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4. Pediatrics MCQs

Practice Set 212 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 4221

Topic: 4. Pediatrics

Review the clinical image.

A 2-year-old child presents with delayed walking and short stature. The pelvic radiograph reveals coxa vara and distinctly absent ossification of the femoral heads and severely delayed ossification of the pubic symphysis. What is the most likely diagnosis?

. Achondroplasia
. Multiple Epiphyseal Dysplasia
. Morquio Syndrome
. Spondyloepiphyseal Dysplasia Congenita
. Pseudoachondroplasia

Correct Answer & Explanation

. Spondyloepiphyseal Dysplasia Congenita

Explanation

The combination of severe delayed ossification of the femoral heads and pubic bones in an infant or toddler is strongly indicative of SED Congenita. Multiple epiphyseal dysplasia and Morquio typically present later in childhood.

Question 4222

Topic: 4. Pediatrics

A 7-year-old girl with Spondyloepiphyseal Dysplasia Congenita is noted to have progressive coxa vara. Radiographs show a neck-shaft angle of 85 degrees. What is the primary biomechanical rationale for performing a subtrochanteric valgus osteotomy in this patient?

. To prevent progression to a nonunion (pseudoarthrosis) of the femoral neck
. To prevent posterior hip dislocation
. To correct excessive femoral anteversion
. To stimulate physeal growth and increase overall height
. To prevent secondary slipped capital femoral epiphysis

Correct Answer & Explanation

. To prevent progression to a nonunion (pseudoarthrosis) of the femoral neck

Explanation

A severe neck-shaft angle (< 90 degrees) or high Hilgenreiner-epiphyseal angle (> 60 degrees) results in high shear forces across the femoral neck. A valgus osteotomy converts shear forces into compressive forces, promoting ossification and preventing pseudoarthrosis.

Question 4223

Topic: 4. Pediatrics

While performing a physical examination on a newborn later diagnosed with Spondyloepiphyseal Dysplasia Congenita, you note a bilateral structural foot deformity. What is the most common foot anomaly associated with this skeletal dysplasia?

. Talipes equinovarus
. Calcaneovalgus
. Congenital vertical talus
. Pes planovalgus
. Tarsal coalition

Correct Answer & Explanation

. Talipes equinovarus

Explanation

Talipes equinovarus (clubfoot) is the most common congenital foot deformity seen in patients with Spondyloepiphyseal Dysplasia Congenita. It typically requires standard Ponseti casting, though surgical release is more frequently needed than in idiopathic cases.

Question 4224

Topic: 4. Pediatrics

A 13-year-old male presents with bilateral hip pain and stiffness. Examination reveals a short trunk with normal limb proportions. Radiographs demonstrate premature osteoarthritis of the hips and characteristic humped vertebral endplates in the lumbar spine. His maternal uncle required bilateral total hip arthroplasties at age 35. A mutation in which of the following genes is most likely responsible?

. COL2A1
. FGFR3
. TRAPPC2
. COMP
. SLC26A2

Correct Answer & Explanation

. TRAPPC2

Explanation

Spondyloepiphyseal dysplasia tarda (SEDT) is an X-linked recessive disorder caused by a mutation in the TRAPPC2 (formerly SEDL) gene. It is characterized by short-trunk dwarfism, characteristic heaped-up vertebral endplates, and premature osteoarthritis, particularly of the hips.

Question 4225

Topic: Pediatric Hip

Which of the following clinical features most reliably differentiates Spondyloepiphyseal Dysplasia Congenita (SEDC) from Morquio syndrome (Mucopolysaccharidosis Type IV) in a 6-year-old patient with short-trunk dwarfism and atlantoaxial instability?

. Presence of odontoid hypoplasia
. Disproportionate short trunk
. Presence of corneal clouding
. Development of coxa vara
. Presence of a barrel-shaped chest

Correct Answer & Explanation

. Presence of corneal clouding

Explanation

While both SEDC and Morquio syndrome present with short-trunk dwarfism, coxa vara, and odontoid hypoplasia, Morquio syndrome features corneal clouding and normal intelligence. SEDC involves myopia and retinal detachments but lacks corneal clouding.

Question 4226

Topic: Pediatric Hip

A 4-year-old boy with a known COL2A1 mutation is being evaluated in the orthopedic clinic for a waddling gait.

Based on the typical natural history of his skeletal dysplasia, which of the following hip deformities is most likely present?

. Coxa valga
. Progressive coxa vara
. Anterolateral bowing of the femur
. Slipped capital femoral epiphysis
. Protrusio acetabuli

Correct Answer & Explanation

. Progressive coxa vara

Explanation

Spondyloepiphyseal dysplasia congenita (SEDC) frequently involves delayed ossification of the femoral head and neck, leading to progressive coxa vara. This often requires corrective proximal femoral valgus osteotomy to improve hip mechanics and gait.

Question 4227

Topic: 4. Pediatrics
A newborn presents with a short trunk, cleft palate, and a barrel chest. Radiographs show flattened vertebral bodies (platyspondyly) and the absence of ossification in the knees and feet. The parents are of normal height and have no significant medical history. Which type of collagen is quantitatively or qualitatively abnormal in this infant?
. Type I
. Type II
. Type III
. Type IV
. Type X

Correct Answer & Explanation

. Type II

Explanation

The clinical presentation is classic for Spondyloepiphyseal Dysplasia Congenita (SEDC). SEDC is caused by a heterozygous mutation in the COL2A1 gene, resulting in abnormal synthesis of Type II collagen, which is crucial for normal hyaline cartilage development.

Question 4228

Topic: 4. Pediatrics

A 10-year-old boy presents with a 3-month history of left hip pain and a limping gait. He is overweight. Radiographs show widening of the physis, subchondral lucency, and flattening of the femoral head epiphysis with medial and posterior displacement. What is the most critical immediate management step?

. Analgesia and activity modification
. Magnetic Resonance Imaging (MRI) of the hip
. Immediate non-weight-bearing and referral for surgical pinning
. Aspiration of the hip joint to rule out infection
. Physical therapy for strengthening hip abductors

Correct Answer & Explanation

. Immediate non-weight-bearing and referral for surgical pinning

Explanation

The description is classic for Slipped Capital Femoral Epiphysis (SCFE). Given the acute or acute-on-chronic presentation, immediate non-weight-bearing is crucial to prevent further slippage and potential osteonecrosis. Prompt surgical pinning in situ is the definitive treatment to stabilize the physis. Delay can lead to worsening slip, chondrolysis, or avascular necrosis. MRI may be useful for atypical presentations or early avascular necrosis, but it is not the most critical immediate step when SCFE is clinically and radiographically evident.

Question 4229

Topic: Pediatric Hip

A 6-month-old infant is diagnosed with developmental dysplasia of the hip (DDH) after a positive Barlow test and limited abduction on clinical examination, confirmed by ultrasound showing a dislocated hip (Graf type IV). What is the most appropriate initial treatment?

. Close observation with serial ultrasounds
. Double diapering
. Pavlik harness application
. Spica cast immobilization
. Open reduction of the hip

Correct Answer & Explanation

. Pavlik harness application

Explanation

For infants aged 0-6 months with a dislocatable or dislocated hip (Graf type IIc or worse), a Pavlik harness is the gold standard initial treatment. It maintains the hip in flexion and abduction, promoting concentric reduction and acetabular development. Double diapering is ineffective. Spica cast or open reduction is reserved for harness failures or older infants/children where the harness is no longer effective.

Question 4230

Topic: Pediatric Hip

Which of the following describes the 'UnPappy' clinical sign in the context of developmental dysplasia of the hip (DDH)?

. Asymmetry of gluteal folds
. Limited hip abduction
. Galeazzi sign (apparent leg length discrepancy)
. Positive Ortolani maneuver
. Clicking sensation during hip rotation

Correct Answer & Explanation

. Asymmetry of gluteal folds

Explanation

Asymmetry of the gluteal (or thigh) folds is often referred to as a 'Pappy' sign, or simply gluteal fold asymmetry. It is an indirect sign of DDH and indicates tightness of adductor muscles or shortening of the thigh, but it is not a direct diagnostic maneuver for hip instability. Limited hip abduction is a more specific and consistent clinical finding. Ortolani and Barlow tests are direct tests for hip stability. Galeazzi sign is apparent leg length discrepancy due to hip dislocation.

Question 4231

Topic: Pediatric Upper Extremity & Spine

In the surgical management of adolescent idiopathic scoliosis (AIS), what is the primary goal of instrumentation and fusion?

. To eliminate all spinal curvature
. To prevent further progression of the curve
. To restore normal spinal flexibility
. To decompress any neural elements
. To correct the rib hump deformity

Correct Answer & Explanation

. To prevent further progression of the curve

Explanation

The primary goal of surgical instrumentation and fusion in AIS is to prevent further progression of the curve and to achieve a balanced spine. While some correction of the curve and the rib hump is achieved, the aim is not to eliminate all curvature or restore normal flexibility (as fusion limits motion). Decompression is not typically the primary goal in AIS unless there's neurological compromise, which is rare.

Question 4232

Topic: 4. Pediatrics
A 3-month-old infant presents with a 'click' heard during hip examination. Ortolani and Barlow tests are negative. Limited abduction is noted. Ultrasound shows an alpha angle of 55 degrees and a beta angle of 65 degrees. What is the Graf classification of this hip?
. Type I (Normal)
. Type IIa (Physiologically immature)
. Type IIb (Immature)
. Type IIIa (Dislocated, good reduction)
. Type IV (Dislocated, poor reduction)

Correct Answer & Explanation

. Type IIb (Immature)

Explanation

According to Graf's classification for hip ultrasound, an alpha angle of 55 degrees (normal > 60 degrees) and a beta angle of 65 degrees (normal < 55 degrees) would classify this hip as Type IIb. This indicates an immature hip with a dysplastic acetabular roof, usually requiring intervention (e.g., Pavlik harness) in an infant over 3 months of age. A normal hip (Type I) would have an alpha angle > 60 and beta < 55. Type IIa is for infants <3 months with similar angles, considered physiologically immature, often just observed. Type III and IV are dislocated hips.

Question 4233

Topic: Pediatric Hip
A 4-year-old child presents with a painless limp and thigh atrophy. Radiographs show increased density and fragmentation of the femoral head epiphysis. What is the most appropriate initial management?
. Immediate surgical femoral osteotomy
. Non-weight-bearing with crutches
. Containment methods such as bracing or abduction osteotomy
. Physical therapy for range of motion exercises
. Oral corticosteroids

Correct Answer & Explanation

. Containment methods such as bracing or abduction osteotomy

Explanation

The clinical presentation and radiographic findings are consistent with Legg-Calvรฉ-Perthes disease. The primary goal of management is containment of the femoral head within the acetabulum to maintain its spherical shape during revascularization and remodeling, thereby preventing collapse and promoting a better long-term outcome. This is achieved through various containment methods, including bracing (e.g., Scottish Rite brace) or surgical osteotomies (femoral or pelvic) for specific age groups and stages of the disease, depending on the severity of involvement. Non-weight-bearing alone is generally insufficient as a definitive treatment in most cases, and physical therapy is an adjunct, not primary treatment for containment.

Question 4234

Topic: Pediatric Hip
A 1-year-old child presents with a limp, and a 'waddling' gait. Physical examination reveals limited hip abduction and internal rotation bilaterally, and an exaggerated lumbar lordosis. Radiographs show bilateral hip dislocations. What is the most likely diagnosis?
. Developmental dysplasia of the hip (DDH)
. Cerebral palsy
. Legg-Calvรฉ-Perthes disease
. Slipped capital femoral epiphysis (SCFE)
. Transient synovitis

Correct Answer & Explanation

. Developmental dysplasia of the hip (DDH)

Explanation

The clinical presentation (limp, waddling gait, limited abduction/internal rotation, exaggerated lumbar lordosis to compensate for dislocated hips) and radiographic findings (bilateral hip dislocations) in a 1-year-old are highly suggestive of developmental dysplasia of the hip (DDH). At this age, the dislocations are often fixed, and the typical newborn clinical tests may no longer be positive. SCFE and Perthes are conditions of older children. Cerebral palsy could cause gait abnormalities, but primary bilateral hip dislocation is more indicative of DDH. Transient synovitis is acute and self-limiting.

Question 4235

Topic: Pediatric Lower Extremity

A 16-year-old male presents with insidious onset of anterior knee pain, localized just below the patella, worse with activity. Physical examination reveals tenderness and a prominent bump over the tibial tubercle. Radiographs show fragmentation of the tibial tubercle apophysis. What is the most likely diagnosis?

. Patellofemoral pain syndrome
. Jumper's knee (patellar tendinopathy)
. Osgood-Schlatter disease
. Sinding-Larsen-Johansson disease
. Tibial stress fracture

Correct Answer & Explanation

. Osgood-Schlatter disease

Explanation

The clinical presentation (adolescent male, anterior knee pain, tenderness/prominence of tibial tubercle, pain with activity) and radiographic findings (fragmentation of the tibial tubercle apophysis) are classic for Osgood-Schlatter disease. This is a traction apophysitis of the tibial tubercle, often associated with growth spurts and repetitive quadriceps contraction. Sinding-Larsen-Johansson disease is similar but affects the inferior pole of the patella. Patellofemoral pain syndrome is typically diffuse anterior knee pain, and jumper's knee affects the patellar tendon itself.

Question 4236

Topic: Pediatric Hip

A 48-year-old female with Crowe Type IV developmental dysplasia of the hip (DDH) undergoes total hip arthroplasty. The surgeon plans to bring the acetabulum to the true anatomical hip center to restore biomechanics and leg length. What is a specific major intraoperative challenge or potential postoperative complication associated with this strategy in Crowe Type IV DDH?

. Increased risk of heterotopic ossification due to extensive soft tissue dissection
. Increased risk of femoral nerve palsy due to tension on the nerve
. Difficulties with primary stability of the acetabular component in dysplastic bone
. High risk of sciatic nerve palsy due to excessive limb lengthening
. Increased blood loss due to superior gluteal artery injury

Correct Answer & Explanation

. High risk of sciatic nerve palsy due to excessive limb lengthening

Explanation

In Crowe Type IV DDH, the femoral head is significantly displaced superiorly, leading to a chronically shortened limb. Reconstructing the hip at the true anatomical center can require substantial lengthening of the limb, often exceeding 4 cm. This significant lengthening can put the sciatic nerve under extreme tension, leading to a high risk of sciatic nerve palsy, which can be devastating. Intraoperative neuromonitoring, sequential lengthening, and careful soft tissue releases (e.g., adductor tenotomy, psoas release, femoral shortening osteotomy) are often employed to mitigate this risk. Femoral nerve palsy is less common with posterior approaches but can occur with anterior retraction. Heterotopic ossification is a general risk but not specific to limb lengthening. Acetabular stability is a concern but addresses by various grafting and component selection, not the primary concern of nerve injury with lengthening.

Question 4237

Topic: Pediatric Hip

A 55-year-old patient with a severe valgus neck-shaft angle (coxa valga) and femoral head hypoplasia secondary to Legg-Calve-Perthes disease in childhood presents with end-stage arthritis requiring THA. What specific technical consideration is paramount during femoral preparation in this case?

. Using a shorter femoral stem to avoid stress shielding in the distal femur.
. Careful reaming to avoid varus malpositioning and potential impingement.
. Performing a subtrochanteric shortening osteotomy to address limb length discrepancy.
. Utilizing an undersized broach technique to prevent femoral fracture.
. Using a high offset femoral stem to improve abductor tension and reduce impingement.

Correct Answer & Explanation

. Utilizing an undersized broach technique to prevent femoral fracture.

Explanation

Patients with Legg-Calve-Perthes disease often have significant proximal femoral deformities, including coxa valga, femoral head hypoplasia, and a narrowed, often anteverted femoral canal. These morphological abnormalities make femoral preparation challenging during THA. The narrowed canal, combined with the often dense bone, significantly increases the risk of intraoperative femoral fracture (Option D) during reaming and broaching. Therefore, using an undersized broach, careful progressive reaming, and potentially considering custom stems or non-standard stem designs are crucial. While addressing offset (Option E) and limb length discrepancy (Option C, with shortening osteotomy) are important considerations in THA, the immediate and most critical technical concern during femoral preparation in this specific context is preventing fracture. Reaming to avoid varus malpositioning (Option B) is important in any THA, but the specific anatomy of Perthes makes fracture a higher risk. Shorter stems (Option A) are not directly related to the unique challenges of Perthes morphology.

Question 4238

Topic: Pediatric Hip

A 13-year-old obese male presents to the emergency department unable to bear weight on his right leg after a minor slip. Radiographs reveal a severe slipped capital femoral epiphysis (SCFE). According to the Loder classification, this is an unstable SCFE. Which of the following best defines the primary clinical significance of an unstable SCFE?

. A higher risk of chondrolysis
. A displacement of greater than 50% of the femoral neck width
. A slip angle greater than 60 degrees
. A substantially higher risk of avascular necrosis (AVN) of the femoral head
. An absolute indication for a prophylactic pinning of the contralateral hip

Correct Answer & Explanation

. A substantially higher risk of avascular necrosis (AVN) of the femoral head

Explanation

The Loder classification divides SCFE into stable (able to bear weight with or without crutches) and unstable (unable to bear weight even with crutches). The primary clinical significance of an unstable SCFE is a dramatically higher risk of avascular necrosis (AVN), which can occur in up to 20-50% of unstable cases compared to nearly 0% in stable cases.

Question 4239

Topic: Pediatric Lower Extremity

During the initiation of the Ponseti method for a rigid idiopathic clubfoot in a 2-week-old infant, the first manipulative step prior to applying the first long-leg cast is designed to correct the cavus deformity. Which of the following maneuvers is correct to achieve this?

. Elevating the first ray to align the forefoot with the hindfoot
. Depressing the first ray to increase the medial arch
. Abducting the forefoot while applying counter-pressure over the calcaneocuboid joint
. Dorsiflexing the entire midfoot against a tight Achilles tendon
. Forced eversion of the hindfoot to correct the varus

Correct Answer & Explanation

. Elevating the first ray to align the forefoot with the hindfoot

Explanation

In the Ponseti method, the first step is correcting the cavus, which is driven by a relatively plantarflexed first ray compared to the lateral rays. The first ray must be elevated (dorsiflexed) to supinate the forefoot and align it with the hindfoot, establishing a proper mechanical block to further correct adductus and varus.

Question 4240

Topic: 4. Pediatrics

A 4-year-old child, previously successfully treated for an idiopathic clubfoot with the Ponseti method, presents with a recurring deformity. Gait analysis reveals dynamic supination of the foot during the swing phase, with the child walking on the lateral border of the foot. The foot is completely flexible passively. What is the most appropriate surgical management?

. Repeat percutaneous Achilles tenotomy
. Posteromedial soft tissue release
. Calcaneal sliding osteotomy
. Transfer of the entire tibialis anterior tendon to the lateral cuneiform
. Triple arthrodesis

Correct Answer & Explanation

. Transfer of the entire tibialis anterior tendon to the lateral cuneiform

Explanation

Dynamic supination during the swing phase in a relapsed clubfoot that is passively correctable is classic for overpowering of the tibialis anterior. The treatment of choice in a child older than 2.5 to 3 years is a full transfer of the tibialis anterior tendon to the lateral cuneiform (TATT), which converts the deforming supinatory force into a dorsiflexor force.

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