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 11981
Topic: 2. Trauma
A 19-year-old male sustains a minimally displaced fracture of the proximal pole of the scaphoid. The orthopedic surgeon recommends internal fixation due to the high risk of nonunion and avascular necrosis (AVN). The vulnerability of the proximal pole to AVN is primarily due to its reliance on retrograde blood flow from which of the following vessels?
Correct Answer & Explanation
. Dorsal carpal branch of the radial artery
Explanation
The scaphoid receives 70% to 80% of its blood supply from the dorsal carpal branch of the radial artery. These vessels enter the scaphoid at the distal pole and dorsal ridge, flowing retrogradely to supply the proximal pole. A fracture at the proximal pole disrupts this intraosseous retrograde flow, significantly increasing the risk of AVN.
Question 11982
Topic: 2. Trauma
A patient presents with a mid-shaft humeral fracture (Holstein-Lewis type) and a concomitant high radial nerve palsy. Examination reveals a complete wrist drop and inability to extend the metacarpophalangeal joints. Which of the following radial nerve-innervated muscles will definitively maintain its function in this specific injury pattern?
Correct Answer & Explanation
. Triceps brachii
Explanation
The branches of the radial nerve that supply the triceps brachii arise in the axilla and proximal humerus, proximal to the mid-shaft and spiral groove regions. Therefore, in a mid-shaft humeral fracture with radial nerve palsy, elbow extension (triceps function) is preserved, while the brachioradialis and all downstream extensors are paralyzed.
Question 11983
Topic: 2. Trauma
A 27-year-old male suffers a severe crush injury to his left hand in an industrial press. He presents with severe, unrelenting pain out of proportion to the injury and the hand is adopting an intrinsic-minus posture. If a complete hand fasciotomy is required, how many distinct fascial compartments must be released?
Correct Answer & Explanation
. 10
Explanation
There are 10 distinct fascial compartments in the hand that may require release in the setting of compartment syndrome. These are: four dorsal interosseous compartments, three volar interosseous compartments, the hypothenar compartment, the thenar compartment, and the adductor pollicis compartment.
Question 11984
Topic: 2. Trauma
A 45-year-old male sustains a wrist injury. Radiographs demonstrate an intra-articular fracture of the volar rim of the distal radius with volar subluxation of the carpus. This injury pattern is best described as a:
Correct Answer & Explanation
. Barton fracture
Explanation
A Barton fracture is a shear-type, intra-articular fracture of the distal radius with dislocation or subluxation of the radiocarpal joint. It can be volar (more common) or dorsal. A Smith fracture is an extra-articular distal radius fracture with volar angulation.
Question 11985
Topic: 2. Trauma
A 55-year-old female treated non-operatively for a nondisplaced distal radius fracture presents 6 weeks post-injury with a sudden inability to actively extend her thumb interphalangeal joint. The tenodesis effect is absent for the thumb. What is the primary pathomechanical cause of this complication?
Correct Answer & Explanation
. Ischemia and mechanical attrition at the Lister tubercle
Explanation
Extensor pollicis longus (EPL) rupture after nondisplaced distal radius fractures typically occurs due to mechanical attrition and focal ischemia within the intact third dorsal compartment. The standard treatment is an extensor indicis proprius (EIP) to EPL tendon transfer.
Question 11986
Topic: 2. Trauma
A 24-year-old male presents with a proximal pole scaphoid nonunion. Which vessel provides the primary retrograde blood supply to the proximal pole of the scaphoid, predisposing this specific fracture location to avascular necrosis?
Correct Answer & Explanation
. Dorsal carpal branch of the radial artery
Explanation
The dorsal carpal branch of the radial artery enters the dorsal ridge of the scaphoid distally and provides retrograde blood flow to the proximal pole. Because of this retrograde supply, proximal pole fractures have a high risk of avascular necrosis and nonunion.
Question 11987
Topic: 2. Trauma
A surgeon plans to use a cannulated screw for an intra-articular fracture. What is the primary biomechanical advantage of a cannulated screw compared to a solid screw of the same external diameter?
Correct Answer & Explanation
. Ability to guide the screw with a K-wire, improving accuracy.
Explanation
The primary biomechanical advantage of a cannulated screw mentioned here is the ability to guide the screw with a K-wire. This allows for precise placement, especially in intra-articular fractures where anatomical reduction and specific screw trajectories are critical. Cannulationreducestorsional and bending strength compared to a solid screw of the same external diameter because it removes material from the core. Pullout strength is related to thread design and bone quality, not cannulation directly.
Question 11988
Topic: 2. Trauma
A fracture is stabilized using a compression plate. What is the primary mechanism by which this implant promotes healing?
Correct Answer & Explanation
. It provides absolute stability, promoting direct (primary) bone healing.
Explanation
Compression plating aims to achieve absolute stability at the fracture site. By compressing the fracture fragments, it reduces interfragmentary motion to a negligible level (less than 2%). This environment promotes direct bone healing (primary bone healing), where osteons directly bridge the fracture gap without significant callus formation. This contrasts with intramedullary nails, which are load-sharing and promote secondary healing.
Question 11989
Topic: 2. Trauma
Regarding the vascular supply of the femoral head, which artery is MOST susceptible to disruption in a femoral neck fracture, leading to osteonecrosis?
Correct Answer & Explanation
. Medial circumflex femoral artery (MCFA)
Explanation
The medial circumflex femoral artery (MCFA) is the predominant blood supply to the femoral head in adults, particularly via its retinacular branches that ascend along the femoral neck. Fractures of the femoral neck, especially displaced ones, frequently disrupt these retinacular vessels, leading to ischemia and subsequent osteonecrosis of the femoral head. The artery of the ligamentum teres contributes to blood supply in childhood and some adults but is often insufficient on its own. The LCFA supplies the anterior thigh, and profundra femoris is a main thigh artery. Superior gluteal supplies gluteal muscles.
Question 11990
Topic: Lower Extremity Trauma
The primary biomechanical role of the menisci in the knee joint is to:
Correct Answer & Explanation
. Increase the congruity between the femoral condyles and tibial plateau.
Explanation
The menisci are C-shaped fibrocartilaginous structures that sit on the tibial plateau. Their primary biomechanical roles include increasing the contact area between the femoral condyles and tibial plateau, which significantly reduces contact stress on the articular cartilage. They also contribute to joint stability, shock absorption, and some lubrication, but increasing congruity and reducing stress are their most critical functions. Ligaments limit hyperextension and provide varus/valgus stability.
Question 11991
Topic: 2. Trauma
Regarding imaging principles, which modality is BEST suited for visualizing cortical bone breaches and complex fracture patterns, especially in intra-articular fractures?
Correct Answer & Explanation
. Computed Tomography (CT) scan
Explanation
Computed Tomography (CT) scans provide excellent cross-sectional imaging with high spatial resolution and contrast for bone. It is superior to plain radiographs for demonstrating complex fracture patterns, cortical bone breaches, impaction, and intra-articular involvement, aiding in surgical planning. MRI is superior for soft tissue, cartilage, and marrow edema. Ultrasound has limited utility for bone visualization due to acoustic shadowing. Bone scintigraphy shows metabolic activity.
Question 11992
Topic: 2. Trauma
What is the main advantage of dynamic hip screw (DHS) fixation over multiple cancellous screws for intertrochanteric hip fractures?
Correct Answer & Explanation
. Allows controlled collapse and impaction at the fracture site.
Explanation
A Dynamic Hip Screw (DHS) system is designed to allow controlled collapse and impaction at the fracture site. The sliding barrel and lag screw construct permits controlled shortening of the femoral neck, allowing the fracture fragments to dynamically impact. This impaction increases the stability of the fracture and promotes secondary bone healing. It does not provide absolute stability; rather, it provides relative stability. While it provides good rotational stability, 'controlled collapse and impaction' is its unique and primary advantage for this fracture type.
Question 11993
Topic: 2. Trauma
The use of locked plating systems in fracture fixation primarily aims to:
Correct Answer & Explanation
. Create an angularly stable construct, particularly useful in osteoporotic bone.
Explanation
Locked plating systems (e.g., Locking Compression Plates - LCPs) utilize screws that lock into the plate, creating a fixed-angle construct. This angular stability makes the plate-screw construct function as an internal fixator, independent of plate-to-bone compression. This is particularly advantageous in osteoporotic bone, comminuted fractures, or metaphyseal/epiphyseal fractures where traditional compression plating might not achieve stable purchase. It aims for relative stability and minimizes periosteal stripping, but its primary distinction is angular stability.
Question 11994
Topic: 2. Trauma
A 25-year-old male falls from a height and presents with acute severe back pain and neurological deficits in his lower limbs. CT scan shows a burst fracture of L1 with significant retropulsion into the spinal canal and canal compromise of 50%. What is the most appropriate surgical management strategy for this unstable fracture with neurological compromise?
Correct Answer & Explanation
. Posterior spinal fusion and decompression
Explanation
For an unstable thoracolumbar burst fracture with significant canal compromise and neurological deficit, surgical intervention is indicated. A posterior approach with pedicle screw fixation and direct or indirect decompression (e.g., laminectomy or posterolateral decompression) is a widely accepted and effective strategy. It allows for stabilization of the fracture and adequate decompression of the neural elements, often achievable in a single stage. Anterior approaches are also valid but might be considered for isolated anterior column reconstruction or specific kyphotic deformities, sometimes requiring a two-stage procedure. Vertebroplasty and kyphoplasty are not suitable for unstable fractures with neurological deficits.
Question 11995
Topic: 2. Trauma
A 60-year-old male with a known history of prostate cancer presents with sudden onset of severe right femoral pain after a minor fall. X-rays show a lytic lesion in the subtrochanteric region of the femur with cortical breakthrough. What is the most appropriate immediate management for this impending or actual pathological fracture?
Correct Answer & Explanation
. Prophylactic internal fixation
Explanation
This scenario describes an impending or actual pathological fracture due to metastatic bone disease. A lytic lesion with cortical breakthrough in a high-stress area like the subtrochanteric region of the femur carries a very high risk of complete fracture. The most appropriate immediate management is prophylactic internal fixation (e.g., with an intramedullary nail) to prevent a catastrophic complete fracture, stabilize the bone, and provide immediate pain relief. Radiation therapy, bisphosphonates, and chemotherapy are important adjunctive treatments for the underlying disease and pain control, but they do not address the immediate mechanical instability. Observation is inappropriate given the impending or actual fracture.
Question 11996
Topic: 2. Trauma
A 28-year-old male sustains a high-energy trauma leading to a Gustilo-Anderson Type II open femoral shaft fracture. What is the most critical initial step in managing this open fracture?
Correct Answer & Explanation
. IV antibiotics and tetanus prophylaxis
Explanation
For any open fracture, the absolute immediate priority after initial assessment and basic life support is the administration of intravenous broad-spectrum antibiotics and tetanus prophylaxis. This intervention significantly reduces the risk of infection, which is the most devastating complication of open fractures. While surgical debridement and irrigation are critical and should be performed urgently (ideally within 6 hours), antibiotics should be administered even before the patient reaches the operating theatre. Other steps like stabilization and angiogram follow, and primary wound closure is generally contraindicated in open fractures.
Question 11997
Topic: 2. Trauma
A 40-year-old male is admitted with multiple injuries after a high-speed motor vehicle collision, including an unstable pelvic fracture, a closed femoral shaft fracture, and a closed head injury with GCS 10. He is hemodynamically stable after initial resuscitation. When is definitive fixation of the femoral shaft fracture generally considered most appropriate in a polytrauma patient with a GCS of 10?
Correct Answer & Explanation
. After stabilization of head injury, usually 3-7 days ('damage control orthopaedics')
Explanation
In polytrauma patients, particularly those with a significant head injury (GCS <12) or other severe systemic injuries (e.g., severe chest or abdominal trauma), the principles of 'damage control orthopaedics' (DCO) are applied. This involves initial temporary stabilization (often external fixation) of long bone fractures to control hemorrhage and pain, followed by definitive fixation (e.g., intramedullary nailing) after 3-7 days. This delay allows the patient to stabilize physiologically, avoids a 'second hit' phenomenon from major surgery during the acute inflammatory phase, and allows for better neurological assessment for head injuries. 'Early total care' (fixation within 24 hours) is typically reserved for hemodynamically stable patients without severe associated systemic injuries.
Question 11998
Topic: 2. Trauma
A 20-year-old male sustains a mid-shaft clavicle fracture with 100% displacement and 2 cm of shortening. He is a keen weightlifter and desires the fastest and most reliable return to activity. What is the most appropriate management for this fracture to optimize outcome and early return to sport?
Correct Answer & Explanation
. Open reduction and internal fixation with plate and screws
Explanation
While many clavicle fractures can be treated non-operatively, significant displacement (>100%), shortening (>1.5-2 cm), or comminution are increasingly recognized indications for surgical fixation, especially in young, active patients, overhead athletes, or those demanding a fast and reliable return to high-level activity. Open reduction and internal fixation with plate and screws is the most common and effective method, providing stable fixation, restoring anatomical alignment, and allowing for early mobilization and rehabilitation, which typically leads to a faster and more predictable return to sport compared to non-operative management for these specific fracture patterns.
Question 11999
Topic: 2. Trauma
A 25-year-old male sustains a tibia shaft fracture. Six hours post-injury, he complains of increasing pain disproportionate to the injury, pain on passive stretching of the toes, and numbness between the first and second toes. Distal pulses are palpable. What is the most appropriate immediate intervention?
Correct Answer & Explanation
. Urgent fasciotomy
Explanation
This clinical scenario describes acute compartment syndrome of the lower leg. The cardinal signs are pain out of proportion to the injury, pain on passive stretching of the muscles in the affected compartment (e.g., toe extension for anterior compartment), and early neurological deficits (numbness in the first web space indicates deep peroneal nerve involvement). It is critical to recognize that distal pulses can remain palpable even with severe compartment syndrome. Urgent fasciotomy is the only definitive treatment to relieve the elevated intracompartmental pressures and prevent irreversible tissue damage (muscle ischemia and nerve injury). While removing constrictive dressings can be helpful, it is insufficient if compartment syndrome is already established. Delaying for compartment pressure monitoring in a clear clinical case is often not advisable, as the diagnosis is primarily clinical.
Question 12000
Topic: 2. Trauma
A 45-year-old male presents following a high-speed motor vehicle collision. He is hemodynamically unstable, with a heart rate of 120 bpm and blood pressure of 80/50 mmHg. Physical examination reveals a widely abducted lower extremity, perineal ecchymosis, and scrotal swelling. A Foley catheter insertion is attempted but meets resistance. A CT scan confirms an open-book pelvic fracture (APC-III) with significant symphyseal diastasis and sacral fractures. Which of the following is the most appropriate immediate next step in management after initial ATLS protocol?
Correct Answer & Explanation
. Application of a circumferential pelvic binder
Explanation
The most immediate and life-saving intervention for a hemodynamically unstable patient with an open-book pelvic fracture (APC-III) after initial ATLS assessment is the application of a circumferential pelvic binder. This maneuver reduces pelvic volume, compresses vascular structures, and helps tamponade hemorrhage, thereby improving hemodynamic stability. While other interventions like angiography/embolization, C-clamp, or external fixation may be required, they are typically performed after initial stabilization with a binder. Laparotomy would be considered for identified intra-abdominal hemorrhage, but the initial focus is on the pelvic instability as the primary source of bleeding in this scenario. The urethral injury (resistance to Foley) needs to be addressed with a suprapubic catheter, but it is secondary to hemodynamic instability in this critical phase.
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