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 5741
Topic: 2. Trauma
A 55-year-old male sustains a severely displaced 4-part proximal humerus fracture. Based on modern quantitative perfusion studies, injury to which of the following vessels places the humeral head at the greatest risk for avascular necrosis?
Correct Answer & Explanation
. Posterior humeral circumflex artery
Explanation
Historically, the anterior humeral circumflex artery (arcuate branch) was thought to be the main blood supply to the humeral head. However, modern cadaveric perfusion studies demonstrate that the posterior humeral circumflex artery actually provides the predominant blood supply to the articular segment.
Question 5742
Topic: 2. Trauma
A 24-year-old cyclist crashes directly onto the point of his shoulder. Radiographs demonstrate a Type V acromioclavicular (AC) joint injury with 150% superior displacement of the distal clavicle relative to the acromion. Which of the following describes the status of the stabilizing ligaments?
Correct Answer & Explanation
. Complete rupture of both the AC and coracoclavicular ligaments
Explanation
A Type V acromioclavicular joint injury is characterized by greater than 100% superior displacement of the distal clavicle into the trapezius fascia. This severe displacement is biomechanically impossible without complete rupture of both the acromioclavicular and coracoclavicular (conoid and trapezoid) ligaments.
Question 5743
Topic: 2. Trauma
A 40-year-old male sustained a highly comminuted radial head fracture from a fall. He underwent isolated radial head excision. Three months later, he presents with severe ulnar-sided wrist pain and radiographs demonstrate proximal migration of the radius. Injury to which anatomic structure was missed initially?
Correct Answer & Explanation
. Interosseous membrane
Explanation
The patient has an Essex-Lopresti lesion, consisting of a radial head fracture, interosseous membrane disruption, and distal radioulnar joint instability. Radial head excision in the setting of an unrecognized interosseous membrane tear leads to catastrophic proximal radial migration.
Question 5744
Topic: 2. Trauma
Which carpal bone is most commonly fractured?
Correct Answer & Explanation
. Scaphoid
Explanation
The scaphoid is by far the most commonly fractured carpal bone, accounting for 60-70% of all carpal fractures. Its unique blood supply (proximal pole supplied by branches entering distally) predisposes it to avascular necrosis and nonunion. Lunate, Triquetrum, Trapezium, and Capitate fractures are less common.
Question 5745
Topic: 2. Trauma
Which type of distal radius fracture is characterized by a dorsal displacement of the distal fragment?
Correct Answer & Explanation
. Colles' fracture
Explanation
Colles' fracture is a common extra-articular fracture of the distal radius with dorsal angulation and displacement of the distal fragment. Smith's fracture (reverse Colles') involves volar displacement. Barton's fracture is an intra-articular fracture involving the dorsal or volar rim of the radius. Chauffeur's (Hutchinson) fracture is an oblique fracture of the radial styloid. Galeazzi fracture is a fracture of the radial shaft with dislocation of the distal radioulnar joint (DRUJ).
Question 5746
Topic: 2. Trauma
A 55-year-old man presents with progressive inability to fully extend his ring finger, accompanied by a firm nodule in his palmar fascia. Over time, he develops a fixed flexion contracture of the ring finger MCP and PIP joints. What is the most definitive treatment for a severe contracture causing functional impairment?
Correct Answer & Explanation
. Segmental fasciectomy
Explanation
This describes Dupuytren's contracture. For severe contractures causing functional impairment, segmental fasciectomy (or partial fasciectomy) remains the gold standard for definitive treatment, offering the most complete and longest-lasting release, especially for established contractures. Enzyme injection and percutaneous needle fasciotomy are less invasive options that are effective for certain types of cords and less severe contractures but have higher recurrence rates. Steroid injections are generally ineffective, and splinting alone cannot reverse established contractures.
Question 5747
Topic: 2. Trauma
A 30-year-old presents with a crushing injury to his hand. He has severe pain, swelling, and a rapidly developing compartment syndrome. Which of the following intrinsic muscles of the hand are not typically contained within the interosseous compartments that are most commonly affected?
Correct Answer & Explanation
. Thenar muscles
Explanation
The thenar muscles (abductor pollicis brevis, flexor pollicis brevis, opponens pollicis) are located in the thenar compartment, which is separate from the interosseous compartments (dorsal and palmar) and the hypothenar compartment. The dorsal and palmar interossei, adductor pollicis, and lumbricals are all contained within or intimately associated with the interosseous compartments, making them primary contributors to and victims of hand compartment syndrome.
Question 5748
Topic: 2. Trauma
A 70-year-old female sustains a comminuted, intra-articular distal radius fracture that is irreducible with closed reduction attempts. She has severe osteoporosis. What is generally considered the most appropriate surgical management for this fracture in an active patient?
Correct Answer & Explanation
. Open reduction and internal fixation with a volar locking plate
Explanation
For comminuted, intra-articular, irreducible distal radius fractures, especially in osteoporotic bone, open reduction and internal fixation (ORIF) with a volar locking plate has become the gold standard. Volar locking plates provide stable fixation, allow for early range of motion, and can effectively hold fragments in osteoporotic bone. External fixation can be used but often requires supplementary K-wires and may not achieve anatomical reduction of intra-articular fragments as well. Cast immobilization alone is insufficient for unstable, intra-articular fractures. Ulnar shortening osteotomy addresses ulnar-sided issues, not primarily distal radius fracture fixation.
Question 5749
Topic: 2. Trauma
What is the primary indication for non-operative management of a stable, non-displaced scaphoid fracture?
Correct Answer & Explanation
. Short arm thumb spica cast for 8-12 weeks or until radiographic union
Explanation
Stable, non-displaced scaphoid fractures are typically managed non-operatively with a long arm thumb spica cast for 6 weeks, followed by a short arm thumb spica cast for another 6 weeks, or until radiographic evidence of union is seen (total 8-12+ weeks). Due to the scaphoid's tenuous blood supply and high nonunion rate, prolonged immobilization is often necessary. Short immobilization periods or early mobilization risk nonunion.
Question 5750
Topic: 2. Trauma
A 50-year-old male sustains a distal phalanx fracture of his ring finger. The fracture is non-displaced and involves the nailbed. What is the most important aspect of initial management to prevent long-term complications?
Correct Answer & Explanation
. Evacuation of subungual hematoma and nailbed repair
Explanation
Distal phalanx fractures, especially those involving the nailbed (Seymour fractures or crushing injuries), have a high risk of complications if the nailbed injury is not addressed. A subungual hematoma often indicates a nailbed laceration. Prompt evacuation of the hematoma and meticulous repair of the nailbed are crucial to prevent infection, nail deformities, and osteomyelitis. Operative fixation is rarely needed for non-displaced fractures. Splinting should be protective, but nailbed repair is paramount. Antibiotics may be used, but surgical repair is the key step.
Question 5751
Topic: 2. Trauma
A patient with a significant crush injury to the hand is unable to perform active finger extension, despite an intact radial nerve and no obvious tendon laceration. There is also marked swelling and tenderness in the dorsal hand. What is the most likely diagnosis?
Correct Answer & Explanation
. Compartment syndrome of the dorsal hand
Explanation
Compartment syndrome can occur in the hand, affecting both intrinsic muscle compartments and, less commonly, the extrinsic compartments, including the dorsal extrinsic compartment. Marked swelling and pain, coupled with neurological deficits (like inability to extend digits despite intact proximal nerve), should raise high suspicion for compartment syndrome. Extensor tendon rupture would typically have an obvious laceration or mechanism of rupture. Dorsal wrist ganglion is a benign mass. Superficial radial nerve compression causes sensory loss. Joint capsular tear does not explain the widespread deficit.
Question 5752
Topic: 2. Trauma
Which type of fracture involving the distal radius is characterized by an intra-articular fracture with a dorsal rim fragment and dorsal displacement of the carpus?
Correct Answer & Explanation
. Dorsal Barton's fracture
Explanation
A dorsal Barton's fracture is an intra-articular fracture of the distal radius involving the dorsal rim, with the carpus and articular fragment displacing dorsally. This is a shear fracture. Colles' is extra-articular dorsal displacement. Smith's is volar displacement. Chauffeur's is a radial styloid fracture. Galeazzi is a radial shaft fracture with DRUJ dislocation.
Question 5753
Topic: 2. Trauma
A 25-year-old industrial worker sustains a high-pressure paint injection injury to the volar tip of his index finger. The puncture wound is 1mm, with minimal swelling and mild pain. What is the most appropriate immediate management?
Correct Answer & Explanation
. Admit for emergent open surgical debridement and decompression in the operating room
Explanation
High-pressure injection injuries are surgical emergencies associated with a high rate of amputation due to chemical necrosis and compartment syndrome. Despite a benign initial appearance, they mandate immediate open surgical debridement and extensive decompression in the operating room.
Question 5754
Topic: 2. Trauma
A 22-year-old male presents with a proximal pole scaphoid nonunion diagnosed 18 months after a fall. MRI confirms avascular necrosis (AVN) of the proximal pole. Which of the following surgical options offers the highest rate of union?
Correct Answer & Explanation
. 1,2 Intercompartmental supraretinacular artery (1,2 ICSRA) vascularized bone graft
Explanation
For a proximal pole scaphoid nonunion with AVN, vascularized bone grafting (such as the 1,2 ICSRA or medial femoral condyle graft) is required to restore blood supply and maximize union rates. Non-vascularized grafts have highly unacceptably high failure rates in the presence of established AVN.
Question 5755
Topic: 2. Trauma
Fasciotomy for compartment syndrome of the hand requires thorough decompression. How many distinct fascial compartments are recognized in the hand?
Correct Answer & Explanation
. 14
Explanation
There are 10 recognized compartments in the hand. These consist of four dorsal interosseous, three volar interosseous, the thenar, the hypothenar, and the adductor pollicis compartments.
Question 5756
Topic: 2. Trauma
A 45-year-old male sustains a high-energy trauma resulting in a closed Gustilo-Anderson Type I fracture of the tibia and fibula. He is stabilized, and 6 hours post-injury, he complains of excruciating pain in the calf disproportionate to the injury. On examination, his calf is tense, and passive dorsiflexion of the ankle elicits severe pain. Distal pulses are present, and capillary refill is brisk. Which of the following is the most appropriate next step in management?
Correct Answer & Explanation
. Measure compartment pressures in the affected calf.
Explanation
The clinical presentation of excruciating pain disproportionate to the injury, a tense calf, and pain on passive stretching of the muscles are classic signs of acute compartment syndrome, despite the presence of distal pulses and brisk capillary refill. The most appropriate next step is to measure compartment pressures. If pressures are elevated (typically within 30 mmHg of diastolic blood pressure, or absolute pressure >30-45 mmHg), emergent fasciotomy is indicated. Delaying diagnosis and treatment can lead to irreversible muscle and nerve damage. While vascular injury is a concern in high-energy trauma, the clinical picture is more suggestive of compartment syndrome. Pain relief alone without addressing the underlying pathology is inappropriate. Open reduction and internal fixation of the fracture would typically follow fasciotomy if required, but the immediate life-saving/limb-saving step is addressing compartment syndrome. Elevation of the limb and ice packs are contraindicated as they can further compromise perfusion.
Question 5757
Topic: 2. Trauma
A 32-year-old construction worker falls from a height, sustaining a closed midshaft femur fracture. He is hemodynamically stable. Plain radiographs confirm the diagnosis. What is the definitive treatment for this injury in a healthy adult?
Correct Answer & Explanation
. Intramedullary nailing.
Explanation
Intramedullary nailing is the gold standard definitive treatment for closed midshaft femur fractures in healthy adults. It provides excellent stability, allows for early weight-bearing, and has high union rates with low complication rates. Traction and cast application are historical treatments largely abandoned due to prolonged bed rest, stiffness, and less predictable results. External fixation is primarily used for open fractures, polytrauma patients requiring damage control, or temporarily stabilizing high-energy injuries, not as a definitive treatment for closed fractures. Plate and screw fixation is an option for certain fracture patterns (e.g., supracondylar, very proximal) or specific patient populations, but IM nailing is preferred for midshaft. Skeletal traction followed by cast is a dated approach.
Question 5758
Topic: 2. Trauma
A 28-year-old male sustains an isolated ankle injury during a football game. Clinical examination reveals tenderness over the distal fibula and medial malleolus, with instability on stress testing. Radiographs show a bimalleolar ankle fracture. Which of the following statements regarding its management is most accurate?
Correct Answer & Explanation
. Open reduction and internal fixation (ORIF) is typically required to restore ankle stability and congruence.
Explanation
Bimalleolar ankle fractures are unstable injuries involving both the lateral (fibula) and medial (tibia) malleoli. They disrupt the ankle mortise, leading to instability. Open reduction and internal fixation (ORIF) is the standard of care to restore anatomical alignment, stability, and congruence of the ankle joint. This minimizes the risk of post-traumatic arthritis and improves functional outcomes. Non-operative treatment is generally reserved for stable, isolated malleolar fractures or patients who are unfit for surgery. External fixation is rarely used as a definitive treatment for isolated bimalleolar fractures but may be used as a temporary measure in severe open injuries. Ankle fusion is a salvage procedure for severe arthritis, not a primary treatment for acute fractures. A significant deltoid ligament injury (often implied in a bimalleolar fracture, or evidenced by widening of the medial clear space) effectively creates a 'trimalleolar equivalent' injury and contributes to instability, and its reduction is crucial, though direct repair is not always needed if bony fixation achieves stability.
Question 5759
Topic: 2. Trauma
A 55-year-old male falls onto an outstretched hand, sustaining a comminuted distal radius fracture with significant dorsal angulation and articular involvement (AO Type C3). He is a moderately active individual. What is the most appropriate surgical management for this fracture?
Correct Answer & Explanation
. Volar locking plate fixation.
Explanation
A comminuted, significantly displaced distal radius fracture with articular involvement (AO Type C3) in an active individual typically requires anatomical reduction and stable internal fixation. Volar locking plate fixation has become the gold standard for these fractures, offering stable fixation, allowing early range of motion, and providing excellent control of volar/dorsal tilt and radial length. Closed reduction and splinting alone are unlikely to maintain an adequate reduction for this type of unstable fracture. External fixation may be used temporarily or in conjunction with pinning, but alone, it may not achieve or maintain adequate reduction of articular fragments. Percutaneous pinning is suitable for less displaced or less comminuted fractures. Dorsal plating is an option but is associated with higher rates of extensor tendon irritation and rupture compared to volar plating.
Question 5760
Topic: 2. Trauma
A 7-year-old boy presents with pain and swelling in his left thigh following a playground fall. Radiographs show a midshaft femur fracture. He is hemodynamically stable. Which of the following is the most appropriate definitive management option for this patient?
Correct Answer & Explanation
. Flexible intramedullary nailing.
Explanation
For a midshaft femur fracture in a 7-year-old, flexible intramedullary nailing (e.g., Ender nails or titanium elastic nails, TENs) is a common and appropriate definitive treatment. It provides stable fixation, allows for early mobilization and weight-bearing, and minimizes the risk of growth plate injury as the nails are inserted retrograde from the distal femur or antegrade from the greater trochanteric apophysis (avoiding the physis). Spica casting is an option for younger children (typically under 5-6 years old) or for less complex fractures but can be cumbersome and associated with complications like skin breakdown. Rigid intramedullary nailing is generally reserved for older adolescents or adults due to the risk of avascular necrosis of the femoral head or damage to the greater trochanteric physis. Submuscular plating is an alternative, but IM nailing is often preferred due to less soft tissue stripping. External fixation is usually reserved for open fractures, polytrauma, or significant soft tissue injury as a temporary or definitive option but is not typically the first choice for isolated closed fractures in this age group.
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