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2. Trauma MCQs

Practice Set 66 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 1301

Topic: 2. Trauma
A 7-year-old child sustains a diaphyseal fracture of the ulna associated with a fracture of the radial neck, but without a true dislocation of the radiocapitellar joint. According to the Bado classification system, how is this injury appropriately categorized?
. Bado type I
. Bado type II
. Bado type III
. Bado type IV
. Monteggia equivalent

Correct Answer & Explanation

. Monteggia equivalent

Explanation

A fracture of the ulnar diaphysis combined with a radial neck fracture, rather than a radiocapitellar dislocation, is considered a Monteggia equivalent lesion. It shares a similar mechanism and requires careful restoration of radiocapitellar alignment.

Question 1302

Topic: 2. Trauma

Which of the following mechanisms of injury is most classically associated with a Bado Type I Monteggia fracture-dislocation?

. Direct blow to the posterior aspect of the ulna
. Fall on an outstretched hand with the forearm in hyperpronation
. Fall onto a flexed elbow
. Forced supination with extreme valgus stress
. Axial load applied to a hyperflexed elbow

Correct Answer & Explanation

. Fall on an outstretched hand with the forearm in hyperpronation

Explanation

A Bado Type I Monteggia fracture (anterior dislocation of the radial head with anteriorly angulated ulnar fracture) classically results from a fall on an outstretched hand with the forearm in hyperpronation. This forces the radial head anteriorly as the ulna fails in tension.

Question 1303

Topic: 2. Trauma
According to the Bado classification, what specific defining feature distinguishes a type IV Monteggia injury from the other three types?
. Posterior dislocation of the radial head
. Lateral dislocation of the radial head
. Concomitant fracture of the radial shaft
. Associated olecranon fracture
. Irreducibility of the radial head due to annular ligament interposition

Correct Answer & Explanation

. Associated olecranon fracture

Explanation

A Bado type IV Monteggia injury is uniquely defined by fractures of the diaphyses of both the radius and the ulna, accompanied by an anterior dislocation of the radial head. This is distinct from types I, II, and III, which involve only an ulnar fracture.

Question 1304

Topic: 2. Trauma
A 7-year-old boy sustains a forearm fracture. Radiographs reveal a fracture of the proximal third of the ulna with lateral dislocation of the radial head. According to the Bado classification, what type of Monteggia lesion is this?
. Type I
. Type II
. Type III
. Type IV
. Equivalent

Correct Answer & Explanation

. Type III

Explanation

Bado type III Monteggia fractures are characterized by a proximal ulnar fracture with a lateral or anterolateral dislocation of the radial head. This type of Monteggia lesion is most commonly observed in the pediatric population.

Question 1305

Topic: 2. Trauma

In the context of a terrible triad injury of the elbow, which portion of the coronoid is most critical to address surgically to restore stability against varus and posteromedial rotatory instability?

. Coronoid tip
. Anterolateral facet
. Anteromedial facet
. Sublime tubercle
. Brachialis insertion

Correct Answer & Explanation

. Anteromedial facet

Explanation

The anteromedial facet of the coronoid is crucial for providing resistance to varus and posteromedial rotatory instability. Fractures involving this facet, even if small, typically require rigid fixation to prevent chronic subluxation.

Question 1306

Topic: 2. Trauma

A 45-year-old female sustains an isolated Bado Type II Monteggia fracture-dislocation. What is the most appropriate definitive management for this patient?

. Closed reduction and long-arm casting in supination
. Open reduction internal fixation (ORIF) of the ulna alone
. ORIF of the ulna with open reduction of the radial head
. ORIF of the ulna and radial head resection
. External fixation with annular ligament reconstruction

Correct Answer & Explanation

. Open reduction internal fixation (ORIF) of the ulna alone

Explanation

In adults, Monteggia fractures are treated operatively with rigid ORIF of the ulna. Anatomic reduction of the ulna almost always indirectly reduces the radial head, making open reduction of the radial head necessary only if it remains incarcerated.

Question 1307

Topic: 2. Trauma

A 9-year-old child presents with a missed Bado Type I Monteggia fracture 6 months post-injury. Radiographs show a malunited proximal ulna and a chronically anteriorly dislocated radial head. Which procedure is required to successfully restore radiocapitellar alignment?

. Isolated annular ligament reconstruction
. Ulnar osteotomy with or without annular ligament reconstruction
. Radial head excision
. Radial osteotomy
. Distal radioulnar joint fusion (Sauve-Kapandji)

Correct Answer & Explanation

. Ulnar osteotomy with or without annular ligament reconstruction

Explanation

In chronic missed Monteggia fractures in children, the ulnar malunion must be addressed with a corrective osteotomy (often angulation and lengthening) to allow the radial head to properly reduce. Soft tissue procedures alone, such as annular ligament reconstruction, are insufficient.

Question 1308

Topic: Upper Extremity Trauma

The 'terrible triad' of the elbow is classically caused by a fall on an outstretched hand resulting in a specific cascade of forces. Which of the following biomechanical mechanisms best describes this injury?

. Valgus, pronation, and axial load
. Varus, supination, and axial load
. Valgus, supination, and axial load
. Varus, pronation, and axial load
. Hyperextension, pronation, and distraction

Correct Answer & Explanation

. Valgus, supination, and axial load

Explanation

The terrible triad of the elbow typically results from an axial load applied to a supinated forearm combined with a valgus posterolateral rotatory force. This causes failure progressing circularly from the lateral side to the anterior side, and finally to the medial side.

Question 1309

Topic: 2. Trauma

Following non-operative treatment of an adult Monteggia fracture, a patient develops a symptomatic nonunion of the ulna with persistent radial head dislocation. What is the most significant long-term consequence if the radiocapitellar joint is left chronically dislocated?

. Cubital tunnel syndrome
. Posterior interosseous nerve palsy
. Proximal radioulnar joint synostosis
. Valgus instability and progressive arthritis
. Avascular necrosis of the radial head

Correct Answer & Explanation

. Valgus instability and progressive arthritis

Explanation

Chronic radial head dislocation leads to progressive valgus instability, elbow stiffness, and advanced radiocapitellar and ulnohumeral osteoarthritis. This emphasizes the critical need for anatomic ulnar length restoration and rigid fixation in adult Monteggia injuries.

Question 1310

Topic: 2. Trauma

A 22-year-old gymnast sustains an injury to her forearm. Radiographs reveal a fracture of the ulnar diaphysis, a fracture of the radial neck, and an intact radiocapitellar joint. Which classification best describes this injury?

. Galeazzi fracture
. Bado Type IV Monteggia
. Monteggia equivalent
. Essex-Lopresti lesion
. Nightstick fracture

Correct Answer & Explanation

. Monteggia equivalent

Explanation

A Monteggia equivalent lesion includes injuries with similar mechanisms and instability patterns but without true radial head dislocation. Examples include an ulnar diaphyseal fracture combined with a radial neck fracture.

Question 1311

Topic: Upper Extremity Trauma

A patient successfully undergoes ORIF for a terrible triad injury with rigid fixation of the coronoid and radial head, and a robust LCL repair. What is the most appropriate early postoperative rehabilitation protocol to prevent stiffness while maintaining stability?

. Immobilization at 90 degrees flexion for 6 weeks
. Active extension and passive flexion starting post-op day 1
. Active-assisted range of motion in full pronation
. Passive range of motion in full supination
. Continuous passive motion starting at 3 weeks

Correct Answer & Explanation

. Active-assisted range of motion in full pronation

Explanation

Early active-assisted range of motion is critical to prevent elbow stiffness. Exercises are typically performed with the forearm in pronation, which uses the crossed intact radius and ulna to protect the repaired lateral collateral ligament complex from varus stress.

Question 1312

Topic: 2. Trauma

Bado Type II (posterior) Monteggia fractures in adults are frequently associated with which of the following concomitant injuries?

. Coronoid fractures and radial head fractures
. Distal radioulnar joint (DRUJ) disruptions
. Scaphoid fractures
. Median nerve avulsions
. Triceps tendon ruptures

Correct Answer & Explanation

. Coronoid fractures and radial head fractures

Explanation

Bado Type II Monteggia fractures in adults are often highly complex injuries, frequently presenting as part of a variant or extended 'terrible triad' pattern that includes fractures of the coronoid process and radial head.

Question 1313

Topic: 2. Trauma

A 55-year-old male presents with a Bado Type II (posterior) Monteggia fracture-dislocation. Based on this adult injury pattern, what is the most commonly associated concomitant injury?

. Anterior interosseous nerve palsy
. Distal radioulnar joint (DRUJ) dislocation
. Capitellar shear fracture
. Radial head or neck fracture
. Median nerve entrapment

Correct Answer & Explanation

. Radial head or neck fracture

Explanation

A Bado Type II (posterior) Monteggia fracture is the most common variant seen in adults. It has a high association with radial head or neck fractures, which often complicates surgical management and worsens the overall prognosis.

Question 1314

Topic: 2. Trauma

You are treating a 7-year-old child with a Bado Type I Monteggia fracture. After anatomic reduction and provisional fixation of the ulnar shaft, the radial head remains persistently dislocated anteriorly. What is the most likely anatomic structure preventing reduction of the radial head?

. Brachialis muscle belly
. Median nerve
. Biceps tendon
. Radial nerve
. Annular ligament

Correct Answer & Explanation

. Annular ligament

Explanation

If the radial head remains irreducible after anatomic restoration of ulnar length and alignment in a Monteggia fracture, the most common cause is the interposition of a torn annular ligament or joint capsule.

Question 1315

Topic: 2. Trauma
A 6-year-old boy is diagnosed with a Bado type III Monteggia fracture (lateral dislocation of the radial head). On examination, he cannot actively extend his fingers or thumb, but wrist extension with radial deviation is preserved. What is the affected nerve, and what is the standard management for this deficit?
. Posterior interosseous nerve; observation for 2-3 months
. Posterior interosseous nerve; immediate surgical exploration
. Anterior interosseous nerve; observation for 2-3 months
. Radial nerve proper; immediate surgical exploration
. Ulnar nerve; immediate surgical exploration

Correct Answer & Explanation

. Posterior interosseous nerve; observation for 2-3 months

Explanation

Bado type III Monteggia fractures are highly associated with posterior interosseous nerve (PIN) palsies. These are typically traction neuropraxias that resolve spontaneously, so the standard management is observation for 2 to 3 months before considering nerve exploration.

Question 1316

Topic: 2. Trauma

A 30-year-old construction worker falls from a height. Radiographs demonstrate a perilunate dislocation accompanied by fractures through the scaphoid, capitate, and radial styloid. There is no evidence of purely ligamentous dissociation between the lunate and the intact surrounding carpus. How is this injury pattern classified?

. Lesser arc injury
. Greater arc injury
. Mayfield Stage II injury
. Barton fracture-dislocation
. Essex-Lopresti injury

Correct Answer & Explanation

. Greater arc injury

Explanation

Greater arc injuries involve a ring of bone fractures surrounding the lunate (e.g., scaphoid, capitate, triquetrum, radial styloid). In contrast, lesser arc injuries consist of purely ligamentous disruptions strictly around the lunate itself.

Question 1317

Topic: 2. Trauma
A 68-year-old female sustains a fall, resulting in a Mason-Johnston Type II radial head fracture. Radiographs demonstrate a single displaced fragment involving 35% of the articular surface with a 3 mm step-off. Clinically, she has a palpable mechanical block to terminal forearm pronation and supination. What is the most appropriate initial management strategy?
. Sling immobilization for 3 weeks followed by physiotherapy
. Open reduction and internal fixation (ORIF)
. Radial head excision
. Radial head replacement
. Attempt closed reduction under local anesthetic

Correct Answer & Explanation

. Sling immobilization for 3 weeks followed by physiotherapy

Explanation

A Mason-Johnston Type II radial head fracture with a mechanical block to forearm rotation, even with moderate displacement, is a strong indication for surgical intervention. The mechanical block signifies impingement of the displaced fragment, which will prevent full range of motion and lead to chronic dysfunction if not addressed. For a single, displaced fragment, open reduction and internal fixation (ORIF) is the preferred treatment to restore articular congruity and eliminate the mechanical block. Sling immobilization alone is insufficient. Radial head excision is generally reserved for severely comminuted fractures not amenable to ORIF or in low-demand patients, and carries risks of proximal radial migration. Radial head replacement is typically indicated for highly comminuted (Type III/IV) fractures or in cases of associated instability (e.g., Essex-Lopresti, terrible triad). Attempting closed reduction is unlikely to succeed with a palpable block from a displaced articular fragment.

Question 1318

Topic: 2. Trauma

A 29-year-old male presents with a radial head fracture after a motorcycle accident. Initial radiographs are shown below. While the elbow appears stable, the surgeon is concerned about potential associated injuries that are frequently missed in the initial evaluation. Which of the following associated injuries is *most* commonly missed in the initial evaluation of an isolated radial head fracture?

. Medial collateral ligament tear
. Coronoid process fracture
. Capitellum chondral injury
. Distal radio-ulnar joint (DRUJ) instability
. Olecranon fracture

Correct Answer & Explanation

. Distal radio-ulnar joint (DRUJ) instability

Explanation

Correct Answer: DWhile all listed injuries can occur with radial head fractures, distal radio-ulnar joint (DRUJ) instability, often indicative of an Essex-Lopresti lesion, is frequently missed in the initial evaluation. It may not be immediately apparent on elbow radiographs and can present insidiously with wrist pain and instability days or weeks after the initial injury. A high index of suspicion and careful examination of the wrist, along with ipsilateral wrist radiographs (looking for proximal radial migration), are crucial. Coronoid and MCL injuries are typically associated with elbow dislocations (e.g., terrible triad) and are usually more obvious. Capitellum chondral injuries are less common and often require advanced imaging or arthroscopy. Olecranon fractures are usually clearly visible on initial X-rays.

Question 1319

Topic: 2. Trauma

Regarding the surgical fixation of a complex intra-articular distal humerus fracture, such as the one shown in the CT reconstruction, what is the most biomechanically stable construct for dual plating?

. Two parallel plates on the posterior surface
. A single long plate spanning the medial and lateral columns
. Orthogonal plating (medial and posterior/posterolateral plates)
. Two plates applied to the anterior surface
. Parallel plating (two plates on the medial and lateral columns)

Correct Answer & Explanation

. Orthogonal plating (medial and posterior/posterolateral plates)

Explanation

Correct Answer: COrthogonal plating, typically with a medial plate and a posterior or posterolateral plate, creates a more stable construct biomechanically than parallel plating. This configuration provides support against both valgus/varus and torsional forces, acting as a '90-90' system (relative to each other, not the bone's long axis). This multiplanar stability is crucial for complex, comminuted fractures to allow early range of motion. Parallel plating (two plates on the medial and lateral columns) is also a strong construct, particularly for stabilizing the columns, but biomechanical studies often show orthogonal plating to be superior in complex fractures due to better load distribution and resistance to displacement. Posterior plates alone or anterior plates are insufficient for complex intra-articular fractures.

Question 1320

Topic: 2. Trauma

Following ORIF of a distal humerus fracture, a patient develops severe progressive elbow stiffness despite successful fracture healing confirmed by radiographs. What is the most common cause of this complication after successful fracture healing?

. Nonunion of the fracture
. Post-traumatic heterotopic ossification (HO)
. Ulnar nerve entrapment
. Chronic infection
. Radial head subluxation

Correct Answer & Explanation

. Post-traumatic heterotopic ossification (HO)

Explanation

Correct Answer: BPost-traumatic heterotopic ossification (HO) is a common cause of severe elbow stiffness after distal humerus fractures and their surgical treatment, even after successful fracture healing. It involves the formation of mature lamellar bone in soft tissues where bone does not normally exist, which can restrict motion significantly. While nonunion can cause pain and instability, it doesn't directly cause stiffness in the same way HO does. Ulnar nerve entrapment typically causes paresthesia and weakness, not direct mechanical stiffness. Chronic infection is possible but less common than HO. Radial head subluxation is not a typical complication leading to global stiffness after a distal humerus fracture.

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