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2. Trauma MCQs

Practice Set 536 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 10701

Topic: 2. Trauma

In the setting of a high-energy Schatzker VI tibial plateau fracture, the use of a staged protocol involving initial placement of a spanning external fixator is primarily aimed at minimizing the risk of which of the following complications?

. Nonunion
. Malunion
. Deep infection and wound breakdown
. Post-traumatic osteoarthritis
. Popliteal artery injury

Correct Answer & Explanation

. Nonunion

Explanation

The staged protocol (initial spanning external fixation followed by delayed internal fixation 1-3 weeks later) for high-energy tibial plateau and pilon fractures was developed primarily to allow severe soft tissue swelling to subside. This strategy has significantly reduced the historically high rates of deep infection, wound breakdown, and soft tissue sloughing associated with immediate open reduction and internal fixation.

Question 10702

Topic: 2. Trauma

A 45-year-old construction worker falls from a roof, sustaining a closed, intra-articular calcaneus fracture. Computed tomography reveals a Sanders Type II fracture. Based on large prospective randomized trials, which patient demographic is most likely to benefit from operative over nonoperative management?

. Patients over 65 years of age receiving worker's compensation
. Women over 50 years of age not receiving worker's compensation
. Young, male patients with a lighter workload who are not receiving worker's compensation
. Young, male patients with a heavy workload receiving worker's compensation
. Patients with severe peripheral neuropathy

Correct Answer & Explanation

. Patients over 65 years of age receiving worker's compensation

Explanation

In Buckley's landmark randomized controlled trial on calcaneus fractures, while there was no significant difference in functional outcomes overall between operative and nonoperative groups, subgroup analysis demonstrated that young, healthy patients, women, and those not receiving worker's compensation with a lighter workload had significantly better outcomes with operative management. Worker's compensation was a strong predictor of poor outcomes regardless of the treatment modality.

Question 10703

Topic: 2. Trauma

Which of the following clinical or radiographic findings is considered an absolute indication for immediate open reduction and internal fixation of an acute midshaft clavicle fracture?

. 100% vertical displacement of the fracture fragments
. 2 cm of shortening
. Open fracture
. Presence of a perpendicular Z-fragment
. Female patient with cosmetic concerns

Correct Answer & Explanation

. 100% vertical displacement of the fracture fragments

Explanation

Absolute indications for ORIF of an acute clavicle fracture include open fractures, skin tenting with impending soft tissue compromise, associated subclavian artery or vein injury, and floating shoulder (sometimes considered relative depending on displacement). Factors such as >2 cm shortening, 100% displacement, and Z-fragments are considered relative indications where surgery may improve functional outcomes but is not absolutely mandated.

Question 10704

Topic: 2. Trauma
According to current guidelines for a Gustilo-Anderson Grade III open tibial shaft fracture with massive soft tissue stripping and heavy farmyard soil contamination, what is the most appropriate initial empiric intravenous antibiotic regimen?
. First-generation cephalosporin alone
. First-generation cephalosporin and an aminoglycoside
. First-generation cephalosporin, an aminoglycoside, and high-dose penicillin
. Vancomycin and Piperacillin/Tazobactam
. Fluoroquinolone alone

Correct Answer & Explanation

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

Explanation

Grade III open fractures classically require a first-generation cephalosporin (e.g., cefazolin) for Gram-positive coverage and an aminoglycoside (e.g., gentamicin) or a third-generation cephalosporin for Gram-negative coverage. If there is farmyard contamination, massive crush injury, or possible bowel contamination, high-dose penicillin is added specifically to cover Clostridium species to prevent gas gangrene.

Question 10705

Topic: 2. Trauma

According to the Hertel radiographic criteria, which of the following factors is the most accurate predictor of humeral head ischemia following a complex proximal humerus fracture?

. Medial hinge disruption > 2 mm
. Head-split component
. Calcar length < 8 mm attached to the articular segment
. Varus angulation > 45 degrees
. Displacement of the greater tuberosity > 1 cm

Correct Answer & Explanation

. Medial hinge disruption > 2 mm

Explanation

Hertel described several criteria for predicting ischemia of the humeral head in proximal humerus fractures. The most significant individual predictor is a short metaphyseal head extension (calcar length) of less than 8 mm attached to the articular segment. Disruption of the medial hinge > 2 mm and an anatomic neck fracture pattern are also highly predictive, especially when combined.

Question 10706

Topic: 2. Trauma

A 28-year-old male is admitted after a motorcycle accident with a closed, highly comminuted tibial shaft fracture. You suspect compartment syndrome. The patient is hypotensive with a mean arterial pressure (MAP) of 60 mmHg and diastolic blood pressure of 45 mmHg. Intracompartmental pressure testing reveals a pressure of 25 mmHg in the anterior compartment. What is the most appropriate management?

. Urgent four-compartment fasciotomy
. Elevation of the limb above the level of the heart
. Serial clinical exams and fluid resuscitation
. Application of a long leg cast
. Administration of intravenous mannitol

Correct Answer & Explanation

. Urgent four-compartment fasciotomy

Explanation

Acute compartment syndrome is diagnosed when the Delta P (diastolic blood pressure minus the intracompartmental pressure) is less than 30 mmHg. In this hypotensive patient, the Delta P is 45 - 25 = 20 mmHg. A Delta P < 30 mmHg indicates a critical lack of tissue perfusion, necessitating urgent four-compartment fasciotomy regardless of the absolute compartment pressure being under 30 mmHg.

Question 10707

Topic: 2. Trauma
A 25-year-old female sustains a vertical, Pauwels type III femoral neck fracture. Which of the following biomechanical characteristics is most associated with this fracture pattern, and what is the preferred fixation strategy to prevent failure?
. High compressive forces; multiple cancellous screws
. High shear forces; sliding hip screw with a derotation screw
. High tensile forces; cephalomedullary nail
. High shear forces; bipolar hemiarthroplasty
. High compressive forces; dynamic condylar screw

Correct Answer & Explanation

. High shear forces; sliding hip screw with a derotation screw

Explanation

Pauwels type III fractures are vertically oriented (angle > 50 degrees to the horizontal) and are subjected to high shear forces, making them mechanically unstable and highly prone to varus collapse and nonunion. A fixed-angle device, such as a sliding hip screw (frequently augmented with a derotation screw), provides superior biomechanical stability against these shear forces compared to multiple parallel cancellous screws.

Question 10708

Topic: 2. Trauma

A 55-year-old female underwent non-operative treatment with a short arm cast for a non-displaced distal radius fracture. Eight weeks later, she suddenly cannot actively extend her thumb interphalangeal joint. What is the most common pathophysiologic mechanism for this complication?

. Iatrogenic laceration from cast removal
. Ischemic necrosis and mechanical attrition of the extensor pollicis longus (EPL) tendon at Lister's tubercle
. Rupture of the extensor pollicis brevis (EPB) tendon
. Posterior interosseous nerve (PIN) entrapment within the fracture callus
. Flexor pollicis longus (FPL) rupture

Correct Answer & Explanation

. Iatrogenic laceration from cast removal

Explanation

Extensor pollicis longus (EPL) tendon rupture is a classic complication following non-displaced or minimally displaced distal radius fractures. The pathophysiology involves mechanical attrition of the tendon over the fracture callus or roughened bone near Lister's tubercle, compounded by ischemia within the tight intact third extensor compartment due to fracture hematoma and swelling.

Question 10709

Topic: 2. Trauma

During tension band wiring of a simple transverse olecranon fracture, the figure-of-eight wire is placed to convert which of the following forces into compressive forces at the articular surface during active elbow flexion?

. Valgus forces
. Varus forces
. Shear forces
. Tensile forces
. Rotational forces

Correct Answer & Explanation

. Valgus forces

Explanation

The biomechanical principle of tension band wiring relies on placing the implant on the tension side of the bone. In the olecranon, the triceps muscle pulls on the proximal fragment, creating distractive tensile forces across the posterior cortex. The figure-of-eight wire counteracts this and dynamically converts these tensile forces on the posterior cortex into stabilizing compressive forces at the anterior articular surface during elbow flexion.

Question 10710

Topic: 2. Trauma

A patient presents with a high-energy OTA/AO type 43-C3 pilon fracture accompanied by severe soft tissue swelling and hemorrhagic fracture blisters. The patient is placed in a spanning external fixator. Which of the following clinical findings indicates the optimal timing to safely proceed with definitive open reduction and internal fixation?

. Normalization of the erythrocyte sedimentation rate (ESR)
. Re-epithelialization of hemorrhagic fracture blisters and presence of the skin 'wrinkle sign'
. Resolution of all ecchymosis on the foot
. Visible callus formation on radiographs
. Exactly 7 days post-injury, regardless of swelling

Correct Answer & Explanation

. Normalization of the erythrocyte sedimentation rate (ESR)

Explanation

Definitive surgical fixation of high-energy pilon fractures must be delayed until the soft tissue envelope has recovered to minimize catastrophic wound complications. The appearance of skin wrinkles (the 'wrinkle sign') on the anterior ankle and the re-epithelialization of fracture blisters are the primary clinical indicators that the interstitial edema has sufficiently subsided to safely allow for surgical incisions.

Question 10711

Topic: 2. Trauma

A 30-year-old male sustains a 'floating knee' injury (ipsilateral femoral and tibial shaft fractures) from a motor vehicle collision. He has been adequately resuscitated and is hemodynamically stable. According to standard orthopedic trauma protocols, which bone should typically be fixed first and what is the primary rationale?

. Tibia first, to re-establish the mechanical axis of the lower leg.
. Tibia first, because the lower leg is more prone to acute compartment syndrome.
. Femur first, to establish proximal stability, reduce massive blood loss, and facilitate positioning for tibial nailing.
. Femur first, to clear the medullary canal and reduce the risk of fat embolism syndrome.
. Both should be fixed simultaneously using a single antegrade nail spanning the knee joint.

Correct Answer & Explanation

. Tibia first, to re-establish the mechanical axis of the lower leg.

Explanation

In the management of a floating knee injury in a hemodynamically stable patient, the standard surgical sequence is to stabilize the femur first. Fixation of the femur establishes proximal skeletal control, significantly reduces ongoing hemorrhage from the large thigh compartment, and makes the physical manipulation, traction, and positioning of the leg required for subsequent tibial nailing much easier and safer.

Question 10712

Topic: 2. Trauma

A 45-year-old male is involved in a high-speed motor vehicle collision and sustains an acetabular fracture. Plain radiographs demonstrate disruption of both the iliopectineal and ilioischial lines. An obturator oblique view reveals a classic 'spur sign'. Based on these radiographic findings, what is the correct diagnosis?

. Transverse acetabular fracture
. T-type acetabular fracture
. Both column acetabular fracture
. Anterior column posterior hemitransverse fracture
. Isolated posterior column fracture

Correct Answer & Explanation

. Transverse acetabular fracture

Explanation

The 'spur sign' is a pathognomonic radiographic feature of a both column acetabular fracture seen on the obturator oblique view. It represents the intact segment of the ilium attached to the axial skeleton, protruding posterosuperiorly to the displaced articular fragment. Disruption of both the iliopectineal and ilioischial lines indicates involvement of both the anterior and posterior columns.

Question 10713

Topic: 2. Trauma

A 32-year-old female sustains a subtrochanteric femur fracture. Due to the powerful muscle attachments on the proximal femur, the proximal fragment assumes a classic, predictable deformity. Which combination of deforming forces acts on the proximal fragment in this fracture pattern?

. Flexion, abduction, and internal rotation
. Flexion, abduction, and external rotation
. Extension, adduction, and internal rotation
. Extension, abduction, and external rotation
. Flexion, adduction, and external rotation

Correct Answer & Explanation

. Flexion, abduction, and internal rotation

Explanation

The proximal fragment of a subtrochanteric femur fracture is characteristically held in flexion (by the iliopsoas attaching to the lesser trochanter), abduction (by the gluteus medius and minimus attaching to the greater trochanter), and external rotation (by the short external rotators).

Question 10714

Topic: 2. Trauma

In evaluating a proximal humerus fracture for potential head ischemia, Hertel described several radiographic criteria. Which of the following findings is the most reliable predictor of humeral head ischemia?

. Calcar length (metaphyseal head extension) less than 8 mm
. Medial hinge disruption less than 2 mm
. A fracture involving the surgical neck alone
. Valgus impaction of the articular segment
. Greater tuberosity displacement of 5 mm

Correct Answer & Explanation

. Calcar length (metaphyseal head extension) less than 8 mm

Explanation

Hertel identified several key predictors of humeral head ischemia in proximal humerus fractures. The strongest predictors include a calcar length (metaphyseal extension of the articular fragment) of less than 8 mm, disruption of the medial hinge by greater than 2 mm, and an anatomic neck fracture pattern. These findings suggest disruption of the critical arcuate artery network.

Question 10715

Topic: 2. Trauma

In the context of polytrauma, the decision to proceed with Damage Control Orthopedics (DCO) rather than Early Total Care (ETC) for major long bone fractures is guided by patient physiology. Which of the following admission parameters strongly favors the use of DCO?

. Arterial pH of 7.35
. Initial serum lactate of 1.2 mmol/L
. Base deficit greater than 6 mmol/L
. Core body temperature of 36.0 degrees Celsius
. Systolic blood pressure consistently above 110 mmHg

Correct Answer & Explanation

. Arterial pH of 7.35

Explanation

Damage Control Orthopedics (DCO) involves provisional stabilization (e.g., external fixation) to avoid the 'second hit' of definitive surgery in an unstable patient. Markers of a 'borderline' or 'in extremis' patient who should receive DCO include: Base deficit > 6, Lactate > 2.5 mmol/L, pH < 7.24, core temperature < 34°C, and prolonged hypotension or coagulopathy.

Question 10716

Topic: 2. Trauma

A 25-year-old male undergoes a standard two-incision, four-compartment fasciotomy of the lower leg for acute compartment syndrome. During the lateral incision, placed midway between the fibula and the anterior tibial crest, which nerve is at greatest risk of iatrogenic injury as it exits the deep fascia in the distal third of the leg?

. Deep peroneal nerve
. Superficial peroneal nerve
. Sural nerve
. Saphenous nerve
. Tibial nerve

Correct Answer & Explanation

. Deep peroneal nerve

Explanation

The superficial peroneal nerve lies in the lateral compartment and pierces the deep fascia to become subcutaneous at the junction of the middle and distal thirds of the leg. It is highly susceptible to injury during the lateral longitudinal incision of a dual-incision leg fasciotomy if the incision is carried too far anteriorly or performed blindly.

Question 10717

Topic: 2. Trauma

A 35-year-old male sustains a high-energy Pilon fracture.

On presentation, the ankle is grossly swollen with multiple tense fracture blisters. What is the standard of care for initial surgical management?

. Immediate open reduction and internal fixation (ORIF) with dual plating
. Immediate intramedullary nailing of the tibia
. Spanning external fixation across the ankle joint with delayed definitive ORIF
. Primary tibiotalar arthrodesis
. Closed reduction and casting until swelling subsides

Correct Answer & Explanation

. Immediate open reduction and internal fixation (ORIF) with dual plating

Explanation

High-energy Pilon (distal tibia) fractures are notoriously associated with severe soft tissue envelopes that cannot tolerate acute open incisions (high risk of necrosis and deep infection). The gold standard approach is staged management: acute application of a joint-spanning external fixator to restore length and alignment, followed by definitive ORIF once the soft tissues have stabilized (typically 10-21 days later, indicated by the 'wrinkle sign').

Question 10718

Topic: 2. Trauma

The Mangled Extremity Severity Score (MESS) is historically used as a tool to help determine whether to amputate or salvage a severely injured limb. Which of the following combinations of variables comprises the MESS criteria?

. Skeletal/soft tissue injury, Limb ischemia time, Presence of shock, and Patient age
. Mechanism of injury, Contamination level, Nerve transection, and Lactate level
. Fracture comminution, Vascular injury level, Gender, and Time to surgery
. Soft tissue loss size, Associated head injury, Patient age, and Venous outflow
. Skin defect size, Base deficit, Muscle necrosis, and Bone loss

Correct Answer & Explanation

. Skeletal/soft tissue injury, Limb ischemia time, Presence of shock, and Patient age

Explanation

The Mangled Extremity Severity Score (MESS) is calculated using four variables: M (Skeletal and soft tissue injury extent), E (Limb Ischemia duration and severity), S (Shock presence and duration), and A (Age of the patient). While no score perfectly dictates treatment, historically a score of 7 or higher suggests a low probability of successful salvage.

Question 10719

Topic: 2. Trauma

A 26-year-old male trauma patient presents with an isolated closed ipsilateral femoral shaft fracture and tibial shaft fracture (a 'floating knee'). He is hemodynamically stable. According to best practice guidelines for minimizing complications, what is the most appropriate sequence of operative intervention?

. Simultaneous bilateral external fixation only
. Intramedullary nailing of the tibia followed by intramedullary nailing of the femur
. Intramedullary nailing of the femur followed by intramedullary nailing of the tibia
. Plate fixation of the femur followed by external fixation of the tibia
. Nonoperative casting of the tibia and intramedullary nailing of the femur

Correct Answer & Explanation

. Simultaneous bilateral external fixation only

Explanation

In a stable patient with a floating knee, it is recommended to fix the femur first. Intramedullary nailing of the femur stabilizes the largest long bone, rapidly decreases the systemic inflammatory response and risk of fat emboli, and crucially provides a stable base against which the knee can be flexed to facilitate subsequent intramedullary nailing of the tibia.

Question 10720

Topic: Pelvic & Acetabular Trauma

A 32-year-old male arrives in the trauma bay hemodynamically unstable following a crush injury. Radiographs show a widened pubic symphysis consistent with an APC-II (open book) pelvic ring injury. A decision is made to apply a pelvic binder. To maximize mechanical advantage and effectively reduce the pelvic volume, over which specific anatomic landmark should the binder be centered?

. Anterior superior iliac spines (ASIS)
. Iliac crests
. Greater trochanters
. Symphysis pubis
. Umbilicus

Correct Answer & Explanation

. Anterior superior iliac spines (ASIS)

Explanation

To effectively reduce pelvic volume and stabilize an 'open book' pelvic fracture, a pelvic binder (or sheet) must be centered directly over the greater trochanters of the femurs. Placing it higher, over the iliac crests or ASIS, can ironically act as a fulcrum to splay the pelvis further open and fails to provide adequate compression to the posterior pelvic ring.

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