is a complete physeal separation without metaphyseal or epiphyseal involvement. Galeazzi and Monteggia fractures are specific forearm fracture-dislocations.

Question 10035

Topic: 2. Trauma

A 25-year-old male sustains a high-energy tibial plateau fracture. He develops increasing pain, swelling, and paresthesias in his leg. On examination, the leg is tense, and passive ankle dorsiflexion elicits severe pain. Distal pulses are present. What is the most appropriate immediate action?

. Administer IV opioids and elevate the limb
. Obtain an urgent CT angiogram
. Perform compartment pressure measurements
. Apply ice packs and monitor closely
. Perform a diagnostic arthroscopy

Correct Answer & Explanation

. Perform compartment pressure measurements

Explanation

This patient's symptoms (increasing pain, swelling, paresthesias, tense leg, pain with passive stretch) in the setting of a high-energy tibial plateau fracture are highly suggestive of acute compartment syndrome. Although distal pulses are present, compartment syndrome is a clinical diagnosis, and absent pulses are a late and unreliable sign. The most appropriate immediate action is to perform compartment pressure measurements to confirm the diagnosis. If pressures are elevated (typically within 30 mmHg of diastolic pressure or >30 mmHg absolute, depending on protocol), an emergent fasciotomy is indicated to prevent irreversible muscle and nerve damage. Delaying treatment for imaging or conservative measures is inappropriate and risks permanent disability.

Question 10036

Topic: 2. Trauma

What is the most common cause of non-union in long bone fractures?

. Patient's age
. Inadequate immobilization
. Infection
. Soft tissue interposition
. Open fracture

Correct Answer & Explanation

. Inadequate immobilization

Explanation

Inadequate stabilization/immobilization and insufficient blood supply (leading to inadequate biological response) are the two most common causes of non-union. While infection, soft tissue interposition, and open fractures can certainly contribute to non-union, failure to provide a stable mechanical environment for healing is a predominant factor. Age is a factor but not the primary cause of non-union.

Question 10037

Topic: 2. Trauma

Which of the following describes the preferred initial treatment for a displaced midshaft clavicle fracture in a healthy, active adult?

. Figure-of-eight brace
. Sling immobilization for 6 weeks
. Plate and screw osteosynthesis
. Intramedullary nailing
. Immediate physical therapy to maintain range of motion

Correct Answer & Explanation

. Plate and screw osteosynthesis

Explanation

For a displaced midshaft clavicle fracture in a healthy, active adult, plate and screw osteosynthesis (open reduction internal fixation) is often the preferred treatment. While non-operative management (sling immobilization) can be successful, displaced fractures, especially with significant shortening or comminution, have a higher risk of non-union, malunion, and prolonged recovery with non-operative treatment. Surgical fixation can provide earlier return to function, improved cosmesis, and lower non-union rates in appropriately selected patients. Figure-of-eight braces have been shown to be no more effective than slings and can cause discomfort. Intramedullary nailing is less commonly used for clavicle fractures. Immediate physical therapy without stabilization is contraindicated.

Question 10038

Topic: 2. Trauma

What is the primary concern when managing a dislocated knee (tibiofemoral dislocation)?

. Damage to the cruciate ligaments
. Meniscal tears
. Articular cartilage damage
. Neurovascular injury, especially the popliteal artery
. Fractures of the tibial plateau

Correct Answer & Explanation

. Neurovascular injury, especially the popliteal artery

Explanation

Neurovascular injury, particularly to the popliteal artery, is the MOST critical concern in a dislocated knee. The popliteal artery runs in close proximity to the posterior knee joint, and it can be stretched, kinked, or torn during dislocation, leading to limb-threatening ischemia. Immediate reduction and thorough neurovascular assessment (including ankle-brachial index - ABI, and potentially CT angiography) are paramount. While ligamentous injuries (ACL, PCL, MCL, LCL), meniscal tears, and articular cartilage damage are almost always present and require subsequent management, the vascular status dictates immediate limb salvage efforts.

Question 10039

Topic: 2. Trauma

A 25-year-old male presents to the emergency department after a high-energy tibia fracture. Six hours post-reduction and casting, he complains of severe pain disproportionate to the injury, pain on passive dorsiflexion of the great toe, and paresthesias in the foot. His distal pulses are palpable. Intracompartmental pressure measurements are obtained. Which of the following pressure differentials (diastolic blood pressure - intracompartmental pressure) is most concerning for impending acute compartment syndrome requiring fasciotomy?

. 25 mmHg
. 35 mmHg
. 40 mmHg
. 10 mmHg
. 50 mmHg

Correct Answer & Explanation

. 10 mmHg

Explanation

The critical threshold for surgical intervention in acute compartment syndrome is typically when the delta pressure (diastolic blood pressure - intracompartmental pressure) falls to less than 30 mmHg. A delta pressure of 10 mmHg indicates a severe compromise in perfusion pressure to the muscles within the compartment, placing the limb at high risk for irreversible ischemic damage and necessitates urgent fasciotomy. While absolute intracompartmental pressures (e.g., >30 mmHg or >40 mmHg) are often cited, the delta pressure provides a more physiological indicator, accounting for the patient's systemic blood pressure.

Question 10040

Topic: 2. Trauma

A patient with a distal radius fracture is placed in a circumferential plaster cast. Several hours later, they complain of increasing pain, paresthesias in the median nerve distribution, and pain with passive extension of the fingers. The cast feels tight. What is the most appropriate initial action?

. Administer stronger analgesics and observe.
. Elevate the limb and apply ice.
. Loosen the cast by splitting it down to the skin on both sides.
. Measure compartment pressures through the cast.
. Remove the cast completely and re-apply a new one.

Correct Answer & Explanation

. Loosen the cast by splitting it down to the skin on both sides.

Explanation

The patient's symptoms are highly suggestive of impending acute compartment syndrome, likely exacerbated by the tight circumferential cast. The most appropriate initial action to mitigate this risk and potentially avert full-blown compartment syndrome is to immediately loosen the cast. This means splitting the cast (and underlying padding) completely down to the skin on both sides (bivalving), or even removing the cast entirely if symptoms persist. While elevation and ice might be general measures, they are insufficient for relieving critical extrinsic compression. Measuring compartment pressures through a tight cast is not the initial action; the priority is to relieve the external compression first. Stronger analgesics mask symptoms and delay diagnosis.

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