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2. Trauma MCQs

Practice Set 573 of 640

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 11441

Topic: 2. Trauma

The Sanders classification of intra-articular calcaneus fractures is heavily utilized for surgical planning. This classification is based on the number of articular fragments visualized on which specific imaging slice?

. Sagittal MRI T1-weighted image
. Axial CT image through the sustentaculum tali
. Coronal CT image through the widest portion of the posterior facet
. Sagittal CT image through the anterior process
. Standard lateral radiograph

Correct Answer & Explanation

. Sagittal MRI T1-weighted image

Explanation

The Sanders classification is determined by the number and location of fracture lines on a coronal CT slice at the widest point of the posterior articular facet. It accurately predicts the surgical complexity and prognosis.

Question 11442

Topic: 2. Trauma

According to the findings of the Lower Extremity Assessment Project (LEAP) study, which of the following clinical factors is considered an absolute indication for primary amputation in severe lower extremity trauma?

. Complete disruption of the posterior tibial nerve with loss of plantar sensation
. A Mangled Extremity Severity Score (MESS) greater than 7
. Warm ischemia time exceeding 4 hours
. Severe crush injury with massive muscle necrosis
. There are no absolute indications; initial loss of plantar sensation does not preclude a successful salvage

Correct Answer & Explanation

. Complete disruption of the posterior tibial nerve with loss of plantar sensation

Explanation

The LEAP study fundamentally changed trauma dogma by demonstrating that initial loss of plantar sensation is not an absolute indication for amputation. Many patients with initially insensate feet regained protective sensation after successful limb salvage.

Question 11443

Topic: 2. Trauma

A 45-year-old male sustains a bicondylar tibial plateau fracture with a large posteromedial coronal shear fragment. Which surgical approach is most appropriate for direct visualization and buttress plating of this specific fragment?

. Anterolateral approach
. Posteromedial approach
. Direct posterior approach
. Medial parapatellar approach
. Extended lateral extensile approach

Correct Answer & Explanation

. Anterolateral approach

Explanation

The posteromedial approach allows direct visualization and application of an anti-glide or buttress plate to the apex of the posteromedial coronal shear fragment. An anterolateral approach alone cannot adequately reduce or stabilize this posterior structural injury.

Question 11444

Topic: 2. Trauma
A 28-year-old female sustains a vertically oriented (Pauwels type III) femoral neck fracture. Which fixation construct provides the highest biomechanical stability for this specific fracture pattern?
. Three parallel cancellous screws
. Sliding hip screw (SHS) with an anti-rotation screw
. Proximal femoral nail (PFN)
. Dynamic condylar screw (DCS)
. Cannulated screws in an inverted triangle configuration

Correct Answer & Explanation

. Sliding hip screw (SHS) with an anti-rotation screw

Explanation

Biomechanical studies demonstrate that a sliding hip screw with a derotation screw provides superior stability for vertically oriented, high-shear (Pauwels III) femoral neck fractures compared to parallel cancellous screws. This fixed-angle construct better resists the high shear forces acting at the fracture site.

Question 11445

Topic: 2. Trauma
A 32-year-old male sustains a Gustilo-Anderson Type IIIB open tibia fracture. Following thorough debridement and skeletal stabilization, what is the optimal timeframe for soft tissue coverage to minimize deep infection rates?
. Within 72 hours
. Within 7 to 10 days
. After 14 days when robust granulation tissue forms
. After 21 days
. Immediate coverage during the index debridement, regardless of contamination

Correct Answer & Explanation

. Within 72 hours

Explanation

Classic studies by Godina, supported by current trauma guidelines, demonstrate that early soft tissue coverage (within 72 hours) of Type IIIB open tibia fractures significantly reduces infection rates and improves flap survival. Delays beyond this period allow bacterial colonization to progress to invasive infection.

Question 11446

Topic: 2. Trauma

Which of the following physiologic parameters is the strongest indication for Damage Control Orthopedics (DCO) rather than Early Total Care (ETC) in a polytraumatized patient with bilateral femur fractures?

. Base deficit of 2.0 mmol/L
. Serum lactate of 1.5 mmol/L
. Platelet count of 150,000/mcL
. Core temperature of 33 degrees Celsius
. Urine output of 1.5 mL/kg/hr

Correct Answer & Explanation

. Base deficit of 2.0 mmol/L

Explanation

Hypothermia (core temperature < 35°C), acidosis, and coagulopathy constitute the "lethal triad" of trauma and are absolute indications for Damage Control Orthopedics. A core temperature of 33°C indicates severe physiologic derangement, precluding safe prolonged definitive surgery.

Question 11447

Topic: 2. Trauma
Six weeks after open reduction and internal fixation of a Hawkins type III talar neck fracture, a radiolucent band is seen in the subchondral bone of the talar dome on the AP mortise radiograph. What does this radiographic finding indicate?
. Avascular necrosis of the talar body
. Septic arthritis of the ankle joint
. Revascularization and intact blood supply to the talar body
. Impending nonunion of the talar neck
. Osteochondral defect of the talar dome

Correct Answer & Explanation

. Revascularization and intact blood supply to the talar body

Explanation

The Hawkins sign is a subchondral radiolucent band seen at 6 to 8 weeks post-injury, representing disuse osteopenia and subchondral bone resorption. Its presence requires an intact vascular supply, thereby serving as a highly reliable indicator that avascular necrosis of the talar body will not occur.

Question 11448

Topic: 2. Trauma

During a four-compartment fasciotomy of the lower leg using a dual-incision technique, the surgeon must ensure adequate decompression of all muscle compartments. Which compartment is most frequently inadequately decompressed, leading to residual myonecrosis?

. Anterior compartment
. Lateral compartment
. Superficial posterior compartment
. Deep posterior compartment
. Peroneal compartment

Correct Answer & Explanation

. Anterior compartment

Explanation

The deep posterior compartment is anatomically protected and challenging to fully release, making it the most common site of missed or inadequate decompression in lower extremity fasciotomies. Failure to release the soleus bridge from the tibia leaves this compartment dangerously pressurized.

Question 11449

Topic: 2. Trauma

A patient presents with an acetabular fracture. CT imaging shows a fracture line separating the ilium into two halves, traversing the weight-bearing dome. The anterior and posterior columns are detached from the axial skeleton, but the articular surface of the separated columns remains congruent with the femoral head. What is the diagnosis?

. Transverse fracture
. T-type fracture
. Anterior column posterior hemitransverse fracture
. Both-column fracture
. Posterior column with posterior wall fracture

Correct Answer & Explanation

. Transverse fracture

Explanation

The hallmark of a both-column acetabular fracture is the complete detachment of all articular segments from the intact axial skeleton (iliac wing). The "secondary congruence sign", where the detached fractured columns fall medially but remain congruent with the femoral head, is classic for this injury.

Question 11450

Topic: 2. Trauma

What is the optimal screw configuration for internally fixing a lateral coronal shear fracture (Hoffa fracture) of the distal femur to maximize biomechanical stability and prevent displacement during knee flexion?

. Anterior-to-posterior oriented fully threaded screws
. Posterior-to-anterior oriented lag screws
. Anterior-to-posterior oriented lag screws
. Medial-to-lateral fully threaded screws
. Dual tension band wiring

Correct Answer & Explanation

. Anterior-to-posterior oriented fully threaded screws

Explanation

Biomechanical studies have shown that anterior-to-posterior (AP) directed lag screws placed perpendicular to the fracture plane provide the most stable fixation for Hoffa fractures. This orientation best resists the posterior shear forces experienced by the condyle during active knee flexion.

Question 11451

Topic: 2. Trauma

Which of the following is the most reliable radiographic parameter on plain films to diagnose a syndesmotic injury requiring surgical fixation in an acute rotational ankle fracture?

. Tibiofibular overlap of less than 10 mm on the AP view
. Tibiofibular clear space greater than 6 mm on the AP view
. Medial clear space widening greater than 4 mm on a gravity stress view
. Talar tilt greater than 2 degrees compared to the contralateral side
. Decreased Bohler's angle

Correct Answer & Explanation

. Tibiofibular overlap of less than 10 mm on the AP view

Explanation

In the setting of a suspected syndesmotic injury (e.g., Weber B or C fractures), medial clear space widening greater than 4 mm on a gravity stress or weight-bearing view is the most reliable radiographic predictor of deep deltoid and syndesmotic instability requiring fixation. Simple measurements of tibiofibular overlap or clear space on static non-stress views are less sensitive and specific due to rotational variations.

Question 11452

Topic: 2. Trauma

A 22-year-old elite collegiate basketball player sustains a fifth metatarsal fracture. Radiographs show a transverse fracture at the metaphyseal-diaphyseal junction extending into the fourth-fifth intermetatarsal articulation. He wishes to return to play as rapidly and safely as possible. What is the standard of care?

. Short leg walking boot for 6 weeks
. Non-weight-bearing short leg cast for 6-8 weeks
. Intramedullary screw fixation
. Open reduction and locking plate fixation
. Primary excision of the proximal fragment and peroneus brevis advancement

Correct Answer & Explanation

. Short leg walking boot for 6 weeks

Explanation

This is a classic Zone 2 (Jones) fracture. Due to the watershed blood supply in this region, there is a high risk of nonunion or delayed union. In high-level athletes who desire early return to sport, intramedullary screw fixation is the gold standard, demonstrating faster time to union and earlier return to play compared to nonoperative management.

Question 11453

Topic: 2. Trauma

A 19-year-old track athlete presents with insidious onset dorsal midfoot pain. MRI confirms a non-displaced stress fracture of the tarsal navicular. What is the most appropriate initial management?

. Weight-bearing in a stiff-soled shoe for 4 weeks
. Weight-bearing as tolerated in a controlled ankle motion (CAM) boot
. Non-weight-bearing in a short leg cast for 6 weeks
. Percutaneous placement of a retrograde 4.0 mm screw
. Open reduction, bone grafting, and internal fixation

Correct Answer & Explanation

. Weight-bearing in a stiff-soled shoe for 4 weeks

Explanation

Navicular stress fractures occur in the relatively avascular central third of the bone. For non-displaced navicular stress fractures, strict non-weight-bearing in a short leg cast for 6 to 8 weeks is the most appropriate initial management. Weight-bearing treatments have unacceptably high rates of nonunion or delayed union. Surgery is reserved for displaced fractures or failure of strict conservative care.

Question 11454

Topic: 2. Trauma

In the management of high-energy distal tibia pilon fractures (OTA/AO 43C), what is the primary rationale for utilizing a staged protocol consisting of immediate spanning external fixation followed by delayed definitive open reduction and internal fixation (ORIF)?

. It significantly decreases the time to radiographic bony union.
. It minimizes the incidence of severe soft tissue complications.
. It provides superior long-term functional joint outcomes compared to early ORIF.
. It reduces the risk of postoperative deep vein thrombosis.
. It entirely negates the need for bone grafting of metaphyseal defects.

Correct Answer & Explanation

. It significantly decreases the time to radiographic bony union.

Explanation

High-energy pilon fractures are associated with massive soft tissue swelling and injury. Historically, immediate ORIF led to catastrophic wound necrosis and deep infection rates over 30%. The staged protocol (span and scan) allows the soft tissue envelope to recover (usually 10-21 days) before definitive surgical approaches, drastically lowering the rate of wound complications and deep infection.

Question 11455

Topic: 2. Trauma

A 22-year-old elite runner presents with insidious onset dorsal midfoot pain. CT scan demonstrates a dorsal cortical break in the navicular that does not propagate into the plantar cortex. Which of the following best describes the blood supply of the tarsal navicular that predisposes to this specific injury pattern?

. Radial branches from dorsalis pedis and medial plantar arteries causing a central watershed zone
. A single nutrient artery branching directly from the posterior tibial artery
. Retrograde blood supply originating from the medial cuneiform
. A rich anastomotic network primarily from the lateral plantar artery
. Predominant supply from the peroneal artery perforators

Correct Answer & Explanation

. Radial branches from dorsalis pedis and medial plantar arteries causing a central watershed zone

Explanation

The tarsal navicular receives its blood supply from radial branches of the dorsalis pedis artery dorsally and the medial plantar artery plantarly. This creates a central avascular 'watershed' zone in the middle third of the bone, heavily predisposing it to stress fractures and nonunions, particularly in running athletes.

Question 11456

Topic: 2. Trauma

When utilizing an extensile lateral approach for open reduction and internal fixation of a displaced intra-articular calcaneus fracture, the full-thickness flap must be elevated in a subperiosteal plane. Which of the following vascular structures must be preserved within the flap to ensure adequate soft tissue healing and prevent necrosis?

. Sural artery
. Lateral calcaneal artery
. Medial calcaneal artery
. Dorsalis pedis artery
. Perforating branch of the peroneal artery

Correct Answer & Explanation

. Sural artery

Explanation

The lateral calcaneal artery, a branch of the peroneal artery, provides the primary blood supply to the corner of the extensile lateral flap used in calcaneus fracture ORIF. The flap must be elevated full-thickness (subperiosteal) to protect this vessel and minimize the risk of wound edge necrosis.

Question 11457

Topic: Lower Extremity Trauma

A 26-year-old skier presents with posterolateral ankle pain and a snapping sensation behind the lateral malleolus. Ultrasound confirms anterior subluxation of the peroneal tendons out of the retromalleolar groove during active ankle dorsiflexion and eversion. Which anatomical structure is primarily incompetent in this condition?

. Inferior extensor retinaculum
. Superior peroneal retinaculum
. Calcaneofibular ligament
. Posterior talofibular ligament
. Peroneus brevis tendon

Correct Answer & Explanation

. Inferior extensor retinaculum

Explanation

The superior peroneal retinaculum (SPR) is the primary restraint against anterior subluxation of the peroneal tendons. Injury or avulsion of the SPR from the fibula (often accompanied by a 'fleck sign' on radiographs) leads to dynamic subluxation of the tendons over the lateral malleolus.

Question 11458

Topic: 2. Trauma

A 30-year-old male sustains a severe crush injury to the foot. The surgeon is concerned about foot compartment syndrome and prepares to measure compartment pressures. How many distinct osseofascial compartments are classically described in the foot?

. 3
. 4
. 5
. 7
. 9

Correct Answer & Explanation

. 3

Explanation

There are classically 9 distinct compartments in the foot: the medial, lateral, superficial central, calcaneal (deep central), and 4 interosseous compartments. Accurate knowledge is essential when performing fasciotomies for compartment syndrome of the foot, typically requiring a dual dorsal approach and sometimes a medial approach to decompress fully.

Question 11459

Topic: 2. Trauma

A 20-year-old collegiate track athlete presents with insidious onset dorsal midfoot pain. A CT scan confirms a non-displaced stress fracture of the tarsal navicular. Which specific anatomic region of the navicular is most prone to stress fractures due to its precarious blood supply?

. Medial tuberosity
. Plantar articular margin
. Central third
. Lateral third
. Dorsal lip

Correct Answer & Explanation

. Medial tuberosity

Explanation

The central third of the tarsal navicular is a relative 'watershed' area with a tenuous vascular supply, making it highly susceptible to stress fractures, delayed union, and nonunion. Initial management for a non-displaced fracture in this specific zone typically involves strict non-weight bearing cast immobilization for a minimum of 6 weeks.

Question 11460

Topic: 2. Trauma

A 19-year-old collegiate basketball player sustains a fracture at the metaphyseal-diaphyseal junction of the fifth metatarsal. Which of the following factors most strongly supports the indication for early intramedullary screw fixation rather than conservative management?

. The presence of a symptomatic os vesalianum
. The fracture extending into the articular surface of the cuboid
. The patient's status as a high-demand elite athlete
. The fracture being anatomically located in Zone I
. The presence of open physes

Correct Answer & Explanation

. The presence of a symptomatic os vesalianum

Explanation

A fracture strictly at the metaphyseal-diaphyseal junction is a Zone II (Jones) fracture. Because of the watershed blood supply in this region, these fractures are notorious for a high rate of delayed union or nonunion. Early intramedullary screw fixation is highly recommended for elite and high-demand athletes to minimize the risk of nonunion and dramatically expedite their return to play.

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