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 12161
Topic: 2. Trauma
When evaluating a patient for acute compartment syndrome of the leg following a tibial fracture, which pressure measurement best correlates with the need for emergent fasciotomy?
Correct Answer & Explanation
. Diastolic blood pressure minus compartment pressure < 30 mmHg
Explanation
A Delta P (diastolic blood pressure minus compartment pressure) of less than 30 mmHg is the most reliable threshold for diagnosing acute compartment syndrome. Absolute pressures can be misleading, especially in hypotensive patients.
Question 12162
Topic: Lower Extremity Trauma
A solid intramedullary nail has a radius of 'r'. If a new solid nail is manufactured with a radius of '2r', how much will its bending rigidity increase?
Correct Answer & Explanation
. 16 times
Explanation
The bending rigidity (area moment of inertia) of a solid cylinder is proportional to the radius raised to the fourth power (r^4). Therefore, doubling the radius (2r)^4 results in a 16-fold increase in bending rigidity.
Question 12163
Topic: Pelvic & Acetabular Trauma
In an anterior-posterior compression (APC) type III pelvic ring injury, which of the following ligaments is disrupted, causing severe rotational and vertical instability?
Correct Answer & Explanation
. Anterior and posterior sacroiliac ligaments, sacrotuberous, and sacrospinous ligaments
Explanation
An APC III injury involves complete disruption of the symphysis pubis along with the anterior and posterior sacroiliac, sacrotuberous, and sacrospinous ligaments. This leads to complete pelvic dissociation and profound hemodynamic instability.
Question 12164
Topic: 2. Trauma
A patient presents with inability to actively extend the wrist and digits, and loss of sensation over the dorsal first web space following a mid-shaft humerus fracture. Which cord of the brachial plexus gives rise to the nerve responsible for these deficits?
Correct Answer & Explanation
. Posterior cord
Explanation
The patient has a radial nerve palsy, which commonly complicates mid-shaft humerus fractures (Holstein-Lewis type). The radial nerve is a terminal branch of the posterior cord of the brachial plexus.
Question 12165
Topic: 2. Trauma
According to the Gustilo-Anderson classification, an open tibial shaft fracture with a 6 cm laceration, extensive periosteal stripping, and adequate soft-tissue coverage without the need for a flap is classified as:
Correct Answer & Explanation
. Type IIIA
Explanation
A Type IIIA fracture is defined as an open fracture with extensive soft tissue damage and periosteal stripping, but adequate soft tissue coverage remains. Type IIIB requires a flap for coverage, and Type IIIC involves an arterial injury requiring repair.
Question 12166
Topic: 2. Trauma
A 32-year-old male sustains a closed tibial shaft fracture. Which of the following is the most sensitive early clinical indicator of developing acute compartment syndrome?
Correct Answer & Explanation
. Pain out of proportion and with passive stretch
Explanation
Pain out of proportion to the injury and exacerbated by passive stretch of the muscles in the involved compartment is the most reliable and earliest clinical sign of acute compartment syndrome. Pulselessness and paresis are late and irreversible signs.
Question 12167
Topic: 2. Trauma
According to the modified Gustilo-Anderson classification, a 4 cm laceration over a tibia fracture with extensive periosteal stripping requiring a local rotational flap for coverage is classified as:
Correct Answer & Explanation
. Type IIIB
Explanation
A Gustilo-Anderson Type IIIB fracture is defined by extensive soft tissue injury, periosteal stripping, and bone exposure requiring a local or free flap for soft tissue coverage. Type IIIA has adequate periosteal coverage despite extensive lacerations.
Question 12168
Topic: Lower Extremity Trauma
During a pivot-shift test for an anterior cruciate ligament (ACL) deficient knee, the tibia reduces at approximately 20-30 degrees of flexion. Which structure is primarily responsible for generating the force that reduces the tibia?
Correct Answer & Explanation
. Iliotibial band
Explanation
The pivot-shift test demonstrates a subluxated tibia in extension that reduces in flexion. The iliotibial band (ITB) changes from an extensor to a flexor at 20-30 degrees of flexion, creating a posterior force vector that reduces the anteriorly subluxated lateral tibial plateau.
Question 12169
Topic: 2. Trauma
A hypotensive trauma patient with a mechanically unstable anterior-posterior compression (APC-III) pelvic ring injury is resuscitated and a pelvic binder is applied. To be biomechanically effective and safely reduce pelvic volume, the binder must be centered over which anatomical landmarks?
Correct Answer & Explanation
. Greater trochanters
Explanation
To effectively reduce pelvic volume and control venous bleeding in an open-book pelvic fracture, a pelvic binder or sheet must be centered at the level of the greater trochanters. Placing it over the iliac crests is less effective and can paradoxically open the pelvis further.
Question 12170
Topic: 2. Trauma
A patient presents with a severe open tibia fracture after a motorcycle collision. The Mangled Extremity Severity Score (MESS) is used to help determine the need for amputation versus limb salvage. Which of the following variables is NOT a component of the MESS criteria?
Correct Answer & Explanation
. Degree of wound contamination
Explanation
The MESS criteria include skeletal/soft tissue injury, limb ischemia, shock, and patient age. Degree of contamination is part of the Gustilo-Anderson classification but is not a formally scored variable in the MESS system.
Question 12171
Topic: 2. Trauma
A 45-year-old male presents with a painful midshaft femur nonunion 8 months after intramedullary nailing. Radiographs show abundant callus formation around the fracture site with a visible radiolucent line. What is the most appropriate definitive management?
Correct Answer & Explanation
. Exchange nailing with a larger diameter nail
Explanation
The presence of abundant callus (hypertrophic nonunion) indicates adequate biology but insufficient mechanical stability. Exchange nailing provides increased stiffness and stability, which is the primary treatment requirement.
Question 12172
Topic: 2. Trauma
A 22-year-old basketball player sustains a fracture of the fifth metatarsal. Radiographs show a transverse fracture at the metaphyseal-diaphyseal junction, extending into the 4th-5th intermetatarsal articulation. What is the blood supply to this specific region, and what is the corresponding diagnosis?
Correct Answer & Explanation
. Zone 2 (Jones) fracture, characterized by a vascular watershed area with precarious blood supply
Explanation
A classic Jones fracture occurs in Zone 2, which is the metaphyseal-diaphyseal junction of the fifth metatarsal extending into the 4th-5th intermetatarsal articulation. This is a recognized vascular watershed area, which makes these fractures prone to delayed union or nonunion. Zone 1 is the tuberosity (good cancellous blood supply), and Zone 3 is the proximal diaphysis distal to the 4th-5th articulation.
Question 12173
Topic: 2. Trauma
A 42-year-old construction worker falls from a height, sustaining a high-energy displaced intra-articular tibial plafond (pilon) fracture. The soft tissues are tense with massive swelling and fracture blisters. What is the standard of care regarding the timing and strategy of fixation?
Correct Answer & Explanation
. Immediate spanning external fixation with delayed definitive internal fixation of the tibia once soft tissues permit
Explanation
High-energy pilon fractures with severe soft tissue compromise (Tscherne grade 2 or 3) are managed with a staged protocol to minimize catastrophic soft tissue complications (infection, wound breakdown). The standard of care is temporary spanning external fixation (often with fibular fixation to restore length) followed by delayed definitive open reduction and internal fixation (ORIF) of the tibia once the soft tissue envelope has healed (appearance of skin wrinkles, resolution of blisters), usually 10-21 days later.
Question 12174
Topic: 2. Trauma
A 20-year-old competitive track athlete presents with an insidious onset of vague dorsal midfoot pain. Plain radiographs are normal, but an MRI confirms a non-displaced stress fracture of the central third of the tarsal navicular. What is the recommended initial management?
Correct Answer & Explanation
. Strict non-weight bearing in a short leg cast for 6 to 8 weeks
Explanation
Navicular stress fractures are high-risk fractures due to the watershed blood supply in the central third of the bone. For non-displaced fractures, strict non-weight bearing (NWB) in a cast for 6 to 8 weeks is the gold standard initial treatment to ensure healing and prevent progression to nonunion. Allowing weight-bearing in a boot has unacceptably high failure rates.
Question 12175
Topic: 2. Trauma
During a severe external rotation injury to the ankle, a bony avulsion of the anterior inferior tibiofibular ligament (AITFL) from its tibial attachment is identified on a CT scan. What is the eponymous name of this specific fracture fragment?
Correct Answer & Explanation
. Tillaux-Chaput fragment
Explanation
The Tillaux-Chaput fragment is the anterolateral tibial avulsion of the anterior inferior tibiofibular ligament (AITFL). The Wagstaffe (or Le Fort-Wagstaffe) fragment is the fibular avulsion of the AITFL. The Volkmann fragment is the posterolateral tibial avulsion of the posterior inferior tibiofibular ligament (PITFL).
Question 12176
Topic: 2. Trauma
A 22-year-old professional soccer player presents with acute lateral foot pain after a cutting maneuver. Radiographs demonstrate a transverse fracture of the fifth metatarsal extending into the fourth-fifth intermetatarsal articulation. What is the most appropriate management for this athlete?
Correct Answer & Explanation
. Intramedullary screw fixation
Explanation
The radiograph describes a Zone II fracture of the proximal fifth metatarsal (Jones fracture), which occurs at the metaphyseal-diaphyseal junction and extends into the 4th-5th intermetatarsal facet. Due to a vascular watershed area in this region, these fractures are prone to delayed union or nonunion. In elite or professional athletes, early operative intervention with an intramedullary screw is the gold standard. It significantly decreases the rate of nonunion and reduces the time to return to play compared to conservative management.
Question 12177
Topic: 2. Trauma
A 22-year-old professional soccer player sustains a Zone 2 fracture of the proximal fifth metatarsal. He wishes to return to play as soon as possible. What is the most appropriate management?
Correct Answer & Explanation
. Intramedullary screw fixation
Explanation
Zone 2 fractures (Jones fractures) involve the vascular watershed area and have a higher risk of nonunion. Intramedullary screw fixation is recommended for high-level athletes to ensure reliable union and an expedited return to sport.
Question 12178
Topic: 2. Trauma
A 40-year-old male sustains a high-energy closed OTA/AO 43-C3 pilon fracture with severe soft tissue swelling and fracture blisters. What is the most appropriate initial management?
Correct Answer & Explanation
. Spanning external fixation and delayed definitive ORIF once soft tissues allow
Explanation
High-energy pilon fractures with severe soft tissue compromise should be managed with damage-control orthopedics. A spanning external fixation allows for soft tissue recovery, followed by delayed definitive ORIF, significantly reducing the risk of wound complications.
Question 12179
Topic: 2. Trauma
A 35-year-old male sustains a severe ankle injury. Radiographs show a posterior fracture-dislocation of the ankle that is irreducible in the emergency department. The fibula appears displaced behind the posterior tubercle of the tibia. What is this specific injury pattern called?
Correct Answer & Explanation
. Bosworth fracture-dislocation
Explanation
A Bosworth fracture-dislocation involves the proximal fibular fragment becoming locked behind the posterior tubercle of the tibia, making closed reduction impossible and necessitating emergent open reduction.
Question 12180
Topic: Lower Extremity Trauma
In assessing a patient with a suspected syndesmotic injury, radiographs are obtained. Which radiographic parameter is considered the most reliable indicator of syndesmotic widening on a standard AP or Mortise view?
Correct Answer & Explanation
. Tibiofibular clear space > 6 mm measured 1 cm proximal to the plafond
Explanation
A tibiofibular clear space greater than 5-6 mm on either the AP or Mortise view is the most reliable and reproducible radiographic parameter indicating syndesmotic widening.
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