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2. Trauma MCQs

Practice Set 235 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 4681

Topic: 2. Trauma

A 30-year-old male with a comminuted tibial shaft fracture complains of increasing pain despite narcotic administration. His blood pressure is 110/65 mmHg. Which of the following intracompartmental pressure measurements is an absolute indication for emergency four-compartment fasciotomy?

. Absolute compartment pressure of 25 mmHg
. Absolute compartment pressure of 30 mmHg
. Delta P (Diastolic BP minus compartment pressure) of 40 mmHg
. Delta P (Diastolic BP minus compartment pressure) of 20 mmHg
. Mean arterial pressure (MAP) minus compartment pressure of 40 mmHg

Correct Answer & Explanation

. Delta P (Diastolic BP minus compartment pressure) of 20 mmHg

Explanation

Acute compartment syndrome is reliably diagnosed when the Delta P (diastolic blood pressure minus the absolute compartment pressure) is less than 30 mmHg. A Delta P of 20 mmHg necessitates an emergent fasciotomy.

Question 4682

Topic: 2. Trauma

An 80-year-old female with a well-fixed posterior-stabilized total knee arthroplasty sustains a displaced, comminuted distal femur fracture. The femoral component remains stable. What is the most appropriate surgical treatment?

. Revision to a distal femoral replacement (megaprosthesis)
. Retrograde intramedullary nailing
. Open reduction and internal fixation with a lateral locking plate
. Nonoperative management in a hinged knee brace
. Revision of the femoral component with a long cemented stem

Correct Answer & Explanation

. Open reduction and internal fixation with a lateral locking plate

Explanation

For a displaced periprosthetic distal femur fracture with a stable implant, ORIF with a lateral locking plate is the standard of care. A posterior-stabilized box often precludes the use of a retrograde intramedullary nail.

Question 4683

Topic: 2. Trauma
A 14-year-old male sustains a type III tibial tubercle avulsion fracture. Several hours after closed reduction, he develops severe pain and paresthesias in the first web space of his foot. Injury to which of the following vessels is most commonly responsible for this specific complication?
. Popliteal artery
. Anterior tibial recurrent artery
. Posterior tibial artery
. Fibular (peroneal) artery
. Descending genicular artery

Correct Answer & Explanation

. Anterior tibial recurrent artery

Explanation

Tibial tubercle avulsion fractures carry a high risk of anterior compartment syndrome due to laceration or avulsion of the anterior tibial recurrent artery, which traverses directly adjacent to the tubercle.

Question 4684

Topic: 2. Trauma

A 28-year-old male sustains a low-velocity gunshot wound to the right knee. Radiographs reveal a retained bullet fragment within the intra-articular space but no fractures. What is the most appropriate management?

. Observation and immediate weight-bearing
. Intravenous antibiotics for 7 days and serial radiographs
. Arthroscopic or open removal of the intra-articular bullet and joint lavage
. Total synovectomy and bullet removal
. Extra-articular extraction after waiting 6 weeks for encapsulation

Correct Answer & Explanation

. Arthroscopic or open removal of the intra-articular bullet and joint lavage

Explanation

Retained intra-articular bullets must be surgically removed (arthroscopically or open) due to the severe mechanical third-body wear they cause, as well as the risk of systemic lead toxicity and lead arthropathy.

Question 4685

Topic: 2. Trauma

When managing an extra-articular distal femur fracture with a lateral locking plate using bridge plating principles, which of the following mechanical factors most significantly contributes to the risk of hypertrophic nonunion?

. Leaving too long of a working length
. Using titanium instead of stainless steel plates
. Placing locking screws too close to the fracture site
. Using a plate that is too short
. Failing to achieve anatomic reduction of the metadiaphyseal fragments

Correct Answer & Explanation

. Placing locking screws too close to the fracture site

Explanation

Hypertrophic nonunion in bridge plating occurs when the construct is overly rigid. Placing screws too close to the fracture site decreases the "working length" and construct compliance, preventing the necessary micromotion for secondary bone healing.

Question 4686

Topic: Pelvic & Acetabular Trauma
A 36-year-old male presents 3 weeks after a motorcycle crash with a large, fluctuant swelling over his greater trochanter. MRI confirms a fluid collection between the subcutaneous fat and the fascia lata. Which of the following is the most appropriate definitive management for this chronic Morel-Lavallée lesion?
. Observation as it will spontaneously resolve
. Percutaneous aspiration and compressive wrapping
. Open debridement, capsulectomy, and sclerodesis
. Incision and drainage with packing left open
. Intravenous antibiotics for 6 weeks

Correct Answer & Explanation

. Open debridement, capsulectomy, and sclerodesis

Explanation

Chronic Morel-Lavallée lesions develop a fibrous pseudocapsule that prevents fluid resorption. Definitive treatment requires excision of this capsule via open debridement, frequently combined with sclerodesis.

Question 4687

Topic: 2. Trauma
A 42-year-old male sustains a Gustilo-Anderson type IIIB open tibial shaft fracture. Following initial aggressive surgical debridement and external fixation, what is the optimal timeframe for definitive soft-tissue flap coverage to maximize limb salvage?
. Within 24 hours
. Between 3 and 7 days
. Between 10 and 14 days
. After 21 days when granulation tissue is fully formed
. Delayed coverage is preferred to allow spontaneous epithelialization

Correct Answer & Explanation

. Between 3 and 7 days

Explanation

The trauma literature demonstrates that definitive soft-tissue flap coverage for Gustilo type IIIB open tibial fractures is optimally performed within 3 to 7 days post-injury to minimize infection and optimize outcomes.

Question 4688

Topic: 2. Trauma

A 35-year-old male sustains a bicondylar tibial plateau fracture with a large posteromedial shear fragment. A posteromedial approach is planned for isolated fixation of this fragment. Which of the following defines the correct surgical interval for this approach?

. Between the medial head of the gastrocnemius and the soleus
. Between the pes anserinus anteriorly and the medial head of the gastrocnemius posteriorly
. Between the semimembranosus and the semitendinosus
. Between the popliteus and the posterior tibial nerve
. Between the medial collateral ligament and the anterior tibialis

Correct Answer & Explanation

. Between the pes anserinus anteriorly and the medial head of the gastrocnemius posteriorly

Explanation

The posteromedial approach to the tibial plateau utilizes the interval between the pes anserinus tendons anteriorly and the medial head of the gastrocnemius posteriorly. Retracting the gastrocnemius laterally protects the neurovascular bundle.

Question 4689

Topic: 2. Trauma

A 25-year-old man presents with a high-energy anterior knee dislocation. He has an absent dorsalis pedis pulse, a pale foot, and a cool extremity. Ischemia time is currently estimated at 6.5 hours. Orthopedic and vascular surgery are both present in the operating room. What is the most appropriate sequence of management?

. External fixation followed by definitive vascular repair
. Temporary vascular shunt, followed by external fixation, then definitive vascular repair
. Definitive vascular repair followed by external fixation
. Fasciotomies, followed by external fixation, then vascular repair
. Ligamentous reconstruction followed by definitive vascular repair

Correct Answer & Explanation

. Temporary vascular shunt, followed by external fixation, then definitive vascular repair

Explanation

In cases of knee dislocation with prolonged warm ischemia time (greater than 4-6 hours), a temporary vascular shunt should be placed first to restore perfusion. This is followed by rapid skeletal stabilization (external fixation) and then definitive vascular repair and fasciotomies.

Question 4690

Topic: 2. Trauma

A 30-year-old female sustains a proximal third tibial shaft fracture and undergoes intramedullary nailing via a standard infrapatellar approach. Postoperatively, she is noted to have a significant apex anterior (procurvatum) deformity. Which of the following technical maneuvers is most effective at preventing this specific deformity during nailing?

. Use of a suprapatellar approach with the knee in extension
. Placement of a blocking (Poller) screw anterior to the nail in the distal fragment
. Reaming the medullary canal to 2 mm larger than the selected nail
. Placement of a blocking (Poller) screw posterior to the nail in the proximal fragment
. Flexing the knee to 120 degrees during nail insertion

Correct Answer & Explanation

. Use of a suprapatellar approach with the knee in extension

Explanation

Proximal tibia fractures are highly prone to procurvatum and valgus deformities when nailed via an infrapatellar approach. Utilizing a semi-extended suprapatellar approach relaxes the extensor mechanism, significantly reducing the risk of apex anterior angulation.

Question 4691

Topic: 2. Trauma

A 45-year-old male is undergoing locked plate fixation for a comminuted distal femur fracture (OTA 33-C2). To optimize the biomechanical environment for secondary bone healing, the surgeon wishes to decrease the stiffness of the construct. Which of the following modifications will best achieve this goal?

. Using stainless steel instead of titanium plates
. Decreasing the working length of the plate by placing screws immediately adjacent to the fracture
. Leaving 2 to 3 screw holes empty directly adjacent to the fracture site
. Placing bi-cortical locking screws in all available plate holes
. Using a shorter plate to minimize soft tissue stripping

Correct Answer & Explanation

. Leaving 2 to 3 screw holes empty directly adjacent to the fracture site

Explanation

Increasing the working length of the plate by omitting screws in the holes immediately adjacent to the fracture site decreases construct stiffness. This allows for increased micromotion, which promotes secondary bone healing via callus formation.

Question 4692

Topic: 2. Trauma

A 22-year-old athlete sustains a displaced coronal plane fracture of the lateral femoral condyle (Hoffa fracture). Open reduction and internal fixation is planned. Which of the following screw configurations provides the most biomechanically stable fixation for this specific fracture pattern?

. Two 3.5mm fully threaded screws placed anterior-to-posterior
. Two 6.5mm partially threaded cancellous screws placed anterior-to-posterior
. Two 6.5mm partially threaded cancellous screws placed posterior-to-anterior
. A single 4.5mm cortical screw placed laterally as a lag screw
. Two 3.5mm cortical screws placed medial-to-lateral

Correct Answer & Explanation

. Two 6.5mm partially threaded cancellous screws placed posterior-to-anterior

Explanation

Hoffa fractures (OTA 33-B3) are coronal shear fractures. Biomechanical studies demonstrate that screws placed directed posterior-to-anterior provide superior pullout strength and stability compared to anterior-to-posterior screws.

Question 4693

Topic: 2. Trauma
A 14-year-old boy presents with severe anterior knee pain after a jumping injury. Radiographs reveal a displaced avulsion fracture of the tibial tubercle with a fracture line extending into the proximal tibial physis (Ogden Type III). He is admitted for observation after cast immobilization. Which of the following complications is he at highest risk for, and what is the underlying pathoanatomy?
. Popliteal artery thrombosis due to intimal tear
. Common peroneal nerve palsy due to traction
. Anterior compartment syndrome due to injury to the anterior tibial recurrent artery
. Deep vein thrombosis due to immobilization
. Genu recurvatum due to premature closure of the posterior physis

Correct Answer & Explanation

. Anterior compartment syndrome due to injury to the anterior tibial recurrent artery

Explanation

Adolescents with Ogden Type III tibial tubercle avulsion fractures are at high risk for acute anterior compartment syndrome. This is due to bleeding from the anterior tibial recurrent artery, which is frequently torn during the avulsion.

Question 4694

Topic: 2. Trauma

A 50-year-old polytrauma patient with bilateral femur fractures, multiple rib fractures, and pulmonary contusions arrives in the emergency department. His initial lactate is 4.5 mmol/L, pH is 7.21, and base excess is -8. According to the principles of Damage Control Orthopedics (DCO), what is the most appropriate initial management for his femur fractures?

. Bilateral reamed intramedullary nailing within 24 hours
. Bilateral unreamed intramedullary nailing within 24 hours
. Bilateral external fixation with conversion to intramedullary nails when physiology normalizes
. Open reduction and internal fixation with dynamic compression plates
. Skeletal traction until definitive nailing at day 14

Correct Answer & Explanation

. Bilateral external fixation with conversion to intramedullary nails when physiology normalizes

Explanation

This patient exhibits borderline/unstable physiology (elevated lactate, acidosis, significant base deficit). DCO dictates rapid, minimally invasive stabilization with external fixation to minimize the secondary inflammatory hit, followed by definitive fixation once stabilized.

Question 4695

Topic: 2. Trauma

A 38-year-old male sustains a severe closed crush injury to his right thigh. He reports increasing pain out of proportion to the injury. Which of the following parameters is considered the most reliable threshold for diagnosing acute compartment syndrome and indicating the need for immediate fasciotomy?

. Absolute intracompartmental pressure > 20 mmHg
. Delta P (Diastolic Blood Pressure minus Compartment Pressure) < 30 mmHg
. Delta P (Mean Arterial Pressure minus Compartment Pressure) < 40 mmHg
. Delta P (Systolic Blood Pressure minus Compartment Pressure) < 30 mmHg
. Absolute intracompartmental pressure > 25 mmHg

Correct Answer & Explanation

. Delta P (Diastolic Blood Pressure minus Compartment Pressure) < 30 mmHg

Explanation

The Delta P value (Diastolic BP - Compartment Pressure) is the most reliable threshold for diagnosing acute compartment syndrome. A Delta P of less than 30 mmHg indicates inadequate capillary perfusion and necessitates emergency fasciotomy.

Question 4696

Topic: 2. Trauma

A 32-year-old man sustains an isolated, closed, transverse midshaft femur fracture. He is hemodynamically stable. The decision is made to perform reamed intramedullary nailing. Which of the following factors has been most strongly associated with the development of Acute Respiratory Distress Syndrome (ARDS) following this procedure?

. The use of reaming versus unreamed techniques
. The presence of an associated occult traumatic brain injury
. Concomitant severe chest trauma with bilateral pulmonary contusions
. The timing of surgery being performed less than 12 hours from injury
. The use of a titanium instead of a stainless steel nail

Correct Answer & Explanation

. Concomitant severe chest trauma with bilateral pulmonary contusions

Explanation

In patients undergoing intramedullary nailing for femur fractures, the strongest predictor for the development of ARDS is the presence of severe concomitant chest trauma (pulmonary contusions). Reaming itself has not been shown to increase ARDS rates compared to unreamed nailing in stable patients.

Question 4697

Topic: 2. Trauma

A 55-year-old woman undergoes open reduction and internal fixation of a displaced transverse patella fracture using a standard anterior tension band wiring technique. What is the primary biomechanical principle by which this construct provides stable fixation?

. It provides static compression across the articular surface regardless of knee position.
. It converts tension forces at the anterior patellar surface into compression forces at the articular surface during knee flexion.
. It acts as a neutralization plate, preventing shear forces from distracting the fracture.
. It converts compression forces at the articular surface into tension forces at the anterior cortex during knee extension.
. It acts purely as an internal splint to prevent varus and valgus stress.

Correct Answer & Explanation

. It converts tension forces at the anterior patellar surface into compression forces at the articular surface during knee flexion.

Explanation

The anterior tension band wiring principle relies on placing the implant on the tension side (anterior cortex). As the knee flexes, the extensor mechanism exerts a distractive force anteriorly, which the tension band resists and converts into compressive forces at the articular surface.

Question 4698

Topic: 2. Trauma
A 26-year-old male sustained a Gustilo IIIB open tibia fracture following a motorcycle accident. He underwent initial thorough debridement and external fixation. According to Godina's classic principles, to minimize the risk of deep infection and flap failure, soft tissue coverage should ideally be performed within what time frame from the initial injury?
. 24 hours
. 72 hours
. 7 days
. 14 days
. 21 days

Correct Answer & Explanation

. 72 hours

Explanation

Godina's landmark study demonstrated that early soft tissue coverage (traditionally within 72 hours) of severe open tibia fractures significantly decreases the rates of deep infection, flap failure, and nonunion compared to delayed coverage.

Question 4699

Topic: Pelvic & Acetabular Trauma
A 33-year-old male is struck by a car and sustains a closed degloving injury over his lateral thigh and greater trochanter, clinically recognized as a Morel-Lavallée lesion. Which of the following best describes the specific pathophysiology of this lesion?
. A deep muscular hematoma secondary to a torn vastus lateralis
. A shear injury separating the skin and subcutaneous fat from the underlying fascia, disrupting epifascial perforators
. An acute localized superficial infection leading to necrotizing fasciitis
. A high-pressure injection injury tracking along fascial planes
. An avulsion of the tensor fasciae latae from the iliac crest

Correct Answer & Explanation

. A shear injury separating the skin and subcutaneous fat from the underlying fascia, disrupting epifascial perforators

Explanation

A Morel-Lavallée lesion is a closed degloving injury caused by severe shearing forces that separate the skin and subcutaneous tissue from the underlying deep fascia. This tears the trans-fascial perforating vessels, leading to a hemolymphatic fluid collection.

Question 4700

Topic: 2. Trauma

A 75-year-old female with an indwelling total knee arthroplasty (TKA) sustains a periprosthetic supracondylar femur fracture (Lewis-Rorabeck Type II). The femoral component remains well-fixed. She is treated with a lateral locking plate. Which of the following technical factors most significantly increases the risk of implant failure and nonunion?

. Using a titanium plate instead of stainless steel
. Achieving an inadequate working length by placing too many screws near the fracture site
. Spanning the entire length of the femur with the plate
. Using unicortical locking screws at the level of the femoral component
. Performing the surgery using a minimally invasive submuscular technique

Correct Answer & Explanation

. Achieving an inadequate working length by placing too many screws near the fracture site

Explanation

In bridge plating of periprosthetic distal femur fractures, leaving an inadequate working length (screws placed too close to the fracture line) makes the construct overly stiff. This concentrates strain at the fracture site, leading to delayed union, nonunion, and ultimate plate breakage.

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