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2. Trauma MCQs

Practice Set 227 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 4521

Topic: 2. Trauma

A 45-year-old active female presents with isolated lateral compartment knee osteoarthritis and an anatomic valgus alignment of 12 degrees. A lateral opening-wedge distal femoral osteotomy is planned. Compared to a medial closing-wedge osteotomy, what is a primary biomechanical or surgical advantage of the lateral opening-wedge technique?

. Lower risk of nonunion
. Avoidance of limb shortening
. Earlier time to full weight-bearing
. Decreased risk of patella baja
. Elimination of the need for bone grafting

Correct Answer & Explanation

. Lower risk of nonunion

Explanation

A lateral opening-wedge distal femoral osteotomy preserves or slightly increases limb length, whereas a medial closing-wedge osteotomy causes limb shortening. However, an opening-wedge technique generally has a higher risk of nonunion, requires bone grafting, and entails a longer period of protected weight-bearing.

Question 4522

Topic: 2. Trauma

A 22-year-old collegiate basketball player sustains a Zone 2 fracture of the proximal fifth metatarsal (true Jones fracture). He is treated with intramedullary screw fixation. To optimize biomechanical stability and reduce the risk of nonunion, which of the following screw characteristics is highly recommended?

. A 3.0 mm cannulated partially threaded screw
. The smallest diameter screw possible to preserve endosteal blood supply
. The largest diameter solid screw that fits the intramedullary canal, with all threads engaging the diaphysis distal to the fracture site
. A bioabsorbable interference screw to allow gradual load sharing
. A fully threaded position screw that engages both the proximal and distal fragments to prevent compression

Correct Answer & Explanation

. A 3.0 mm cannulated partially threaded screw

Explanation

For intramedullary screw fixation of Jones fractures, the literature supports using the largest diameter solid screw that fits the intramedullary canal (often 4.5 mm, 5.5 mm, or larger). All threads must pass completely distal to the fracture site to achieve adequate interfragmentary lag compression.

Question 4523

Topic: 2. Trauma

A 78-year-old osteoporotic female falls and sustains a reverse obliquity intertrochanteric femur fracture (AO/OTA 31-A3). Which of the following fixation constructs is biomechanically optimal and associated with the lowest failure rate for this specific fracture pattern?

. Sliding hip screw with a 2-hole sideplate
. Sliding hip screw with a 4-hole sideplate
. Long cephalomedullary nail
. Multiple cancellous lag screws
. Primary total hip arthroplasty

Correct Answer & Explanation

. Long cephalomedullary nail

Explanation

Reverse obliquity intertrochanteric fractures are highly unstable because the main fracture line runs from proximal-medial to distal-lateral. A cephalomedullary nail is biomechanically superior as it prevents medial displacement of the femoral shaft, a common failure mode seen when sliding hip screws are improperly used here.

Question 4524

Topic: Pelvic & Acetabular Trauma
A 45-year-old male sustains a severe pelvic ring injury after a crush accident. Radiographs reveal an anteroposterior compression (APC) injury. According to the Young-Burgess classification, which finding differentiates an APC III injury from an APC II injury?
. Symphyseal diastasis greater than 2.5 cm
. Rupture of the anterior sacroiliac, sacrotuberous, and sacrospinous ligaments
. Complete disruption of the posterior sacroiliac ligament complex
. Vertical displacement of the hemipelvis
. Associated vascular injury in the retroperitoneum

Correct Answer & Explanation

. Complete disruption of the posterior sacroiliac ligament complex

Explanation

An APC II injury involves disruption of the anterior sacroiliac ligaments with an intact posterior SI hinge. An APC III injury implies complete dissociation of the hemipelvis due to concurrent disruption of the robust posterior sacroiliac ligaments, severely increasing pelvic volume and instability.

Question 4525

Topic: 2. Trauma
A 28-year-old male sustains a midshaft fibula fracture after being kicked during a karate tournament and develops compartment syndrome isolated to the lateral compartment of his leg. If left untreated, which of the following sensory or motor deficits would be expected?
. Decreased sensation on the dorsum of his foot involving the hallux, 3rd, and 4th toes
. Inability to plantar flex the ankle
. Decreased sensation on the dorsum of his foot involving the first webspace
. Inability to dorsiflex the ankle
. Inability to abduct his toes

Correct Answer & Explanation

. Decreased sensation on the dorsum of his foot involving the hallux, 3rd, and 4th toes

Explanation

The clinical vignette describes a scenario of isolated compartment syndrome in the lateral compartment of the leg. The only nervous structure residing in the lateral compartment is the superficial peroneal nerve. In compartment syndrome of the lateral leg compartment, failure of prompt surgical fasciotomy would present as a sensory deficit of the superficial peroneal nerve presenting as numbness on the dorsum of his foot involving the hallux, 3rd, and 4th toes.

Question 4526

Topic: Lower Extremity Trauma

A 50-year-old female presents with an acute onset of medial knee pain after a deep squat. MRI reveals a complete radial tear adjacent to the medial meniscus posterior root attachment. What are the biomechanical consequences of this specific injury if left untreated?

. Decreased contact pressure in the medial compartment
. Complete loss of hoop stresses, functionally equivalent to a total medial meniscectomy
. Increased resting tension on the lateral collateral ligament
. Pathologic medial translation of the tibia relative to the femur
. Functional equivalence to an isolated anterior cruciate ligament tear

Correct Answer & Explanation

. Decreased contact pressure in the medial compartment

Explanation

A complete medial meniscus posterior root tear unanchors the meniscus from the tibial plateau. This disrupts the meniscus's ability to convert axial compressive loads into circumferential hoop stresses. Biomechanically, this results in significant meniscal extrusion under load and is equivalent to a total medial meniscectomy, leading to vastly increased peak contact pressures and rapid onset of unicompartmental osteoarthritis.

Question 4527

Topic: 2. Trauma

Tarsal navicular stress fractures are notoriously difficult to heal and carry a high risk of delayed union or nonunion. This complication is primarily attributed to a watershed zone of relative avascularity located in which specific anatomic portion of the navicular bone?

. Medial third
. Central third
. Lateral third
. Plantar half
. Dorsal tuberosity

Correct Answer & Explanation

. Medial third

Explanation

The blood supply to the tarsal navicular relies on branches from the dorsalis pedis and medial plantar arteries, entering primarily from the medial (tuberosity) and lateral (dorsal) aspects. The intraosseous microvascular network converges toward the center of the bone, creating a central third watershed zone that is relatively avascular. This renders the central third highly susceptible to stress fractures and explains the high rates of delayed union and nonunion if not managed aggressively.

Question 4528

Topic: 2. Trauma

A 22-year-old collegiate basketball player sustains a fracture at the diaphyseal junction of the proximal fifth metatarsal. Radiographs show a transverse fracture line without sclerosis (Zone 3). To minimize the risk of nonunion and allow early return to play, what is the treatment of choice?

. Non-weight bearing in a short leg cast for 6 weeks
. Weight-bearing as tolerated in a stiff-soled shoe
. Intramedullary screw fixation
. Plantar plating with bone grafting
. Excision of the proximal fragment and peroneus brevis advancement

Correct Answer & Explanation

. Non-weight bearing in a short leg cast for 6 weeks

Explanation

Zone 3 fractures (diaphyseal stress fractures) occur in a vascular watershed area and have a high rate of nonunion, especially in high-level athletes. Intramedullary screw fixation is the gold standard to ensure healing and expedite return to sports.

Question 4529

Topic: 2. Trauma
A 34-year-old male sustains a Hawkins Type III talar neck fracture following a motor vehicle collision. At 8 weeks post-ORIF, an AP radiograph of the ankle demonstrates a subchondral radiolucent band in the talar dome. What does this radiographic finding indicate?
. Avascular necrosis of the talar body
. Impending post-traumatic arthritis
. Intact vascularity to the talar body
. Nonunion of the talar neck
. Osteomyelitis

Correct Answer & Explanation

. Intact vascularity to the talar body

Explanation

The Hawkins sign is a subchondral radiolucent band seen at 6-8 weeks post-injury, indicating subchondral bone resorption. This requires an intact blood supply, thereby confirming preserved vascularity to the talar body and excluding avascular necrosis.

Question 4530

Topic: 2. Trauma

A 21-year-old collegiate basketball player sustains an acute transverse fracture at the metaphyseal-diaphyseal junction of the fifth metatarsal (Zone 2) during a game. To minimize the risk of nonunion and expedite his return to play, what is the treatment of choice?

. Short leg non-weight-bearing cast for 6 weeks
. Intramedullary screw fixation
. Plating with locking screws
. Excision of the proximal fragment
. Stiff-soled shoe with progressive weight-bearing

Correct Answer & Explanation

. Intramedullary screw fixation

Explanation

Zone 2 (Jones) fractures occur in a vascular watershed area with a high rate of nonunion. In competitive athletes, intramedullary screw fixation is recommended to ensure healing and allow for a faster return to play.

Question 4531

Topic: 2. Trauma
A 32-year-old male falls from a height and sustains a Hawkins Type III fracture of the talar neck. What is the approximate rate of avascular necrosis (AVN) of the talar body associated with this specific injury pattern?
. 0 to 10%
. 15 to 20%
. 30 to 50%
. 75 to 100%
. 100% invariably

Correct Answer & Explanation

. 75 to 100%

Explanation

A Hawkins Type III fracture is a displaced talar neck fracture with dislocation of both the subtalar and tibiotalar joints. It severely disrupts the blood supply, leading to an AVN rate of 75% to 100%.

Question 4532

Topic: Lower Extremity Trauma

You are performing a medial opening wedge high tibial osteotomy (HTO) on a 40-year-old active male with medial compartment osteoarthritis and varus malalignment. To optimize load distribution and long-term survivorship of the osteotomy, where should the postoperative mechanical axis pass on the tibial plateau (measured from medial to lateral)?

. 0% (Extreme medial edge)
. 30% (Medial compartment)
. 62% (Slightly lateral to the center of the plateau)
. 85% (Lateral compartment)
. 100% (Extreme lateral edge)

Correct Answer & Explanation

. 62% (Slightly lateral to the center of the plateau)

Explanation

The target for correction in an HTO is the Fujisawa point, which is located at approximately 62% of the tibial plateau width from medial to lateral. This transfers the mechanical axis slightly into the healthy lateral compartment, relieving medial stress.

Question 4533

Topic: 2. Trauma

According to the criteria described by Hertel et al. for proximal humerus fractures, which of the following combinations of radiographic findings is most predictive of humeral head ischemia?

. Metaphyseal extension > 8 mm and an intact medial hinge
. Metaphyseal extension < 8 mm and a disrupted medial hinge
. Surgical neck fracture with greater tuberosity displacement > 5 mm
. Anatomic neck fracture with an intact medial hinge
. Three-part fracture with metaphyseal extension > 8 mm

Correct Answer & Explanation

. Metaphyseal extension < 8 mm and a disrupted medial hinge

Explanation

Hertel established classic predictors of humeral head ischemia following proximal humerus fractures. The most critical predictors are an anatomic neck fracture, a short calcar segment (metaphyseal extension < 8 mm), and disruption of the medial hinge (> 2 mm displacement). The combination of a disrupted medial hinge and short metaphyseal extension has a positive predictive value of 97% for humeral head ischemia.

Question 4534

Topic: 2. Trauma

A 28-year-old polytrauma patient sustains an isolated, closed body and neck fracture of the scapula. According to current consensus guidelines, which of the following radiographic parameters is considered an absolute indication for Open Reduction and Internal Fixation (ORIF)?

. Glenopolar angle of 35 degrees
. Medial/lateral translation of 10 mm
. Angular deformity of 25 degrees
. Intra-articular glenoid displacement of 5 mm
. Presence of an ipsilateral clavicle fracture

Correct Answer & Explanation

. Intra-articular glenoid displacement of 5 mm

Explanation

Most scapula body fractures are treated nonoperatively. However, absolute indications for ORIF generally involve significant intra-articular disruption or massive displacement that compromises shoulder biomechanics. Indications include intra-articular glenoid step-off > 4-5 mm, glenopolar angle < 22 degrees, medial/lateral displacement > 20 mm, and angular deformity > 45 degrees. An ipsilateral clavicle fracture (floating shoulder) is a relative indication, often treated by fixing the clavicle alone.

Question 4535

Topic: 2. Trauma

A 19-year-old male sustains a midshaft clavicle fracture during a cycling accident. Which of the following factors most significantly increases the risk of nonunion if this injury is treated nonoperatively?

. Male gender
. Comminution without displacement
. Initial shortening greater than 2 cm
. Age under 20 years
. Presence of a butterfly fragment with 5 mm of translation

Correct Answer & Explanation

. Initial shortening greater than 2 cm

Explanation

The risk of nonunion in nonoperatively managed midshaft clavicle fractures is historically cited at 1-5%, but modern studies show it can be up to 15% in specific subsets. The most significant risk factors for nonunion are complete displacement (no cortical contact) and shortening greater than 2 cm. Advanced age and female gender have also been noted as risk factors in some studies, but > 2 cm shortening and 100% displacement remain the strongest mechanical predictors.

Question 4536

Topic: 2. Trauma

A 45-year-old male presents with a closed, spiral fracture of the distal third of the humerus (Holstein-Lewis fracture). On initial examination, the patient has normal radial nerve function. A coaptation splint is applied in the emergency department. Upon re-evaluation post-reduction, the patient is unable to extend his wrist or fingers and has numbness in the first dorsal web space. What is the most appropriate next step in management?

. Remove the splint, perform a gentle re-reduction, and reapply the splint
. Order an urgent EMG/NCS to confirm the level of the lesion
. Discharge the patient with a dynamic extension splint and follow-up in 2 weeks
. Immediate surgical exploration of the radial nerve and fracture fixation
. Observation; normal nerve function is expected to return in 3-4 months

Correct Answer & Explanation

. Immediate surgical exploration of the radial nerve and fracture fixation

Explanation

A radial nerve palsy that develops AFTER a closed reduction of a humeral shaft fracture is an absolute indication for immediate surgical exploration. The nerve may be entrapped in the fracture site (especially in a distal third Holstein-Lewis fracture). If the palsy was present on initial presentation (prior to manipulation), observation and functional bracing would be appropriate.

Question 4537

Topic: 2. Trauma
A 6-year-old girl is brought to the emergency department after falling from monkey bars. Radiographs demonstrate an isolated fracture of the ulnar shaft with dorsal angulation and an associated posterior dislocation of the radial head. According to the Bado classification, what type of Monteggia lesion is this?
. Type I
. Type II
. Type III
. Type IV
. Type V

Correct Answer & Explanation

. Type II

Explanation

The Bado classification categorizes Monteggia fractures based on the direction of radial head dislocation. Type I: Anterior dislocation (most common). Type II: Posterior dislocation (ulna typically bowed dorsally). Type III: Lateral dislocation. Type IV: Anterior dislocation with fractures of both the radius and ulna shafts.

Question 4538

Topic: 2. Trauma

A 24-year-old male is evaluated for compartment syndrome following a high-energy tibia fracture.

Intracompartmental pressures are measured. According to standard trauma protocols, a four-compartment fasciotomy is indicated if the "Delta P" falls below what threshold?

. 10 mm Hg
. 20 mm Hg
. 30 mm Hg
. 40 mm Hg
. 50 mm Hg

Correct Answer & Explanation

. 10 mm Hg

Explanation

Delta P is defined as the diastolic blood pressure minus the intracompartmental pressure. A Delta P of less than 30 mm Hg is the widely accepted threshold that indicates inadequate tissue perfusion and mandates emergent fasciotomy to prevent irreversible ischemic muscle and nerve damage.

Question 4539

Topic: 2. Trauma

A 21-year-old male arrives at the trauma bay following an assault. He sustained a low-velocity gunshot wound to the right thigh. Radiographs reveal a closed, simple transverse midshaft femur fracture with the bullet retained in the posterolateral thigh musculature. The patient is hemodynamically stable with normal distal pulses. What is the standard of care for this injury?

. Formal irrigation and debridement of the bullet tract followed by external fixation
. Formal irrigation and debridement of the bullet tract followed by IM nailing
. Local wound care, antibiotics, tetanus prophylaxis, and IM nailing without tract debridement
. Nonoperative management with a spica cast
. Immediate bullet extraction to prevent lead toxicity, followed by IM nailing

Correct Answer & Explanation

. Formal irrigation and debridement of the bullet tract followed by external fixation

Explanation

For low-velocity gunshot wounds resulting in a diaphyseal femur fracture, routine formal irrigation and debridement (I&D) of the bullet tract is not indicated. Standard treatment includes local wound care, tetanus prophylaxis, appropriate short-course antibiotics, and standard definitive fixation (usually intramedullary nailing). Bullet removal is only indicated if it is intra-articular, causing nerve impingement, or lying within a vessel.

Question 4540

Topic: Upper Extremity Trauma
A 32-year-old male falls directly onto the point of his shoulder while snowboarding. Clinical exam reveals a prominent clavicle, and radiographs show the distal clavicle displaced posteriorly into the trapezius muscle. According to the Rockwood classification of acromioclavicular (AC) joint injuries, what type of injury is this?
. Type II
. Type III
. Type IV
. Type V
. Type VI

Correct Answer & Explanation

. Type IV

Explanation

The Rockwood classification of AC joint injuries is based on the direction and degree of clavicle displacement. Type I: sprain. Type II: AC torn, CC intact. Type III: AC and CC torn, 25-100% superior displacement. Type IV: Posterior displacement of the distal clavicle into the trapezius fascia. Type V: Superior displacement >100%. Type VI: Inferior displacement under the coracoid/acromion.

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