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2. Trauma MCQs

Practice Set 457 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 9121

Topic: Lower Extremity Trauma

A 12-year-old boy presents with limited knee range of motion and aching pain. Imaging is shown below, demonstrating a protruding bone mass extending into the popliteal fossa. The mass originates from the epiphysis. What is the estimated incidence of this specific developmental disorder?




. 1 in 10,000
. 1 in 100,000
. 1 in 1,000,000
. 1 in 10,000,000

Correct Answer & Explanation

. 1 in 1,000,000

Explanation

Correct Answer: 1 in 1,000,000The images demonstrate DEH of the distal femur. Dysplasia epiphysealis hemimelica is a very rare skeletal developmental disorder with an estimated incidence of 1 in 1,000,000.

Question 9122

Topic: 2. Trauma

A 5-year-old boy is evaluated for a bony mass around the knee. Which of the following is NOT a typical presenting symptom of Dysplasia Epiphysealis Hemimelica (DEH)?

. Bone-hard mass
. Joint deformity
. Aching pains
. Limited range of motion
. Pathological fracture

Correct Answer & Explanation

. Pathological fracture

Explanation

Correct Answer: Pathological fractureThe most common presenting symptoms of DEH include the presence of a mass with the consistency of bone, joint deformity, aching pains, and limited range of motion. Pathological fractures are not a typical presenting feature of this condition.

Question 9123

Topic: Lower Extremity Trauma

In a patient with Dysplasia Epiphysealis Hemimelica of the distal femur, what advanced imaging modality is considered the gold standard for evaluating the extent of the unossified cartilaginous cap and its relationship to the articular surface prior to surgery?

. Computed Tomography (CT) without contrast
. Technetium-99m bone scan
. Magnetic Resonance Imaging (MRI)
. Positron Emission Tomography (PET)
. Diagnostic Ultrasound

Correct Answer & Explanation

. Magnetic Resonance Imaging (MRI)

Explanation

MRI is the most useful imaging modality for DEH because it clearly delineates the radiolucent cartilaginous cap. It precisely shows the lesion's relationship with the normal epiphysis and articular cartilage.

Question 9124

Topic: 2. Trauma

Which of the following is the most common anatomic location for the development of Dysplasia Epiphysealis Hemimelica (Trevor disease)?

. Proximal humerus
. Distal femur
. Proximal ulna
. Distal radius
. Proximal femur

Correct Answer & Explanation

. Distal femur

Explanation

Dysplasia Epiphysealis Hemimelica most commonly involves the lower extremities in over 85% of cases. The distal femur, proximal tibia, and talus are the most frequently affected sites.

Question 9125

Topic: Lower Extremity Trauma

A 5-year-old boy is diagnosed with symptomatic Dysplasia Epiphysealis Hemimelica of the distal femur. Surgical intervention is planned. Which imaging modality is most critical for preoperative evaluation of the unossified cartilaginous extent of the lesion and joint congruity?

. Computed Tomography (CT)
. Magnetic Resonance Imaging (MRI)
. Technetium-99m Bone Scan
. Positron Emission Tomography (PET)
. Ultrasound

Correct Answer & Explanation

. Magnetic Resonance Imaging (MRI)

Explanation

MRI is the imaging modality of choice for DEH because it accurately delineates the unossified cartilaginous cap. It helps determine the extent of joint involvement and aids in preoperative planning.

Question 9126

Topic: Lower Extremity Trauma

An 8-year-old boy presents with a bony prominence over the medial aspect of the knee. Radiographs reveal an irregular, multi-lobulated ossified mass arising from the medial epiphysis of the distal femur.

If surgical intervention is planned, which advanced imaging modality is most critical for accurately evaluating the unossified cartilaginous cap and joint congruity prior to excision?

. Positron Emission Tomography (PET)
. Computed Tomography (CT) without contrast
. Magnetic Resonance Imaging (MRI)
. Triple-phase bone scan
. Diagnostic ultrasound

Correct Answer & Explanation

. Magnetic Resonance Imaging (MRI)

Explanation

MRI is the imaging modality of choice for surgical planning in DEH. It accurately delineates the extent of the unossified cartilaginous cap, assesses the integrity of the surrounding articular cartilage, and helps surgeons plan an excision that avoids disrupting normal joint structures.

Question 9127

Topic: 2. Trauma

When utilizing the 'lengthening over a nail' (LON) technique for lower extremity deformity correction, what is the primary biomechanical and clinical advantage over traditional isolated Ilizarov lengthening?

. Allows for immediate full weight-bearing during distraction
. Decreases the total duration of external fixation and risk of regenerate fracture
. Eliminates the need for a corticotomy
. Reduces the rate of deep intramedullary infection compared to isolated external fixation
. Increases the speed of distraction to 2.0 mm per day

Correct Answer & Explanation

. Decreases the total duration of external fixation and risk of regenerate fracture

Explanation

The LON technique allows the external fixator to be removed immediately after the distraction phase is complete, relying on the intramedullary nail for stability during consolidation. This significantly reduces the external fixator index time and prevents axial deviation or fracture of the regenerate.

Question 9128

Topic: Lower Extremity Trauma

Mechanical Axis Deviation (MAD) of the lower extremity is standardly defined as:

. The angle between the anatomical and mechanical axes of the femur
. The perpendicular distance from the center of the knee joint to the mechanical axis line
. The intersection of the joint orientation lines of the femur and tibia
. The difference between the medial proximal tibial angle and lateral distal femoral angle
. The distance from the tibial plateau to the tibial tubercle

Correct Answer & Explanation

. The perpendicular distance from the center of the knee joint to the mechanical axis line

Explanation

MAD is quantified by drawing the mechanical axis line from the center of the femoral head to the center of the ankle mortise. The perpendicular distance from this line to the center of the knee joint determines the magnitude of the deviation.

Question 9129

Topic: Lower Extremity Trauma

A 45-year-old patient presents with knee pain and a 10-degree valgus alignment. Radiographs reveal a mechanical Lateral Distal Femoral Angle (mLDFA) of 81 degrees and a medial Proximal Tibial Angle (mPTA) of 87 degrees. What is the most appropriate corrective osteotomy?

. Medial opening-wedge high tibial osteotomy
. Lateral closing-wedge high tibial osteotomy
. Medial closing-wedge distal femoral osteotomy
. Distal tibial osteotomy
. Focal dome osteotomy of the tibial tubercle

Correct Answer & Explanation

. Medial closing-wedge distal femoral osteotomy

Explanation

The normal mLDFA is approximately 87 degrees and normal mPTA is 87 degrees. An mLDFA of 81 degrees indicates the valgus deformity is located entirely in the distal femur, requiring a distal femoral osteotomy.

Question 9130

Topic: Lower Extremity Trauma

A patient with a severe mechanical axis deviation is evaluated for deformity correction. Radiographs demonstrate a mechanical Lateral Distal Femoral Angle (mLDFA) of 98 degrees and a Medial Proximal Tibial Angle (MPTA) of 87 degrees. What is the primary source of the patient's deformity?

. Proximal tibia valgus
. Distal femur varus
. Distal femur valgus
. Proximal tibia varus
. Intra-articular ligamentous laxity

Correct Answer & Explanation

. Distal femur varus

Explanation

A normal mLDFA is approximately 85 to 90 degrees. An mLDFA of 98 degrees indicates a significant varus deformity of the distal femur, while the MPTA of 87 degrees falls within normal limits.

Question 9131

Topic: Lower Extremity Trauma

When evaluating a patient for lower extremity deformity correction, how is the mechanical axis deviation (MAD) objectively measured on standing full-length anteroposterior radiographs?

. The angle between the anatomical axis of the femur and the anatomical axis of the tibia
. The perpendicular distance from the center of the knee joint to the mechanical axis line connecting the center of the femoral head to the center of the ankle
. The angle formed by the intersection of the mechanical axis of the femur and the mechanical axis of the tibia
. The distance between the center of the tibial plateau and the mechanical axis of the femur
. The angle between the joint line of the knee and the ground

Correct Answer & Explanation

. The perpendicular distance from the center of the knee joint to the mechanical axis line connecting the center of the femoral head to the center of the ankle

Explanation

Mechanical axis deviation (MAD) is measured in millimeters as the perpendicular distance from the center of the knee joint to the mechanical axis of the entire lower extremity. A medial MAD indicates varus, while a lateral MAD indicates valgus.

Question 9132

Topic: Lower Extremity Trauma

A 45-year-old active patient with symptomatic isolated lateral compartment osteoarthritis and a mechanical valgus alignment of 12 degrees undergoes a medial closing-wedge distal femoral osteotomy. Which of the following is an expected biomechanical outcome of this specific osteotomy technique compared to a lateral opening-wedge technique?

. Increased ipsilateral leg length
. Decreased ipsilateral leg length
. Increased tension on the iliotibial band
. Distalization of the patella relative to the joint line
. Increased posterior tibial slope

Correct Answer & Explanation

. Decreased ipsilateral leg length

Explanation

A medial closing-wedge osteotomy of the distal femur inherently removes bone, leading to a shortening of the leg. Conversely, a lateral opening-wedge osteotomy adds length to the lateral column, generally increasing total leg length.

Question 9133

Topic: Lower Extremity Trauma



When performing a primary TKA on a patient with a significant diaphyseal varus bowing of the femur, utilizing a standard intramedullary alignment rod that traverses the entire diaphysis without accounting for the bow will most likely result in which of the following errors?

. Excessive valgus cut of the distal femur
. Excessive varus cut of the distal femur
. Excessive extension of the femoral component
. Excessive flexion of the femoral component
. Anterior notching of the distal femur

Correct Answer & Explanation

. Excessive valgus cut of the distal femur

Explanation

A long intramedullary rod placed in a femur with a coronal varus bow will align laterally at its distal end. If the standard valgus angle is dialed in based on this malaligned rod, the resulting distal femoral cut will be in excessive valgus.

Question 9134

Topic: Lower Extremity Trauma

The Paley multiplier method is frequently used to predict limb length discrepancy at skeletal maturity. This predictive method is primarily based on which of the following parameters?

. The patient's current height percentile plotted on CDC growth charts
. Skeletal age determined strictly by the Greulich and Pyle atlas
. Chronological age-specific coefficients
. Extrapolation of previous longitudinal radiographic measurements
. The Green-Anderson remaining growth charts for the distal femur

Correct Answer & Explanation

. Chronological age-specific coefficients

Explanation

The Paley multiplier method simplifies limb length discrepancy prediction by using chronologic age-specific coefficients (multipliers). The current bone length or discrepancy is multiplied by this coefficient to estimate the ultimate measurement at maturity.

Question 9135

Topic: 2. Trauma

A 2-year-old child with NF1 presents with anterolateral bowing of the tibia and an impending fracture as seen in the clinical and radiographic image.

What is the gold standard surgical principle for managing established tibial pseudoarthrosis in this condition?

. Casting until skeletal maturity
. Resection and circular external fixation alone
. Resection of the pseudoarthrosis, intramedullary fixation, and bone grafting
. Plate osteosynthesis without resection
. Early amputation

Correct Answer & Explanation

. Resection of the pseudoarthrosis, intramedullary fixation, and bone grafting

Explanation

Congenital pseudoarthrosis of the tibia in NF1 requires aggressive management. Successful treatment involves complete resection of the hamartomatous tissue, robust intramedullary fixation, and extensive bone grafting.

Question 9136

Topic: 2. Trauma
An 8-month-old infant with multiple café-au-lait spots is noted to have isolated anterolateral bowing of the tibia. Radiographs confirm a dysplastic tibia without a fracture. What is the recommended initial management to alter the natural history of this condition?
. Observation, as this specific deformity typically resolves spontaneously.
. Immediate prophylactic intramedullary rodding.
. Application of a total contact orthosis (e.g., clamshell brace).
. Epiphysiodesis of the contralateral limb to prevent leg length discrepancy.
. Surgical excision of the thickened periosteum with bone grafting.

Correct Answer & Explanation

. Application of a total contact orthosis (e.g., clamshell brace).

Explanation

Anterolateral bowing in NF1 signals impending congenital pseudarthrosis of the tibia (CPT). Before a fracture occurs, standard initial management is a total contact orthosis (bracing) to protect the tibia and prevent or delay fracture, although the natural history often eventually leads to fracture.

Question 9137

Topic: 2. Trauma

A 3-year-old girl with Neurofibromatosis type 1 presents with anterolateral bowing of her left tibia. Radiographs show narrowing of the medullary canal and early cortical thickening. What is the natural history of this specific tibial deformity if left untreated?

. Spontaneous resolution by skeletal maturity
. Progression to a malignant peripheral nerve sheath tumor
. High risk of fracture followed by intractable nonunion
. Overgrowth of the limb causing significant leg length discrepancy
. Conversion to an expansile osteolytic lesion

Correct Answer & Explanation

. High risk of fracture followed by intractable nonunion

Explanation

Anterolateral bowing of the tibia in NF-1 is highly associated with congenital pseudarthrosis of the tibia (CPT). Due to abnormal, thick hamartomatous periosteum impairing osteogenesis, fractures in this area typically result in intractable nonunions.

Question 9138

Topic: 2. Trauma

A 65-year-old female sustains a displaced 4-part proximal humerus fracture. When evaluating the initial radiographs to determine the risk of subsequent avascular necrosis (AVN) of the humeral head, which of the following findings (Hertel's criteria) is the most reliable predictor of ischemia?

. Metaphyseal head extension (calcar length) of 12 mm
. Medial hinge disruption greater than 2 mm
. Greater tuberosity displacement of 5 mm
. Angulation of the surgical neck of 30 degrees
. An intact lesser tuberosity

Correct Answer & Explanation

. Medial hinge disruption greater than 2 mm

Explanation

Correct Answer: BHertel et al. described specific radiographic criteria that are highly predictive of ischemia and subsequent avascular necrosis (AVN) of the humeral head following proximal humerus fractures. The most critical predictors of ischemia are: 1) a short calcar segment (metaphyseal head extension < 8 mm), 2) disruption of the medial hinge (> 2 mm of displacement), and 3) an anatomic neck fracture pattern. A medial hinge disruption > 2 mm indicates severe displacement that likely tears the critical ascending branch of the anterior humeral circumflex artery and the intraosseous anastomoses from the posterior humeral circumflex artery. A calcar length of 12 mm (Option A) is protective against AVN. Tuberosity displacement and surgical neck angulation alone are less predictive of AVN than the integrity of the medial hinge and calcar.

Question 9139

Topic: 2. Trauma

A 14-year-old male gymnast presents with acute medial elbow pain after a dismount. Radiographs reveal a displaced medial epicondyle fracture. The elbow joint is concentrically reduced. Which of the following is considered an absolute indication for open reduction and internal fixation (ORIF) of this injury?

. Displacement of the fragment by 4 mm
. Displacement of the fragment by 8 mm
. Mild ulnar nerve paresthesias
. Incarceration of the fracture fragment within the joint
. The patient's status as a high-demand overhead athlete

Correct Answer & Explanation

. Incarceration of the fracture fragment within the joint

Explanation

Correct Answer: DMedial epicondyle fractures in pediatric and adolescent patients are common. The absolute indications for surgical intervention (ORIF) are an open fracture and incarceration of the medial epicondyle fragment within the elbow joint (which blocks motion and damages articular cartilage). Relative indications, which are highly debated in the literature, include displacement > 5-15 mm, ulnar nerve dysfunction (especially if progressive or severe), and high-demand athletic status (e.g., throwing athletes or gymnasts who require profound valgus stability). However, incarceration within the joint is universally recognized as an absolute indication for surgery.

Question 9140

Topic: 2. Trauma

A 65-year-old female sustains a complex proximal humerus fracture. When evaluating her radiographs to determine the risk of subsequent avascular necrosis (AVN) of the humeral head, which of the following findings is the MOST reliable predictor of ischemia according to the Hertel criteria?

. Greater tuberosity displacement greater than 5 mm.
. Metaphyseal head extension (calcar length) of less than 8 mm.
. Angulation of the surgical neck greater than 45 degrees.
. Presence of an isolated lesser tuberosity fracture.
. Comminution of the lateral humeral cortex.

Correct Answer & Explanation

. Metaphyseal head extension (calcar length) of less than 8 mm.

Explanation

Correct Answer: BHertel et al. described specific radiographic criteria that are highly predictive of humeral head ischemia and subsequent avascular necrosis (AVN) following proximal humerus fractures. The most critical predictors include a short metaphyseal head extension (calcar length) of less than 8 mm, disruption of the medial periosteal hinge, and an anatomic neck fracture pattern. A calcar length of <8 mm indicates that the fracture has occurred very close to the articular surface, severely compromising the ascending branch of the anterior humeral circumflex artery and the intraosseous anastomoses from the posterior humeral circumflex artery. While tuberosity displacement and angulation are important for overall fracture classification (e.g., Neer criteria) and functional outcomes, the specific measurement of the posteromedial calcar segment is the strongest independent predictor of AVN.

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