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2. Trauma MCQs

Practice Set 556 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 11101

Topic: 2. Trauma

In the surgical management of a hemodynamically unstable patient with a high-energy pelvic ring injury, what is the primary pathophysiological rationale for utilizing Damage Control Orthopedics (DCO)?

. To achieve rigid anatomic articular reduction immediately
. To mitigate the severity of the "second hit" systemic inflammatory response syndrome (SIRS)
. To allow for definitive internal fixation within the first 12 hours
. To entirely eliminate the need for post-operative intensive care
. To restore full weight-bearing status on postoperative day one

Correct Answer & Explanation

. To achieve rigid anatomic articular reduction immediately

Explanation

Damage Control Orthopedics focuses on rapid, provisional fracture stabilization (e.g., external fixation) to minimize surgical trauma. This strategy prevents the exacerbation of systemic inflammation, often termed the "second hit," which can trigger catastrophic multiorgan failure.

Question 11102

Topic: 2. Trauma

A 78-year-old female sustains a distal femur fracture above a well-fixed posterior-stabilized TKA (Lewis-Rorabeck Type II). The fracture is comminuted and extends to the metaphyseal-diaphyseal junction. Which of the following is the most appropriate surgical treatment?

. Hinged knee brace and non-weight-bearing
. Revision to a distal femoral replacement endoprosthesis
. Open reduction and internal fixation with a lateral locking plate
. Retrograde intramedullary nailing through the intercondylar notch
. Revision of the femoral component with a long-stem TKA

Correct Answer & Explanation

. Hinged knee brace and non-weight-bearing

Explanation

Lewis-Rorabeck Type II fractures (displaced fracture, well-fixed prosthesis) are primarily treated with open reduction and internal fixation, usually with a laterally applied periarticular locking plate. While retrograde nailing is an option for some fractures, many posterior-stabilized knee designs feature a closed intercondylar box that blocks nail passage.

Question 11103

Topic: Lower Extremity Trauma

A surgeon is performing a primary total knee arthroplasty. After making the initial bone cuts, trial components are placed. The knee is found to be tight in flexion but well-balanced in extension. Which of the following technical adjustments is the most appropriate to address this mismatch?

. Resect more distal femur
. Upsize the femoral component
. Recut the tibia with increased posterior slope
. Release the posterior capsule
. Recut the distal femur in more valgus

Correct Answer & Explanation

. Resect more distal femur

Explanation

A knee that is tight in flexion but balanced in extension has an isolated tight flexion gap. Increasing the posterior slope of the tibial cut resects more posterior tibial bone, effectively increasing the flexion gap without significantly altering the extension gap. Resecting more distal femur or releasing the posterior capsule would affect the extension gap.

Question 11104

Topic: 2. Trauma
A 35-year-old male presents with severe groin pain. Plain radiographs of the pelvis demonstrate a 'crescent sign' in the anterosuperior aspect of the left femoral head, indicative of a subchondral fracture, but the overall contour of the femoral head is maintained with preserved joint space. According to the Ficat and Arlet classification for osteonecrosis, what stage does this represent?
. Stage I
. Stage II
. Stage III
. Stage IV
. Stage V

Correct Answer & Explanation

. Stage III

Explanation

In the Ficat and Arlet classification of femoral head osteonecrosis: Stage I has normal x-rays but abnormal MRI/bone scan. Stage II shows cystic/sclerotic changes with a normal contour. Stage III is characterized by subchondral fracture (the crescent sign) and early subchondral collapse, but joint space is preserved. Stage IV involves secondary osteoarthritis with joint space narrowing.

Question 11105

Topic: Upper Extremity Trauma
In the setting of a Type III acromioclavicular (AC) joint separation, both the AC ligaments and coracoclavicular (CC) ligaments are torn. Which of the following structures acts as the primary restraint to superior translation of the distal clavicle?
. Conoid ligament
. Trapezoid ligament
. Acromioclavicular capsular ligaments
. Coracoacromial ligament
. Superior transverse scapular ligament

Correct Answer & Explanation

. Conoid ligament

Explanation

The coracoclavicular (CC) ligament complex consists of the conoid and trapezoid ligaments. Biomechanical studies have demonstrated that the conoid ligament (which is located posteromedially) is the primary restraint to superior translation of the distal clavicle. The trapezoid ligament (located anterolaterally) serves primarily to resist axial compression of the AC joint. The AC capsular ligaments primarily resist anterior-posterior translation.

Question 11106

Topic: 2. Trauma

Recent anatomic studies utilizing advanced vascular mapping have challenged traditional orthopedic teaching regarding the principal arterial supply to the proximal humerus. According to current literature (e.g., Hettrich et al.), which artery provides the majority of the blood supply to the humeral head?

. Anterolateral branch of the anterior humeral circumflex artery (arcuate artery)
. Posterior humeral circumflex artery
. Thoracoacromial artery
. Suprascapular artery
. Circumflex scapular artery

Correct Answer & Explanation

. Anterolateral branch of the anterior humeral circumflex artery (arcuate artery)

Explanation

Historically, the anterolateral branch of the anterior humeral circumflex artery (the arcuate artery) was considered the primary blood supply to the humeral head. However, modern quantitative anatomic studies (such as the landmark 2010 study by Hettrich et al.) demonstrated that the posterior humeral circumflex artery provides approximately 64% of the blood supply to the humeral head, while the anterior humeral circumflex artery supplies only about 36%. This shift in understanding highlights the critical role of the posterior vessels in preventing avascular necrosis following proximal humerus fractures.

Question 11107

Topic: Upper Extremity Trauma

A 28-year-old professional pitcher presents with medial elbow pain during the late cocking phase of throwing. MRI confirms a full-thickness tear of the anterior bundle of the ulnar collateral ligament (UCL). Where is the typical anatomic insertion of this crucial stabilizing bundle on the ulna?

. Sublime tubercle
. Olecranon tip
. Coronoid tip
. Supinator crest
. Radial notch

Correct Answer & Explanation

. Sublime tubercle

Explanation

The anterior bundle of the medial UCL inserts on the sublime tubercle, located at the anteromedial margin of the coronoid process. This bundle is the primary restraint to valgus stress at the elbow during the throwing motion.

Question 11108

Topic: 2. Trauma

A 40-year-old patient falls from a ladder and sustains an Essex-Lopresti injury. Which combination of anatomic lesions defines this highly unstable injury pattern?

. Radial head fracture, distal radioulnar joint disruption, and interosseous membrane tear
. Galeazzi fracture with concurrent distal radioulnar joint disruption
. Monteggia fracture with anterior radial head dislocation
. Coronoid fracture, radial head fracture, and lateral collateral ligament tear
. Isolated capitellum fracture with medial collateral ligament tear

Correct Answer & Explanation

. Radial head fracture, distal radioulnar joint disruption, and interosseous membrane tear

Explanation

An Essex-Lopresti lesion is characterized by a longitudinal radioulnar dissociation involving a radial head fracture, tearing of the interosseous membrane, and disruption of the distal radioulnar joint (DRUJ). Radial head excision without replacement in this setting leads to catastrophic proximal radial migration.

Question 11109

Topic: 2. Trauma

A 45-year-old male sustains a displaced midshaft clavicle fracture after a bicycle accident. Which of the following represents an absolute, universally accepted indication for acute open reduction and internal fixation?

. Fracture shortening of 1.5 cm
. Complete superior displacement of the medial fragment
. Skin tenting without necrosis
. Open fracture
. Severe comminution with a Z-shaped butterfly fragment

Correct Answer & Explanation

. Fracture shortening of 1.5 cm

Explanation

Absolute indications for acute operative intervention of a clavicle fracture include open fractures, impending skin compromise (necrosis), and concomitant neurovascular injury. Shortening, displacement, and standard skin tenting are relative indications based on patient activity and risk profile.

Question 11110

Topic: Upper Extremity Trauma
A 32-year-old cyclist falls onto the point of his shoulder. Radiographs reveal a 150% superior displacement of the clavicle relative to the acromion, and the coracoclavicular interval measures 28 mm. According to the Rockwood classification, what is the injury type and optimal management?
. Type III, non-operative management
. Type III, operative management
. Type V, non-operative management
. Type V, operative management
. Type IV, non-operative management

Correct Answer & Explanation

. Type V, operative management

Explanation

Displacement of the clavicle between 100% and 300% characterizes a Rockwood Type V injury. This high-grade acromioclavicular joint separation typically requires operative management to restore anatomy and biomechanics.

Question 11111

Topic: 2. Trauma

A 35-year-old male develops severe heterotopic ossification (HO) following ORIF of a distal humerus fracture, restricting his elbow arc of motion to 30-60 degrees. When is the optimal time to perform surgical excision of the HO?

. Immediately once seen on radiographs to prevent progression
. At 3 months, provided alkaline phosphatase levels have normalized
. At 6 months post-injury, regardless of radiographic appearance
. Once radiographs show mature trabecular bone and clinical progression of stiffness has halted
. After 2 years to ensure complete metabolic inactivity

Correct Answer & Explanation

. Immediately once seen on radiographs to prevent progression

Explanation

Excision of HO should be performed when the bone is radiographically mature (distinct trabecular pattern and sharp cortical margins) and the clinical exam demonstrates no further progressive loss of motion. This typically occurs between 6 to 9 months post-injury.

Question 11112

Topic: 2. Trauma

A 19-year-old male presents to the trauma bay after a high-speed MVC with shortness of breath, dysphagia, and a prominent depression at the medial end of the clavicle. A posterior sternoclavicular dislocation is suspected. What is the most appropriate imaging modality to confirm the diagnosis and assess associated structures?

. AP chest radiograph
. Serendipity view radiograph
. CT scan of the chest with IV contrast
. MRI of the brachial plexus
. Ultrasound of the sternoclavicular joint

Correct Answer & Explanation

. AP chest radiograph

Explanation

A CT scan with IV contrast is the gold standard for evaluating posterior sternoclavicular dislocations. It accurately defines the bony displacement and evaluates for potentially life-threatening injuries to the great vessels, trachea, and esophagus.

Question 11113

Topic: 2. Trauma

A 34-year-old male sustains a spiral fracture of the distal third of the humeral shaft (Holstein-Lewis fracture) following an arm-wrestling match. He has a complete radial nerve palsy on presentation. What is the most appropriate initial management?

. Immediate open exploration of the radial nerve and ORIF
. Placement in a coaptation splint and observation of the nerve
. External fixation to span the fracture
. Immediate nerve grafting
. Electromyography (EMG) before any treatment

Correct Answer & Explanation

. Immediate open exploration of the radial nerve and ORIF

Explanation

Primary radial nerve palsy associated with a closed humeral shaft fracture (including the Holstein-Lewis variant) is initially treated expectantly with splinting or functional bracing. Over 85% of these nerve palsies spontaneously recover without immediate exploration.

Question 11114

Topic: 2. Trauma

A 65-year-old female sustains a displaced proximal humerus fracture. Which of the following radiographic findings (Hertel's criteria) is the most reliable predictor of subsequent humeral head avascular necrosis (AVN)?

. Medial hinge disruption > 2 mm
. Anatomical neck fracture line
. Calcar comminution
. Greater tuberosity displacement > 5 mm
. Posteromedial metaphyseal head extension < 8 mm

Correct Answer & Explanation

. Medial hinge disruption > 2 mm

Explanation

Hertel criteria predict ischemia of the humeral head in proximal humerus fractures. The most reliable single predictor is a posteromedial metaphyseal head extension of less than 8 mm, as it indicates loss of the primary blood supply from the posterior humeral circumflex artery.

Question 11115

Topic: 2. Trauma

A 30-year-old male sustains a comminuted, unsalvageable radial head fracture and distal radioulnar joint (DRUJ) dislocation. He undergoes radial head excision without arthroplasty. What is the most likely long-term biomechanical complication of this specific management?

. Ulnohumeral arthritis
. Proximal migration of the radius with ulnocarpal impaction
. Heterotopic ossification of the interosseous membrane
. Varus posteromedial rotatory instability
. Posterior interosseous nerve palsy

Correct Answer & Explanation

. Ulnohumeral arthritis

Explanation

This patient has an Essex-Lopresti injury (radial head fracture, interosseous membrane disruption, and DRUJ dislocation). Excision of the radial head without replacement in this setting removes the secondary stabilizer, resulting in progressive proximal migration of the radius and severe ulnocarpal impaction.

Question 11116

Topic: 2. Trauma

According to the Hertel criteria for proximal humerus fractures, which combination of radiographic findings carries the highest positive predictive value for ischemia and subsequent avascular necrosis of the humeral head?

. Anatomic neck fracture, disrupted medial hinge, and calcar length less than 8 mm
. Surgical neck fracture, intact medial hinge, and calcar length greater than 8 mm
. Greater tuberosity fracture with greater than 1 cm displacement
. Lesser tuberosity fracture with intra-articular extension
. Head-split fracture with severe valgus impaction

Correct Answer & Explanation

. Anatomic neck fracture, disrupted medial hinge, and calcar length less than 8 mm

Explanation

Hertel demonstrated that the combination of an anatomic neck fracture, a disrupted posteromedial hinge, and a metaphyseal head extension (calcar length) of less than 8 mm highly predicts humeral head ischemia.

Question 11117

Topic: 2. Trauma

In the natural history of an untreated scaphoid waist fracture, the carpus typically collapses into a Dorsal Intercalated Segment Instability (DISI) pattern. What biomechanical consequence directly drives this specific deformity?

. Loss of the radioscaphocapitate ligament integrity
. Volar rotation of the distal scaphoid fragment with extension of the lunate
. Dorsal rotation of the distal scaphoid fragment with flexion of the lunate
. Attrition of the lunotriquetral ligament
. Proximal migration of the capitate into the radiocarpal space

Correct Answer & Explanation

. Loss of the radioscaphocapitate ligament integrity

Explanation

In a scaphoid waist nonunion, the distal pole tends to flex (volar rotation) due to the pull of the STT joint capsule and FCR, creating a 'humpback' deformity. Because the proximal scaphoid pole remains attached to the lunate via the intact scapholunate interosseous ligament, the uncoupled lunate extends under the normal physiologic influence of the triquetrum, leading to a DISI deformity.

Question 11118

Topic: 2. Trauma

A 28-year-old male presents with a chronic proximal pole scaphoid nonunion and avascular necrosis (AVN). A free vascularized medial femoral condyle (MFC) bone graft is planned. Which vascular pedicle is primarily harvested to supply this graft?

. Lateral superior genicular artery
. Descending genicular artery
. Medial inferior genicular artery
. Sural artery
. Anterior tibial recurrent artery

Correct Answer & Explanation

. Lateral superior genicular artery

Explanation

The free medial femoral condyle (MFC) vascularized bone graft is primarily supplied by the descending genicular artery (DGA), or alternatively the superomedial genicular artery if the DGA is insufficient. It provides excellent structural support and robust vascularity for challenging scaphoid nonunions complicated by AVN.

Question 11119

Topic: 2. Trauma

Scaphoid fractures in children are rare but can occasionally result in nonunion. Compared to adults, which anatomic location of the scaphoid is most frequently fractured and at highest risk for nonunion in the pediatric population?

. Proximal pole
. Waist
. Distal pole
. Tubercle
. Scaphoid articular surface with the capitate

Correct Answer & Explanation

. Proximal pole

Explanation

In the pediatric population, the ossification center of the scaphoid develops distally to proximally. Consequently, pediatric scaphoid fractures most commonly involve the distal pole, in contrast to adults where waist fractures heavily predominate. Nonunions, though rare, tend to occur at the distal pole in children.

Question 11120

Topic: 2. Trauma

When evaluating a scaphoid nonunion with magnetic resonance imaging (MRI), which sequence and specific finding most reliably indicates the presence of avascular necrosis (AVN) in the proximal pole?

. High signal intensity on T1-weighted images
. High signal intensity on T2-weighted images
. Failure to enhance following intravenous gadolinium administration on T1-weighted images
. Bone marrow edema on STIR sequences
. Low signal intensity on T2-weighted images alone

Correct Answer & Explanation

. High signal intensity on T1-weighted images

Explanation

While a low signal on T1 is a sign of ischemia or edema, it is not highly specific for true AVN, as bone marrow edema from the nonunion can produce similar findings. The most reliable MRI indicator of avascular necrosis is the lack of enhancement of the proximal pole on T1-weighted fat-suppressed images following the administration of intravenous gadolinium contrast.

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