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2. Trauma MCQs

Practice Set 511 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 10201

Topic: 2. Trauma

A 45-year-old male sustains a 'floating shoulder' injury (ipsilateral midshaft clavicle fracture and scapular neck fracture) following a motorcycle collision. Which of the following radiographic parameters is the most recognized indication for operative fixation of this injury?

. Clavicular displacement greater than 5 mm
. Glenopolar angle (GPA) less than 22 degrees
. Presence of more than two ipsilateral rib fractures
. Scapular neck angulation of 10 degrees
. Coracoclavicular distance increased by 20%

Correct Answer & Explanation

. Glenopolar angle (GPA) less than 22 degrees

Explanation

A 'floating shoulder' results from ipsilateral fractures of the clavicle and scapular neck, disrupting the superior shoulder suspensory complex. While many can be treated non-operatively, significant displacement warrants surgery to prevent long-term shoulder dysfunction. The glenopolar angle (GPA) assesses the rotational displacement of the glenoid. A normal GPA is 30-45 degrees. A GPA of less than 20-22 degrees indicates severe inferomedial tilt of the glenoid and is a strong indication for surgical fixation (usually starting with the clavicle).

Question 10202

Topic: 2. Trauma

A 32-year-old male sustains a Galeazzi fracture-dislocation. He undergoes open reduction and internal fixation of the radial shaft. Intra-operatively, the distal radioulnar joint (DRUJ) remains unstable in supination. Which of the following characteristics of the radius fracture most significantly increases the risk of post-fixation DRUJ instability?

. Fracture located within 7.5 cm of the distal articular surface
. Fracture located greater than 7.5 cm from the distal articular surface
. Presence of an associated median nerve neuropraxia
. Dorsal angulation of the primary fracture apex
. Comminution limited strictly to the middle third of the radius

Correct Answer & Explanation

. Fracture located within 7.5 cm of the distal articular surface

Explanation

Galeazzi fractures are fractures of the distal third of the radial shaft with associated disruption of the DRUJ. Bado and others have classified these based on distance from the articular surface. Fractures occurring within 7.5 cm of the distal radial articular surface (Type I) have a significantly higher rate of DRUJ instability (up to 55%) following anatomic fixation of the radius compared to fractures >7.5 cm proximal to the joint (Type II, ~6% instability rate).

Question 10203

Topic: 2. Trauma
A 40-year-old male is involved in a dashboard injury and sustains a posterior hip dislocation. Post-reduction CT scan reveals a fracture of the femoral head with the fracture line extending cephalad to the fovea capitis, with a 2.5 mm step-off of the articular surface. According to the Pipkin classification, what is the stage and appropriate management?
. Pipkin I; manage with protected weight bearing for 6 weeks
. Pipkin I; manage with ORIF via a surgical dislocation approach
. Pipkin II; manage with ORIF of the femoral head
. Pipkin III; manage with primary Total Hip Arthroplasty
. Pipkin IV; manage with conservative spica casting

Correct Answer & Explanation

. Pipkin II; manage with ORIF of the femoral head

Explanation

Pipkin classification defines femoral head fractures associated with posterior hip dislocations. Pipkin I fractures occur caudad to the fovea capitis (non-weight bearing portion); Pipkin II fractures occur cephalad to the fovea capitis (weight-bearing portion). A step-off of >1 mm in a Pipkin II fracture necessitates Open Reduction and Internal Fixation (ORIF) to restore joint congruity and reduce post-traumatic arthritis risk. Pipkin III includes a femoral neck fracture, and Pipkin IV includes an acetabular fracture.

Question 10204

Topic: Pelvic & Acetabular Trauma
A 50-year-old male arrives at the trauma bay in hemorrhagic shock following an anteroposterior compression (APC III) pelvic ring injury. Emergency medical services placed a commercial pelvic binder in the field. Upon evaluation, to maximize the mechanical closure of the pelvic ring and tamponade the presacral venous plexus bleeding, the pelvic binder must be accurately centered over which anatomic landmark?
. Iliac crests
. Anterior superior iliac spines
. Greater trochanters
. Symphysis pubis
. Femoral neck

Correct Answer & Explanation

. Greater trochanters

Explanation

Pelvic binders are critical in the acute management of mechanically unstable, open-book pelvic ring injuries (APC II/III) to reduce pelvic volume and tamponade venous bleeding. To be effective, the binder must be placed directly over the greater trochanters. Placement too high (e.g., over the iliac crests) is a common error and may paradoxically open the pelvis further or fail to reduce the volume adequately.

Question 10205

Topic: 2. Trauma

A 30-year-old male with a comminuted tibial shaft fracture complains of severe, unrelenting pain out of proportion to the injury. His blood pressure is 105/65 mmHg. Intracompartmental pressure testing of the anterior compartment yields a value of 40 mmHg. What is the calculated Delta P, and what is the most appropriate management?

. Delta P is 25 mmHg; elevate the leg and observe
. Delta P is 65 mmHg; elevate the leg and observe
. Delta P is 25 mmHg; immediate four-compartment fasciotomy
. Delta P is 65 mmHg; immediate four-compartment fasciotomy
. Delta P is 40 mmHg; administer IV mannitol

Correct Answer & Explanation

. Delta P is 25 mmHg; immediate four-compartment fasciotomy

Explanation

Delta P is calculated as Diastolic Blood Pressure minus Intracompartmental Pressure (Delta P = DBP - ICP). In this patient, 65 mmHg - 40 mmHg = 25 mmHg. A Delta P of less than 30 mmHg is an absolute indication for immediate four-compartment fasciotomy of the lower leg to prevent irreversible muscle and nerve necrosis associated with acute compartment syndrome.

Question 10206

Topic: 2. Trauma

A 35-year-old motorcycle accident victim presents with a flail upper extremity, ipsilateral clavicle fracture, and absent radial pulse. You suspect scapulothoracic dissociation. Which of the following radiographic measurements is most reliably used to diagnose this condition on a non-rotated AP chest radiograph?

. Scapular index > 1.07
. Acromiohumeral interval < 7mm
. Coracoclavicular distance > 13mm
. Glenopolar angle < 30 degrees
. Lateral center edge angle < 20 degrees

Correct Answer & Explanation

. Scapular index > 1.07

Explanation

Scapulothoracic dissociation is defined by complete disruption of the scapulothoracic articulation with lateral displacement of the scapula, often accompanied by severe brachial plexus and subclavian vessel injury. The radiographic diagnosis is made using the scapular index, which is the ratio of the distance from the thoracic midline to the medial border of the scapula on the injured side compared to the normal side. A ratio of > 1.07 is highly specific for the diagnosis.

Question 10207

Topic: Pelvic & Acetabular Trauma

A 38-year-old female presents in hemorrhagic shock following a crush injury to the pelvis. Radiographs demonstrate a vertical shear pelvic ring disruption with marked displacement of the sacroiliac joint. Despite the application of a pelvic binder and massive transfusion protocol, she remains hemodynamically unstable. If arterial bleeding is contributing to her shock, which artery is most likely injured in the posterior aspect of this pelvic ring disruption?

. Internal pudendal artery
. Superior gluteal artery
. Obturator artery
. Inferior epigastric artery
. External iliac artery

Correct Answer & Explanation

. Superior gluteal artery

Explanation

While venous bleeding (from the presacral venous plexus) and cancellous bone bleeding are the most common sources of hemorrhage in pelvic fractures overall, arterial bleeding can be catastrophic. The superior gluteal artery is the most frequently injured artery in posterior pelvic ring disruptions, particularly those involving sacral fractures or major sacroiliac joint disruptions. The internal pudendal and obturator arteries are more commonly injured in anterior ring disruptions (e.g., rami fractures).

Question 10208

Topic: 2. Trauma

When evaluating a proximal humerus fracture for the risk of developing avascular necrosis (AVN) of the humeral head, Hertel described specific radiographic criteria that predict ischemia. Which of the following findings is the most reliable predictor of subsequent ischemia?

. Metaphyseal extension of the head fragment (calcar length) < 8 mm
. Displacement of the greater tuberosity > 1 cm
. Intact medial hinge
. Angulation of the surgical neck > 45 degrees
. Valgus impaction of the humeral head

Correct Answer & Explanation

. Metaphyseal extension of the head fragment (calcar length) < 8 mm

Explanation

Hertel's criteria for predicting ischemia in proximal humerus fractures identified that a calcar length (metaphyseal extension of the humeral head fragment) of less than 8 mm, combined with disruption of the medial hinge, are the most reliable predictors of humeral head ischemia and subsequent AVN. A calcar length > 8 mm and an intact medial hinge are protective, as they preserve the intraosseous blood supply from the anterior and posterior circumflex humeral arteries.

Question 10209

Topic: 2. Trauma

A 25-year-old male is admitted to the ICU with a severely comminuted tibia fracture. He is sedated and intubated. An intracompartmental pressure monitor is placed in the anterior compartment of his leg, yielding a pressure of 45 mmHg. His systemic blood pressure is 110/65 mmHg. What is the calculated Delta P, and what is the indicated management?

. Delta P is 20 mmHg; proceed with emergent four-compartment fasciotomy
. Delta P is 20 mmHg; continue close observation
. Delta P is 65 mmHg; proceed with emergent four-compartment fasciotomy
. Delta P is 65 mmHg; continue close observation
. Delta P is 45 mmHg; proceed with emergent four-compartment fasciotomy

Correct Answer & Explanation

. Delta P is 20 mmHg; proceed with emergent four-compartment fasciotomy

Explanation

Acute compartment syndrome is a surgical emergency. The definitive diagnostic metric is the Delta P, which is calculated as the Diastolic Blood Pressure minus the Intracompartmental Pressure. In this case, 65 mmHg - 45 mmHg = 20 mmHg. A Delta P of less than 30 mmHg (some sources cite <20-30 mmHg) is widely accepted as an absolute indication for emergent fasciotomy due to inadequate tissue perfusion. Since the Delta P is 20 mmHg, immediate four-compartment fasciotomy is indicated.

Question 10210

Topic: 2. Trauma

A 35-year-old male sustains a posterior wall acetabular fracture following a motor vehicle collision. The hip was reduced in the ED. Which of the following radiographic or intraoperative findings is considered an absolute indication for operative fixation (ORIF) of the posterior wall?

. A posterior wall fracture involving 15% of the posterior wall width on CT
. A roof arc angle of 60 degrees
. Marginal impaction of the acetabular articular surface
. A stable hip joint on dynamic fluoroscopic examination under anesthesia
. Presence of a posterior column fracture line that does not displace

Correct Answer & Explanation

. Marginal impaction of the acetabular articular surface

Explanation

Absolute indications for ORIF of a posterior wall acetabular fracture include hip joint instability (often defined as >20-50% wall involvement, or dynamic instability on Exam Under Anesthesia), an irreducible fracture-dislocation, intra-articular incarcerated fragments, and marginal impaction of the articular surface. Marginal impaction cannot be reduced closed and requires surgical elevation, bone grafting, and fixation to restore the articular congruity and prevent rapid post-traumatic arthrosis. A wall size <20% is typically stable and can often be treated non-operatively if congruent.

Question 10211

Topic: 2. Trauma
A 42-year-old farmer sustains an open midshaft tibia fracture (Gustilo-Anderson Type IIIA) after his leg is caught in a tractor. The wound is heavily contaminated with soil and organic material. In addition to prompt surgical debridement, which intravenous antibiotic regimen is most appropriate according to standard trauma guidelines?
. A first-generation cephalosporin alone
. A first-generation cephalosporin and an aminoglycoside
. A first-generation cephalosporin, an aminoglycoside, and high-dose penicillin
. Vancomycin and Piperacillin-Tazobactam
. Clindamycin and a fluoroquinolone

Correct Answer & Explanation

. A first-generation cephalosporin, an aminoglycoside, and high-dose penicillin

Explanation

For Gustilo-Anderson Type III open fractures, standard prophylaxis includes a first-generation cephalosporin (for Gram-positive coverage) and an aminoglycoside (for extended Gram-negative coverage). In cases of farm-related injuries, highly contaminated soil injuries, or potential bowel contamination, there is a high risk of anaerobic infection, specifically Clostridium perfringens. Therefore, high-dose penicillin is added to the regimen to provide necessary anaerobic coverage.

Question 10212

Topic: 2. Trauma
A 40-year-old male sustains a Schatzker Type IV (medial) tibial plateau fracture following a high-energy motor vehicle collision. Due to the mechanism and specific fracture pattern, which critical anatomic structure is at the highest risk of injury and must be meticulously evaluated?
. Common peroneal nerve
. Anterior tibial artery
. Popliteal artery
. Saphenous nerve
. Superficial peroneal nerve

Correct Answer & Explanation

. Popliteal artery

Explanation

A Schatzker Type IV fracture involves the medial tibial plateau. Unlike lateral plateau fractures (Schatzker I-III) which are often lower energy, medial plateau fractures typically result from high-energy varus forces. They are clinically treated as knee dislocation equivalents. Because the popliteal artery is tethered proximally at the adductor hiatus and distally at the soleus arch, the severe hyperextension/varus mechanism places the popliteal artery at extreme risk for traction injury, intimal tear, or transection.

Question 10213

Topic: 2. Trauma
In young adults with femoral neck fractures, the Pauwels classification is frequently used to assess biomechanical stability. Which feature of a Pauwels Type III fracture is most directly responsible for its high rates of nonunion and osteonecrosis?
. A horizontal fracture line creating excessive compressive forces
. A highly vertical fracture line creating excessive shear forces
. Extensive comminution of the anterior femoral neck
. Extension of the fracture into the greater trochanter
. Concomitant disruption of the ligamentum teres

Correct Answer & Explanation

. A highly vertical fracture line creating excessive shear forces

Explanation

The Pauwels classification is based on the angle of the fracture line relative to the horizontal plane. Type I is <30 degrees, Type II is 30-50 degrees, and Type III is >50 degrees (highly vertical). A vertical fracture line converts the weight-bearing loads across the hip joint into shear forces rather than compressive forces. This high shear environment leads to extreme instability, making it difficult to achieve stable internal fixation, thereby significantly increasing the risk of mechanical failure, nonunion, and subsequent osteonecrosis.

Question 10214

Topic: 2. Trauma

A 25-year-old male is brought to the trauma bay after sustaining a low-velocity civilian gunshot wound to the mid-thigh. Radiographs show a comminuted midshaft femur fracture. The bullet passed 'through and through'. The patient is neurovascularly intact with no expanding hematoma, and soft tissues are relatively clean. What is the standard operative management for this injury?

. Immediate formal open debridement of the entire bullet tract followed by external fixation
. Local superficial wound care, tetanus prophylaxis, and acute reamed intramedullary nailing
. Skeletal traction for 2 weeks followed by delayed intramedullary nailing
. Routine formal angiography of the extremity followed by plating
. Excision of all ballistic fragments through extensive surgical approaches and casting

Correct Answer & Explanation

. Local superficial wound care, tetanus prophylaxis, and acute reamed intramedullary nailing

Explanation

Civilian, low-velocity gunshot wounds resulting in femur fractures generally behave like closed fractures regarding infection risk. Standard of care includes local superficial wound debridement/irrigation in the ER, tetanus prophylaxis, appropriate short-term IV antibiotics, and acute intramedullary nailing. Formal operative debridement of the entire bullet tract is unnecessary and may increase morbidity, provided there is no severe contamination (e.g., shotgun wadding), vascular compromise, or intra-articular bullet retention.

Question 10215

Topic: 2. Trauma

A 22-year-old professional basketball player presents with lateral foot pain after a cutting maneuver. Radiographs demonstrate an acute, non-displaced Zone 2 fracture of the proximal fifth metatarsal (Jones fracture). To minimize the risk of nonunion and allow for the fastest, most reliable return to elite play, what is the recommended treatment?

. Non-weight bearing in a short leg cast for 6 to 8 weeks
. Weight-bearing as tolerated in a stiff-soled post-op shoe
. Surgical fixation using a solid intramedullary screw
. Open reduction and dual-plate fixation with bone grafting
. Primary excision of the proximal fragment and peroneus brevis advancement

Correct Answer & Explanation

. Surgical fixation using a solid intramedullary screw

Explanation

A Jones fracture occurs in Zone 2 of the proximal fifth metatarsal (the metaphyseal-diaphyseal junction), a vascular watershed area with a high propensity for delayed union or nonunion. While non-operative management (non-weight bearing cast) can be successful in the general population, intramedullary screw fixation is recommended for elite athletes. Surgical fixation significantly decreases the time to union, decreases the nonunion rate, and allows for a faster and more predictable return to sport.

Question 10216

Topic: 2. Trauma
A 45-year-old male is brought to the trauma bay after a crush injury. He is hypotensive with a blood pressure of 80/50 mmHg. An AP pelvis radiograph reveals an 'open book' (APC III) pelvic ring injury. A pelvic binder is requested. To biomechanically optimize the closure of the pelvic ring and control hemorrhage, at what anatomical level should the binder be centered?
. Iliac crests
. Anterior superior iliac spines (ASIS)
. Greater trochanters
. Symphysis pubis
. Subtrochanteric femur

Correct Answer & Explanation

. Greater trochanters

Explanation

Pelvic binders should be centered directly over the greater trochanters to effectively close the pelvic ring and reduce pelvic volume. Placement over the iliac crests can paradoxically open the pelvis further in certain fracture patterns.

Question 10217

Topic: 2. Trauma

A 35-year-old female undergoes open reduction and internal fixation for a Hawkins Type II talar neck fracture. At her 8-week follow-up, an AP ankle radiograph reveals a distinct band of subchondral radiolucency in the talar dome. What does this radiographic finding signify?

. Avascular necrosis of the talar body
. Deep surgical site infection
. Intact vascularity of the talar body
. Impending nonunion of the fracture
. Hardware failure

Correct Answer & Explanation

. Intact vascularity of the talar body

Explanation

This finding describes the Hawkins sign, which is subchondral osteopenia observed 6-8 weeks post-injury. It indicates intact vascularity and bone resorption, making avascular necrosis highly unlikely.

Question 10218

Topic: 2. Trauma

A 30-year-old male sustains a closed, highly comminuted midshaft tibial fracture. His blood pressure is 110/70 mmHg. He reports out-of-proportion pain, and intracompartmental pressure testing of the anterior compartment yields a value of 45 mmHg. What is the most appropriate next step in management?

. Immediate four-compartment fasciotomy
. Immediate single-compartment (anterior) fasciotomy
. Elevate the leg above the level of the heart
. Remove the splint and reassess in 2 hours
. Administer intravenous mannitol

Correct Answer & Explanation

. Immediate four-compartment fasciotomy

Explanation

Compartment syndrome is diagnosed when the Delta P (Diastolic BP minus Compartment Pressure) is less than 30 mmHg. In this case, Delta P is 25 mmHg (70 - 45), indicating immediate four-compartment fasciotomy.

Question 10219

Topic: 2. Trauma

A 40-year-old male sustains a closed, distal-third spiral fracture of the humeral shaft (Holstein-Lewis type). His initial neurologic exam in the emergency department is fully intact. Following a closed reduction and application of a coaptation splint, the patient is unable to actively extend his wrist or fingers. What is the most appropriate next step in management?

. Observation and repeat examination in 24 hours
. MRI of the affected upper extremity
. Immediate surgical exploration of the radial nerve
. Electromyography (EMG) testing in 3 weeks
. Adjustment of the splint to relieve pressure

Correct Answer & Explanation

. Immediate surgical exploration of the radial nerve

Explanation

A secondary radial nerve palsy that develops after a closed reduction attempt of a humerus shaft fracture is an absolute indication for surgical exploration. This is to identify and resolve potential nerve entrapment within the fracture site.

Question 10220

Topic: 2. Trauma

A 70-year-old female sustains a subtrochanteric femur fracture. Preoperatively, the proximal fracture fragment is observed to be displaced into flexion, abduction, and external rotation. Which muscle is primarily responsible for the significant flexion deformity of this proximal fragment?

. Gluteus medius
. Gluteus maximus
. Iliopsoas
. Adductor longus
. Tensor fasciae latae

Correct Answer & Explanation

. Iliopsoas

Explanation

In subtrochanteric fractures, the iliopsoas tendon inserts on the lesser trochanter and acts as the primary deforming force pulling the proximal fragment into flexion.

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