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2. Trauma MCQs

Practice Set 488 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 9741

Topic: 2. Trauma

What is the primary reason for performing an 'internal fasciotomy' by widely incising the interosseous membrane during some forearm ORIF procedures?

. To decompress the median nerve.
. To facilitate bone graft placement.
. To address suspected compartment syndrome prophylactically.
. To improve visualization of the fracture site.
. To release tension and allow for easier reduction.

Correct Answer & Explanation

. To address suspected compartment syndrome prophylactically.

Explanation

Widely incising the interosseous membrane, sometimes referred to as an 'internal fasciotomy,' is performed primarily to address or prevent compartment syndrome (Option C). This is a controversial technique, and actual compartment syndrome requires formal fasciotomies of all compartments. However, in cases of severe trauma or high suspicion, opening the interosseous membrane can help decompress the deep compartments. It is not primarily for nerve decompression (A), bone graft (B), visualization (D), or easier reduction (E), though it might incidentally help with the latter by releasing interosseous tension.

Question 9742

Topic: 2. Trauma

Which type of both bones forearm fracture is most likely to be treated non-operatively in an adult?

. Completely displaced mid-diaphyseal fractures.
. Fractures with more than 10 degrees of angulation.
. Minimally displaced ulna shaft fracture with an intact radius.
. Open Gustilo-Anderson Type I fractures.
. Fractures with significant shortening of 1 cm.

Correct Answer & Explanation

. Minimally displaced ulna shaft fracture with an intact radius.

Explanation

A minimally displaced ulna shaft fracture with an intact radius (Option C) is the most likely to be treated non-operatively in an adult. This is often referred to as an 'isolated ulna shaft' or 'nightstick' fracture. The intact radius acts as a splint, and the risk of malunion or non-union is lower compared to true both bones fractures. The other options (A, B, E) represent criteria for surgical intervention due to displacement, angulation, or shortening. Open fractures (D) require surgical debridement.

Question 9743

Topic: 2. Trauma

What is the critical range of elbow flexion to prevent rotational displacement in a long arm cast for a mid-shaft forearm fracture?

. 0-30 degrees.
. 30-60 degrees.
. 60-90 degrees.
. 90-120 degrees.
. 120-150 degrees.

Correct Answer & Explanation

. 90-120 degrees.

Explanation

A long arm cast should immobilize the elbow at approximately 90 degrees of flexion (Option D, 90-120 degrees encompasses this). This prevents forearm rotation by limiting supination and pronation, effectively stabilizing the fracture. Less flexion (A, B, C) allows for more rotational movement, while excessive flexion (E) can be uncomfortable and compromise circulation or nerve function.

Question 9744

Topic: 2. Trauma

In a 3-year-old child with a minimally displaced complete transverse fracture of both the radius and ulna, what is the most appropriate management, considering remodeling potential?

. ORIF with flexible IM nails.
. Closed reduction and long-arm cast.
. External fixation.
. Observation.
. Open reduction with K-wires.

Correct Answer & Explanation

. Closed reduction and long-arm cast.

Explanation

For a 3-year-old child with a minimally displaced complete transverse fracture, closed reduction and long-arm cast (Option B) is the most appropriate initial management. Younger children have excellent remodeling potential, and complete transverse fractures are often stable after reduction and casting. Surgical intervention (A, C, E) is reserved for unstable, irreducible, or severely displaced fractures. Observation (D) is not appropriate for a complete fracture.

Question 9745

Topic: 2. Trauma

What is the most common direction of displacement of the distal fragment of the ulna relative to the proximal ulna in a mid-diaphyseal ulna fracture?

. Proximal migration.
. Distal migration.
. Anterior angulation.
. Posterior angulation.
. Neutral.

Correct Answer & Explanation

. Proximal migration.

Explanation

Proximal migration (Option A) of the distal ulnar fragment is the most common displacement pattern due to the pull of the wrist flexors and extensors. The interosseous membrane, if intact, can also influence this by transmitting shortening from the radius. Angulation can occur in any plane depending on the mechanism, but axial shortening is very common.

Question 9746

Topic: 2. Trauma

Which anatomical structure provides the main blood supply to the diaphyseal forearm bones?

. Periosteal vessels.
. Metaphyseal vessels.
. Nutrient arteries.
. Articular vessels.
. Vascular plexuses from surrounding muscles.

Correct Answer & Explanation

. Nutrient arteries.

Explanation

The nutrient arteries (Option C), primarily the radial and ulnar nutrient arteries, are the main blood supply to the diaphyseal cortex of the forearm bones. These arteries enter the bone obliquely and branch longitudinally. While periosteal vessels (A) and surrounding muscle vascularity (E) contribute, especially after trauma or periosteal stripping, the nutrient arteries are the dominant source for the healthy diaphysis. Metaphyseal (B) and articular (D) vessels supply those specific regions.

Question 9747

Topic: 2. Trauma

Which of the following describes the 'stress riser' phenomenon relevant to forearm refractures after plate removal?

. Increased bone density around previous screw holes.
. Weakened bone at previous screw holes where stress concentrates.
. Overgrowth of bone preventing rotation.
. Fatigue fracture of the plate material itself.
. Increased flexibility of the bone after plate removal.

Correct Answer & Explanation

. Weakened bone at previous screw holes where stress concentrates.

Explanation

The 'stress riser' phenomenon (Option B) refers to points of stress concentration within the bone, typically at previous screw holes after hardware removal. These holes weaken the bone cortex, making it more susceptible to refracture at these specific sites when subjected to bending or torsional forces. The bone is not denser (A), and it's not plate fatigue (D). While flexibility (E) might seem plausible, the key is the localized weakness and stress concentration.

Question 9748

Topic: 2. Trauma

When performing intramedullary nailing of the ulna in a child, which anatomical location is the preferred entry point to minimize growth plate injury?

. Olecranon tip.
. Ulnar styloid.
. Proximal metaphysis, distal to the olecranon physis.
. Distal metaphysis, proximal to the ulnar physis.
. Mid-diaphyseal ulna, directly at the fracture site.

Correct Answer & Explanation

. Proximal metaphysis, distal to the olecranon physis.

Explanation

For intramedullary nailing of the ulna in children, the preferred entry point is typically the proximal metaphysis, distal to the olecranon physis (Option C). This avoids damage to the olecranon growth plate, which can lead to cubitus varus or other deformities. The olecranon tip (A) is too close to the physis. The ulnar styloid (B) and distal metaphysis (D) are for distal fractures. Mid-diaphyseal (E) is generally avoided for an entry point unless a specific technique (e.g., small children) necessitates it and is generally not for an IM nail.

Question 9749

Topic: 2. Trauma

What is the most accurate method to assess for rotational malunion after a forearm fracture that has clinically significant loss of pronation/supination?

. Clinical estimation of forearm rotation compared to the contralateral side.
. Standard AP and lateral radiographs.
. CT scan with 3D reconstruction and specific rotational measurements.
. MRI scan of the forearm.
. Ultrasound assessment of muscle contracture.

Correct Answer & Explanation

. CT scan with 3D reconstruction and specific rotational measurements.

Explanation

A CT scan with 3D reconstruction and specific rotational measurements (Option C) is the most accurate method to quantify rotational malunion of the forearm. Plain radiographs (B) are generally unreliable for assessing rotational malalignment. Clinical estimation (A) is a screening tool but lacks precision. MRI (D) is excellent for soft tissues but less accurate for bone rotation than CT. Ultrasound (E) is not for bone malunion.

Question 9750

Topic: 2. Trauma

The use of an 'over-contoured' plate on the tension side of a diaphyseal forearm fracture is designed to achieve which biomechanical effect?

. Neutralize shear forces.
. Provide interfragmentary compression via dynamic compression.
. Create a compression force across the far cortex.
. Act as a buttress against axial load.
. Minimize stress shielding.

Correct Answer & Explanation

. Create a compression force across the far cortex.

Explanation

Over-contouring a plate slightly beyond the anatomical curve on the tension side of a diaphyseal fracture (e.g., volar side of the radius) ensures that when the screws are tightened, a compression force is created across the far cortex (Option C). This helps to counteract the bending forces that tend to cause gapping on the far cortex and enhances stability, promoting primary bone healing. It complements interfragmentary compression (B) but is a distinct biomechanical principle of achieving far cortical compression, especially valuable in oblique or shorter segments.

Question 9751

Topic: 2. Trauma

Which intraoperative complication is specific to the reaming process during intramedullary nailing of the forearm bones?

. Neurovascular injury during incision.
. Perforation of the bone cortex.
. Hardware prominence.
. Acute compartment syndrome.
. Delayed union.

Correct Answer & Explanation

. Perforation of the bone cortex.

Explanation

Perforation of the bone cortex (Option B) is a specific intraoperative complication directly associated with the reaming process during intramedullary nailing. Aggressive or misdirected reaming can lead to cortical breach, potentially weakening the bone, creating a stress riser, or even causing iatrogenic fracture. Neurovascular injury during incision (A) is a general surgical risk. Hardware prominence (C) is a common post-op issue. Acute compartment syndrome (D) and delayed union (E) are broader complications, not specific to reaming.

Question 9752

Topic: 2. Trauma

What is the recommended period of initial immobilization with a long arm cast following successful closed reduction of a stable, non-displaced both bones forearm fracture in a 4-year-old child?

. 2-3 weeks.
. 4-6 weeks.
. 6-8 weeks.
. 8-10 weeks.
. 10-12 weeks.

Correct Answer & Explanation

. 4-6 weeks.

Explanation

For a stable, non-displaced both bones forearm fracture in a 4-year-old, a long arm cast is typically maintained for 4-6 weeks (Option B). Children of this age have rapid healing potential. After this period, clinical and radiographic signs of early union should be evident, and the child can often transition to a short arm cast or remove the cast and begin gentle activity. Longer periods of immobilization increase stiffness risk without significant additional benefit for stable fractures in young children.

Question 9753

Topic: 2. Trauma

What is the primary risk of using a tight dressing or cast after surgical debridement of an infected hand wound?

. A. Increased risk of wound dehiscence.
. B. Impaired neurovascular status and compartment syndrome.
. C. Enhanced bacterial growth due to warmth.
. D. Faster absorption of antibiotics.
. E. Promotion of scar tissue formation.

Correct Answer & Explanation

. B. Impaired neurovascular status and compartment syndrome.

Explanation

The primary risk of using a tight dressing or cast on an acutely inflamed or infected hand is the potential for impaired neurovascular status and the development of compartment syndrome. Edema from inflammation and surgery can increase interstitial pressure within the confined fascial compartments of the hand, compromising blood flow and nerve function. Loose, bulky dressings and elevation are generally preferred. Wound dehiscence (A) is less likely with a tight dressing, but the consequences of a tight dressing are far more severe. Bacterial growth (C) might be minimally affected, but not the primary concern. Faster antibiotic absorption (D) is not a mechanism. Scar formation (E) is a chronic process, not an acute risk.

Question 9754

Topic: 2. Trauma

Which classification system, although not strictly for Galeazzi, can be helpful for describing distal radial shaft fractures, providing a framework for understanding comminution and displacement?

. Salter-Harris classification
. AO/OTA classification
. Garden classification
. Gustilo-Anderson classification
. Neer classification

Correct Answer & Explanation

. AO/OTA classification

Explanation

The AO/OTA classification system is a comprehensive system used for classifying long bone fractures, including those of the radial diaphysis (AO type 22). It provides detailed information on fracture location, comminution, and morphology, which is valuable for surgical planning in Galeazzi fractures. Salter-Harris is for physeal injuries. Garden is for femoral neck fractures. Gustilo-Anderson is for open fractures. Neer is for proximal humerus fractures.

Question 9755

Topic: 2. Trauma

What is the primary goal of achieving anatomical reduction and rigid internal fixation of the radial shaft in a Galeazzi fracture?

. To prevent compartment syndrome
. To facilitate early wrist flexion
. To indirectly restore DRUJ stability by restoring radial length and rotation
. To protect the superficial radial nerve
. To improve grip strength by shortening the radius

Correct Answer & Explanation

. To indirectly restore DRUJ stability by restoring radial length and rotation

Explanation

The primary goal of anatomical reduction and rigid internal fixation of the radial shaft in a Galeazzi fracture is to restore radial length, rotation, and alignment. By doing so, tension in the interosseous membrane and DRUJ ligaments is normalized, which often indirectly restores stability to the distal radioulnar joint. A stable DRUJ is critical for pain-free forearm rotation and function.

Question 9756

Topic: 2. Trauma

What percentage of adult Galeazzi fractures, if treated non-operatively, are expected to result in malunion and poor outcomes?

. Less than 10%
. Approximately 20-30%
. Approximately 40-50%
. Greater than 60%
. Nearly 100%

Correct Answer & Explanation

. Greater than 60%

Explanation

Historically, non-operative management of adult Galeazzi fractures has been associated with unacceptably high rates of malunion and DRUJ instability, often reported to be 50-100%. This poor outcome with conservative treatment is the primary reason why ORIF is the gold standard for adults. While not strictly 100%, 'greater than 60%' accurately reflects the high failure rate, making non-operative treatment unsuitable for most adults.

Question 9757

Topic: 2. Trauma

What is the typical appearance of the forearm in a patient with a Galeazzi fracture-dislocation on clinical inspection?

. Ulnar deviation of the wrist with dorsal prominence of the radial head
. Shortened, radially deviated forearm with a prominent ulnar head dorsally
. Forearm held in supination with volar prominence of the ulnar head
. Marked valgus deformity at the elbow
. Flattening of the ulnar side of the wrist with radial head dislocation

Correct Answer & Explanation

. Shortened, radially deviated forearm with a prominent ulnar head dorsally

Explanation

In a Galeazzi fracture-dislocation, the radial shaft fracture often leads to shortening, and the DRUJ disruption (commonly dorsal dislocation of the ulna) results in a noticeable prominence of the ulnar head dorsally, with the wrist often appearing radially deviated due to the loss of radial support and muscle pull. The forearm may be held in pronation.

Question 9758

Topic: 2. Trauma

Which classification system is used for distal radioulnar joint instability and can guide management decisions in Galeazzi injuries?

. Gustilo-Anderson
. AO/OTA
. Essex-Lopresti
. Palmer classification (for TFCC injuries)
. Mason classification

Correct Answer & Explanation

. Palmer classification (for TFCC injuries)

Explanation

While not a classification of the Galeazzi fracture itself, the Palmer classification is widely used for triangular fibrocartilage complex (TFCC) injuries, which are frequently associated with DRUJ instability in Galeazzi fractures. Understanding the type of TFCC tear (traumatic vs. degenerative) helps guide the need for direct repair or debridement when addressing DRUJ instability. Gustilo-Anderson is for open fractures, AO/OTA for long bone fractures, Essex-Lopresti for radial head fractures with interosseous membrane disruption, and Mason for radial head fractures.

Question 9759

Topic: 2. Trauma

A 28-year-old active individual develops a symptomatic nonunion of a previously treated Galeazzi fracture. What is the most appropriate management strategy?

. Continue cast immobilization for an extended period
. Ulnar shortening osteotomy to decompress the DRUJ
. Revision ORIF of the radius with bone grafting and addressing DRUJ instability
. Perform a Darrach procedure
. Activity modification and pain management

Correct Answer & Explanation

. Revision ORIF of the radius with bone grafting and addressing DRUJ instability

Explanation

A symptomatic nonunion of a Galeazzi fracture requires surgical intervention to achieve union. The most appropriate strategy is revision open reduction and internal fixation of the radial shaft, typically with autologous bone grafting to promote healing. Concomitantly, the DRUJ stability must be re-evaluated and addressed as persistent instability is common with nonunion. Ulnar shortening or Darrach procedures are salvage options for chronic DRUJ issues after union or for irreducible malunions, not primarily for nonunion of the radius itself.

Question 9760

Topic: 2. Trauma

Which of the following types of forearm plates is generally preferred for fixation of the radial shaft in a Galeazzi fracture due to its superior biomechanical properties in resisting bending, torsion, and axial loads?

. Dynamic Compression Plate (DCP)
. Limited Contact Dynamic Compression Plate (LC-DCP)
. Locking Compression Plate (LCP)
. 1/3 tubular plate
. Reconstruction plate

Correct Answer & Explanation

. Locking Compression Plate (LCP)

Explanation

Locking Compression Plates (LCPs) are generally preferred for diaphyseal forearm fractures, including Galeazzi fractures. They combine the principles of compression plating with fixed-angle locking screw technology, providing superior angular stability. This construct effectively creates an internal fixator, offering enhanced resistance to bending, torsion, and axial loads, which is particularly beneficial in comminuted fractures or osteoporotic bone, ensuring stable fixation and promoting early rehabilitation.

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