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 9361
Topic: 2. Trauma
In internal fixation, what is the 'near cortex' in the context of a lag screw?
Correct Answer & Explanation
. The cortical bone into which the screw threads are designed to purchase.
Explanation
For a lag screw, the 'near cortex' refers to the bone segment closer to the screw head through which the screw shaft passes freely, without its threads engaging the bone. This is achieved by overdrilling this cortex with a drill bit equal to the screw's outer diameter, creating a 'glide hole.' The 'far cortex' is the bone segment furthest from the screw head, into which the screw threads purchase to generate compression (C).
Question 9362
Topic: 2. Trauma
What is the primary role of a 'tension band' screw or pin in a tension band wiring construct?
Correct Answer & Explanation
. To anchor the cerclage wire and prevent distraction on the tension side.
Explanation
In a tension band wiring construct (e.g., for patella or olecranon fractures), the K-wires or intramedullary screw (referred to here as a 'tension band screw/pin') serve as an anchor point. Their primary role is to prevent distraction of the fracture fragments on the tension side and provide a stable fulcrum around which the cerclage wire can operate, converting tensile forces into compressive forces on the fracture site. They do not provide primary axial load-bearing (A) or compress the fragments directly (B) (the wire does the compression). They are not primarily buttresses (D) or for rotation (E).
Question 9363
Topic: 2. Trauma
Which of the following describes the most crucial advantage of using cannulated screws for femoral neck fractures?
Correct Answer & Explanation
. Their hollow core allows precise insertion over a guide wire, reducing risk of malposition.
Explanation
The most crucial advantage of cannulated screws for femoral neck fractures is the ability for precise placement over a pre-inserted guide wire (B). This technique allows for accurate targeting of the bone fragments, optimal screw trajectory, and verification of reduction and position before definitive screw insertion, minimizing the risk of malposition or iatrogenic damage. They generally have slightlylessbending strength than solid screws of comparable outer diameter (A). They are not always self-drilling (C) and are typically metallic, not absorbable (D). While they provide compression, it's not superior to solid screws (E).
Question 9364
Topic: 2. Trauma
A fracture is fixed with a long plate and multiple unicortical locking screws. What is the primary biomechanical rationale for unicortical screw usage in this scenario?
Correct Answer & Explanation
. To minimize damage to periosteal blood supply and avoid far cortex risks (nerves/vessels).
Explanation
Unicortical locking screws, particularly with locking plates, can provide sufficient stability while minimizing soft tissue stripping on the far side and avoiding potential damage to nerves, vessels, or other critical structures on the opposite cortex. They also help preserve the periosteal blood supply by not compressing the far cortex. They typically havelesspull-out strength than bicortical screws (A) but may be sufficient for certain constructs. Flexibility (B) is plate design, not screw characteristic. While unicortical fixation can allow for some controlled micromotion, the primary rationale is often safety and preservation of biology (C), rather than deliberately promoting micromotion (D). Cost (E) is generally not the primary driver for choosing unicortical fixation.
Question 9365
Topic: 2. Trauma
A 35-year-old male is brought to the ER after a high-speed motor vehicle collision. He is hypotensive (BP 80/40 mmHg), tachycardic (HR 130 bpm), and has bilateral femur fractures, an open tibia fracture, and obvious chest trauma. After initial resuscitation with fluids and blood, his vital signs remain unstable. What is the most appropriate orthopedic management strategy in this scenario?
Correct Answer & Explanation
. Damage control orthopedics focusing on temporary stabilization of the most critical injuries (e.g., external fixation of femurs), followed by definitive fixation once stable.
Explanation
The patient is physiologically unstable (hypotensive, tachycardic) despite initial resuscitation, indicating ongoing shock and a high risk of complications from prolonged definitive surgery. In such cases, the principle of 'Damage Control Orthopedics' (DCO) is paramount. This involves temporary stabilization of critical long bone fractures (e.g., femur fractures, open tibia fractures) using external fixation to control hemorrhage, reduce pain, and facilitate patient transport and resuscitation, without subjecting the patient to the physiological stress of definitive, lengthy procedures. Once physiological stability is achieved (usually 24-72 hours later), definitive fixation is performed. Immediate definitive nailing (A) or simultaneous definitive ORIF (D) is contraindicated in unstable patients due to the risk of exacerbating the systemic inflammatory response ('second hit') and worsening outcomes. External fixation of all fractures (B) is part of DCO, but the specific wording 'Damage control orthopedics focusing on temporary stabilization... followed by definitive fixation once stable' better encapsulates the comprehensive strategy. Splinting and transfer (E) might be relevant if the receiving hospital cannot perform DCO, but it's not the management strategy itself for an orthopedic surgeon in an appropriate facility.
Question 9366
Topic: 2. Trauma
A 70-year-old female undergoes a revision total hip arthroplasty due to aseptic loosening of the femoral component. Intraoperatively, during femoral component extraction, a longitudinal fracture of the proximal femur is noted, extending just distal to the lesser trochanter. The fracture is non-displaced and appears stable. The new revision stem provides good press-fit distal fixation past the fracture. What is the appropriate management of this intraoperative fracture (Vancouver B1 equivalent)?
Correct Answer & Explanation
. Cerclage wiring or cable fixation around the fracture.
Explanation
This scenario describes an intraoperative periprosthetic fracture, specifically a Vancouver B1 equivalent (fracture around a well-fixed stem, or, in this case, a new stem providing good distal fixation past the fracture). For stable, non-displaced fractures that are engaged by the new stem, cerclage wiring or cabling (B) is the most appropriate and common method to achieve compression and rotational stability, promoting healing without compromising the primary stability of the prosthesis. Relying on the stem alone (A) is risky for healing. Plate and screw fixation (C) might be overtreatment or could interfere with stem stability/biology. Removing the stem (D) is unnecessary and would jeopardize the revision. Converting to a longer, cemented stem (E) is not indicated if the press-fit stem provides good fixation past the fracture.
Question 9367
Topic: 2. Trauma
A 28-year-old male sustains a spiral fracture of the tibia. He is treated with intramedullary nailing, achieving rigid fixation and appropriate alignment. What is the predominant mode of bone healing expected in this scenario?
Correct Answer & Explanation
. Secondary bone healing via callus formation.
Explanation
Intramedullary nailing, while providing robust stabilization, typically allows for some micromotion at the fracture site (relative stability). This environment promotes secondary bone healing, which involves the formation of a periosteal and endosteal callus, followed by remodeling. Primary (direct/contact) bone healing (B) occurs only with absolute rigidity (e.g., lag screw compression or compression plating) where there is no gap and no motion. Intramembranous ossification (C) is a type of bone formation, but the mode of healing in a fracture is primary or secondary. Cartilaginous healing (D) is part of secondary healing, but 'secondary bone healing' is the overarching term. Distraction osteogenesis (E) is a specific technique for limb lengthening, not a natural mode of fracture healing.
Question 9368
Topic: 2. Trauma
A 45-year-old male sustains a Gustilo-Anderson Type IIIA open tibia fracture after a motorcycle accident. The wound is grossly contaminated, and he arrives in the emergency department 4 hours post-injury. He is hemodynamically stable. After initial assessment and antibiotics, what is the most appropriate next step in management?
Correct Answer & Explanation
. Urgent formal irrigation and debridement in the operating room.
Explanation
For all Gustilo-Anderson open fractures, particularly Type IIIA with gross contamination, urgent formal irrigation and debridement in the operating room is the critical next step after initial assessment, stabilization, and antibiotic administration. This aims to remove all foreign material and devitalized tissue to minimize infection risk. 'Time to debridement' is a debated topic, but generally, earlier debridement (within 6-8 hours, often sooner) is preferred for grossly contaminated wounds. Immediate definitive nailing is often performed after debridement, but debridement comes first. Wound closure in the ED is absolutely contraindicated for open fractures. Delayed debridement until the next day significantly increases infection risk for a grossly contaminated wound. NPWT is used after debridement, not as a substitute for it.
Question 9369
Topic: 2. Trauma
A 30-year-old male sustains a high-energy pelvic injury after being crushed between two vehicles. He is hemodynamically unstable despite resuscitation. Radiographs and CT scan show a vertically unstable pelvic fracture involving disruption of the symphysis pubis and bilateral sacroiliac joints (Tile C / Young-Burgess LC-III equivalent). What is the most appropriate initial orthopedic intervention for this patient's pelvic injury?
Correct Answer & Explanation
. Application of a pelvic binder or sheet wrap.
Explanation
The patient has a high-energy, vertically unstable pelvic fracture and is hemodynamically unstable. The immediate priority in such cases is to control hemorrhage. A pelvic binder or sheet wrap is a crucial, rapid, and non-invasive initial maneuver to reduce pelvic volume, stabilize the fracture, and tamponade bleeding. This buys time for further resuscitation and definitive management. While external fixation is often used, applying a binder is faster and can be done immediately in the ED. Open reduction and posterior fixation are definitive surgical procedures and are not the initial intervention for an unstable patient. Observation alone is insufficient for an unstable patient with an unstable pelvic fracture.
Question 9370
Topic: 2. Trauma
A 30-year-old male sustains a closed tibia shaft fracture. He undergoes successful intramedullary nailing. Six hours post-surgery, he develops excruciating leg pain, disproportionate to the injury, unrelieved by analgesics. His neurological exam is intact, but passive dorsiflexion of the ankle causes severe pain, and the leg feels tense. Distal pulses are palpable. Intracompartmental pressure measurements are obtained: Anterior 55 mmHg, Lateral 25 mmHg, Deep Posterior 40 mmHg, Superficial Posterior 20 mmHg. Diastolic blood pressure is 60 mmHg. What is the most appropriate immediate management?
This patient presents with classical signs and symptoms of acute compartment syndrome (ACS) after a tibia fracture and nailing: excruciating pain disproportionate to the injury, pain with passive stretch (dorsiflexion of ankle stretching anterior compartment), and a tense compartment. While distal pulses are often preserved early, the elevated intracompartmental pressures are diagnostic. The critical threshold for fasciotomy is often considered a delta pressure (diastolic BP - intracompartmental pressure) of < 30 mmHg, or absolute pressures > 30-45 mmHg, especially with clinical signs. Here, for the anterior compartment, the delta P is 60-55 = 5 mmHg, which is severely abnormal and indicates ACS. Urgent unilateral fasciotomy (C) of the affected leg is the only definitive treatment for ACS to prevent irreversible muscle and nerve damage. Reassurance and observation (A), elevation/ice (D), and mannitol (E) are contraindicated or ineffective for established ACS. Bilateral fasciotomy (B) is not indicated unless both legs are affected.
Question 9371
Topic: 2. Trauma
A 32-year-old male sustains a high-energy pelvic injury after a motor vehicle collision. Radiographs show a pelvic ring injury and a vertical sacral fracture involving the S1 and S2 nerve root foramina, extending into the sacroiliac joint. He presents with sensory deficits in the S2-S4 distribution and bowel/bladder dysfunction. According to the Denis classification, what type of sacral fracture does this represent, and what is its most significant implication?
Correct Answer & Explanation
. Type III (medial to foramen); high risk of cauda equina syndrome.
Explanation
The Denis classification categorizes sacral fractures based on their relationship to the sacral foramen and spinal canal. A Type I fracture involves the sacral ala lateral to the foramen. A Type II (transforaminal) fracture passes through the sacral foramen, often causing radicular symptoms. A Type III fracture (medial to the foramen) extends into the sacral canal, placing the cauda equina directly at risk. The description of sensory deficits in S2-S4 distribution and bowel/bladder dysfunction is indicative of cauda equina syndrome, which is characteristic of a Denis Type III sacral fracture. Type IV is a rare anterior sacral fracture. Type V is not a Denis classification type, but U-type or H-type sacral fractures are spinopelvic dissociations that cause significant instability.
Question 9372
Topic: 2. Trauma
A 28-year-old male sustains a Gustilo-Anderson Type IIIB open tibia fracture with significant soft tissue loss, exposed bone, and gross contamination after a motorcycle crash. He arrives in the ED 2 hours post-injury. After initial resuscitation, what is the most critical immediate next step in fracture management?
Correct Answer & Explanation
. Extensive surgical debridement of devitalized tissue and irrigation.
Explanation
For a Gustilo-Anderson Type IIIB open tibia fracture with significant soft tissue loss, exposed bone, and gross contamination, extensive surgical debridement and irrigation is the single most critical immediate step after initial resuscitation. This procedure directly addresses the high risk of infection by removing devitalized tissue (which serves as a nidus for bacterial growth) and foreign material, significantly reducing the bacterial load. While administration of broad-spectrum intravenous antibiotics is crucial and should be initiated promptly (within 3 hours), the effectiveness of antibiotics is greatly diminished without thorough debridement. Provisional stabilization with an external fixator is also important but follows debridement to allow access to the wound. Angiography would be indicated if vascular compromise is suspected, but the scenario does not explicitly state this. Wound closure is typically delayed, often after repeat debridements, to ensure no devitalized tissue remains and to allow for appropriate soft tissue coverage.
Question 9373
Topic: 2. Trauma
A 40-year-old male sustains a severe open-book pelvic fracture (APC Type III) after being run over by a vehicle. He is hemodynamically unstable despite initial fluid resuscitation. What is the most critical immediate management step after initial resuscitation and assessment in the trauma bay?
Correct Answer & Explanation
. External fixation of the pelvis.
Explanation
For a hemodynamically unstable patient with a severe open-book pelvic fracture (APC Type III, implying significant pubic symphysis diastasis and posterior instability), the most critical immediate step after initial resuscitation is mechanical stabilization of the pelvis. This is typically achieved with an external fixator or a pelvic binder (often applied even pre-hospital). Mechanical stabilization reduces the pelvic volume, thereby tamponading bleeding from venous plexuses and cancellous bone surfaces, and stabilizes the fracture fragments, which often significantly improves hemodynamic stability. Pelvic angiography and embolization is indicated if the patient remains hemodynamically unstable after mechanical stabilization, suggesting arterial bleeding. Immediate laparotomy is for intra-abdominal bleeding, not primary pelvic hemorrhage control. Transfer to CT scan is inappropriate for a hemodynamically unstable patient. Urethral catheterization is important for monitoring urine output and assessing for genitourinary injury but does not address life-threatening pelvic hemorrhage.
Question 9374
Topic: 2. Trauma
A 28-year-old male sustains an open tibia shaft fracture (Gustilo-Anderson Type IIIB), a closed femoral shaft fracture, and a closed head injury (GCS 10) in a motor vehicle accident. He is hemodynamically stable. After initial resuscitation, what is the most appropriate initial surgical management strategy for his fractures?
Correct Answer & Explanation
. Definitive intramedullary nailing of the femoral fracture, external fixation of the tibia
Explanation
In polytrauma patients with a concomitant head injury (GCS < 12-14 typically), 'Early Appropriate Care' or 'Damage Control Orthopedics' (DCO) principles apply. For the femoral fracture in a hemodynamically stable patient, early definitive intramedullary nailing (within 24 hours) is generally preferred as it minimizes the inflammatory response, aids in early mobilization, and has systemic benefits. However, the Gustilo-Anderson Type IIIB open tibia fracture carries a high risk of infection and typically warrants thorough debridement and initial external fixation to protect soft tissues and allow for serial debridements and wound management, followed by delayed definitive fixation once the soft tissue envelope is stable. Nailing an acute Type IIIB open fracture is generally avoided due to infection risk. Thus, a combination approach is most appropriate.
Question 9375
Topic: 2. Trauma
A 45-year-old male sustains a high-energy Pilon fracture (distal tibial plafond) with significant comminution, articular impaction, and severe soft tissue swelling. Initial management includes external fixation and elevation. After 7 days, the swelling has resolved, and the 'wrinkle sign' is present. A CT scan confirms the articular fragments. What is the most appropriate definitive surgical management strategy?
Correct Answer & Explanation
. Staged ORIF, typically involving an anteromedial approach with limited posterior approach if necessary, following soft tissue recovery
Explanation
High-energy Pilon fractures are characterized by severe soft tissue injury, making immediate definitive open reduction and internal fixation (ORIF) risky due to wound complications. The standard of care involves a staged approach: initial external fixation for stabilization and soft tissue rest, followed by definitive ORIF once the soft tissue envelope has recovered (evidenced by the 'wrinkle sign' and reduced swelling). The specific surgical approach (e.g., anteromedial, anterolateral, posteromedial, or combined) depends on the fracture pattern and required access for articular reduction. Primary arthrodesis is typically a salvage procedure for severe comminution or failed ORIF. Definitive external fixation alone may not achieve adequate articular reduction or stability for high-energy fractures. BKA is a last resort.
Question 9376
Topic: 2. Trauma
A 30-year-old male has chronic osteomyelitis of the tibia, 6 months post open fracture, with multiple failed debridements and a positive culture for Pseudomonas aeruginosa. After thorough debridement, he is left with a 6 cm tibial bone defect and significant soft tissue compromise. What is the most appropriate reconstructive technique for addressing both the infection and the bone defect in this complex scenario?
Correct Answer & Explanation
. Masquelet technique (induced membrane with bone grafting).
Explanation
The Masquelet technique, also known as the induced membrane technique, is a highly effective two-stage procedure for treating large bone defects, especially those complicated by chronic osteomyelitis and soft tissue deficits. It involves radical debridement, placement of a cement spacer to induce a vascularized membrane, followed by removal of the spacer and delayed bone grafting within the membrane. This membrane provides a biologically favorable, infection-resistant environment for bone healing and is particularly useful for achieving bone reconstruction in compromised settings. While vascularized fibula flaps are excellent for large defects with soft tissue needs, the Masquelet technique specifically leverages biological principles for bone regeneration in a contaminated environment.
Question 9377
Topic: 2. Trauma
A patient with severe osteoporosis requires fixation of a comminuted distal femur fracture. Which biomechanical principle is most critical to consider when selecting an implant and surgical technique for improved fixation stability in osteoporotic bone?
Correct Answer & Explanation
. Utilizing locking plate technology.
Explanation
In osteoporotic bone, conventional screw fixation relies heavily on friction between the screw and bone, which is significantly compromised due to poor bone quality. Locking plate technology employs screws that thread directly into the plate, creating a fixed-angle construct that provides angular stability (a 'fixed-angle internal fixator') independent of the bone-screw interface compression. This biomechanical principle is crucial for achieving stable fixation, preventing screw pullout, and distributing loads effectively across the fracture site in compromised bone, offering superior stability compared to non-locking systems in osteoporotic bone.
Question 9378
Topic: 2. Trauma
A 12-year-old girl with a history of short stature and multiple prior fractures presents with new onset severe right knee pain after a minor fall. Radiographs reveal generalized osteopenia, short bowed long bones, and a supracondylar femoral fracture with evidence of malunion of previous fractures. Genetic testing confirms a diagnosis of Osteogenesis Imperfecta Type I. Given her age and specific diagnosis, what is the most appropriate long-term orthopedic management strategy that should be considered to prevent future fractures and improve bone quality?
Correct Answer & Explanation
. Intramedullary rodding of long bones, particularly the femur and tibia, combined with bisphosphonate therapy.
Explanation
Osteogenesis Imperfecta (OI) Type I is a common form characterized by mild bone fragility, blue sclerae, and normal stature or mild short stature. The most appropriate long-term orthopedic management for children with recurrent fractures and significant deformity in OI involves a combination of medical and surgical approaches. Intramedullary rodding (telescoping or non-telescoping) of long bones, particularly the femurs and tibias, is crucial to prevent fractures, correct deformity, and facilitate weight-bearing and ambulation. This is often combined with bisphosphonate therapy (e.g., pamidronate, zoledronate), which has been shown to decrease fracture rates and improve bone mineral density in children with severe OI, although its use in mild OI is more controversial but often considered in symptomatic cases like this. Strict bed rest (Option A) is detrimental due to disuse osteopenia. Calcium and Vitamin D (Option B) are essential but insufficient alone. Growth hormone (Option D) is not a primary treatment for bone fragility in OI. Serial casting (Option E) is not a primary long-term solution for preventing fractures and bowing in OI; surgical correction is often required.
Question 9379
Topic: 2. Trauma
A 28-year-old male falls from a height and sustains a comminuted intra-articular fracture of the distal tibia (pilon fracture), classified as an AO 43-C3. The soft tissue envelope is significantly swollen, and there are blistering and skin creases present. What is the optimal surgical timing and approach for this fracture?
Correct Answer & Explanation
. Delayed ORIF after resolution of soft tissue swelling, utilizing a staged protocol with initial external fixation.
Explanation
Pilon fractures, especially high-energy, comminuted, intra-articular types (AO 43-C3), are frequently associated with severe soft tissue injury. The presence of significant swelling, blistering, and skin creases indicates a compromised soft tissue envelope that is not conducive to immediate definitive open reduction and internal fixation (ORIF). Operating in such conditions significantly increases the risk of wound dehiscence, infection, and skin necrosis. The optimal approach is a staged protocol: initial management involves temporary stabilization with an external fixator (spanning or hybrid) to restore length, alignment, and indirectly reduce the fracture fragments, while protecting the soft tissues. Definitive ORIF is then performed electively, typically 7-14 days later, once the soft tissue swelling has subsided (the 'wrinkle sign' is present, and blisters have healed). Immediate ORIF (Option A) in this scenario carries high complication rates. Arthroscopic reduction (Option C) is not typically sufficient for comminuted pilon fractures. Closed reduction and casting (Option D) is insufficient for unstable intra-articular fractures. External fixation only (Option E) may be an option for highly comminuted, unsalvageable ankles but usually not for a salvageable pilon.
Question 9380
Topic: 2. Trauma
A 35-year-old male is involved in a high-speed motor vehicle collision. He presents with severe pain in the left hip and inability to bear weight. Physical examination reveals a shortened, internally rotated, and adducted left lower extremity. There is also a palpable pulsatile mass in the left groin. What is the most critical immediate diagnostic step?
Correct Answer & Explanation
. Portable AP pelvis radiograph.
Explanation
The presentation (shortened, internally rotated, adducted leg) is classic for a posterior hip dislocation. The palpable pulsatile mass in the groin is highly suspicious for a femoral artery injury, which is a limb-threatening emergency. While vascular injury is critical, the immediate diagnostic step in an unstable patient with suspected hip dislocation is a portable AP pelvis radiograph (Option C). This confirms the dislocation, rules out obvious femoral neck fracture before reduction, and provides an initial assessment of associated pelvic or acetabular fractures. Although vascular consultation and imaging are essential, confirming the dislocation and femoral artery involvement with a plain film (which is quick and readily available) guides the sequence of subsequent interventions. Immediate reduction (Option A) should be performed as soon as possible, but after a quick radiograph to ensure it's a posterior dislocation without a contraindicating femoral neck fracture and to document any associated bony injury. A CT angiogram (Option B) would follow the plain film to fully characterize the vascular injury. MRI (Option D) is not an acute emergency diagnostic tool. Vascular surgeon consultation (Option E) is crucial, but diagnostic imaging is a prerequisite.
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