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2. Trauma MCQs

Practice Set 407 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 8121

Topic: 2. Trauma

A 24-year-old male sustains an acute, non-displaced fracture of the proximal pole of the scaphoid after a fall. What is the primary anatomic and pathophysiological rationale for recommending surgical fixation with a headless compression screw over prolonged cast immobilization in this specific scenario?

. Proximal pole fractures have a higher rate of nonunion and avascular necrosis due to retrograde blood supply.
. Cast immobilization is poorly tolerated, leading to irreversible stiffness in young, active patients.
. Proximal pole fractures are almost universally associated with complete scapholunate ligament tears.
. Surgical fixation significantly decreases the long-term risk of carpal tunnel syndrome.
. Percutaneous pinning is biomechanically superior to screw fixation for proximal pole variants.

Correct Answer & Explanation

. Proximal pole fractures have a higher rate of nonunion and avascular necrosis due to retrograde blood supply.

Explanation

The scaphoid receives its primary blood supply from branches of the radial artery that enter distally and flow in a retrograde fashion. Fractures of the proximal pole profoundly disrupt this blood supply, resulting in a high risk of avascular necrosis and nonunion. Surgical fixation is highly recommended even for non-displaced proximal pole fractures to achieve rigid stability and optimize the chances of union.

Question 8122

Topic: 2. Trauma

A 48-year-old female sustains a fall from a height, resulting in a complex elbow injury requiring urgent orthopedic intervention. The diagnosis of a 'terrible triad' injury of the elbow is established. Which of the following combinations of injuries strictly defines this classic clinical entity?

. Elbow dislocation, radial head fracture, and coronoid fracture
. Elbow dislocation, olecranon fracture, and radial head fracture
. Medial epicondyle fracture, radial head fracture, and coronoid fracture
. Elbow dislocation, lateral condyle fracture, and capitellum fracture
. Monteggia fracture-dislocation, coronoid fracture, and radial head fracture

Correct Answer & Explanation

. Elbow dislocation, radial head fracture, and coronoid fracture

Explanation

The 'terrible triad' of the elbow describes a specific and highly unstable injury pattern consisting of an elbow dislocation (typically posterior or posterolateral), a radial head fracture, and a coronoid fracture. It represents a sequential failure of the primary and secondary stabilizers of the elbow, often requiring operative repair of the lateral collateral ligament complex and restoration of the radial head and coronoid to permit early range of motion.

Question 8123

Topic: 2. Trauma

The primary blood supply to the articular segment of the humeral head in an adult is predominantly provided by which of the following vessels?

. Posterior humeral circumflex artery (PHCA)
. Anterior humeral circumflex artery (AHCA)
. Thoracoacromial artery
. Suprascapular artery
. Circumflex scapular artery

Correct Answer & Explanation

. Posterior humeral circumflex artery (PHCA)

Explanation

Historically, the anterior humeral circumflex artery (AHCA), specifically its anterolateral ascending branch (arcuate artery), was thought to provide the main blood supply to the humeral head. However, more recent anatomic and perfusion studies (e.g., Brooks et al., Hettrich et al.) have demonstrated that the posterior humeral circumflex artery (PHCA) provides the majority (up to 64%) of the blood supply to the humeral head. This has important implications in proximal humerus fracture surgery and predicting avascular necrosis.

Question 8124

Topic: 2. Trauma

A 65-year-old female sustains a displaced 3-part proximal humerus fracture. Based on quantitative anatomical studies, which of the following arterial structures provides the predominant blood supply to the humeral head and is most at risk in anatomic neck fractures?

. Anterior humeral circumflex artery
. Posterior humeral circumflex artery
. Suprascapular artery
. Thoracoacromial artery
. Circumflex scapular artery

Correct Answer & Explanation

. Anterior humeral circumflex artery

Explanation

Recent anatomical studies (e.g., Hettrich et al.) have demonstrated that the posterior humeral circumflex artery provides the predominant blood supply to the humeral head (approximately 64% of the volume). This finding shifts the traditional paradigm, which historically emphasized the anterolateral branch (arcuate artery) of the anterior humeral circumflex artery. Disruption of this primary blood supply significantly increases the risk of avascular necrosis.

Question 8125

Topic: 2. Trauma

A 35-year-old man presents after a high-speed motorcycle accident with a completely flail left upper extremity and a massively swollen shoulder. Radiographs show lateral displacement of the scapula and a widely displaced midshaft clavicle fracture. What vascular injury is most commonly associated with this specific pattern of injury?

. Axillary artery
. Subclavian artery
. Brachial artery
. Suprascapular artery
. Thoracoacromial artery

Correct Answer & Explanation

. Axillary artery

Explanation

The clinical picture describes scapulothoracic dissociation, a severe, high-energy closed injury involving traumatic disruption of the scapulothoracic articulation. It is characterized by lateral displacement of the scapula, clavicle fracture or acromioclavicular/sternoclavicular joint disruption, and severe soft tissue injury. The subclavian artery and the brachial plexus are the most commonly injured neurovascular structures, often leading to a flail and ischemic limb. Amputation is frequently required due to the severity of the complete brachial plexus avulsion and vascular disruption.

Question 8126

Topic: Upper Extremity Trauma

A 32-year-old male presents with profound elbow stiffness 5 months after surgical management of a terrible triad injury (radial head arthroplasty, LCL repair, coronoid fixation). Radiographs demonstrate heterotopic ossification (HO) bridging the radiocapitellar joint with mature, sharp cortical margins and distinct trabecular patterns. His clinical range of motion has plateaued despite aggressive therapy. What is the most appropriate management regarding surgical excision?

. Immediate excision, as waiting increases the risk of joint degeneration
. Wait until 12-18 months post-injury to allow for complete metabolic quiescence
. Surgical excision now, as the HO is radiographically mature and ROM has plateaued
. Preoperative radiation therapy followed by delayed excision at 1 year
. Perform a manipulation under anesthesia prior to considering open excision

Correct Answer & Explanation

. Immediate excision, as waiting increases the risk of joint degeneration

Explanation

Historically, surgical excision of heterotopic ossification (HO) was delayed until 12-18 months when bone scans showed metabolic quiescence. However, contemporary evidence demonstrates that early excision (typically between 4 to 6 months) is safe and effective once the HO is radiographically mature (showing distinct trabeculae and sharp margins) and the patient's clinical range of motion has plateaued. Early excision allows for earlier rehabilitation and does not have an increased rate of recurrence compared to delayed excision, provided proper prophylaxis (NSAIDs or radiation) is used postoperatively.

Question 8127

Topic: Upper Extremity Trauma

A 25-year-old hockey player sustains a direct blow to the superior aspect of his right shoulder. Clinical examination reveals marked prominence of the distal clavicle. Radiographs confirm a Type V acromioclavicular (AC) joint separation, with the clavicle displaced superiorly by 200% relative to the acromion. Which anatomical structure represents the primary static restraint to superior translation of the distal clavicle?

. Acromioclavicular ligaments
. Coracoclavicular ligaments
. Coracoacromial ligament
. Short head of the biceps tendon
. Clavipectoral fascia

Correct Answer & Explanation

. Acromioclavicular ligaments

Explanation

The coracoclavicular (CC) ligaments, consisting of the conoid and trapezoid ligaments, act as the primary static restraints to superior and inferior translation of the clavicle relative to the scapula. The acromioclavicular (AC) ligaments are the primary restraints to anteroposterior translation. A Type V AC separation involves complete disruption of both the AC and CC ligaments, along with tearing of the deltotrapezial fascia, leading to severe superior displacement of the clavicle (100% to 300% of the contralateral side).

Question 8128

Topic: 2. Trauma

According to Hertel's criteria, which of the following combinations of radiographic findings following a proximal humerus fracture most accurately predicts a high probability of humeral head ischemia?

. Fracture of the anatomical neck, short calcar segment (< 8 mm), and disrupted medial hinge (> 2 mm)
. Fracture of the surgical neck, long calcar segment (> 8 mm), and disrupted medial hinge (> 2 mm)
. Fracture of the anatomical neck, short calcar segment (< 8 mm), and intact medial hinge
. Fracture of the surgical neck, short calcar segment (< 8 mm), and intact medial hinge
. Fracture of the anatomical neck, long calcar segment (> 8 mm), and disrupted medial hinge (> 2 mm)

Correct Answer & Explanation

. Fracture of the anatomical neck, short calcar segment (< 8 mm), and disrupted medial hinge (> 2 mm)

Explanation

Hertel et al. established criteria to predict the likelihood of ischemia in the humeral head following proximal humerus fractures. The triad most predictive of ischemia includes a fracture line passing through the anatomical neck, a short calcar (metaphyseal) segment of less than 8 mm attached to the articular segment, and a disrupted medial hinge (loss of medial cortical contact > 2 mm). When all three of these criteria are present, the positive predictive value for ischemia reaches 97%.

Question 8129

Topic: 2. Trauma

A 22-year-old man falls on an outstretched hand and presents with anatomic snuffbox tenderness. Radiographs show a non-displaced fracture through the proximal pole of the scaphoid. What is the most appropriate management strategy and its primary rationale?

. Nonoperative management in a short-arm cast; because proximal pole fractures have high union rates
. Nonoperative management in a long-arm thumb spica cast; because proximal pole fractures have a robust blood supply
. Surgical fixation; because proximal pole fractures have a high rate of nonunion due to a tenuous retrograde blood supply
. Surgical fixation; to acutely prevent the development of a dorsal intercalated segment instability (DISI) deformity
. Immediate proximal row carpectomy; because proximal pole fractures inevitably progress to avascular necrosis

Correct Answer & Explanation

. Nonoperative management in a short-arm cast; because proximal pole fractures have high union rates

Explanation

The scaphoid receives its primary blood supply from branches of the radial artery entering at the dorsal ridge near the waist, resulting in a retrograde blood flow to the proximal pole. Because of this tenuous blood supply, fractures of the proximal pole are at a significantly high risk for nonunion and avascular necrosis. Even when completely non-displaced, surgical fixation (typically via a dorsal percutaneous or mini-open approach) is the recommended management for proximal pole scaphoid fractures to optimize the chances of union and allow for earlier mobilization.

Question 8130

Topic: 2. Trauma

A 24-year-old man presents with chronic wrist pain 8 months after a fall. Radiographs show a scaphoid proximal pole fracture nonunion. MRI demonstrates low T1 and T2 signal intensity throughout the proximal pole, indicating avascular necrosis (AVN). There is no radioscaphoid arthritis. Which of the following is the most appropriate surgical treatment?

. Scaphoid excision and four-corner fusion
. Proximal row carpectomy
. Non-vascularized iliac crest bone grafting and headless compression screw
. Vascularized bone graft (e.g., 1,2-ICSRA or medial femoral condyle) and rigid fixation
. Percutaneous screw fixation alone

Correct Answer & Explanation

. Scaphoid excision and four-corner fusion

Explanation

In the presence of a proximal pole scaphoid nonunion with avascular necrosis (AVN), indicated by low T1 and T2 MR signal without punctate bleeding intraoperatively, vascularized bone grafting is required. Free vascularized grafts like the medial femoral condyle (MFC) graft or pedicled grafts (1,2-ICSRA) are indicated because non-vascularized grafts have a much lower healing rate when AVN is present. Salvage procedures (four-corner fusion, PRC) are reserved for cases with established arthritis.

Question 8131

Topic: Upper Extremity Trauma

A 31-year-old male bodybuilder feels a sudden, painful 'pop' in his anterior chest while performing a heavy bench press. He presents with extensive ecchymosis over the anterior axilla, swelling, and a loss of the normal anterior axillary fold contour. Examination reveals severe weakness in adduction and internal rotation of the humerus. Which of the following anatomical locations is the most common site of rupture for this injury?

. Sternal origin
. Clavicular origin
. Musculotendinous junction
. Intramuscular substance
. Humeral insertion (tendon avulsion)

Correct Answer & Explanation

. Sternal origin

Explanation

Pectoralis major ruptures almost exclusively occur in males lifting heavy weights, particularly during the eccentric phase of the bench press. The most common site of rupture is an avulsion of the tendon from its insertion on the proximal humerus (specifically, the lateral lip of the bicipital groove). The sternocostal head is most frequently involved, as it is subjected to maximal stretch during eccentric loading. Surgical repair via anatomic reattachment to the humerus using suture anchors or cortical buttons provides superior functional and cosmetic outcomes in young, active individuals compared to nonoperative treatment.

Question 8132

Topic: 2. Trauma

A 65-year-old woman with a long-standing history of rheumatoid arthritis sustains a severe intra-articular, comminuted distal humerus fracture (AO/OTA 13-C3). Radiographs demonstrate severe osteopenia and preexisting radiocapitellar joint space narrowing. Which of the following is the most appropriate surgical treatment?

. Open reduction and internal fixation with dual orthogonal plates
. Open reduction and internal fixation with dual parallel plates
. Total elbow arthroplasty
. Hemiarthroplasty of the elbow
. Nonoperative management with a functional brace

Correct Answer & Explanation

. Open reduction and internal fixation with dual orthogonal plates

Explanation

Total elbow arthroplasty (TEA) is the treatment of choice for elderly patients with complex, comminuted intra-articular distal humerus fractures, particularly in the setting of poor bone quality or preexisting inflammatory arthritis (such as rheumatoid arthritis). TEA allows for immediate weight-bearing as tolerated and early range of motion, providing a more reliable outcome than internal fixation in this specific patient demographic.

Question 8133

Topic: 2. Trauma

A 68-year-old osteoporotic woman undergoes open reduction and internal fixation with a locking plate for a displaced 3-part proximal humerus fracture.

Postoperatively, what technical error during fixation most significantly increases her risk of varus collapse and subsequent superior screw cutout?

. Superior placement of the plate relative to the greater tuberosity
. Failure to place inferomedial calcar screws
. Over-penetration of the anterior-posterior screws
. Using a deltopectoral approach rather than an anterolateral approach
. Tying the rotator cuff sutures to the plate instead of bone

Correct Answer & Explanation

. Superior placement of the plate relative to the greater tuberosity

Explanation

In the fixation of proximal humerus fractures with locking plates, restoring medial column support is critical to prevent varus collapse and superior screw cutout. This is best achieved by accurately placing inferomedial screws (calcar screws) into the inferomedial quadrant of the humeral head. Failure to place these screws is a major independent risk factor for construct failure.

Question 8134

Topic: 2. Trauma

A 65-year-old woman sustains a severely displaced 4-part proximal humerus fracture after a motor vehicle collision. A standard AP radiograph

is reviewed. According to the Hertel criteria, which of the following radiographic findings is the most accurate predictor of humeral head ischemia?

. Greater tuberosity displacement of more than 1 cm
. A metaphyseal segment attached to the articular fragment measuring less than 8 mm
. Varus angulation of the humeral head exceeding 45 degrees
. Medial hinge displacement of 1 mm
. Fracture extension into the bicipital groove

Correct Answer & Explanation

. Greater tuberosity displacement of more than 1 cm

Explanation

Hertel et al. described specific criteria highly predictive of humeral head ischemia following proximal humerus fractures. The most critical predictors are a metaphyseal head extension (calcar length) of less than 8 mm, a disrupted medial hinge (>2 mm displacement), and an anatomic neck fracture pattern. When all three are present, the positive predictive value for ischemia is 97%.

Question 8135

Topic: 2. Trauma

A 24-year-old healthy male sustains a completely displaced, 100% translated, midshaft clavicle fracture. After thoroughly discussing operative and nonoperative management, he chooses nonoperative management with a sling. Based on current high-level prospective evidence (such as the Canadian Orthopaedic Trauma Society trials), which of the following is true regarding his expected outcome compared to operative fixation?

. Higher rate of radiographic nonunion, but no clinically significant difference in long-term shoulder functional outcome scores.
. Higher rate of radiographic nonunion and significantly worse long-term shoulder functional outcome scores.
. Lower risk of symptomatic malunion.
. Faster time to radiographic union.
. Equal risk of secondary surgical intervention.

Correct Answer & Explanation

. Higher rate of radiographic nonunion, but no clinically significant difference in long-term shoulder functional outcome scores.

Explanation

Current high-level evidence, including RCTs and meta-analyses, demonstrates that nonoperative management of displaced midshaft clavicle fractures carries a higher risk of nonunion and symptomatic malunion compared to ORIF. However, at long-term follow-up (1-2 years and beyond), there is no clinically significant difference in patient-reported functional outcome scores (e.g., DASH, Constant scores) between the operative and nonoperative groups. Secondary surgical intervention rates are often similar due to the high rate of symptomatic hardware removal in the operative group.

Question 8136

Topic: Upper Extremity Trauma

During a posterior approach with an olecranon osteotomy for open reduction and internal fixation of a comminuted intra-articular distal humerus fracture (AO/OTA type 13C3), which of the following osteotomy configurations is recommended to optimize stability upon repair and minimize articular step-off?

. Transverse osteotomy at the center of the bare area
. Chevron osteotomy with the apex directed distally within the bare area
. Chevron osteotomy with the apex directed proximally within the bare area
. Oblique osteotomy exiting the coronoid process
. Transverse osteotomy through the coronoid fossa

Correct Answer & Explanation

. Transverse osteotomy at the center of the bare area

Explanation

When performing an olecranon osteotomy for distal humerus exposure, a chevron-shaped osteotomy with the apex directed distally (V-shape pointing toward the diaphysis) is recommended. The cut should be made in the center of the 'bare area' (the non-articular portion of the greater sigmoid notch). The distally directed apex provides maximal inherent stability against medial-lateral and rotational translation when compressed, facilitating anatomic restoration and rigid fixation at closure.

Question 8137

Topic: 2. Trauma

A 75-year-old woman with advanced rheumatoid arthritis presents with a severely comminuted intra-articular distal humerus fracture (AO/OTA 13-C3) after a low-energy fall. She is functionally independent but relies on a walker for ambulation. What is the most appropriate surgical intervention to optimize early functional recovery?

. Open reduction and internal fixation with dual orthogonal locking plates
. Total elbow arthroplasty
. Hemiarthroplasty of the elbow
. Olecranon osteotomy with tension band wiring
. Nonoperative management with a hinged elbow brace

Correct Answer & Explanation

. Open reduction and internal fixation with dual orthogonal locking plates

Explanation

In an elderly, low-demand patient with inflammatory arthritis, poor bone quality, and a highly comminuted distal humerus fracture, Total Elbow Arthroplasty (TEA) provides reliable pain relief and allows for immediate post-operative range of motion. ORIF in this setting has a high failure rate due to the inability to achieve stable fixation in osteoporotic bone.

Question 8138

Topic: 2. Trauma

An 82-year-old woman with severe osteoporosis presents with a closed, highly comminuted intra-articular fracture of the distal humerus following a fall. She lives independently and manages all activities of daily living. Examination shows intact neurovascular status. Radiographs demonstrate multi-fragmentary articular involvement with poor bone stock that is not amenable to stable internal fixation. Which of the following is the most appropriate surgical treatment to allow early range of motion?

. Open reduction and internal fixation with dual orthogonal plates
. Total elbow arthroplasty
. Hemiarthroplasty of the distal humerus
. Closed reduction and cast immobilization
. External fixation

Correct Answer & Explanation

. Open reduction and internal fixation with dual orthogonal plates

Explanation

Total elbow arthroplasty (TEA) is an excellent and highly reliable treatment option for comminuted, intra-articular distal humerus fractures in elderly patients with poor bone quality. It provides immediate stability and allows for early range of motion, which is crucial for preventing severe elbow stiffness. Studies demonstrate that in patients over 65 with complex distal humerus fractures, TEA offers more predictable functional outcomes and lower reoperation rates compared to open reduction and internal fixation (ORIF).

Question 8139

Topic: 2. Trauma

A 40-year-old active man complains of persistent shoulder pain and a palpable 'clunking' 8 months after sustaining a midshaft clavicle fracture treated nonoperatively in a sling. Radiographs demonstrate an atrophic nonunion with 2.5 cm of shortening. What is the most appropriate surgical treatment?

. Excision of the pseudoarthrosis without internal fixation
. Intramedullary nailing of the clavicle
. Open reduction and internal fixation with a plate and screws alone
. Open reduction and internal fixation with a plate and screws combined with autologous bone grafting
. Coracoclavicular ligament reconstruction

Correct Answer & Explanation

. Excision of the pseudoarthrosis without internal fixation

Explanation

Atrophic nonunions lack adequate biological activity and require both mechanical stability and biological stimulation to heal. The gold standard for treating a symptomatic, atrophic midshaft clavicle nonunion is open reduction and internal fixation (ORIF) with a plate and screws supplemented with autologous bone graft (often from the iliac crest) to stimulate osteogenesis.

Question 8140

Topic: 2. Trauma

A 62-year-old woman is treated with a volar locking plate for a comminuted intra-articular distal radius fracture. Eight weeks postoperatively, she presents to the clinic complaining that she suddenly lost the ability to actively flex the interphalangeal joint of her thumb. Passive thumb interphalangeal joint motion is full and painless. What is the most likely etiology of her current presentation?

. Anterior interosseous nerve (AIN) palsy
. Attritional rupture of the flexor pollicis longus (FPL) tendon
. Attritional rupture of the extensor pollicis longus (EPL) tendon
. Adhesions of the flexor digitorum profundus (FDP) tendons
. Unrecognized acute compartment syndrome

Correct Answer & Explanation

. Anterior interosseous nerve (AIN) palsy

Explanation

Volar locking plates placed distal to the 'watershed line' of the distal radius can irritate the overlying flexor tendons. The flexor pollicis longus (FPL) tendon is the most commonly injured flexor tendon due to attrition against prominent hardware, leading to delayed spontaneous rupture. Extensor tendon ruptures (like EPL) are more commonly associated with nonoperative treatment or prominent dorsal screws piercing the dorsal cortex.

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