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2. Trauma MCQs

Practice Set 215 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 4281

Topic: 2. Trauma

During a high-energy knee trauma, the popliteal artery is at high risk of traction injury. Anatomically, this vessel is uniquely susceptible because it is securely tethered at two primary locations proximally and distally. These two locations are the:

. Adductor hiatus and soleal arch
. Popliteal fossa and medial head of the gastrocnemius
. Posterior capsule and popliteus muscle belly
. Common peroneal nerve sheath and fibular neck
. Biceps femoris and semimembranosus insertions

Correct Answer & Explanation

. Adductor hiatus and soleal arch

Explanation

The popliteal artery is fixed proximally at the adductor hiatus (exiting Hunter's canal) and distally at the fibrous arch of the soleus. Because it is securely tethered between these two points, it has very little mobility to accommodate extreme displacements (like a knee dislocation), making it highly vulnerable to traction tears and intimal damage.

Question 4282

Topic: 2. Trauma
A 30-year-old male presents following a motorcycle accident. Radiographs reveal ipsilateral fractures of the femoral shaft and an intra-articular tibial plateau fracture. According to the Fraser classification of floating knee injuries, this represents a:
. Type I
. Type IIa
. Type IIb
. Type IIc
. Type III

Correct Answer & Explanation

. Type IIa

Explanation

The Fraser classification for floating knees: Type I = extra-articular femur and extra-articular tibia. Type IIa = extra-articular femur and intra-articular tibia. Type IIb = intra-articular femur and extra-articular tibia. Type IIc = intra-articular femur and intra-articular tibia.

Question 4283

Topic: 2. Trauma
Which of the following descriptions accurately characterizes a Letenneur Type I fracture of the distal femur?
. Extra-articular supracondylar distal femur fracture
. Vertical coronal fracture of the posterior femoral condyle extending from the posterior cortex to the distal articular surface
. Small osteochondral posterior condylar fragment
. Sagittal split of the medial condyle
. Coronal fracture of the anterior trochlea

Correct Answer & Explanation

. Vertical coronal fracture of the posterior femoral condyle extending from the posterior cortex to the distal articular surface

Explanation

The Letenneur classification describes coronal plane (Hoffa) fractures of the distal femur. Type I is a vertical fracture involving the entire condyle, parallel to the posterior cortex. Type II is a smaller fragment parallel to the base of the condyle. Type III is an oblique fracture line.

Question 4284

Topic: 2. Trauma
Among the different patterns of tibial plateau fractures described by the Schatzker classification, which pattern is classically associated with the highest risk of acute compartment syndrome?
. Schatzker I
. Schatzker II
. Schatzker III
. Schatzker IV
. Schatzker VI

Correct Answer & Explanation

. Schatzker VI

Explanation

Schatzker VI fractures involve a bicondylar plateau fracture with complete metaphyseal-diaphyseal dissociation. These are severe, high-energy injuries that result in significant soft tissue trauma and bleeding, carrying the highest risk (up to 20%) of acute compartment syndrome among tibial plateau fractures.

Question 4285

Topic: 2. Trauma

A 30-year-old male sustains a high-energy axial load injury to a flexed knee during a motorcycle collision. CT imaging reveals a coronal shear fracture of the lateral femoral condyle (Hoffa fracture). When planning internal fixation, which of the following constructs provides the greatest biomechanical stability for this specific fracture pattern?

. Anterior-to-posterior oriented cancellous lag screws
. Posterior-to-anterior oriented cancellous lag screws
. Lateral anatomically contoured locking plate alone without lag screws
. Medial parapatellar approach with a crossed smooth Kirschner wire construct
. External fixation spanning the knee joint

Correct Answer & Explanation

. Anterior-to-posterior oriented cancellous lag screws

Explanation

A Hoffa fracture is a coronal shear fracture of the distal femoral condyle (most commonly lateral). Biomechanical studies demonstrate that posterior-to-anterior (PA) directed lag screws provide significantly greater pull-out strength and stability compared to anterior-to-posterior (AP) directed screws, due to the denser bone in the anterior metaphysis and the mechanical advantage against the predominant shear forces.

Question 4286

Topic: Lower Extremity Trauma

A 45-year-old female presents with a Schatzker IV tibial plateau fracture involving a large, displaced posteromedial articular fragment. The surgeon plans an open reduction and internal fixation via a posteromedial approach. To safely access the posterior column of the tibial plateau, the surgical interval is developed between which two structures?

. The medial head of the gastrocnemius and the soleus
. The medial head of the gastrocnemius and the pes anserinus/semimembranosus
. The lateral head of the gastrocnemius and the biceps femoris
. The popliteus muscle substance and the posterolateral corner
. The sartorius and the gracilis

Correct Answer & Explanation

. The medial head of the gastrocnemius and the soleus

Explanation

The posteromedial approach to the tibial plateau is performed utilizing the internervous/intermuscular interval between the medial head of the gastrocnemius (retracted laterally with the neurovascular bundle) and the pes anserinus tendons/semimembranosus (retracted medially). This allows direct visualization and buttress plating of posteromedial shear fragments.

Question 4287

Topic: 2. Trauma

A 78-year-old female with a well-fixed total knee arthroplasty (TKA) sustains a periprosthetic distal femur fracture (Lewis-Rorabeck Type II). She is treated with a lateral locked plating construct. Which of the following technical errors is most likely to increase the risk of aseptic nonunion in this scenario?

. Use of titanium plates rather than stainless steel
. Decreased plate working length by filling all screw holes directly adjacent to the fracture
. Use of far-cortical locking screws
. Spanning the fracture site to achieve relative stability without primary compression
. Using a plate that spans the entire length of the femur

Correct Answer & Explanation

. Use of titanium plates rather than stainless steel

Explanation

Locked plating constructs rely on relative stability to promote secondary bone healing via callus formation. Decreasing the plate 'working length' (the distance between the two innermost screws closest to the fracture on either side) makes the construct overly rigid. This severely limits interfragmentary micro-motion, which is necessary for callus formation, ultimately increasing the risk of nonunion and subsequent implant failure.

Question 4288

Topic: 2. Trauma

A 35-year-old male undergoes a dual-incision (anterolateral and posteromedial) fasciotomy for acute compartment syndrome of the lower leg following a high-energy Schatzker VI tibial plateau fracture. Despite the procedure, he has persistent, excruciating pain with passive extension of the great toe. Which compartment was most likely inadequately decompressed?

. Anterior compartment
. Lateral compartment
. Superficial posterior compartment
. Deep posterior compartment
. Peroneal compartment

Correct Answer & Explanation

. Anterior compartment

Explanation

Pain with passive extension of the great toe (stretching the flexor hallucis longus) or toes (flexor digitorum longus) indicates ischemia in the deep posterior compartment. The deep posterior compartment is the most commonly missed or inadequately released compartment during a dual-incision fasciotomy, usually because the surgeon fails to adequately detach the soleus bridge from the posteromedial border of the tibia.

Question 4289

Topic: 2. Trauma

A proximal third extra-articular tibia fracture is treated with an intramedullary nail using a traditional superior parapatellar approach. Due to the inherent muscular forces on the proximal fragment, what is the most common resultant malalignment post-operatively?

. Apex posterior (recurvatum) and varus
. Apex posterior (recurvatum) and valgus
. Apex anterior (procurvatum) and varus
. Apex anterior (procurvatum) and valgus
. Pure axial shortening without angulation

Correct Answer & Explanation

. Apex posterior (recurvatum) and varus

Explanation

Proximal third tibia fractures treated with standard intramedullary nailing have a notorious tendency to fall into apex anterior (procurvatum) and valgus deformity. The apex anterior deformity is caused by the pull of the patellar tendon on the proximal fragment, while the valgus deformity is partly due to the broad unconstrained metaphyseal bone, lateral start points, and sometimes the pull of the IT band/pes anserinus. Strategies like suprapatellar nailing, blocking screws, or semi-extended positioning help prevent this.

Question 4290

Topic: 2. Trauma

A 32-year-old male sustains an ipsilateral femur fracture and tibia fracture (floating knee) during a high-speed motor vehicle collision. Compared to isolated lower extremity fractures, a floating knee injury carries a significantly higher rate (up to 50%) of which of the following occult, but crucial, local associated injuries?

. Compartment syndrome of the thigh
. Sciatic nerve complete transection
. Ipsilateral knee ligamentous disruption
. Popliteal artery complete transection
. Patellar tendon avulsion from the tibial tubercle

Correct Answer & Explanation

. Ipsilateral knee ligamentous disruption

Explanation

Patients with a floating knee (ipsilateral fractures of the femur and tibia, Blake and McBryde / Fraser classification) sustain massive energy transfer through the limb. The incidence of associated knee ligament injuries (especially ACL, PCL, and collaterals) in floating knee injuries is exceptionally high, reported to be up to 50%. These ligamentous injuries are often initially missed due to the distraction of the adjacent gross fractures.

Question 4291

Topic: 2. Trauma
A 12-year-old male sustains a Salter-Harris II fracture of the distal femur due to a severe hyperextension injury. The distal metaphyseal fragment is displaced anteriorly. What is the classic reduction maneuver for this fracture pattern in the emergency department?
. Knee extension with posterior translation of the distal fragment
. Knee flexion with anterior translation of the distal fragment
. Knee extension with longitudinal traction only
. Hyperflexion with varus stress
. Longitudinal traction with internal rotation

Correct Answer & Explanation

. Knee flexion with anterior translation of the distal fragment

Explanation

In distal femur physeal fractures resulting from hyperextension, the distal fragment is displaced anteriorly. To reduce an anteriorly displaced distal fragment, the knee is typically flexed to relax the gastrocnemius, and the fragment is translated posteriorly. Note: The provided options are limited, but the standard reduction for an anteriorly displaced distal fragment involves flexion and posterior translation.

Question 4292

Topic: 2. Trauma
A 40-year-old male sustains a Gustilo-Anderson Type IIIB open fracture of the proximal third of the tibia with a massive soft tissue defect and exposed bone. After adequate serial debridements, the orthoplastic team plans soft tissue coverage. Which of the following is the most appropriate local muscle flap for this specific location?
. Soleus rotational flap
. Medial gastrocnemius rotational flap
. Sural artery fasciocutaneous flap
. Anterolateral thigh free flap
. Reverse sural flap

Correct Answer & Explanation

. Medial gastrocnemius rotational flap

Explanation

For soft tissue coverage of exposed bone in the tibia, local rotational muscle flaps are chosen based on the third of the leg involved. The medial gastrocnemius rotational flap is the workhorse for proximal-third tibia defects. The soleus flap is used for middle-third defects. Distal-third defects typically lack adequate local muscle bulk and require free tissue transfer.

Question 4293

Topic: 2. Trauma

A 35-year-old male sustains an isolated coronal shear fracture of the lateral femoral condyle (Hoffa fracture). Which anatomical structure's origin is located on the posterior aspect of this osteochondral fragment and acts as a primary deforming force?

. Plantaris
. Popliteus
. Lateral head of the gastrocnemius
. Soleus
. Short head of the biceps femoris

Correct Answer & Explanation

. Lateral head of the gastrocnemius

Explanation

The lateral head of the gastrocnemius originates on the posterior aspect of the lateral femoral condyle. Its pull acts as a primary deforming force in lateral Hoffa fractures, often displacing the osteochondral fragment posteriorly and inferiorly.

Question 4294

Topic: 2. Trauma
A 10-year-old boy falls from a bicycle and sustains a displaced Meyers and McKeever Type III tibial eminence fracture. A closed reduction is attempted but fails due to a soft tissue block. Which anatomical structure is most commonly incarcerated beneath the fragment?
. Anterior horn of the lateral meniscus
. Anterior horn of the medial meniscus
. Posterior cruciate ligament stump
. Infrapatellar plica
. Superficial medial collateral ligament

Correct Answer & Explanation

. Anterior horn of the lateral meniscus

Explanation

In displaced tibial eminence fractures (Type II and III), the anterior horn of the lateral meniscus or the transverse intermeniscal ligament frequently becomes entrapped beneath the bony fragment, physically blocking a successful closed reduction.

Question 4295

Topic: 2. Trauma

A 68-year-old female sustains a comminuted distal femur fracture. A lateral locking plate is applied using minimally invasive techniques. Which of the following biomechanical modifications will best promote secondary bone healing by decreasing construct stiffness?

. Using a shorter plate to minimize the working length
. Filling every screw hole in the plate to maximize fixation
. Using far-cortical locking screws in the diaphyseal segment
. Placing the plate at a minimum distance of 1 cm from the bone
. Using rigid titanium cables around the fracture site

Correct Answer & Explanation

. Using far-cortical locking screws in the diaphyseal segment

Explanation

Far-cortical locking screws reduce the stiffness of locking plate constructs by allowing parallel interfragmentary motion. This symmetric micromotion promotes robust secondary bone healing and callus formation, reducing the risk of nonunion.

Question 4296

Topic: Pelvic & Acetabular Trauma
A 22-year-old male is admitted after a motorcycle accident with an anterior-posterior compression (APC) type III pelvic ring injury and remains hemodynamically unstable despite initial fluid resuscitation and pelvic binder application. Pelvic angiography is performed. Which vascular structure is most likely the source of arterial bleeding in this specific injury pattern?
. Superior gluteal artery
. Internal pudendal artery
. External iliac artery
. Femoral artery
. Inferior mesenteric artery

Correct Answer & Explanation

. Internal pudendal artery

Explanation

In APC pelvic fractures, the anterior ring disruption most commonly injures anterior branches of the internal iliac artery, particularly the internal pudendal and obturator arteries. Conversely, lateral compression or vertical shear fractures more commonly injure the superior gluteal artery.

Question 4297

Topic: 2. Trauma

A 32-year-old male suffers a highly comminuted closed tibia fracture. Progressive leg pain and pain on passive toe stretch raise suspicion for acute compartment syndrome. Intracompartmental pressures are measured. What is the generally accepted threshold (Delta P) for performing a fasciotomy?

. Absolute compartment pressure > 15 mmHg
. Systolic blood pressure minus compartment pressure < 45 mmHg
. Mean arterial pressure minus compartment pressure < 40 mmHg
. Diastolic blood pressure minus compartment pressure < 30 mmHg
. Absolute compartment pressure > 20 mmHg regardless of blood pressure

Correct Answer & Explanation

. Diastolic blood pressure minus compartment pressure < 30 mmHg

Explanation

The Delta P value, defined as the diastolic blood pressure minus the intracompartmental pressure, is the most reliable indicator for compartment syndrome. A Delta P of less than 30 mmHg represents critical tissue ischemia and is an absolute indication for emergency fasciotomy.

Question 4298

Topic: Lower Extremity Trauma

An 8-year-old boy presents with a painless snapping sensation in his lateral knee. MRI reveals a discoid lateral meniscus of the Wrisberg variant. What distinguishes the Wrisberg variant from the complete and incomplete types of discoid menisci?

. It covers the entire tibial plateau articular surface
. It is always associated with a congenital ACL deficiency
. It lacks the normal posterior meniscotibial capsular attachments
. It has an anomalous attachment to the medial femoral condyle
. It only occurs in the medial compartment of the knee

Correct Answer & Explanation

. It lacks the normal posterior meniscotibial capsular attachments

Explanation

The Wrisberg variant of the discoid meniscus is abnormally mobile because it lacks the normal posterior meniscotibial (coronary ligament) attachments. It is anchored posteriorly only by the meniscofemoral ligament of Wrisberg, leading to a hypermobile, snapping meniscus.

Question 4299

Topic: 2. Trauma

A 35-year-old female sustains a high-energy trauma resulting in a coronal shear fracture of the femoral condyle (Hoffa fracture). Which anatomical location is most commonly affected by this fracture pattern, and why?

. Lateral condyle, due to physiological valgus of the knee
. Medial condyle, due to physiological varus of the knee
. Medial condyle, due to the larger size of the medial plateau
. Lateral condyle, due to direct pull of the fibular collateral ligament
. Bilateral condyles simultaneously, due to the extensor mechanism force

Correct Answer & Explanation

. Lateral condyle, due to physiological valgus of the knee

Explanation

Hoffa fractures most commonly involve the lateral femoral condyle. This is due to the physiological valgus alignment of the knee, which directs axial and shear forces predominantly through the lateral compartment during impact.

Question 4300

Topic: 2. Trauma

A 72-year-old female with a 10-year history of alendronate use presents with thigh pain and a subsequent low-energy subtrochanteric femur fracture. Which of the following radiographic features is classically associated with an atypical femur fracture secondary to bisphosphonates?

. Extensive comminution of the medial cortex
. Transverse or short oblique fracture line with lateral cortical thickening (beaking)
. Spiral fracture line extending distally into the diaphysis
. Significant osteopenia isolated to the ipsilateral hip
. Associated complete disruption of the lesser trochanter

Correct Answer & Explanation

. Transverse or short oblique fracture line with lateral cortical thickening (beaking)

Explanation

Atypical femur fractures associated with prolonged bisphosphonate use characteristically present as transverse or short oblique fractures with a medial spike. They are typically preceded by localized periosteal thickening or "beaking" of the lateral cortex.

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