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 4861
Topic: Upper Extremity Trauma
When performing an open or arthroscopic distal clavicle excision for osteolysis, what is the maximum amount of bone that should be resected to preserve the acromioclavicular (AC) ligaments and prevent anterior-posterior instability?
Correct Answer & Explanation
. 5 to 8 mm
Explanation
Distal clavicle resection typically aims for 5 to 8 mm of bone removal. Resecting more than 10 mm risks compromising the superior and posterior AC capsular ligaments, leading to iatrogenic horizontal (AP) instability.
Question 4862
Topic: Upper Extremity Trauma
In the setting of an acromioclavicular (AC) joint dislocation, which of the following ligaments provides the primary restraint to superior translation of the distal clavicle?
Correct Answer & Explanation
. Conoid ligament
Explanation
The conoid ligament is the primary restraint to superior translation of the distal clavicle. The trapezoid ligament primarily resists axial compression to the shoulder.
Question 4863
Topic: 2. Trauma
A radiograph of the pelvis in a trauma patient shows a fracture involving the right acetabulum. Analysis of the standardized radiographic lines reveals that the iliopectineal line is disrupted, but the ilioischial line remains completely intact. The anterior rim of the acetabulum is also fractured. Which Letournel fracture pattern does this most likely represent?
Correct Answer & Explanation
. Anterior column fracture
Explanation
According to the Letournel and Judet classification of acetabular fractures, disruption of the iliopectineal line on an AP radiograph indicates an anterior column or anterior wall fracture. Because the ilioischial line (which defines the posterior column) is intact, this is an isolated anterior column fracture. Transverse and both column fractures would disrupt both lines.
Question 4864
Topic: 2. Trauma
A 45-year-old female sustains a Schatzker IV tibial plateau fracture with a large, displaced posteromedial fragment. Biomechanically, what is the most appropriate internal fixation strategy to address the posteromedial fragment?
Correct Answer & Explanation
. Posteromedial buttress plating
Explanation
Schatzker IV fractures involve the medial tibial plateau. A classic variant includes a coronal fracture line creating a posteromedial fragment. This fragment is subjected to significant shear forces during weight-bearing and knee flexion. Biomechanically, it is best neutralized with a posteromedial buttress plate placed directly at the apex of the fracture, preventing apex-posterior and medial subluxation of the medial femoral condyle.
Question 4865
Topic: 2. Trauma
A 28-year-old male sustains a vertically oriented femoral neck fracture (Pauwels Type III). What is the primary biomechanical advantage of utilizing a sliding hip screw (SHS) with a derotational screw over three parallel cannulated cancellous screws (CCS) for this specific fracture pattern?
Correct Answer & Explanation
. Superior resistance to vertical shear forces
Explanation
Pauwels Type III femoral neck fractures have a vertical fracture line (angle > 50 degrees to the horizontal), resulting in very high vertical shear forces that predispose to varus collapse and nonunion. Biomechanical studies have demonstrated that a fixed-angle construct like a sliding hip screw (SHS) provides significantly greater resistance to vertical shear forces compared to three parallel cannulated screws.
Question 4866
Topic: 2. Trauma
A 25-year-old male is admitted with a highly comminuted, closed tibial shaft fracture. Hours later, he complains of severe leg pain out of proportion to the injury. Compartment pressures are measured. Which of the following threshold formulas is considered the most reliable indicator for diagnosing acute compartment syndrome and proceeding with fasciotomy?
Correct Answer & Explanation
. Diastolic blood pressure minus compartment pressure < 30 mmHg
Explanation
The delta pressure (Delta P) calculation is the most accurate criteria for diagnosing acute compartment syndrome. It is defined as the Diastolic Blood Pressure minus the intracompartmental pressure. A Delta P of less than 30 mmHg indicates inadequate capillary perfusion to the muscle and is an absolute indication for emergent fasciotomy.
Question 4867
Topic: 2. Trauma
A 29-year-old male sustains a low-velocity civilian gunshot wound to the right thigh, resulting in a comminuted midshaft femur fracture. The entrance and exit wounds are 5 mm and clean. He has palpable distal pulses, a normal sensorimotor exam, and an ankle-brachial index of 1.0. What is the most appropriate definitive management?
Correct Answer & Explanation
. Local wound care, tetanus prophylaxis, and standard intramedullary nailing
Explanation
Low-velocity civilian gunshot wounds with associated long bone fractures, clean wounds, and no evidence of vascular compromise do not require formal open irrigation and debridement of the bullet tract. They can be safely treated with local wound care, appropriate tetanus prophylaxis, prophylactic antibiotics, and standard internal fixation (e.g., intramedullary nailing of the femur), with infection rates comparable to closed fractures.
Question 4868
Topic: 2. Trauma
In the surgical treatment of a complex tibial pilon fracture, the articular surface of the distal tibia is frequently split into three primary fragments. The anterolateral fragment (often referred to as the Chaput fragment) is tethered primarily by which of the following ligaments?
In a classical pilon fracture, the three main articular fragments are the medial (tethered by the deltoid ligament), the posterior or Volkmann fragment (tethered by the posterior inferior tibiofibular ligament - PITFL), and the anterolateral or Chaput fragment (tethered by the anterior inferior tibiofibular ligament - AITFL).
Question 4869
Topic: 2. Trauma
A 28-year-old male sustains a highly displaced U-shaped sacral fracture (spinopelvic dissociation) following a 30-foot fall. Decompression and lumbopelvic fixation are planned. Given the typical fracture pattern involving a transverse fracture line through the sacrum, which of the following neurologic deficits is most frequently seen?
Correct Answer & Explanation
. Bowel, bladder, and sexual dysfunction
Explanation
A U-shaped sacral fracture is the classic pattern of spinopelvic dissociation, characterized by bilateral vertical sacral fractures connected by a transverse fracture line. This transverse line typically crosses through the upper sacral segments (S1, S2, or S3). Because the sacral nerve roots (S2-S4) control sphincter function, bowel and bladder dysfunction are highly characteristic and devastating complications of this fracture.
Question 4870
Topic: 2. Trauma
A 45-year-old male sustains an acetabular fracture in a motor vehicle accident. The obturator oblique radiograph demonstrates a classic 'spur sign.' Which of the following Letournel fracture patterns is unequivocally indicated by this radiographic finding?
Correct Answer & Explanation
. Associated both column fracture
Explanation
The 'spur sign' is a pathognomonic radiographic finding seen on the obturator oblique view of the pelvis. It represents the intact strut of iliac bone attached to the sacroiliac joint, sitting above the displaced acetabular columns. Its presence indicates that all articular segments of the acetabulum are detached from the intact axial skeleton, defining an Associated Both Column fracture.
Question 4871
Topic: 2. Trauma
A 45-year-old male sustains a Schatzker IV tibial plateau fracture with a large, displaced posteromedial fragment. Which surgical approach and fixation strategy is biomechanically optimal for this specific fragment?
Correct Answer & Explanation
. Posteromedial approach with anti-glide (buttress) plating
Explanation
Posteromedial fragments in tibial plateau fractures represent a coronal shear injury. They tend to displace distally and posteriorly. Biomechanically, these fragments require direct visualization via a posteromedial approach and fixation with an anti-glide (buttress) plate at the apex of the fracture to effectively resist vertical shear forces. Lateral locked plates typically do not adequately capture or buttress this fragment.
Question 4872
Topic: 2. Trauma
A 25-year-old male sustains a highly vertical (Pauwels Type III) femoral neck fracture. Which of the following fixation constructs provides the highest biomechanical stability against vertical shear forces for this fracture pattern?
Correct Answer & Explanation
. A Dynamic Hip Screw (DHS) with a supplemental derotational screw
Explanation
Pauwels Type III fractures (>50 degrees) are highly unstable due to significant vertical shear forces. Multiple parallel cancellous screws are primarily designed to resist compressive forces and often fail in shear. A fixed-angle device, such as a Dynamic Hip Screw (DHS), provides superior biomechanical resistance to vertical shear. A supplemental derotational cancellous screw is typically added to control rotational instability.
Question 4873
Topic: 2. Trauma
Six weeks after sustaining a displaced talar neck fracture treated with open reduction and internal fixation, an AP radiograph of the ankle demonstrates a subchondral radiolucent band in the dome of the talus. What does this radiographic finding indicate?
Correct Answer & Explanation
. Intact vascularity to the talar body
Explanation
The subchondral radiolucency in the talar dome, visible on an AP radiograph 6 to 8 weeks after a talar neck fracture, is known as the Hawkins sign. It represents subchondral osteopenia secondary to hyperemia from disuse. The presence of hyperemia proves that the talar body has an intact blood supply, making the subsequent development of avascular necrosis (AVN) highly unlikely.
Question 4874
Topic: Pelvic & Acetabular Trauma
A hemodynamically unstable 35-year-old male is brought to the trauma bay following a high-speed motorcycle crash. Pelvic radiographs show a severely widened symphysis pubis and bilateral sacroiliac joint disruption (APC-III). A pelvic binder is to be applied. To effectively maximize reduction of the pelvic volume, at what anatomic level should the binder be centered?
Correct Answer & Explanation
. The greater trochanters
Explanation
To effectively reduce pelvic volume in an open-book (Anteroposterior Compression) pelvic ring injury, a pelvic binder or sheet must be centered directly over the greater trochanters. Placing the binder too proximally over the iliac crests is a common error that can paradoxically widen the pelvic outlet or fail to adequately close the symphyseal diastasis.
Question 4875
Topic: 2. Trauma
A 28-year-old male sustains a closed, middle-third transverse humeral shaft fracture after a wrestling injury. In the emergency department, he is noted to have a complete absence of wrist and finger extension. What is the most appropriate management regarding his nerve deficit?
Correct Answer & Explanation
. Functional bracing and clinical observation of the nerve deficit
Explanation
An acute radial nerve palsy associated with a closed humeral shaft fracture is typically a neuropraxia (or axonotmesis) and has a high rate of spontaneous recovery (up to 90%). The standard of care is functional bracing of the humerus and clinical observation. Surgical exploration is generally reserved for open fractures, penetrating trauma, palsy occurring only after a reduction maneuver, or failure of clinical/EMG recovery after 3-6 months.
Question 4876
Topic: 2. Trauma
A 40-year-old male sustains an isolated coronal shear fracture of the lateral femoral condyle (Hoffa fracture). Which of the following describes the ideal biomechanical screw fixation trajectory to achieve compression across this specific fracture pattern?
Correct Answer & Explanation
. Posterior-to-anterior directed lag screws
Explanation
Hoffa fractures are coronal plane shear fractures of the femoral condyles. Biomechanically, placing lag screws from posterior to anterior (PA) directs the compressive forces perpendicular to the fracture line and articular surface, which provides superior stability against shear compared to anterior-to-posterior (AP) screws. However, due to surgical exposure challenges, AP screws (often supplemented with an anti-glide plate) are frequently used in practice.
Question 4877
Topic: 2. Trauma
A 24-year-old male suffers a severe crush injury to his right calf. The leg is tensely swollen, and he complains of pain out of proportion to the injury. Compartment pressures are measured. At what delta P (systemic diastolic blood pressure minus compartment pressure) is a four-compartment fasciotomy unequivocally indicated?
Correct Answer & Explanation
. Less than 30 mm Hg
Explanation
Acute compartment syndrome is primarily a clinical diagnosis. When pressure measurements are utilized (such as in an unexaminable or equivocal patient), a delta P (Diastolic Blood Pressure - Compartment Pressure) of less than 30 mm Hg is the widely accepted threshold for surgical decompression via fasciotomy. This accounts for the fact that tissue perfusion pressure relies on systemic diastolic blood pressure.
Question 4878
Topic: 2. Trauma
A 21-year-old male falls on an outstretched hand and sustains a fracture of the proximal pole of the scaphoid. The high rate of avascular necrosis and nonunion associated with this specific fracture location is primarily due to the dominant arterial supply entering the scaphoid at which of the following locations?
Correct Answer & Explanation
. The dorsal ridge via branches of the radial artery
Explanation
The scaphoid receives 70-80% of its blood supply from branches of the radial artery that enter the bone distally along the dorsal ridge at the waist. The blood then flows in a retrograde fashion to supply the proximal pole. Because of this retrograde perfusion, fractures at the proximal pole disrupt the blood supply, leading to a high incidence of avascular necrosis.
Question 4879
Topic: 2. Trauma
A 29-year-old male sustains a low-velocity gunshot wound to the right thigh, resulting in a comminuted midshaft femur fracture. Distal pulses are palpable and biphasic on Doppler. There is no expanding hematoma. What is the standard of care regarding antibiotic prophylaxis and definitive fracture management?
Correct Answer & Explanation
. 24 hours of IV cefazolin followed by prompt intramedullary nailing
Explanation
Low-velocity gunshot wounds causing long bone fractures are generally treated as Gustilo-Anderson Type I open fractures. Current evidence dictates that 24 hours of a first-generation cephalosporin (e.g., cefazolin) provides adequate prophylaxis. Standard treatment is prompt reamed intramedullary nailing, which yields excellent union rates and functional outcomes comparable to closed fractures.
Question 4880
Topic: 2. Trauma
A 38-year-old female presents with an isolated coronal shear fracture of the capitellum without involvement of the trochlea or posterior comminution (Bryan-Morrey Type I). Which surgical approach is generally most appropriate for open reduction and internal fixation of this fracture?
Correct Answer & Explanation
. Extended lateral (Kocher or Kaplan) approach
Explanation
The extended lateral approach (utilizing either the Kocher interval between the ECU and anconeus, or the Kaplan interval between the ECRL and EDC) provides direct and excellent visualization of the anterior articular surface of the capitellum and lateral column. It is the workhorse approach for Bryan-Morrey Type I (isolated capitellum) and Type IV (coronal shear) fractures. Olecranon osteotomies are typically reserved for complex, bicolumnar distal humerus fractures.
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