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2. Trauma MCQs

Practice Set 263 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 5241

Topic: 2. Trauma

A 45-year-old male with isolated medial compartment knee osteoarthritis and genu varum is undergoing a medial opening-wedge high tibial osteotomy (HTO). To maintain the patient's native posterior tibial slope during correction, how should the osteotomy gap be dynamically managed?

. The gap should be opened equally anteriorly and posteriorly
. The gap should be opened larger anteriorly than posteriorly
. The gap should be opened approximately twice as much posteriorly as anteriorly
. The anterior cortex should be left intact to act as a tension band
. The osteotomy must be angled proximally to bisect the tibial tubercle

Correct Answer & Explanation

. The gap should be opened approximately twice as much posteriorly as anteriorly

Explanation

The proximal tibia has a triangular cross-section, being narrower anteriorly than posteriorly. To maintain the native posterior tibial slope (~10 degrees) during a medial opening-wedge HTO, the gap must be opened in a roughly 2:1 ratio (posterior gap twice as wide as the anterior gap). Opening it equally will increase the posterior slope.

Question 5242

Topic: Pelvic & Acetabular Trauma

A 38-year-old male sustains an anteroposterior compression type II (APC-II) pelvic ring injury. Based on the Young-Burgess classification, which of the following ligaments must be disrupted to define this specific injury pattern?

. Anterior sacroiliac, sacrotuberous, and sacrospinous ligaments
. Posterior sacroiliac and sacrotuberous ligaments
. Iliolumbar and posterior sacroiliac ligaments
. Anterior sacroiliac and iliolumbar ligaments
. Sacrospinous and posterior sacroiliac ligaments

Correct Answer & Explanation

. Anterior sacroiliac, sacrotuberous, and sacrospinous ligaments

Explanation

An APC-II injury is characterized by symphyseal diastasis and widening of the anterior SI joint. This requires rupture of the anterior sacroiliac ligaments as well as the pelvic floor ligaments (sacrotuberous and sacrospinous). The posterior sacroiliac ligaments remain intact, conferring vertical stability but leaving the pelvis rotationally unstable.

Question 5243

Topic: 2. Trauma
A 25-year-old male sustains a vertically oriented, displaced intracapsular femoral neck fracture (Pauwels Type III). If closed reduction and internal fixation is planned, which of the following constructs provides the greatest biomechanical stability against shear forces and varus collapse?
. Three parallel cancellous lag screws in an inverted triangle
. Dynamic hip screw (DHS) alone
. Dynamic hip screw (DHS) supplemented with an anti-rotation screw
. Proximal femoral nail anti-rotation (PFNA)
. Fully threaded, non-lagged positioning screws

Correct Answer & Explanation

. Dynamic hip screw (DHS) supplemented with an anti-rotation screw

Explanation

Pauwels Type III femoral neck fractures have a vertical fracture line (>50 degrees), subjecting them to high shear forces and a high risk of varus collapse. Biomechanical studies have demonstrated that a fixed-angle device, such as a sliding hip screw (DHS), combined with a derotation screw, provides superior stability against shear compared to multiple parallel cancellous screws.

Question 5244

Topic: 2. Trauma

In the surgical management of a coronal plane shear fracture of the lateral femoral condyle (Hoffa fracture), which of the following screw configurations is biomechanically most stable?

. Anterior-to-posterior directed lag screws
. Posterior-to-anterior directed lag screws
. Inferior-to-superior directed lag screws
. Medial-to-lateral directed lag screws
. Crossed anterior-to-posterior lag screws

Correct Answer & Explanation

. Posterior-to-anterior directed lag screws

Explanation

Biomechanical studies have demonstrated that posterior-to-anterior (PA) directed lag screws provide significantly greater construct stiffness and load to failure compared to anterior-to-posterior (AP) directed screws for Hoffa fractures, as they engage the denser bone of the anterior metaphysis and sit perpendicular to the primary shear forces.

Question 5245

Topic: 2. Trauma
A 28-year-old male sustains a high-energy Pauwels type III (vertical) femoral neck fracture. To maximize biomechanical stability and reduce the risk of varus collapse, which of the following internal fixation constructs is considered superior?
. Three parallel cancellous lag screws in an inverted triangle configuration
. A sliding hip screw (SHS/DHS) with a derotational screw
. Three parallel cancellous lag screws with a highly placed superior screw
. Two crossed cancellous lag screws
. Cephalomedullary nail with dual lag screws

Correct Answer & Explanation

. A sliding hip screw (SHS/DHS) with a derotational screw

Explanation

Pauwels type III fractures are highly vertically oriented and experience significant shear forces. Biomechanical studies consistently show that a fixed-angle device, such as a Sliding Hip Screw (DHS), provides superior resistance to varus collapse and a higher load to failure compared to multiple parallel cancellous screws for vertically oriented femoral neck fractures in young adults. A derotational screw is often added to control rotational instability.

Question 5246

Topic: 2. Trauma

A 45-year-old male sustains a high-energy trauma resulting in a Schatzker type IV tibial plateau fracture. Which of the following associated injuries is most strongly correlated with this specific fracture pattern?

. Lateral meniscus tear
. Anterior cruciate ligament avulsion
. Popliteal artery injury
. Medial collateral ligament tear
. Patellar tendon rupture

Correct Answer & Explanation

. Popliteal artery injury

Explanation

Schatzker type IV is a fracture of the medial tibial plateau. Because the medial plateau is robust, fractures here require high-energy trauma (often a varus force) and are considered knee dislocation equivalents. This fracture pattern carries a significantly higher risk of popliteal artery injury and peroneal nerve injury compared to lateral plateau fractures.

Question 5247

Topic: 2. Trauma

Following an open reduction and internal fixation of a distal femur fracture (AO/OTA 33-C3) using a lateral locked plate, the patient develops a varus collapse. Which of the following technical errors is most strongly associated with this complication?

. Failure to recognize and fix a coronal plane (Hoffa) fracture
. Use of titanium instead of stainless steel plates
. Inadequate lateral soft tissue release
. Leaving the fracture in 5 degrees of valgus during initial fixation
. Over-penetration of the distal locking screws into the medial cortex

Correct Answer & Explanation

. Failure to recognize and fix a coronal plane (Hoffa) fracture

Explanation

Varus collapse after fixation of a distal femur fracture with a lateral locking plate is frequently associated with medial cortical comminution and failure to recognize or adequately stabilize a coronal plane (Hoffa) fracture. Unrecognized coronal shear fractures severely compromise the stability of the distal block, leading to hardware failure or varus collapse.

Question 5248

Topic: 2. Trauma

A 35-year-old male sustains a displaced transverse patella fracture. The surgeon elects to perform an open reduction and internal fixation using a tension band wiring technique. To optimize the biomechanical properties of the construct, how should the K-wires and cerclage wire be positioned?

. K-wires in the anterior half of the patella, cerclage wire posterior to the K-wires
. K-wires strictly in the posterior third of the patella, cerclage wire immediately adjacent to the articular surface
. K-wires parallel in the center of the patella, cerclage wire placed anteriorly over the patella
. K-wires diverging widely from proximal to distal, cerclage wire passed through the quadriceps and patellar tendons
. K-wires parallel in the anterior half, cerclage wire anterior to the K-wires

Correct Answer & Explanation

. K-wires parallel in the center of the patella, cerclage wire placed anteriorly over the patella

Explanation

In a tension band wiring construct for a transverse patella fracture, the K-wires should be placed parallel to each other in the center (mid-substance) of the patella to prevent displacing the fragments when tightened. The figure-of-eight cerclage wire must be placed as anteriorly as possible to convert the tensile forces generated by the extensor mechanism into compressive forces across the articular surface during knee flexion.

Question 5249

Topic: Pelvic & Acetabular Trauma

A 24-year-old male sustains an anteroposterior compression type II (APC-II) pelvic ring injury. According to the Young-Burgess classification, which posterior pelvic ligaments are disrupted and which remain intact in an APC-II injury?

. Anterior sacroiliac ligaments are disrupted; posterior sacroiliac ligaments are intact
. Both anterior and posterior sacroiliac ligaments are disrupted; sacrotuberous ligament is intact
. Anterior sacroiliac ligaments are intact; posterior sacroiliac ligaments are disrupted
. Anterior sacroiliac, sacrotuberous, and sacrospinous ligaments are disrupted; posterior sacroiliac ligaments are intact
. All anterior, posterior, sacrotuberous, and sacrospinous ligaments are disrupted

Correct Answer & Explanation

. Anterior sacroiliac, sacrotuberous, and sacrospinous ligaments are disrupted; posterior sacroiliac ligaments are intact

Explanation

In an APC-II pelvic ring injury ('open book' pelvis), the symphysis pubis is diastatic (>2.5 cm). Posteriorly, the anterior sacroiliac ligaments, as well as the sacrotuberous and sacrospinous ligaments, are disrupted, causing rotational instability. The robust posterior sacroiliac ligaments remain intact, maintaining vertical stability.

Question 5250

Topic: 2. Trauma

A 45-year-old male sustains a Schatzker IV tibial plateau fracture following a high-energy fall. CT imaging reveals a significant posteromedial shear fragment. Which surgical approach and fixation strategy is most biomechanically appropriate for this specific fragment?

. Anterolateral approach with a laterally applied locking plate
. Posteromedial approach with an anti-glide plate placed at the fracture apex
. Anterior midline approach with dual medial and lateral plating
. Arthroscopic-assisted percutaneous anterior-to-posterior screw fixation
. Medial approach with an anteriorly applied spanning plate

Correct Answer & Explanation

. Posteromedial approach with an anti-glide plate placed at the fracture apex

Explanation

Schatzker IV fractures frequently involve a posteromedial shear fragment. A posteromedial approach with an anti-glide (buttress) plate applied at the apex of the fracture is required to prevent distal displacement and provides the most stable construct.

Question 5251

Topic: 2. Trauma

A 40-year-old male sustains a transverse patella fracture with 4 mm of displacement. He is treated surgically with tension band wiring. What is the primary biomechanical principle underlying this specific fixation technique?

. It converts compressive forces at the articular surface into tensile forces
. It converts tensile forces at the anterior cortex into compressive forces at the articular surface during knee flexion
. It acts as a neutralization plate to protect lag screws from torsional stress
. It rigidly splints the fracture to allow for secondary bone healing via callus formation
. It anchors the quadriceps tendon to prevent patella alta during active extension

Correct Answer & Explanation

. It converts tensile forces at the anterior cortex into compressive forces at the articular surface during knee flexion

Explanation

The tension band principle relies on placing the fixation construct on the tension side (anterior surface) of the bone. During knee flexion, it converts the disruptive tensile forces at the anterior cortex into dynamic compressive forces at the articular surface.

Question 5252

Topic: 2. Trauma

A 75-year-old female with severe osteoporosis sustains a comminuted distal femur fracture (OTA 33-C2) immediately proximal to a well-fixed posterior-stabilized total knee arthroplasty. Which of the following surgical constructs provides the greatest biomechanical stability for this specific fracture pattern?

. Non-locking lateral condylar buttress plate
. Retrograde intramedullary nail with an interlocking screw through the polyethylene
. Lateral locking plate combined with a medial spanning plate (dual plating)
. Lateral locking plate extending the entire length of the femur
. Anterolateral plating with unicortical screws distally

Correct Answer & Explanation

. Lateral locking plate combined with a medial spanning plate (dual plating)

Explanation

In severely comminuted periprosthetic distal femur fractures with poor bone stock, an isolated lateral plate is at high risk of varus collapse. Dual plating (lateral locking plate plus a medial plate) provides superior biomechanical stability and prevents medial column failure.

Question 5253

Topic: 2. Trauma

A 28-year-old male is admitted with a closed tibial shaft fracture. Eight hours later, he develops excruciating leg pain out of proportion to the injury and new-onset paresthesias isolated to the first dorsal web space of the foot. Which compartment of the lower leg is most likely experiencing critically elevated pressure?

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

Correct Answer & Explanation

. Anterior compartment

Explanation

The deep peroneal nerve courses through the anterior compartment of the leg and provides sensory innervation to the first dorsal web space. Paresthesias in this specific distribution are a hallmark early neurologic sign of anterior compartment syndrome.

Question 5254

Topic: Lower Extremity Trauma

A medial opening wedge high tibial osteotomy (HTO) is planned for a patient with medial compartment osteoarthritis and varus deformity. If not properly controlled during the procedure, what are the classic unintended effects on tibial slope and patellar height?

. Increased tibial slope and patella baja
. Increased tibial slope and patella alta
. Decreased tibial slope and patella baja
. Decreased tibial slope and patella alta
. No change in tibial slope and patella alta

Correct Answer & Explanation

. Increased tibial slope and patella alta

Explanation

Medial opening wedge HTO traditionally increases the posterior tibial slope (because the medial tibia is triangular and wider anteriorly, so a uniform wedge opens the anterior aspect more) and decreases patellar height (patella baja) relative to the joint line due to the elevation of the tibial plateau above the tibial tubercle.

Question 5255

Topic: Lower Extremity Trauma

A 45-year-old active laborer presents with lateral compartment knee osteoarthritis and a mechanical valgus deformity of 16 degrees. Weight-bearing radiographs reveal the deformity is primarily driven by a mechanical axis deviation in the distal femur. Which of the following is the most appropriate surgical treatment?

. Medial opening wedge high tibial osteotomy
. Lateral closing wedge high tibial osteotomy
. Medial closing wedge distal femoral osteotomy
. Lateral opening wedge high tibial osteotomy
. Tibial tubercle osteotomy

Correct Answer & Explanation

. Medial closing wedge distal femoral osteotomy

Explanation

For severe valgus knee osteoarthritis (>12-15 degrees) originating from a distal femoral deformity, a distal femoral osteotomy (DFO) is indicated. A medial closing wedge or lateral opening wedge DFO corrects the mechanical axis. Tibial osteotomies are contraindicated for severe femoral-based valgus as they would induce an abnormal joint line obliquity.

Question 5256

Topic: Lower Extremity Trauma

A 45-year-old male undergoes a medial opening-wedge high tibial osteotomy (HTO) for isolated medial compartment osteoarthritis and varus deformity. To optimize the long-term survivorship of the osteotomy and unload the medial compartment adequately, where should the postoperative weight-bearing line (WBL) be directed through the tibial plateau?

. 0% (medial edge of the tibial plateau)
. 30% of the plateau width from the medial edge
. 50% (neutral mechanical axis)
. 62.5% of the plateau width from the medial edge
. 80% of the plateau width from the medial edge

Correct Answer & Explanation

. 62.5% of the plateau width from the medial edge

Explanation

The optimal postoperative mechanical axis following a high tibial osteotomy for medial compartment OA intersects the tibial plateau at approximately 62% to 62.5% of its width from the medial edge. This corresponds to the Fujisawa point, which slightly overcorrects the varus deformity to adequately unload the medial compartment.

Question 5257

Topic: 2. Trauma

An 80-year-old woman sustains a Lewis-Rorabeck Type II periprosthetic distal femur fracture (comminuted fracture with a loose femoral component) following a fall. What is the most appropriate surgical management?

. Retrograde intramedullary nailing
. Open reduction internal fixation with a locked plate
. Distal femoral replacement (revision TKA)
. Hinged knee orthosis and protected weight-bearing
. External fixation

Correct Answer & Explanation

. Distal femoral replacement (revision TKA)

Explanation

Lewis-Rorabeck Type II fractures involve a loose component but adequate bone stock; however, comminution in elderly patients often precludes stable fixation. Distal femoral replacement allows for immediate weight-bearing and addresses both the fracture and the loose implant.

Question 5258

Topic: 2. Trauma

A 46-year-old competitive cyclist falls while racing and suffers an isolated fracture as seen in Figure A. He is positioned on a fracture table and a closed reduction maneuver is attempted, unsuccessfully. Which of the following treatment plans is most appropriate?

. Obtain a CT scan intraoperatively to reassess the quality of reduction
. Perform additional closed reduction maneuvers until the reduction is adequate for percutaneous fixation
. As long as the stepoff is less than 7mm in any plane of imaging, it is appropriate to proceed with percutaneous fixation
. Perform an open reduction and internal fixation using a sliding hip screw
. Perform an acute total hip arthroplasty through a direct anterior approach since the patient is on the fracture table

Correct Answer & Explanation

. Perform an open reduction and internal fixation using a sliding hip screw

Explanation

When standard closed reduction maneuvers using a traction table are unsuccessful, displaced femoral neck fracture in young adults (< 50 years old) should be open reduced prior to fixation.Displaced femoral neck fractures in young patients have created many treatment controversies that are ongoing in the literature due to devastating consequences of poor outcomes, including nonunion and osteonecrosis of the femoral head. Although poorly defined, the quality of reduction is associated with rates of both nonunion and osteonecrosis. A closed reduction that is malangulated (>10 degrees varus/valgus or anteversion/retroversion) or has significant displacement (5 mm or more in ANY view) is unacceptable, and an open reduction should be performed. Of course, this can be very difficult to assess in the operating room, where uncalibrated fluoroscopy with difficult to obtain tangential imaging is heavily relied upon to make this assessment. Accordingly, when the quality of closed reduction is questionable, the best treatment plan is to obtain a better reduction with direct visualization of the femoral neck prior to fixation.A systematic review of the literature by Pauyo, et al. cites numerous studies showing a higher incidence of osteonecrosis of the femoral head in patients with displaced femoral neck fractures treated with unsatisfactory reductions. Furthermore, performing multiple closed reduction attempts is also associated with a higher risk of osteonecrosis.Upadhyay et al. performed a randomized controlled trial of 102 patients with femoral neck fractures treated with closed or open reductions, which were randomized. The groups had similar rates of nonunions and osteonecrosis of the femoral head; however, subanalysis revealed a "poor" reduction was the highest predictor of poor outcome, whether the reduction was attempted open or closed. Interestingly, the quality of reduction was more important than the implant used or the timing of surgery (including surgeries performed > 48h after injury).Figure A shows a pre-operative AP x-ray of the patient's high-energy femoral neck fracture. Illustrations A and B are intraoperative fluoroscopic and post-operative CT scans of this same patient, highlighting that fluoroscopy may "hide" the degree of residual displacement.Incorrect Answers:While intriguing, this is not currently the standard of practice; additionally, the stem already states that the reduction is "unsuccessful"Repeated closed reduction maneuvers may further propagate comminution and damage the blood supply to the femoral head, in theoryAny stepoff of 5 mm seen on x-ray is a marker of worse outcomes. Remember, tangential imaging of the femoral neck is difficult to obtain, and if 7 mm is seen, in actuality it may be a larger amount of displacement. Think of the femoral neck as a complex cylindrical tube of bone with asymmetric cortices (e.g. the calcar) - to obtain the perfect fluoroscopic image for measuring maximal displacement, a perfect perpendicular view to this displacement is required, which is very difficult to do before provisional fixation is placed.

Question 5259

Topic: 2. Trauma

An 82-year-old male with severe osteoporosis sustains a Type II odontoid fracture after a low-energy fall. He is neurologically intact, and the fracture has 2 mm of posterior displacement. Based on current evidence, what is the most appropriate management to minimize overall morbidity and mortality?

. Halo vest immobilization for 12 weeks
. Rigid cervical collar immobilization for 8-12 weeks
. Anterior odontoid screw fixation
. Posterior C1-C2 transarticular screw fixation
. Posterior C1-C2 Harms technique (screw/rod construct)

Correct Answer & Explanation

. Rigid cervical collar immobilization for 8-12 weeks

Explanation

In elderly patients (typically >80 years) with Type II odontoid fractures, rigid cervical collar immobilization is increasingly recommended. While nonunion rates are high, most nonunions are stable, fibrous nonunions, and clinical outcomes are acceptable. Operative intervention in this frail demographic carries high morbidity and mortality, as does Halo vest immobilization (associated with fatal respiratory complications in the elderly).

Question 5260

Topic: Pelvic & Acetabular Trauma
According to the Young-Burgess classification, which injured ligamentous structure differentiates an Anteroposterior Compression Type III (APC-III) pelvic ring injury from an APC-II injury?
. Anterior sacroiliac ligaments
. Sacrotuberous ligament
. Sacrospinous ligament
. Symphyseal ligaments
. Posterior sacroiliac ligaments

Correct Answer & Explanation

. Posterior sacroiliac ligaments

Explanation

In the Young-Burgess classification, an APC-II injury involves disruption of the pubic symphysis, anterior sacroiliac ligaments, sacrospinous, and sacrotuberous ligaments, causing an 'open book' pelvis with rotational instability but preserved vertical stability. An APC-III injury includes all the above plus disruption of the strong posterior sacroiliac ligaments, resulting in both rotational and complete vertical instability.

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