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2. Trauma MCQs

Practice Set 214 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 4261

Topic: 2. Trauma
Which of the following findings best describes the acetabular fracture shown in Figure 38?
. Posterior column with articular impaction and a free fragment
. Anterior column with articular impaction
. Posterior wall with an intra-articular fragment
. Posterior wall with articular impaction and a free intra-articular fragment
. Posterior wall with articular impaction

Correct Answer & Explanation

. Posterior wall with articular impaction and a free intra-articular fragment

Explanation

DISCUSSION: The CT scan shows a posterior wall fracture with impaction of the articular surface and a free fragment within the joint. Proper treatment of this injury requires not only reduction and fixation of the posterior wall fragment but also removal of the free fragment and elevation of the depressed articular segment.

Question 4262

Topic: Upper Extremity Trauma
A 28-year-old hockey player has a shoulder deformity after being checked into the boards. Examination reveals that swelling has improved, but there is tenderness along the distal clavicle. Radiographs reveal a grade II acromioclavicular joint separation. Initial management should consist of
. a sling, ice, and isometric exercises.
. a glenohumeral cortisone injection.
. surgical repair of the coracoclavicular ligaments.
. chin-ups and latissimus pull-down exercises.
. cross-chest stretches.

Correct Answer & Explanation

. a sling, ice, and isometric exercises.

Explanation

DISCUSSION: The most common shoulder injury in hockey players is to the acromioclavicular joint. Early rest and control of pain and inflammation is the preferred management. Surgery is reserved for patients with significant coracoclavicular disruption that has failed to respond to nonsurgical management. Cross-chest stretches and overhead exercises may increase symptoms. A cortisone injection within the glenohumeral joint will have little effect.

Question 4263

Topic: 2. Trauma
Figure 36 shows the radiograph of a 28-year-old man who injured his shoulder in a motocross race. Management should consist of
. sling and swathe immobilization.
. early mobilization and strengthening exercises.
. an airplane abduction orthosis.
. stabilization with percutaneous smooth pins.
. open stabilization with coracoclavicular ligament repair and reconstruction.

Correct Answer & Explanation

. open stabilization with coracoclavicular ligament repair and reconstruction.

Explanation

DISCUSSION: Fractures of the distal one third of the clavicle have a high incidence of delayed union (45% to 67%) and nonunion (22% to 33%) with nonsurgical management. Surgical stabilization with tension band techniques or a combination of plate and screw techniques is indicated, especially in young, active patients. In this patient, significant displacement of the fracture implies injury to the coracoclavicular ligaments with a higher risk of delayed union or nonunion. Various surgical treatments have been recommended, but the use of smooth wires is not indicated because of the potential for hardware migration.

Question 4264

Topic: 2. Trauma
A 55-year-old woman fell and sustained an elbow dislocation with a coronoid fracture and a radial head fracture. The elbow is reduced and splinted. What is the most common early complication?
. Brachial artery intimal tear
. Recurrent dislocation
. Forearm compartment syndrome
. Posterior interosseous nerve injury
. Ulnar nerve palsy

Correct Answer & Explanation

. Recurrent dislocation

Explanation

DISCUSSION: The patient has a dislocation of the elbow with displaced coronoid process and radial head fractures. The elbow is extremely unstable after this injury, and recurrent dislocation in a splint is the most common early complication. Skeletal stabilization of the fractures is required to restore stability of the joint. Characteristics of the fractures will determine the techniques required to restore stability.

Question 4265

Topic: 2. Trauma

A 45-year-old female presents with a high-energy Schatzker IV tibial plateau fracture. The fracture line includes a large coronal split of the medial plateau. Closed reduction is attempted but is unsuccessful due to a soft tissue block. Which of the following structures is most commonly entrapped in the fracture site in this specific fracture pattern?

. Medial collateral ligament
. Medial meniscus
. Anterior cruciate ligament
. Popliteus tendon
. Pes anserinus tendons

Correct Answer & Explanation

. Medial collateral ligament

Explanation

A Schatzker IV fracture involves the medial tibial plateau and is often caused by a varus stress combined with axial loading. The medial meniscus and the anterior horn or body can become entrapped within the fracture cleft, preventing anatomic closed reduction. Surgical intervention requires identifying and elevating the entrapped meniscus before reducing and stabilizing the medial plateau.

Question 4266

Topic: 2. Trauma

A 35-year-old male sustains a coronal shear fracture of the lateral femoral condyle (Hoffa fracture). When planning internal fixation, which of the following screw configurations provides the strongest biomechanical construct to resist shear forces?

. Two anterior-to-posterior (AP) directed 3.5mm cortical screws
. Two posterior-to-anterior (PA) directed 6.5mm cancellous lag screws
. Two posterior-to-anterior (PA) directed 3.5mm cortical lag screws
. An anterior-to-posterior (AP) directed lateral locked plate
. Two anterior-to-posterior (AP) directed 6.5mm headless compression screws

Correct Answer & Explanation

. Two anterior-to-posterior (AP) directed 3.5mm cortical screws

Explanation

Hoffa fractures (coronal shear fractures of the femoral condyle, OTA/AO 33-B3) require rigid anatomic fixation. Biomechanical studies have demonstrated that posterior-to-anterior (PA) directed screws are mechanically superior to AP directed screws because the anterior cortical bone of the distal femur is denser and thicker, providing superior thread purchase. Cortical screws placed in lag fashion are generally preferred over cancellous screws for shear fractures.

Question 4267

Topic: 2. Trauma

A 30-year-old male is undergoing intramedullary nailing for a proximal third tibia fracture. The fracture demonstrates an apex anterior (procurvatum) deformity during passage of the reamer. To prevent this malalignment, a Poller (blocking) screw should be placed in which of the following positions relative to the intramedullary nail?

. Posterior to the nail in the proximal fragment
. Anterior to the nail in the proximal fragment
. Medial to the nail in the proximal fragment
. Lateral to the nail in the proximal fragment
. Posterior to the nail in the distal fragment

Correct Answer & Explanation

. Posterior to the nail in the proximal fragment

Explanation

In proximal third tibia fractures, intramedullary nailing often results in an apex anterior (procurvatum) and valgus deformity. This occurs because the nail naturally tracks along the posterior cortex of the short proximal fragment. To prevent procurvatum, a Poller (blocking) screw should be placed posterior to the anticipated path of the nail in the proximal fragment. This forces the nail anteriorly, correcting the apex anterior deformity.

Question 4268

Topic: 2. Trauma

According to the Letournel and Judet classification, which of the following radiographic findings clearly differentiates a transverse-posterior wall acetabular fracture from a both-column acetabular fracture?

. Disruption of the iliopectineal line
. Disruption of the ilioischial line
. The presence of a 'spur sign'
. An intact segment of the articular surface remains attached to the intact ilium
. Involvement of the obturator ring

Correct Answer & Explanation

. Disruption of the iliopectineal line

Explanation

Both transverse-posterior wall fractures and both-column fractures disrupt all the major radiographic lines of the acetabulum (iliopectineal and ilioischial). The distinguishing feature of a both-column fracture is that no portion of the articular surface remains attached to the intact axial skeleton (iliac wing/SI joint). In contrast, in a transverse or transverse-posterior wall fracture, the superior portion of the articular surface (the roof) remains continuous with the intact ilium.

Question 4269

Topic: 2. Trauma
A 38-year-old male sustains a Gustilo-Anderson IIIB open fracture of the middle third of the tibial shaft. After aggressive debridement, there is a 6 x 4 cm anterior soft tissue defect with exposed bone void of periosteum. Which of the following is the most appropriate local flap option for coverage?
. Medial gastrocnemius rotational flap
. Lateral gastrocnemius rotational flap
. Soleus rotational flap
. Sural artery fasciocutaneous flap
. Reverse flow superficial circumflex iliac flap

Correct Answer & Explanation

. Soleus rotational flap

Explanation

Soft tissue coverage for the tibia is traditionally divided into thirds. The proximal third is best covered by a medial or lateral gastrocnemius flap. The middle third is best covered by a soleus rotational flap. The distal third generally lacks adequate local muscle bulk and usually requires a free tissue transfer (free flap).

Question 4270

Topic: 2. Trauma

A 45-year-old male sustains a highly comminuted fracture of the inferior pole of the patella that is not amenable to internal fixation. The surgeon performs a partial patellectomy with advancement and reattachment of the patellar tendon. What is the most significant biomechanical consequence of this procedure?

. Increased patellofemoral contact area, leading to decreased contact pressures
. Decreased moment arm of the extensor mechanism, requiring greater quadriceps force to extend the knee
. Increased mechanical advantage of the quadriceps muscle
. Posterior translation of the instantaneous center of rotation of the knee
. Significant increased risk of patella baja postoperatively

Correct Answer & Explanation

. Increased patellofemoral contact area, leading to decreased contact pressures

Explanation

Excision of the inferior pole of the patella effectively shortens the patella and brings the patellar tendon attachment closer to the center of rotation of the knee. This decreases the moment arm (lever arm) of the extensor mechanism. Consequently, the quadriceps must generate significantly more force to achieve knee extension, which subsequently increases patellofemoral joint reaction forces and contact pressures.

Question 4271

Topic: 2. Trauma

A 29-year-old male presents 9 months after intramedullary nailing of a midshaft femur fracture. He complains of persistent thigh pain. Radiographs demonstrate an oligotrophic nonunion with an intact intramedullary nail and no signs of hardware failure. Laboratory tests (ESR, CRP, WBC) are within normal limits. What is the most reliable definitive surgical treatment for this nonunion?

. Removal of the nail, aggressive reaming, and placement of a larger diameter intramedullary nail
. Dynamization of the current intramedullary nail by removing the proximal interlocking screws
. Plate augmentation leaving the current nail in place without bone grafting
. Removal of the nail and application of a multiplanar external fixator
. Pulsed electromagnetic field bone stimulation

Correct Answer & Explanation

. Removal of the nail, aggressive reaming, and placement of a larger diameter intramedullary nail

Explanation

Exchange nailing is the gold standard and most reliable treatment for an aseptic, oligotrophic, or hypertrophic diaphyseal nonunion of the femur. It involves removing the existing nail, aggressively reaming the canal (which provides local autograft), and inserting a larger-diameter nail. Dynamization is generally only effective if performed early (e.g., 12-24 weeks) in axially stable fracture patterns and is less reliable for established oligotrophic nonunions at 9 months.

Question 4272

Topic: 2. Trauma

A 25-year-old polytrauma patient arrives with bilateral closed femoral shaft fractures, multiple rib fractures, and bilateral pulmonary contusions. Which of the following clinical parameters most strongly indicates the need for damage control orthopedics (temporary external fixation) rather than early definitive intramedullary nailing?

. Arterial pH of 7.38
. Lactate level of 1.5 mmol/L
. Base deficit of 8 mEq/L
. Temperature of 36.5°C
. Urine output of 1.5 mL/kg/hr

Correct Answer & Explanation

. Arterial pH of 7.38

Explanation

In a polytrauma patient, borderline or unstable physiological status favors damage control orthopedics (DCO) to avoid the 'second hit' of systemic inflammation associated with reaming and intramedullary nailing. Criteria indicating a 'borderline' or unstable patient who would benefit from DCO include: Base deficit > 6 mEq/L, Lactate > 2.5 mmol/L, pH < 7.25, temperature < 35°C, or significant coagulopathy/pulmonary compromise.

Question 4273

Topic: 2. Trauma

A 32-year-old male is admitted after suffering a severe crush injury to his right thigh. Which parameter is considered the most accurate threshold for diagnosing acute compartment syndrome of the thigh and proceeding to immediate fasciotomy?

. Absolute compartment pressure > 20 mmHg
. Absolute compartment pressure > 30 mmHg
. Diastolic blood pressure minus compartment pressure (Delta P) < 30 mmHg
. Mean arterial pressure minus compartment pressure < 45 mmHg
. Loss of palpable pulses in the ipsilateral extremity

Correct Answer & Explanation

. Absolute compartment pressure > 20 mmHg

Explanation

The Delta P (diastolic blood pressure minus the absolute compartment pressure) is the most accurate diagnostic parameter for acute compartment syndrome. A Delta P of less than 30 mmHg indicates inadequate capillary perfusion pressure and is an absolute indication for emergency fasciotomy. Absolute pressure > 30 mmHg can lead to overdiagnosis, especially in hypertensive patients, whereas Delta P accounts for the patient's systemic perfusion pressure. Loss of pulses is a very late and often irreversible sign.

Question 4274

Topic: Lower Extremity Trauma

A 19-year-old sustains a high-energy knee dislocation. During evaluation in the emergency department, the knee is completely irreducible despite multiple closed attempts under procedural sedation. The skin over the anteromedial aspect of the knee exhibits a pronounced 'dimple sign' (transverse furrow). What is the specific anatomic cause of this irreducibility?

. Entrapment of the patella within the intercondylar notch
. Buttonholing of the medial femoral condyle through the anteromedial capsule
. Interposition of the torn anterior cruciate ligament stump in the joint
. Dislocation of the fibular head locking the lateral structures
. Entrapment of the popliteal artery behind the tibial plateau

Correct Answer & Explanation

. Entrapment of the patella within the intercondylar notch

Explanation

The 'dimple sign' or transverse furrow across the anteromedial joint line in a posterolateral knee dislocation indicates an irreducible dislocation. This is caused by the medial femoral condyle buttonholing through the anteromedial capsule, medial retinaculum, or vastus medialis. The capsule becomes interposed between the tibia and femur, preventing closed reduction and mandating open surgical reduction.

Question 4275

Topic: Lower Extremity Trauma

A 45-year-old female presents with a Schatzker IV tibial plateau fracture featuring a large posteromedial fragment. A posteromedial surgical approach is planned for buttress plating. 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 pes anserinus tendons
. Between the medial collateral ligament and the pes anserinus
. Between the popliteus muscle and the soleus

Correct Answer & Explanation

. Between the medial head of the gastrocnemius and the soleus

Explanation

The classic posteromedial approach to the tibial plateau utilizes the interval between the pes anserinus (sartorius, gracilis, semitendinosus) anteriorly and the medial head of the gastrocnemius posteriorly. Retracting the medial gastrocnemius posteriorly protects the neurovascular bundle in the popliteal fossa.

Question 4276

Topic: 2. Trauma

A 35-year-old male sustains a coronal plane fracture of the lateral femoral condyle (Hoffa fracture). Open reduction and internal fixation is planned using lag screws. To maximize biomechanical stability and pullout strength, what is the optimal trajectory for the lag screws?

. Anterior to Posterior (A-P)
. Posterior to Anterior (P-A)
. Medial to Lateral
. Lateral to Medial
. Proximal to Distal

Correct Answer & Explanation

. Anterior to Posterior (A-P)

Explanation

Biomechanical studies have demonstrated that Posterior-to-Anterior (P-A) lag screws provide superior stability and pullout strength for lateral Hoffa fractures compared to A-P screws. This is because P-A screws engage the thicker, denser anterior metaphyseal bone of the distal femur, whereas A-P screws end in the relatively thin, osteoporotic posterior condylar bone.

Question 4277

Topic: 2. Trauma

A 35-year-old male sustains a transverse patella fracture and is treated with tension band wiring. For the tension band principle to successfully convert tensile forces into compressive forces at the articular surface during knee flexion, where must the implant be placed?

. On the articular (posterior) surface of the patella
. In the exact center of the patella
. On the anterior surface of the patella
. Circumferentially around the equator of the patella
. Transversely through the mid-substance

Correct Answer & Explanation

. On the articular (posterior) surface of the patella

Explanation

The tension band principle relies on placing the fixation implant on the tension side of a fractured bone to convert tensile distraction forces into articular compressive forces. In the patella, knee flexion creates tension anteriorly and compression posteriorly. Thus, placing the wire on the anterior surface is critical for the construct to function properly.

Question 4278

Topic: 2. Trauma
A 14-year-old male basketball player sustains an Ogden Type III tibial tubercle avulsion fracture (fracture extending into the proximal tibial physis and articular surface). Which of the following is the most feared and potentially devastating early complication associated with this specific injury?
. Genu recurvatum
. Patella baja
. Compartment syndrome
. Popliteal artery tear
. Tibial nonunion

Correct Answer & Explanation

. Compartment syndrome

Explanation

Tibial tubercle avulsion fractures, particularly in adolescents (Ogden III), are highly associated with anterior compartment syndrome. This occurs due to tearing of the recurrent anterior tibial artery, which bleeds into the relatively tight anterior compartment. Vigilant neurovascular monitoring is essential.

Question 4279

Topic: 2. Trauma

A 24-year-old soccer player sustains a twisting injury to the knee. An AP radiograph shows a small elliptic avulsion fracture off the lateral aspect of the proximal tibia just distal to the joint line. This 'Segond fracture' represents an avulsion of which structure?

. Biceps femoris tendon
. Iliotibial band
. Anterolateral ligament (ALL) / capsular complex
. Fibular collateral ligament
. Popliteus tendon

Correct Answer & Explanation

. Biceps femoris tendon

Explanation

A Segond fracture is an avulsion fracture of the lateral tibial plateau, pathognomonic for an Anterior Cruciate Ligament (ACL) tear. It represents an avulsion of the anterolateral capsular complex, notably the Anterolateral Ligament (ALL) and the meniscotibial ligament.

Question 4280

Topic: 2. Trauma

When treating a highly comminuted distal femur fracture with a lateral locking plate using a bridge plating technique, which of the following construct modifications best decreases construct stiffness and promotes secondary bone healing?

. Leaving empty screw holes directly adjacent to the fracture gap
. Filling every screw hole in the plate
. Using shorter mono-cortical screws throughout
. Placing a lag screw directly through the plate
. Using a much thicker stainless steel plate instead of titanium

Correct Answer & Explanation

. Leaving empty screw holes directly adjacent to the fracture gap

Explanation

In bridge plating of comminuted fractures, relative stability is desired to promote secondary bone healing (callus formation). Decreasing construct stiffness allows for interfragmentary micromotion. This is achieved primarily by increasing the 'working length' of the plate, which is done by leaving screw holes empty immediately adjacent to the fracture gap.

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