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2. Trauma MCQs

Practice Set 315 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 6281

Topic: 2. Trauma

A 68-year-old female undergoes open reduction and internal fixation of a distal femur fracture using a lateral locking plate. Six months postoperatively, she presents with implant failure and a nonunion. Radiographs reveal plate breakage at the level of the fracture. Which of the following surgical technique errors most likely contributed to this complication?

. Use of a titanium rather than stainless steel plate
. A small fracture gap combined with a short working length
. Placement of bicortical screws in the proximal segment
. Submuscular, extra-periosteal plate insertion
. Use of a fixed-angle construct in osteoporotic bone

Correct Answer & Explanation

. A small fracture gap combined with a short working length

Explanation

Locking plates provide rigid, fixed-angle constructs ideal for osteoporotic bone. However, if a construct is excessively rigid (e.g., a short working length with locking screws placed too close to the fracture site) and a fracture gap is left, the stress is concentrated entirely on the plate at the level of the gap. This extreme rigidity prevents the micromotion necessary for secondary bone healing (callus formation), ultimately leading to fatigue failure and breakage of the plate before union can occur.

Question 6282

Topic: 2. Trauma

Which of the following physical examination findings is considered the most reliable and earliest clinical indicator of acute compartment syndrome in an alert patient with a closed tibial shaft fracture?

. Palpable tense, 'wood-like' compartments
. Pain out of proportion to the injury and exacerbated by passive stretch
. Paresthesias in the first dorsal web space
. Absent dorsalis pedis and posterior tibial pulses
. Inability to actively dorsiflex the ankle

Correct Answer & Explanation

. Pain out of proportion to the injury and exacerbated by passive stretch

Explanation

Acute compartment syndrome is a surgical emergency characterized by increased pressure within a closed fascial space. While the classic '5 Ps' (pain, pallor, pulselessness, paresthesias, paralysis) are traditionally taught, pain out of proportion to the apparent injury and excruciating pain elicited by passive stretch of the ischemic muscles are the earliest and most sensitive clinical signs. Pulselessness and paralysis are late signs indicating severe and often irreversible tissue necrosis.

Question 6283

Topic: Pelvic & Acetabular Trauma
A 30-year-old male sustains a mechanically and hemodynamically unstable anteroposterior compression (APC-III) pelvic ring injury. A circumferential pelvic binder is applied in the trauma bay. To achieve optimal mechanical stability and maximal reduction in pelvic volume, over which anatomical landmark should the center of the binder be positioned?
. Iliac crests
. Greater trochanters
. Anterior superior iliac spines
. Pubic symphysis
. Umbilicus

Correct Answer & Explanation

. Greater trochanters

Explanation

In hemodynamically unstable patients with open-book pelvic ring injuries, rapid application of a pelvic binder is crucial to reduce pelvic volume and promote the tamponade of venous and cancellous bone bleeding. Biomechanical and clinical studies have definitively shown that positioning the binder directly over the greater trochanters provides the most effective mechanical advantage for closing the symphysis pubis. Placement over the iliac crests is less effective and can paradoxically widen the true pelvis.

Question 6284

Topic: 2. Trauma

In the surgical treatment of a young adult with a displaced, intracapsular femoral neck fracture, which of the following factors is most consistently associated with minimizing the risk of osteonecrosis (AVN) of the femoral head?

. Achieving an anatomic reduction
. Performing a routine capsulotomy
. Fixation within 6 hours of injury
. Use of a sliding hip screw over multiple cancellous screws
. Aspiration of the hip joint hematoma

Correct Answer & Explanation

. Achieving an anatomic reduction

Explanation

Osteonecrosis of the femoral head is a devastating complication following displaced intracapsular femoral neck fractures in young adults. The single most critical, surgeon-controlled factor for minimizing the risk of AVN is achieving an exact, anatomic reduction. A non-anatomic reduction creates abnormal biomechanical stresses and can further kink or compromise the remaining tenuous retinacular blood supply. The roles of capsulotomy and the strict timing of surgery remain debated, but anatomic reduction is universally supported.

Question 6285

Topic: 2. Trauma

During open reduction and internal fixation of a completely displaced, transverse patella fracture, a tension band wiring technique is utilized. What is the primary biomechanical function of the anteriorly placed tension band wire during active knee flexion?

. It converts compressive forces on the articular surface into tensile forces
. It converts tensile forces at the anterior patellar surface into compressive forces at the articular surface
. It acts as a static buttress to prevent anterior translation of the distal pole
. It relies primarily on the stiffness of the Kirschner wires to resist shear forces
. It neutralizes rotational forces across the fracture site

Correct Answer & Explanation

. It converts tensile forces at the anterior patellar surface into compressive forces at the articular surface

Explanation

The tension band principle relies on placing the fixation implant on the tension side of a fractured bone. In the patella, the anterior surface is subjected to significant tensile forces by the extensor mechanism during knee flexion. By applying a wire construct anteriorly, these distractive tensile forces are biomechanically converted into compressive forces across the articular surface. This dynamic compression promotes stability and allows for early active range of motion and primary bone healing.

Question 6286

Topic: 2. Trauma

A 55-year-old male sustains a traumatic posterior hip dislocation. Following a successful closed reduction in the emergency department, what is the most appropriate imaging modality to evaluate for intra-articular loose bodies and ensure concentric reduction?

. Anteroposterior and cross-table lateral radiographs
. Judet view radiographs
. Magnetic Resonance Imaging (MRI)
. Computed Tomography (CT) scan
. Diagnostic musculoskeletal ultrasound

Correct Answer & Explanation

. Computed Tomography (CT) scan

Explanation

Following the reduction of a traumatic hip dislocation, an unenhanced Computed Tomography (CT) scan of the pelvis is the gold standard imaging modality. It is highly sensitive for confirming concentric reduction, detecting subtle retained intra-articular osteochondral fragments (loose bodies), and delineating associated fractures of the acetabulum (such as posterior wall fractures) or femoral head that may not be apparent on standard plain radiographs. This guides the need for subsequent surgical intervention.

Question 6287

Topic: 2. Trauma
A 34-year-old female sustains a Denis Zone I sacral fracture with 1.5 cm of cephalad displacement following a fall from a height. She complains of weakness in foot dorsiflexion and big toe extension. Which nerve root is most likely injured in this specific fracture pattern?
. L4
. L5
. S1
. S2
. S3

Correct Answer & Explanation

. L5

Explanation

Denis Zone I sacral fractures occur lateral to the neural foramina and typically involve the sacral ala. Due to the proximity of the L5 nerve root, which courses over the sacral ala, it is highly susceptible to traction or direct injury, particularly in vertical shear patterns with cephalad displacement. Injury to the L5 root classically presents with weakness in the extensor hallucis longus (EHL) and tibialis anterior. Denis Zone II fractures involve the foramina and commonly cause sciatica (S1, S2 roots), while Zone III fractures involve the central canal and can cause saddle anesthesia and bowel/bladder dysfunction.

Question 6288

Topic: 2. Trauma

A 32-year-old male sustains a displaced basicervical femoral neck fracture following a high-energy trauma. Which of the following internal fixation constructs provides the greatest biomechanical stability for this specific fracture pattern?

. Three parallel cancellous lag screws
. Dynamic hip screw (sliding hip screw) with a derotational screw
. Non-spanning external fixator
. 135-degree angled blade plate
. Two crossed cancellous lag screws

Correct Answer & Explanation

. Dynamic hip screw (sliding hip screw) with a derotational screw

Explanation

Basicervical femoral neck fractures behave biomechanically more like intertrochanteric fractures than traditional intracapsular femoral neck fractures. They are highly unstable and subjected to significant shear forces. Studies have consistently demonstrated that a dynamic hip screw (DHS), combined with an anti-rotation screw to control the proximal fragment during engagement and weight-bearing, provides superior biomechanical stability and a lower rate of failure compared to multiple parallel cancellous screws. Cancellous screws alone have an unacceptably high rate of cut-out and nonunion in basicervical patterns.

Question 6289

Topic: 2. Trauma
A 40-year-old farmer sustains an open midshaft tibia fracture after his leg is caught in a tractor mechanism. The wound is 8 cm long with moderate soft-tissue damage, but there is adequate periosteal coverage of the bone. He is taken to the operating room within 6 hours for surgical debridement. Which of the following intravenous antibiotic regimens is most appropriate for initial management?
. First-generation cephalosporin alone
. First-generation cephalosporin and an aminoglycoside
. First-generation cephalosporin, an aminoglycoside, and high-dose penicillin
. Fluoroquinolone alone
. Vancomycin and Piperacillin-Tazobactam

Correct Answer & Explanation

. First-generation cephalosporin, an aminoglycoside, and high-dose penicillin

Explanation

The patient has a farm-related open fracture, which carries a high risk of profound contamination, particularly with soil-dwelling anaerobes such as Clostridium perfringens, the causative organism of gas gangrene. According to established trauma guidelines for open fractures, standard Grade I or II injuries require a first-generation cephalosporin. Grade III fractures require the addition of Gram-negative coverage (traditionally an aminoglycoside). However, farm injuries, injuries with heavy soil contamination, or those with significant ischemic tissue demand the addition of high-dose penicillin (or ampicillin) to provide prophylactic anaerobic coverage.

Question 6290

Topic: 2. Trauma

A 22-year-old male presents with a closed proximal third tibia fracture. Eight hours post-injury, he complains of severe leg pain out of proportion to the injury that is refractory to intravenous opioids. His leg is swollen and tense, and passive stretch of the great toe severely exacerbates his pain. Pulses remain palpable. Intracompartmental pressure testing is performed. Which of the following pressure measurements establishes an absolute indication for emergent four-compartment fasciotomy?

. An absolute intracompartmental pressure of 20 mmHg
. An absolute intracompartmental pressure of 25 mmHg
. A differential pressure (Diastolic blood pressure minus intracompartmental pressure) of 45 mmHg
. A differential pressure (Diastolic blood pressure minus intracompartmental pressure) of 20 mmHg
. A differential pressure (Mean arterial pressure minus intracompartmental pressure) of 40 mmHg

Correct Answer & Explanation

. A differential pressure (Diastolic blood pressure minus intracompartmental pressure) of 20 mmHg

Explanation

Acute compartment syndrome is primarily a clinical diagnosis (pain out of proportion, pain with passive stretch, tense compartments), but pressure measurements are vital for confirmation, especially in obtunded patients or borderline cases. The most reliable indicator for fasciotomy is the Delta P (differential pressure), calculated as Diastolic Blood Pressure minus Intracompartmental Pressure. A Delta P of less than or equal to 30 mmHg represents critical tissue ischemia and is an absolute indication for emergent fasciotomy. A Delta P of 20 mmHg clearly falls below this critical threshold. Palpable pulses often remain intact even in advanced compartment syndrome and should not be used to rule out the condition.

Question 6291

Topic: 2. Trauma

A 20-year-old man is brought to the emergency department after a high-speed motor vehicle accident. His initial blood pressure is 70/40 mm Hg. He is currently receiving intravenous fluids as well as blood. His Focused Assessment with Sonography for Trauma examination did not show any free fluid in his abdomen and his chest radiograph is unremarkable. An AP pelvis radiograph is shown in Figure 15. What is the next most appropriate step in the management of his pelvic injury?

. Inlet and outlet views of the pelvis to better delineate the injury
. Angiography
. Laparotomy
. Open reduction and internal fixation of the pelvis
. Placement of a pelvic binder around the patient

Correct Answer & Explanation

. Placement of a pelvic binder around the patient

Explanation

This hypotensive patient has an obvious open book injury of the pelvic ring on the AP pelvis radiograph and further radiographs are not needed prior to the initiation of treatment. Although angiography may be indicated if he does not respond to stabilization of his pelvis and fluid/blood administration, temporary stabilization of the pelvis with a sheet or binder should be performed first because it is simple, quick, and has been shown to be effective. This patient does not need a laparotomy at this point since the FAST examination did not show any free intra-abdominal fluid and his chest radiograph was unremarkable, leaving the most likely source of bleeding the pelvic fracture. Open reduction with internal fixation of a pelvic injury is not indicated in an acutely ill patient. Kreig JC, Mohr M, Ellis TJ, et al: Emergent stabilization of pelvic ring injuries by controlled circumferential compression: A clinical trial. J Trauma 2005;59:659-664. Croce MA, Magnotti LJ, Savage SA, et al: Emergent pelvic fixation in patients with exsanguinating pelvic fractures. J Am Coll Surg 2007;204:935-942.

Question 6292

Topic: 2. Trauma

A 7-year-old girl is hit by a motor vehicle and sustains the isolated ipsilateral injuries shown in Figures 16a and 16b. What is the optimal definitive method of treatment?

. Spica cast immobilization
. Rigid reamed nailing of the femur and a short leg cast
. Flexible nailing of the femur and tibia
. Reamed nails of the femur and tibia
. Spanning external fixator

Correct Answer & Explanation

. Flexible nailing of the femur and tibia

Explanation

The child has isolated ipsilateral femoral shaft and tibial shaft fractures. Spica cast immobilization is unlikely to accommodate for shortening and alignment in this child with multiple levels of injury. In this instance, efforts should be made to mobilize a least one level of the limb; therefore, treatment should include flexible nailing of the femur and tibia. Rigid reamed nails are not indicated in this young patient secondary to risk of a growth arrest and osteonecrosis of the proximal femur. Poolman RW, Kocher MS, Bhandari M: Pediatric femoral fractures: A systematic review of 2422 cases. J Orthop Trauma 2006;20:648-654. Anglen JO, Choi L: Treatment options in pediatric femoral shaft fractures. J Orthop Trauma 2005;19:724-733.

Question 6293

Topic: 2. Trauma
A 220-lb 20-year-old man was involved in a motor vehicle accident. His work-up reveals that he has multiple long bone fractures as well as a splenic injury that is currently being managed nonsurgically. His initial blood pressure in the trauma bay was 70/30 mm Hg. After receiving 4 liters of fluid and 3 units of packed red blood cells, his blood pressure is currently 110/70, his heart rate is 100, his urine output is 90 mL/h (normal 0.5 to 1 mL/kg/h), and his core temperature is 97.9 degrees F (36.5 degrees C). At this point, the patient's resuscitation can be described as which of the following?
. Complete based on the normalization of his blood pressure, urine output, and heart rate
. Cannot be determined based on the data presented
. Incomplete based on his fluid requirements calculated using his initial blood pressure as a measure of blood volume loss
. Incomplete since he will need surgery on the long bone fractures and should be "tanked up" prior to losing blood in the operating room
. Incomplete based on his heart rate

Correct Answer & Explanation

. Incomplete based on his fluid requirements calculated using his initial blood pressure as a measure of blood volume loss

Explanation

Although the end points of resuscitation are still unclear, what is known is that normalization of the standard hemodynamic parameters (blood pressure, heart rate, and urine output) is not adequate. Up to 85% of patients with normal hemodynamic parameters can still have inadequate tissue oxygenation or uncompensated shock. The initial base deficit, lactate level, or gastric pHi can be used to stratify patients for resuscitation needs, risks of death, and multiple organ failure (level 1 evidence). The time it takes to normalize the base deficit, the lactate level, or gastric pHi, can predict survival (level 2 evidence). Patients who have been in uncompensated shock (abnormal vital signs) should have their resuscitation monitored using data other than vital signs.

Question 6294

Topic: 2. Trauma

A 30-year-old man who sustained a work-related injury 6 weeks ago reports persistent back and left-sided buttock pain that has been attributed to lumbar transverse process fractures. A pelvic radiograph and CT scans obtained 2 days ago are seen in Figures 17a through 17c. What is the best treatment for his injury?

. Continued nonsurgical management
. Posterior open reduction and internal fixation with tension band plating
. Posterior iliosacral screws
. Anterior open reduction and internal fixation
. Anterior open reduction and internal fixation and posterior fixation

Correct Answer & Explanation

. Anterior open reduction and internal fixation and posterior fixation

Explanation

Fortunately, surgical treatment of sub-acute pelvic ring injuries is relatively uncommon as acute management has become more common. Delayed reconstruction of pelvic ring malunion and impending malunion is rare. Nonsurgical management may have a role as long as the hemipelvis does not flex, shorten, and/or externally rotate. The AP pelvic radiograph suggests that all three motions are happening in this patient. These are just a few of the indications to repair the pelvic ring and this is best done with anterior and posterior fixation. Anterior symphyseal plating will help correct most of the deformity. Posterior fixation can and should be added to lessen the forces on the anterior ring reconstruction when repair is performed in a sub-acute or delayed fashion. Posterior fixation can help obtain a more anatomic reduction and helps decrease the risk of anterior hardware failure. Mears DC: Management of pelvic pseudarthroses and pelvic malunion. Orthopade 1996;25:441-448. Matta JM, Dickson KF, Markovich GD: Surgical treatment of pelvic nonunions and malunions. Clin Orthop Relat Res 1996;329:199-206.

Question 6295

Topic: 2. Trauma

To avoid an injury to the L5 nerve root when placing an S1 sacroiliac screw, what area of the sacrum should be avoided on the lateral C arm image shown in Figure 21?

. A
. B
. C
. D
. E

Correct Answer & Explanation

. A

Explanation

Safe placement of a sacroiliac screw depends on excellent imaging of and understanding of pelvic anatomy. There are variations in the anatomy of the upper sacrum. Patients with dysplasia of the sacrum can have "in-out-in" screws placed that exit the ilium, pass anterior to the sacral ala, and injure the L5 nerve root. To make sure that this does not occur, a lateral image of the sacrum is used to ensure that the starting point is in the "safe zone." The starting point needs to be below the iliac cortical density (ICD) which parallels the sacral alar slope. This will prevent placing screws into the recessed ala of patients with a dysplastic sacrum. The triangular area anterior to the ICD is labeled A in the figure, B represents the sacral canal, C is S2, D is the anterior border of the sacrum, and E represents the greater sciatic notches. Routt ML Jr, Simonian PT, Agnew SG, et al: Radiographic recognition of the sacral alar slope for optimal placement of iliosacral screws: A cadaveric and clinical study. J Orthop Trauma 1996;10:171-177.

Question 6296

Topic: 2. Trauma

Figures 23a and 23b show the radiographs of a 75-year-old woman who sustained an injury to her nondominant hand. Initial treatment should consist of

. closed reduction and splinting.
. open reduction and internal fixation through a volar approach.
. external fixation and Kirschner wire fixation.
. intrafocal pinning and casting.
. acceptance of alignment and bracing.

Correct Answer & Explanation

. closed reduction and splinting.

Explanation

Definitive treatment decisions for displaced distal radius fractures in the elderly are based on a number of factors related to the fracture pattern and patient demographics. The first step in any treatment algorithm is a closed reduction and splinting with reassessment of alignment parameters. This is an extra-articular fracture with dorsal angulation. Low-demand elderly patients can be treated well with accepted minor malreduction. Handoll HH, Madhok R: Conservative interventions for treating distal radial fractures in adults. Cochrane Database Syst Rev 2003;2:CD000314.

Question 6297

Topic: 2. Trauma

A 43-year-old man sustained a closed, intra-articular pilon fracture. It has now been 1 year since he underwent open reduction and internal fixation. Which of the following statements most accurately describes his perceived outcome?

. His clinical outcome will correlate closely with his initial reduction.
. His outcome will correlate with his radiographic score on the Ankle Osteoarthritis Score.
. He will likely require a late ankle arthrodesis.
. He will demonstrate marked limitations with regard to recreational activities.
. He will perceive improvements for a period of over 2 years.

Correct Answer & Explanation

. He will perceive improvements for a period of over 2 years.

Explanation

Marsh and associates retrospectively reviewed 56 tibial plafond fractures and found that the patients perceived improvement in their function and pain for an average of 2.4 years. They demonstrated some limitations in recreational activities but not marked limitations. Patients were unlikely to need a late arthrodesis (13%), and their outcomes did not correlate well with assessments of reduction or arthritis scores.

Question 6298

Topic: 2. Trauma

A 25-year-old male presents after a high-speed motorcycle collision with a closed right femur fracture, left tibial shaft fracture, and bilateral pulmonary contusions. The surgical team is debating between early total care (ETC) and damage control orthopedics (DCO). Which of the following serum markers provides the most reliable indicator of adequate resuscitation to safely proceed with definitive intramedullary nailing of both long bones?

. Hematocrit greater than 30%
. White blood cell count less than 12,000/mm^3
. Serum lactate level less than 2.5 mmol/L
. Fibrinogen level greater than 200 mg/dL
. Platelet count greater than 100,000/mm^3

Correct Answer & Explanation

. Serum lactate level less than 2.5 mmol/L

Explanation

Serum lactate and base deficit are the most reliable clinical markers for assessing tissue perfusion and the adequacy of resuscitation in polytrauma patients. Normalization of serum lactate (typically less than 2.5 mmol/L) indicates adequate tissue perfusion, allowing the surgical team to safely proceed with early total care (ETC) rather than damage control orthopedics (DCO).

Question 6299

Topic: 2. Trauma
A 30-year-old man sustains a closed, isolated, displaced femoral neck fracture. Radiographs demonstrate a vertically oriented fracture line with an angle greater than 50 degrees from the horizontal (Pauwels Type III). What biomechanical construct provides the most stable fixation against the dominant deforming forces for this specific fracture pattern?
. Three parallel partially threaded cancellous lag screws
. A sliding hip screw (SHS) with an anti-rotation screw
. A standard cephalomedullary nail
. Bipolar hemiarthroplasty
. Two fully threaded cortical screws

Correct Answer & Explanation

. A sliding hip screw (SHS) with an anti-rotation screw

Explanation

Pauwels Type III femoral neck fractures have a highly vertical fracture line (>50 degrees), subjecting the fracture to extreme shear forces rather than compressive forces. Biomechanical studies consistently demonstrate that a sliding hip screw (a fixed-angle device) supplemented with a derotational cancellous screw provides superior biomechanical stability against vertical shear forces compared to three parallel cancellous screws.

Question 6300

Topic: 2. Trauma
A 42-year-old farmer sustains a severe open tibia fracture after his leg is caught in a piece of agricultural machinery. The wound is 14 cm long with extensive soft tissue stripping, bone loss, and gross contamination with soil and manure. According to current guidelines, which of the following is the most appropriate initial intravenous antibiotic regimen?
. A first-generation cephalosporin alone
. A first-generation cephalosporin and an aminoglycoside
. A first-generation cephalosporin, an aminoglycoside, and high-dose penicillin
. A fluoroquinolone alone
. Vancomycin and piperacillin-tazobactam

Correct Answer & Explanation

. A first-generation cephalosporin, an aminoglycoside, and high-dose penicillin

Explanation

This is a Gustilo-Anderson Type IIIB open fracture with farm/soil contamination. Standard prophylaxis for Type III open fractures includes a first-generation cephalosporin (for Gram-positive coverage) and an aminoglycoside (for Gram-negative coverage). For farm injuries or gross soil contamination, high-dose penicillin should be added specifically to cover anaerobes, most notably Clostridium perfringens, to prevent gas gangrene.

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