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2. Trauma MCQs

Practice Set 521 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 10401

Topic: 2. Trauma

A 19-year-old male presents with a low-velocity gunshot wound to the right knee. Radiographs confirm a retained intact bullet freely mobile within the joint space, with no associated fracture. What is the most appropriate definitive management for the retained intra-articular bullet?

. Nonoperative management with intravenous antibiotics and early range of motion
. Nonoperative management with a long-leg cast for 6 weeks
. Surgical retrieval (arthroscopic or open) of the bullet
. Immediate above-knee amputation
. Local wound care and delayed primary closure of the bullet tract

Correct Answer & Explanation

. Nonoperative management with intravenous antibiotics and early range of motion

Explanation

A retained bullet within a synovial joint space is an absolute indication for surgical removal (either arthroscopically or open). Synovial fluid can dissolve the bullet's lead, leading to lead arthropathy (severe joint destruction) and systemic lead toxicity (plumbism).

Question 10402

Topic: 2. Trauma

A 38-year-old male sustains a subtrochanteric fracture of the right femur. During open reduction and intramedullary nailing, the surgeon notes classic multi-planar displacement of the proximal fragment. Which set of deforming forces accurately describes the displacement of the proximal fragment?

. Flexion (iliopsoas), Adduction (adductor longus), Internal rotation (gluteus minimus)
. Extension (gluteus maximus), Abduction (gluteus medius), External rotation (piriformis)
. Flexion (iliopsoas), Abduction (gluteus medius/minimus), External rotation (short external rotators)
. Extension (hamstrings), Adduction (adductor magnus), Internal rotation (tensor fasciae latae)
. Flexion (rectus femoris), Adduction (gracilis), External rotation (obturator internus)

Correct Answer & Explanation

. Flexion (iliopsoas), Adduction (adductor longus), Internal rotation (gluteus minimus)

Explanation

In a subtrochanteric femur fracture, the proximal fragment is heavily displaced by muscular attachments: it is flexed by the iliopsoas (attaching to the lesser trochanter), abducted by the gluteus medius and minimus (greater trochanter), and externally rotated by the short external rotators (piriformis, gemelli, obturator internus, quadratus femoris).

Question 10403

Topic: 2. Trauma

During the resuscitation of a polytrauma patient with severe orthopedic injuries, monitoring lactate clearance is critical. A delay in normalizing serum lactate levels beyond what timeframe is most highly predictive of increased mortality, ARDS, and multi-organ failure?

. 6 hours
. 12 hours
. 24 hours
. 48 hours
. 72 hours

Correct Answer & Explanation

. 6 hours

Explanation

Failure to clear serum lactate to normal levels within 24 hours of injury is a strong predictor of increased mortality, ARDS, and multi-organ failure in polytrauma patients.

Question 10404

Topic: 2. Trauma

A 45-year-old male is brought to the ED after a severe crush injury to the pelvis. He is hemodynamically unstable (BP 60/40 mmHg). A pelvic binder is applied, and FAST exam is negative. Despite massive transfusion, he remains in profound hemorrhagic shock. If angiography is delayed, what is the most appropriate next step for temporary hemorrhage control?

. Exploratory laparotomy with internal iliac artery ligation
. Immediate external fixation of the pelvis
. Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) in Zone 1
. Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) in Zone 3
. Pelvic packing via a posterior sacral approach

Correct Answer & Explanation

. Exploratory laparotomy with internal iliac artery ligation

Explanation

REBOA in Zone 3 (distal to the lowest renal artery) is indicated for life-threatening pelvic hemorrhage in patients who are crashing. Zone 1 is typically used for intra-abdominal hemorrhage.

Question 10405

Topic: Pelvic & Acetabular Trauma
A 28-year-old female presents with a closed pelvic ring fracture after being run over by a truck. Examination reveals a large, fluctuant swelling over the greater trochanter with overlying skin bruising and reduced sensation. Which of the following best describes the pathophysiology of this soft tissue injury?
. Direct crush injury leading to rhabdomyolysis of the gluteal musculature
. Shearing force separating the subcutaneous tissue from the underlying fascia, disrupting perforating vessels
. Arterial bleeding from a torn superficial femoral artery expanding into the subcutaneous space
. Lymphatic fluid accumulation due to disruption of inguinal lymph nodes
. Herniation of muscle tissue through a traumatic fascial defect

Correct Answer & Explanation

. Shearing force separating the subcutaneous tissue from the underlying fascia, disrupting perforating vessels

Explanation

This is a Morel-Lavallée lesion, caused by a closed degloving or shearing injury. It results in the separation of skin and subcutaneous fat from the underlying fascial layer, disrupting perforating vessels and causing a hemolymphatic collection.

Question 10406

Topic: 2. Trauma

A 25-year-old male is diagnosed with a posterior wall acetabular fracture after a dashboard injury.

On CT scan, the fracture involves 30% of the posterior wall. What is the most accurate method to determine if this hip requires operative fixation due to instability?

. Measurement of the 'gull sign' on standard AP pelvis radiograph
. Dynamic fluoroscopic stress examination under anesthesia
. 3D reconstruction CT scan measuring exact surface area
. MRI of the hip to assess the posterior capsule and labrum
. Presence of an intra-articular loose body on CT scan

Correct Answer & Explanation

. Measurement of the 'gull sign' on standard AP pelvis radiograph

Explanation

While fractures >50% are typically unstable and <20% are stable, borderline fractures (20-50%) require dynamic stress fluoroscopy under anesthesia to definitively assess hip stability.

Question 10407

Topic: 2. Trauma

A polytrauma patient undergoes damage control orthopedics (DCO) for bilateral femur fractures with temporary external fixation. Which of the following laboratory parameters best indicates that the patient is adequately resuscitated and cleared for Early Total Care (ETC) conversion to intramedullary nailing?

. Serum lactate < 2.0 mmol/L and Base Excess > -2 mEq/L
. Urine output > 0.5 mL/kg/hr for 2 hours
. Hemoglobin > 10 g/dL
. Systolic blood pressure > 100 mmHg without vasopressors
. Normal sinus rhythm with heart rate < 100 bpm

Correct Answer & Explanation

. Serum lactate < 2.0 mmol/L and Base Excess > -2 mEq/L

Explanation

Normalization of serum lactate (< 2.0 mmol/L) and correction of base deficit (> -2 mEq/L) are the most reliable indicators of adequate tissue perfusion and endpoint of resuscitation.

Question 10408

Topic: 2. Trauma
A 40-year-old male falls from a roof, sustaining a highly comminuted transforaminal sacral fracture extending centrally. According to the Denis classification, this involves Zone III. What is the most likely associated neurological complication?
. Isolated L5 nerve root palsy resulting in foot drop
. Femoral neuropathy resulting in quadriceps weakness
. Bowel and bladder sphincter dysfunction
. Complete paraplegia below L1
. Isolated pudendal nerve hyperesthesia

Correct Answer & Explanation

. Bowel and bladder sphincter dysfunction

Explanation

Denis Zone III sacral fractures involve the central sacral canal. They carry a high risk (up to 57%) of sacral nerve root (S2-S4) damage, leading to bowel, bladder, and sexual dysfunction.

Question 10409

Topic: 2. Trauma

A 22-year-old male with a diaphyseal femur fracture develops confusion, tachypnea (RR 30), and hypoxia on post-injury day 2. A petechial rash is noted over his axilla and conjunctiva. According to Gurd's criteria, what is the most critical physiological driver of his respiratory insufficiency?

. Pulmonary contusion with progressive alveolar collapse
. Mechanical obstruction of pulmonary capillaries by neutral fat droplets and subsequent endothelial damage
. Systemic release of interleukin-6 triggering acute respiratory distress syndrome (ARDS)
. Deep vein thrombosis resulting in a large paradoxical embolus
. Fluid overload leading to cardiogenic pulmonary edema

Correct Answer & Explanation

. Pulmonary contusion with progressive alveolar collapse

Explanation

Fat Embolism Syndrome (FES) is characterized by Gurd's major criteria (rash, respiratory failure, cerebral involvement). The pathophysiology involves neutral fat emboli causing both mechanical occlusion and an inflammatory cascade (free fatty acid toxicity) in the pulmonary capillaries.

Question 10410

Topic: 2. Trauma
A 32-year-old male sustains a high-energy tibial plateau fracture. The orthopedic surgeon suspects acute compartment syndrome. The patient's blood pressure is 110/60 mmHg. Intra-compartmental pressures are: Anterior 40 mmHg, Lateral 35 mmHg, Deep Posterior 45 mmHg, Superficial Posterior 30 mmHg. What is the absolute indication for four-compartment fasciotomy in this patient?
. Any single compartment pressure > 30 mmHg
. Mean arterial pressure (MAP) minus compartment pressure < 45 mmHg
. Diastolic blood pressure minus compartment pressure < 30 mmHg
. Systolic blood pressure minus compartment pressure < 40 mmHg
. Loss of palpable dorsalis pedis pulse

Correct Answer & Explanation

. Diastolic blood pressure minus compartment pressure < 30 mmHg

Explanation

The delta pressure (ΔP) is the most reliable indicator for fasciotomy, calculated as Diastolic Blood Pressure minus intra-compartmental pressure. A ΔP < 30 mmHg is an absolute indication for fasciotomy.

Question 10411

Topic: Pelvic & Acetabular Trauma

A 38-year-old pedestrian is struck by a vehicle, sustaining an anterior-posterior compression (APC) type II pelvic ring injury. Which of the following best describes the ligamentous disruption pattern in this specific injury?

. Disruption of the symphysis pubis only, with intact anterior and posterior sacroiliac ligaments
. Disruption of the symphysis pubis, anterior sacroiliac ligaments, and sacrospinous/sacrotuberous ligaments, with intact posterior sacroiliac ligaments
. Complete disruption of the symphysis pubis, anterior, and posterior sacroiliac ligaments
. Disruption of the posterior sacroiliac ligaments with an intact symphysis pubis
. Avulsion of the sacrotuberous ligament with intact anterior sacroiliac ligaments

Correct Answer & Explanation

. Disruption of the symphysis pubis only, with intact anterior and posterior sacroiliac ligaments

Explanation

An APC II injury involves widening of the symphysis pubis >2.5 cm, tearing of the anterior sacroiliac, sacrospinous, and sacrotuberous ligaments. The posterior sacroiliac ligaments remain intact, providing vertical stability.

Question 10412

Topic: 2. Trauma

A 26-year-old male sustains a low-velocity civilian gunshot wound to the mid-thigh. Radiographs show a highly comminuted midshaft femur fracture. The patient has normal distal pulses and intact sensation. The entry and exit wounds are 1 cm each with no gross contamination. What is the most appropriate management?

. Aggressive formal debridement of the bullet tract, temporary external fixation, and delayed nailing
. Local wound care, tetanus prophylaxis, IV antibiotics, and early reamed intramedullary nailing
. Non-operative management with skeletal traction for 6 weeks
. Immediate open reduction and internal fixation with dual plating to bypass the defect
. Exploration of the femoral artery followed by intramedullary nailing

Correct Answer & Explanation

. Aggressive formal debridement of the bullet tract, temporary external fixation, and delayed nailing

Explanation

Low-velocity gunshot wounds causing femur fractures without neurovascular compromise or gross contamination do not require formal tract debridement. They are safely treated with local wound care, antibiotics, and standard intramedullary nailing.

Question 10413

Topic: 2. Trauma

According to the Pape/Hannover criteria for polytrauma patients, which of the following findings would classify a patient as 'borderline' and thus potentially contraindicate Early Total Care (ETC) of major long bone fractures?

. Glasgow Coma Scale (GCS) of 14
. Platelet count < 90,000/µL
. Urine output of 1.0 mL/kg/hr
. Base excess of -1 mEq/L
. Core body temperature of 36.5°C

Correct Answer & Explanation

. Glasgow Coma Scale (GCS) of 14

Explanation

Borderline criteria contraindicating ETC include: Initial lactate >2.5 mmol/L, platelets <90,000/µL, temperature <35°C, bilateral pulmonary contusions, or massive transfusion requirements.

Question 10414

Topic: 2. Trauma

A 29-year-old male motorcyclist sustains an ipsilateral midshaft femur fracture and midshaft tibia fracture (floating knee). He is hemodynamically stable. What is the most widely recommended surgical sequence and its primary rationale?

. Fixation of the tibia first to provide a stable base for femoral reduction
. Fixation of the femur first to stabilize the limb, reduce pulmonary complications, and facilitate knee positioning for tibia fixation
. Simultaneous bilateral external fixation as definitive management
. Plating of both bones to avoid bone marrow embolization entirely
. External fixation of the femur and intramedullary nailing of the tibia

Correct Answer & Explanation

. Fixation of the tibia first to provide a stable base for femoral reduction

Explanation

In a floating knee, femoral fixation is prioritized to decrease systemic embolic load, stabilize the largest bone, and allow the knee to be flexed over a triangle for antegrade tibial nailing.

Question 10415

Topic: 2. Trauma

A 30-year-old male sustains a high-energy diaphyseal femur fracture. Due to the high risk of a concomitant, missed ipsilateral femoral neck fracture, what is the 'gold standard' imaging protocol?

. Standard anteroposterior (AP) and lateral plain radiographs of the femur
. Preoperative MRI of the ipsilateral hip
. Dedicated fine-cut (2mm) CT scan through the femoral neck
. Dynamic fluoroscopy of the hip under general anesthesia prior to draping
. Bone scan on postoperative day 2

Correct Answer & Explanation

. Standard anteroposterior (AP) and lateral plain radiographs of the femur

Explanation

Ipsilateral femoral neck fractures occur in up to 9% of femur shaft fractures and are missed in up to 30% of cases. A dedicated fine-cut CT of the hip is the gold standard for diagnosis.

Question 10416

Topic: 2. Trauma
A 45-year-old farmer sustains a Gustilo-Anderson IIIB open tibia fracture from a tractor rollover. The wound is heavily contaminated with soil and manure. In addition to a first-generation cephalosporin and an aminoglycoside, which antibiotic must be added to the initial regimen?
. Vancomycin
. Ciprofloxacin
. Penicillin
. Clindamycin
. Linezolid

Correct Answer & Explanation

. Penicillin

Explanation

In open fractures with severe soil or farm contamination, High-dose Penicillin (or Metronidazole) must be added to cover anaerobic organisms, specifically Clostridium species, to prevent gas gangrene.

Question 10417

Topic: 2. Trauma
A pelvic binder is applied to a hypotensive patient with an open-book pelvic fracture in the trauma bay. What is the correct anatomical landmark for centering the binder, and what is the most significant complication of leaving it on for >24 hours?
. Centered over the iliac crests; Complication: Paralytic ileus
. Centered over the greater trochanters; Complication: Skin pressure necrosis
. Centered over the symphysis pubis; Complication: Bladder rupture
. Centered over the ASIS; Complication: Lateral femoral cutaneous nerve palsy
. Centered over the lumbar spine; Complication: Compartment syndrome of the gluteus

Correct Answer & Explanation

. Centered over the greater trochanters; Complication: Skin pressure necrosis

Explanation

Pelvic binders must be centered over the greater trochanters to effectively reduce pelvic volume. Prolonged application (>24 hours) drastically increases the risk of pressure necrosis over the trochanters and sacrum.

Question 10418

Topic: 2. Trauma

A 28-year-old male is admitted with a severe closed tibia fracture. His current blood pressure is 110/70 mmHg. Intracompartmental pressure testing of the anterior compartment yields a value of 45 mmHg. What is the most appropriate next step in management?

. Elevate the leg above heart level
. Recheck compartment pressures in 2 hours
. Apply ice and keep the leg dependent
. Immediate four-compartment fasciotomy
. Administer intravenous mannitol

Correct Answer & Explanation

. Elevate the leg above heart level

Explanation

A delta-P (diastolic blood pressure minus compartment pressure) of 30 mmHg or less is an absolute indication for fasciotomy. In this patient, the delta-P is 25 mmHg (70 - 45 = 25), warranting immediate surgical decompression to prevent irreversible ischemia.

Question 10419

Topic: 2. Trauma

A 34-year-old male is brought to the trauma bay after a motorcycle accident. He is hypotensive (BP 75/40 mmHg) and tachycardic (HR 130). Primary survey reveals an 'open book' pelvic fracture. A pelvic binder is immediately applied to reduce pelvic volume and control hemorrhage. To achieve optimal reduction and biomechanical stability to tamponade bleeding, the binder must be centered over which of the following anatomic landmarks?

. Anterior superior iliac spines
. Iliac crests
. Greater trochanters
. Pubic symphysis
. Femoral neck

Correct Answer & Explanation

. Anterior superior iliac spines

Explanation

The correct placement of a pelvic binder is centered over the greater trochanters. Studies have consistently shown that applying the binder at the level of the greater trochanters maximizes the mechanical advantage for closing the pelvic ring (symphysis pubis), thereby reducing pelvic volume and promoting tamponade of venous bleeding. Placement higher over the iliac crests or ASIS is less effective and can paradoxically open the pelvic floor or cause abdominal compression.

Question 10420

Topic: 2. Trauma
A 28-year-old male sustains a high-energy Pauwels type III (vertical) femoral neck fracture. Biomechanical studies comparing fixation methods for this specific highly unstable fracture pattern demonstrate that which of the following constructs provides the greatest resistance to vertical shear forces and subsequent varus collapse?
. Three parallel partially threaded cancellous screws in an inverted triangle
. Three parallel fully threaded cancellous screws
. A sliding hip screw (SHS) with a derotational cancellous screw
. Two parallel partially threaded screws
. Cephalomedullary nail with a single lag screw

Correct Answer & Explanation

. A sliding hip screw (SHS) with a derotational cancellous screw

Explanation

Pauwels type III femoral neck fractures have a fracture angle greater than 50 degrees from the horizontal, subjecting them to high vertical shear forces. Biomechanical evidence shows that a sliding hip screw (SHS) combined with an anti-rotation (derotational) screw provides significantly greater resistance to vertical shear and varus collapse compared to three parallel cancellous screws.

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