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4. Pediatrics MCQs

Practice Set 203 of 334

This practice set contains high-yield board review questions covering key concepts in 4. Pediatrics. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 4041

Topic: 4. Pediatrics

A 7-year-old child presents with a severe congenital scoliosis with a 65-degree thoracolumbar curve and an unsegmented bar with contralateral hemivertebrae. The deformity has shown progression on serial radiographs. What is the most appropriate surgical strategy?

. Observation and bracing.
. Growth-friendly instrumentation (e.g., growing rods).
. Hemivertebrectomy with posterior fusion and instrumentation.
. Anterior vertebral body tethering (VBT).
. Posterior instrumentation without resection.

Correct Answer & Explanation

. Hemivertebrectomy with posterior fusion and instrumentation.

Explanation

Congenital scoliosis with an unsegmented bar and contralateral hemivertebrae represents a highly progressive and rigid deformity due to the continuous growth on one side and absent growth on the other. For severe, progressive curves like 65 degrees in a 7-year-old, surgical intervention is indicated. Hemivertebrectomy with posterior fusion and instrumentation is the definitive treatment to remove the progressive element and achieve maximal correction and fusion. Bracing is generally ineffective for congenital scoliosis. Growing rods are used for flexible, progressive curves in young children to delay fusion but may not provide definitive correction for rigid congenital deformities with unsegmented bars. VBT is for idiopathic scoliosis, not congenital. Posterior instrumentation without resection would not adequately correct or stop the progression from the unsegmented bar.

Question 4042

Topic: Pediatric Hip
A 14-year-old obese male presents with sudden onset of severe right hip pain and inability to bear weight. X-rays show a severe slipped capital femoral epiphysis (SCFE) with >60 degrees posterior slip. Which of the following is the most appropriate initial management strategy?
. Percutaneous in situ pinning without reduction
. Gentle closed reduction followed by in situ pinning
. Open reduction with surgical dislocation and pinning
. Spica casting without surgery
. Traction followed by delayed pinning

Correct Answer & Explanation

. Open reduction with surgical dislocation and pinning

Explanation

For severe unstable SCFE (often defined as >60 degrees slip or inability to bear weight), forceful closed reduction is contraindicated due to a high risk of avascular necrosis (AVN) of the femoral head and chondrolysis. Open reduction, typically via a surgical dislocation approach, allows for controlled reduction of the epiphysis under direct visualization while preserving the vascular supply, followed by stable fixation with pins. Percutaneous in situ pinning without reduction is for stable SCFE. Gentle closed reduction might be considered for less severe unstable slips, but >60 degrees indicates a high risk. Spica casting and traction are not definitive treatments for SCFE.

Question 4043

Topic: Pediatric Upper Extremity & Spine

A 15-year-old female presents with a progressive right thoracic curve measuring 55 degrees on Cobb angle, with significant truncal asymmetry. Her Risser sign is 4. She experiences mild back pain but no neurological deficits. What is the most appropriate management for this patient?

. Observation and serial radiographs
. Brace treatment (TLSO)
. Posterior spinal fusion
. Anterior vertebral body tethering
. Physical therapy and core strengthening

Correct Answer & Explanation

. Posterior spinal fusion

Explanation

For adolescent idiopathic scoliosis (AIS), surgical intervention, typically posterior spinal fusion, is indicated for curves greater than 45-50 degrees, especially in patients who are skeletally immature or approaching skeletal maturity (Risser 4 indicates near skeletal maturity). Brace treatment is generally recommended for progressive curves between 25-45 degrees in skeletally immature patients. Observation is for smaller curves or skeletally mature patients with non-progressive curves. Anterior vertebral body tethering is an emerging technique typically for younger, skeletally immature patients with significant growth remaining. Physical therapy is an adjunct but not a primary treatment for significant, progressive curves.

Question 4044

Topic: Pediatric Upper Extremity & Spine
A 7-year-old child presents 5 days after a fall with a displaced (Gartland Type III) supracondylar humerus fracture. The elbow is significantly swollen and tense, with a palpable but diminished radial pulse. Capillary refill in the fingers is delayed to 4 seconds, and he has pain with passive finger extension. Neurological examination of the median, ulnar, and radial nerves is intact. What is the most urgent management step?
. Immediate closed reduction and percutaneous pinning.
. Order a CT angiogram to assess vascular compromise.
. Observation with elevation and analgesia, reassessing pulses and neurological status.
. Emergency open reduction and internal fixation with vascular exploration.
. Initiate a diagnostic elbow arthrogram.

Correct Answer & Explanation

. Emergency open reduction and internal fixation with vascular exploration.

Explanation

This child presents with a Gartland Type III supracondylar humerus fracture with clear signs of impending vascular compromise: diminished radial pulse, delayed capillary refill, and severe pain with passive finger extension (suggestive of compartment syndrome, though pain is the earliest and most reliable sign). The swelling and delayed presentation (5 days) increase the risk. While closed reduction and pinning is the usual treatment for Gartland III, the presence of critical vascular compromise (pulselessness or diminished pulse with signs of ischemia) mandates immediate surgical intervention. For delayed presentations with severe swelling and vascular compromise, open reduction, vascular exploration (to assess for brachial artery entrapment or injury), and then fixation is often necessary. A CT angiogram delays critical intervention. Observation is contraindicated. An arthrogram is not indicated for vascular compromise.

Question 4045

Topic: 4. Pediatrics
A 9-year-old boy with spastic diplegia (GMFCS Level III) presents with a progressively worsening crouch gait characterized by excessive knee flexion, hip flexion, and ankle dorsiflexion, despite previous hamstring and gastrocnemius lengthenings. Clinical examination reveals patella alta and a stiff-knee gait pattern. Which surgical intervention is most likely indicated to address the specific issue of excessive knee flexion and improve his gait kinematics?
. Proximal femoral varus derotation osteotomy.
. Distal femoral extension osteotomy with patellar tendon advancement.
. Tibial tubercle transfer for patella baja.
. Selective dorsal rhizotomy.
. Repeated hamstring lengthenings.

Correct Answer & Explanation

. Distal femoral extension osteotomy with patellar tendon advancement.

Explanation

A crouch gait in cerebral palsy, especially with patella alta and stiff-knee gait, often results from persistent quadriceps overactivity and weakness of the hip extensors and ankle plantarflexors. Distal femoral extension osteotomy aims to extend the knee by correcting the femorotibial angle. When combined with patellar tendon advancement, it can lower the patella and improve quadriceps leverage, thus addressing the patella alta and the excessive knee flexion in swing phase and stance. Proximal femoral varus derotation osteotomy addresses hip deformities but not directly the knee crouch. Tibial tubercle transfer for patella baja is for the opposite problem. Selective dorsal rhizotomy reduces spasticity but does not correct fixed bony deformities or restore muscle balance in the same way. Repeated hamstring lengthenings alone may exacerbate the crouch if not accompanied by quadriceps balance.

Question 4046

Topic: Pediatric Hip

A 13-year-old male presents with right knee pain and an antalgic gait. Physical exam reveals obligatory external rotation with hip flexion. Radiographs demonstrate posterior and inferior slippage of the right proximal femoral epiphysis. Which of the following is considered a definitive indication for prophylactic in-situ pinning of the contralateral asymptomatic hip in this condition?

. Male sex
. Endocrine disorder such as hypothyroidism
. Slip angle greater than 50 degrees
. Age greater than 14 years
. Duration of symptoms less than 3 weeks

Correct Answer & Explanation

. Endocrine disorder such as hypothyroidism

Explanation

Slipped Capital Femoral Epiphysis (SCFE) frequently occurs bilaterally. Prophylactic pinning of the contralateral hip is indicated in patients with underlying endocrinopathies (e.g., hypothyroidism, renal osteodystrophy) or in very young patients (under 10 years old), due to the exceptionally high risk of bilateral involvement in these cohorts.

Question 4047

Topic: 4. Pediatrics

A 55-year-old male of East Asian descent presents with progressive clumsiness in his hands and a broad-based gait. Lateral cervical spine radiographs show a continuous line of ossification posterior to the vertebral bodies from C3 to C6. Which genetic factor or pathway is most strongly associated with the pathogenesis of this condition?

. Mutation in the COL1A1 gene
. HLA-B27 antigen
. Runx2/Cbfa1 upregulation
. Mutation in the FGFR3 gene
. t(X;18) translocation

Correct Answer & Explanation

. Runx2/Cbfa1 upregulation

Explanation

Ossification of the posterior longitudinal ligament (OPLL) involves ectopic bone formation and is prevalent in East Asian populations. Genetic studies show a strong association with the upregulation of osteogenic genes such as Runx2/Cbfa1, as well as bone morphogenetic proteins (BMPs) and TGF-beta. HLA-B27 is associated with ankylosing spondylitis, COL1A1 with osteogenesis imperfecta, and FGFR3 with achondroplasia.

Question 4048

Topic: Pediatric Hip

An 8-week-old female is being treated with a Pavlik harness for developmental dysplasia of the hip (DDH). During follow-up, the mother notes that the infant is no longer kicking her right leg. Examination reveals decreased active knee extension on the right. What is the most likely cause of this finding?

. Excessive hip abduction in the harness
. Hyperflexion of the hip in the harness
. Ischemic necrosis of the proximal femoral epiphysis
. Brachial plexus traction injury
. Deep infection of the hip joint

Correct Answer & Explanation

. Hyperflexion of the hip in the harness

Explanation

The infant has developed a femoral nerve palsy, a known complication of Pavlik harness treatment. It is caused by excessive hyperflexion of the hip, which compresses the femoral nerve against the inguinal ligament. Treatment involves adjusting the anterior straps to decrease hip flexion. Excessive hip abduction, by contrast, risks avascular necrosis (AVN) of the femoral head.

Question 4049

Topic: Pediatric Hip

When planning a proximal femoral osteotomy for a severe coxa vara deformity using Paley principles, placing the hinge lateral to the CORA along the transverse bisector line will result in:

. An opening wedge correction
. A closing wedge correction
. A neutral wedge correction
. Pure translation without angular correction
. Creation of an iatrogenic rotational deformity

Correct Answer & Explanation

. An opening wedge correction

Explanation

Placing the hinge on the convex side of the deformity (lateral in coxa vara) along the bisector line results in an opening wedge correction. This lengthens the bone while simultaneously correcting the angulation.

Question 4050

Topic: Pediatric Lower Extremity

A U-osteotomy (calcaneal-cuboid-cuneiform osteotomy) for a severe cavovarus foot deformity primarily aims to correct deformity in which plane?

. Coronal plane only
. Sagittal plane only
. Axial plane only
. Multiplanar (sagittal, coronal, and transverse)
. Pure translation without angular change

Correct Answer & Explanation

. Multiplanar (sagittal, coronal, and transverse)

Explanation

The U-osteotomy is a powerful midfoot osteotomy that allows for simultaneous multiplanar correction. It effectively addresses the cavus (sagittal), varus (coronal), and forefoot adduction (transverse) components of the deformity.

Question 4051

Topic: 4. Pediatrics

In Paley's classification of Congenital Femoral Deficiency (CFD), a Type 1 deformity is primarily characterized by:

. An intact femur with normal ossification, mobile hip and knee, but varying shortening
. Pseudarthrosis of the femoral neck with delayed ossification
. Absence of the proximal femur with a unstable, floating knee
. Complete absence of the femur
. A stiff knee with bony ankylosis of the patellofemoral joint

Correct Answer & Explanation

. An intact femur with normal ossification, mobile hip and knee, but varying shortening

Explanation

Paley Type 1 CFD features an intact femur with normal or delayed ossification and mobile hip and knee joints. It is typically associated with limb shortening and proximal deformities such as coxa vara.

Question 4052

Topic: 4. Pediatrics

Which parameter represents the generally accepted optimal rate of distraction osteogenesis in the tibia during Ilizarov deformity correction?

. 0.25 mm per day
. 1.0 mm per day
. 2.0 mm per day
. 3.0 mm per day
. 5.0 mm per day

Correct Answer & Explanation

. 1.0 mm per day

Explanation

The classic optimal rate of distraction for bone regeneration is 1.0 mm per day, typically divided into four equal increments of 0.25 mm. This rate balances the speed of bone regenerate formation with soft tissue accommodation.

Question 4053

Topic: Pediatric Hip

The SUPERhip procedure developed by Dr. Paley for Congenital Femoral Deficiency primarily aims to surgically reconstruct which of the following combined pathomorphologies?

. Anterior dislocation of the hip with a normal femur
. Acetabular dysplasia, severe coxa vara, and femoral retroversion
. Isolated symptomatic coxa valga
. Slipped capital femoral epiphysis with impingement
. Avascular necrosis secondary to Legg-Calve-Perthes disease

Correct Answer & Explanation

. Acetabular dysplasia, severe coxa vara, and femoral retroversion

Explanation

The SUPERhip procedure systematically reconstructs the complex soft tissue and bony deformities inherent to severe CFD. This primarily includes correction of severe coxa vara, femoral retroversion, flexion contractures, and associated acetabular dysplasia.

Question 4054

Topic: Pediatric Hip

In evaluating a patient with severe coxa vara, you note a negative articulotrochanteric distance (ATD). What is the primary biomechanical consequence of this anatomic alignment?

. Increased tension in the hip abductors leading to an antalgic gait
. Decreased mechanical advantage of the abductors leading to a Trendelenburg gait
. Increased lateral offset of the femoral shaft leading to IT band syndrome
. Excessive femoral anteversion causing in-toeing
. Impingement of the lesser trochanter on the ischium

Correct Answer & Explanation

. Decreased mechanical advantage of the abductors leading to a Trendelenburg gait

Explanation

A negative ATD indicates the tip of the greater trochanter is above the center of the femoral head, which severely shortens the lever arm of the hip abductors. This functional weakness results in a classic Trendelenburg lurch.

Question 4055

Topic: Pediatric Lower Extremity

A patient undergoes correction of a severe cavovarus foot using a Taylor Spatial Frame (TSF). During the correction process, the patient complains of progressive numbness and tingling over the plantar aspect of the foot. Which structure is at highest risk during acute/rapid correction of a cavovarus deformity?

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

Correct Answer & Explanation

. Tibial nerve

Explanation

The tibial nerve (and its plantar branches) courses medially and plantarly. As the severe cavovarus deformity is corrected (which involves lengthening the medial column and stretching the plantar tissues), the tibial nerve is at highest risk for traction injury.

Question 4056

Topic: 4. Pediatrics

A 16-year-old patient presents with a recurvatum deformity of the distal tibia following a premature anterior physeal arrest. Preoperative sagittal plane planning requires measurement of the anterior distal tibial angle (ADTA). What is the normal ADTA value?

. 80 degrees
. 90 degrees
. 100 degrees
. 110 degrees
. 120 degrees

Correct Answer & Explanation

. 80 degrees

Explanation

The normal anterior distal tibial angle (ADTA) is approximately 80 degrees (range 78-82 degrees). An ADTA significantly greater than 83 degrees indicates a procurvatum deformity, while an angle less than 78 degrees indicates recurvatum.

Question 4057

Topic: Pediatric Hip

A 14-year-old patient presents with developmental coxa vara. A proximal femoral osteotomy is planned. According to Paley's Rule 1 of deformity correction, to achieve angular correction and realign the mechanical axis without creating a secondary translation deformity, where must the osteotomy and correction hinge be placed relative to the center of rotation of angulation (CORA)?

. Osteotomy proximal to the CORA, hinge at the CORA
. Osteotomy distal to the CORA, hinge proximal to the CORA
. Osteotomy and hinge exactly at the CORA
. Osteotomy in the diaphysis, hinge at the CORA
. Osteotomy and hinge at the level of the lesser trochanter regardless of the CORA

Correct Answer & Explanation

. Osteotomy and hinge exactly at the CORA

Explanation

Paley's Rule 1 states that if the osteotomy and the correction hinge are both placed at the CORA, pure angulation occurs. This corrects the deformity and flawlessly realigns the mechanical axis without introducing any translational displacement.

Question 4058

Topic: 4. Pediatrics

In the Paley "SUPERhip" procedure for Congenital Femoral Deficiency (CFD), a key step to correct the extreme coxa vara and retroversion involves which of the following osteotomies?

. Distal femoral extension osteotomy
. Proximal femoral valgus, flexion, and internal rotation osteotomy
. Proximal femoral varus, extension, and external rotation osteotomy
. Intertrochanteric varus and shortening osteotomy
. Pelvic support osteotomy

Correct Answer & Explanation

. Proximal femoral valgus, flexion, and internal rotation osteotomy

Explanation

The SUPERhip procedure comprehensively addresses the deformities of CFD. It utilizes a proximal femoral osteotomy to create valgus, flexion, and internal rotation to correct the typical coxa vara, extension, and retroversion deformities.

Question 4059

Topic: 4. Pediatrics

When planning an Ilizarov hip reconstruction (pelvic support osteotomy) for severe hip instability, at what exact anatomical level should the proximal valgus-extension osteotomy be performed to maximize pelvic support?

. At the subcapital level of the femoral neck.
. Immediately distal to the lesser trochanter.
. At the level of the ischial tuberosity with the hip in maximum adduction.
. At the mid-diaphysis of the femur.
. At the level of the anterior inferior iliac spine (AIIS).

Correct Answer & Explanation

. At the level of the ischial tuberosity with the hip in maximum adduction.

Explanation

To achieve optimal pelvic support and prevent impingement during ambulation, the proximal valgus-extension osteotomy is performed at the level of the ischial tuberosity while the hip is adducted to its maximum limit. This ensures the proximal femur effectively supports the pelvis.

Question 4060

Topic: 4. Pediatrics

Paley's "Superhip" procedure is utilized for the correction of congenital femoral deficiency (CFD) and associated severe coxa vara. During the extensive soft tissue release required for this procedure, which of the following structures is meticulously preserved and advanced distally, rather than being released or lengthened?

. Iliotibial band
. Rectus femoris
. Gluteus medius and minimus
. Psoas tendon
. Piriformis tendon

Correct Answer & Explanation

. Gluteus medius and minimus

Explanation

In the Superhip procedure for congenital femoral deficiency, the hip abductor musculature (gluteus medius and minimus) is carefully preserved and advanced distally to improve biomechanics. Contracted structures like the IT band, rectus femoris, and psoas are released or lengthened.

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