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4. Pediatrics MCQs

Practice Set 160 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 3181

Topic: 4. Pediatrics
A 4-year-old boy, successfully treated for an idiopathic left clubfoot as an infant using the Ponseti method, presents with recurrence. On physical examination, the foot is plantigrade at rest, but he exhibits dynamic supination during the swing phase of gait. Passive range of motion is full, and the heel easily rests in a neutral position. What is the most appropriate management for this patient?
. Split anterior tibial tendon transfer (SPLATT)
. Full transfer of the anterior tibial tendon to the lateral (third) cuneiform
. Repeat Achilles tenotomy and serial casting
. Lateral column shortening (cuboid decancellation)
. Posteromedial release

Correct Answer & Explanation

. Full transfer of the anterior tibial tendon to the lateral (third) cuneiform

Explanation

Dynamic supination during gait in a relapsed Ponseti-treated clubfoot is a classic presentation caused by an overpowering anterior tibial tendon without a strong evertor counterbalance. The standard treatment described by Ponseti for this specific dynamic deformity is a full transfer of the anterior tibial tendon to the third (lateral) cuneiform. A split anterior tibial tendon transfer (SPLATT) is typically reserved for spastic conditions, such as cerebral palsy or adult stroke, not idiopathic clubfoot relapse.

Question 3182

Topic: Pediatric Upper Extremity & Spine

A 6-year-old girl sustains a severely displaced, extension-type supracondylar humerus fracture. On initial presentation in the emergency department, her hand is pale and pulseless. Following urgent closed reduction and percutaneous pinning in the operating room, the fracture is anatomically aligned, but the hand remains pale, cold, and pulseless after 15 minutes of observation. What is the next most appropriate step in management?

. Observe the hand overnight for improvement in collateral circulation
. Perform an immediate anterior vascular exploration of the brachial artery
. Administer intravenous heparin and obtain a vascular surgery consult
. Remove the pins, flex the elbow to 120 degrees, and repin
. Perform a rapid sequence Doppler ultrasound

Correct Answer & Explanation

. Perform an immediate anterior vascular exploration of the brachial artery

Explanation

A pulseless, pale (white) hand following anatomical reduction and stabilization of a supracondylar humerus fracture is an absolute indication for immediate anterior vascular exploration. The brachial artery may be incarcerated in the fracture site, kinked, or transected. A pulseless but well-perfused (pink, warm) hand can often be closely observed, but a pale and pulseless hand mandates surgical exploration to restore perfusion and prevent ischemic contracture.

Question 3183

Topic: 4. Pediatrics

A 7-year-old boy with spastic quadriplegic cerebral palsy (GMFCS Level V) is evaluated in the clinic. He is non-ambulatory. Pelvic radiographs demonstrate a Reimers Migration Percentage of 55% on the right and 45% on the left, with an intact Shenton's line and minimal degenerative changes. On physical exam, his hips can be abducted to 30 degrees bilaterally. What is the most appropriate surgical intervention?

. Bilateral adductor tenotomies alone
. Observation with repeat radiographs in 6 months
. Bilateral varus derotational osteotomies (VDRO) with pelvic osteotomies
. Proximal femoral resection (Castle procedure)
. Bilateral total hip arthroplasties

Correct Answer & Explanation

. Bilateral varus derotational osteotomies (VDRO) with pelvic osteotomies

Explanation

In older children (typically >4-5 years) with spastic cerebral palsy and a Reimers Migration Percentage greater than 40-50%, soft tissue releases alone (like adductor tenotomies) have an unacceptably high failure rate. Bony reconstruction is indicated, which consists of proximal femoral varus derotational osteotomies (VDRO) frequently combined with pelvic osteotomies (such as Dega or San Diego) to comprehensively address the dysplasia and subluxation before irreversible joint degeneration occurs.

Question 3184

Topic: Pediatric Hip
A 9-year-old boy presents with an 8-month history of a painless limp. Radiographs reveal fragmentation of the left femoral head. According to the Herring lateral pillar classification, the hip is categorized as Type B. Range of motion is well preserved. Based on current evidence, which of the following treatments provides the best long-term radiographic outcome for this patient?
. Strict bed rest and continuous skin traction
. Use of an A-frame abduction orthosis
. Surgical containment (e.g., proximal femoral varus osteotomy)
. Observation and activity modification
. Core decompression of the femoral head

Correct Answer & Explanation

. Surgical containment (e.g., proximal femoral varus osteotomy)

Explanation

The Herring lateral pillar classification and the patient's age at onset dictate treatment in Legg-Calvé-Perthes disease. Multiple multicenter studies have demonstrated that children who are 8 years or older at the onset of symptoms and have a Lateral Pillar Type B or B/C border hip achieve significantly better radiographic and clinical outcomes with surgical containment (such as a proximal femoral osteotomy or pelvic osteotomy) compared to nonoperative management. Those under 8 years generally do well without surgery for Type B, and Type C does poorly regardless of treatment.

Question 3185

Topic: 4. Pediatrics

A 15-year-old severely obese male presents with worsening bilateral bowing of his legs. Standing radiographs reveal severe varus, procurvatum, and internal rotation deformities. The medial proximal tibial physes appear to be prematurely closed, and the mechanical axis passes entirely medial to the knee joints. Which of the following is the most appropriate definitive management?

. Lateral proximal tibial hemiepiphysiodesis (guided growth)
. Multiplanar proximal tibial and fibular osteotomies
. Medial unloader bracing
. Observation until age 18
. Medial tibial plateau elevation alone

Correct Answer & Explanation

. Multiplanar proximal tibial and fibular osteotomies

Explanation

The patient has adolescent Blount disease with severe multiplanar deformity (varus, procurvatum, internal rotation) and closed (or nearing closure) medial physes. Because growth is essentially complete, guided growth (hemiepiphysiodesis) will not be effective in correcting the deformity. The definitive treatment requires multiplanar proximal tibial and fibular osteotomies (often stabilized with an external fixator to allow gradual correction) to restore the mechanical axis.

Question 3186

Topic: Pediatric Hip

A 24-month-old girl presents with a waddling gait. An anteroposterior radiograph of the pelvis demonstrates a completely dislocated left hip. The acetabular index on the left is 42 degrees, compared to 20 degrees on the right. She has not had any prior treatment. What is the most appropriate management strategy?

. Application of a Pavlik harness
. Closed reduction and spica casting
. Open reduction with spica casting alone
. Open reduction, femoral shortening osteotomy, and pelvic osteotomy
. Wait until skeletal maturity for a periacetabular osteotomy

Correct Answer & Explanation

. Open reduction, femoral shortening osteotomy, and pelvic osteotomy

Explanation

In a child of this age (24 months) presenting late with Developmental Dysplasia of the Hip (DDH), closed reduction has an unacceptably high rate of failure and avascular necrosis. The standard of care requires open reduction to clear intra-articular obstacles. Because of the significant secondary acetabular dysplasia (acetabular index >40 degrees), a pelvic osteotomy (e.g., Salter or Pemberton) is necessary. Furthermore, due to severe soft tissue contractures that occur in late presentations, a femoral shortening osteotomy is indicated to relieve joint pressure during reduction, drastically decreasing the risk of avascular necrosis.

Question 3187

Topic: 4. Pediatrics
A 14-year-old girl sustains an inversion injury to her right ankle while playing soccer. Radiographs demonstrate an isolated Salter-Harris type III fracture of the anterolateral aspect of the distal tibial epiphysis. The mechanism of this specific fracture pattern is primarily due to avulsion by which of the following ligamentous structures?
. Anterior talofibular ligament (ATFL)
. Calcaneofibular ligament (CFL)
. Anterior inferior tibiofibular ligament (AITFL)
. Posterior inferior tibiofibular ligament (PITFL)
. Deltoid ligament

Correct Answer & Explanation

. Anterior inferior tibiofibular ligament (AITFL)

Explanation

This patient has a juvenile Tillaux fracture. This injury occurs in older adolescents whose distal tibial physis is partially closed. The typical closure pattern begins centrally, progresses medially, and finally closes laterally. An external rotation force causes the intact anterior inferior tibiofibular ligament (AITFL) to avulse the still-open anterolateral portion of the distal tibial epiphysis, resulting in a Salter-Harris III fracture.

Question 3188

Topic: Pediatric Hip

A 13-year-old obese male presents with a 1-day history of extreme left groin pain following a minor fall. He is completely unable to bear weight on the left leg, even with the assistance of crutches. Radiographs reveal a severe left slipped capital femoral epiphysis (SCFE). He is scheduled for urgent surgical stabilization. Which of the following surgical steps is associated with the highest increased risk of postoperative avascular necrosis (AVN) in this patient?

. Performing an anterior capsulotomy prior to pinning
. Forceful or repeated closed reduction maneuvers prior to fixation
. Inadvertent penetration of the joint space with a guidewire during drilling
. Using two screws instead of a single screw for fixation
. Performing the procedure via a percutaneous approach

Correct Answer & Explanation

. Forceful or repeated closed reduction maneuvers prior to fixation

Explanation

This patient has an unstable SCFE, defined clinically by the inability to bear weight even with assistive devices. Unstable SCFE has a significantly high baseline risk for avascular necrosis (up to 47%). Performing forceful or repeated closed reduction maneuvers drastically increases this risk by further disrupting the already tenuous retinacular blood supply to the epiphysis. Current recommendations advise against forceful reduction; incidental repositioning may occur by simply placing the patient on the fracture table. A capsulotomy (option 0) is actually advocated by many surgeons to decrease intracapsular pressure and potentially reduce AVN risk.

Question 3189

Topic: 4. Pediatrics

A 6-year-old child with spastic quadriplegic cerebral palsy (GMFCS level V) presents for routine follow-up. An AP pelvis radiograph demonstrates a migration percentage of 48% bilaterally. What is the most appropriate management?

. Observation with repeat radiographs in 1 year
. Botulinum toxin injection to the bilateral hip adductors
. Bilateral adductor tenotomies and observation
. Bilateral femoral varus derotational osteotomies (VDRO) and pelvic osteotomies
. Bilateral total hip arthroplasties

Correct Answer & Explanation

. Bilateral femoral varus derotational osteotomies (VDRO) and pelvic osteotomies

Explanation

In children with cerebral palsy, a migration percentage (Reimer's migration index) greater than 40-50% typically warrants bony reconstruction to prevent painful dislocation and ensure seating of the femoral head. Soft tissue releases (adductor tenotomy) are generally insufficient once the migration percentage exceeds 40% in older children. Bony reconstruction typically involves a proximal femoral varus derotational osteotomy (VDRO) combined with a pelvic osteotomy (e.g., Dega or San Diego).

Question 3190

Topic: 4. Pediatrics

A 5-year-old girl sustains a severely displaced extension-type supracondylar humerus fracture. On arrival in the emergency department, her hand is pink and well-perfused, but the radial pulse is not palpable. After prompt closed reduction and percutaneous pinning in the operating room, the hand remains pink and warm with a capillary refill of less than 2 seconds, but the pulse remains non-palpable. What is the next most appropriate step?

. Observation and hospital admission for 24-48 hours
. Immediate open exploration of the brachial artery
. Emergent CT angiography of the upper extremity
. Immediate removal of pins and transition to open reduction
. Administration of intravenous heparin

Correct Answer & Explanation

. Observation and hospital admission for 24-48 hours

Explanation

The 'pink, pulseless' hand after reduction and pinning of a pediatric supracondylar humerus fracture should be managed with close observation and admission for 24-48 hours. The collateral circulation in these cases is sufficient to perfuse the hand. Most pulses return within a few days to weeks. Immediate vascular exploration is indicated for a 'white, pulseless' (ischemic) hand that does not improve after fracture reduction.

Question 3191

Topic: Pediatric Hip

A 6-week-old female infant is diagnosed with a completely dislocated but reducible left hip (Developmental Dysplasia of the Hip). She is placed in a Pavlik harness. At the 3-week follow-up ultrasound, the left hip remains dislocated within the harness. What is the next best step in management?

. Continue the Pavlik harness for an additional 3 weeks
. Perform a closed reduction and spica casting under general anesthesia
. Perform an open reduction and capsulorrhaphy
. Transition the patient to a rigid abduction orthosis (e.g., Ilfeld or Rhino Cruiser)
. Perform a femoral shortening osteotomy

Correct Answer & Explanation

. Transition the patient to a rigid abduction orthosis (e.g., Ilfeld or Rhino Cruiser)

Explanation

If a Pavlik harness fails to reduce a dislocated hip within 3-4 weeks, continuing its use is contraindicated due to the risk of 'Pavlik harness disease' (damage to the posterior acetabular wall) and avascular necrosis. The generally accepted next step is a trial of a rigid abduction orthosis. If the rigid orthosis also fails, the next step would be closed reduction and spica casting under anesthesia, potentially with an arthrogram.

Question 3192

Topic: Pediatric Hip

A 12-year-old obese boy presents with left groin and knee pain for 2 months. Radiographs confirm a mild, stable slipped capital femoral epiphysis (SCFE) on the left. In which of the following scenarios is prophylactic percutaneous pinning of the contralateral (asymptomatic) right hip most strongly indicated?

. Patient age greater than 14 years
. The slip on the left side is classified as 'unstable'
. Presence of an underlying endocrine disorder
. Patient BMI > 95th percentile
. Male gender

Correct Answer & Explanation

. Presence of an underlying endocrine disorder

Explanation

Prophylactic pinning of the contralateral hip is strongly considered in patients at a high risk of developing bilateral SCFE. Classic indications for prophylactic pinning include underlying endocrine disorders (such as hypothyroidism, renal osteodystrophy, or panhypopituitarism), a history of previous radiation therapy, and a young age at presentation (typically < 10 years for boys, < 11 years for girls) with widely open triradiate cartilage.

Question 3193

Topic: Pediatric Hip
A 7-year-old boy presents with a painless limp of 3 months' duration. Radiographs show sclerosis, fragmentation, and lateral displacement of the right capital femoral epiphysis, consistent with Legg-Calvé-Perthes disease. Which of the following radiographic findings represents one of Catterall's 'head-at-risk' signs, indicating a poorer prognosis?
. Medial subluxation of the femoral head
. Narrowing of the teardrop distance
. Anterior physeal closure
. Increased height of the lateral pillar
. Calcification lateral to the epiphysis

Correct Answer & Explanation

. Calcification lateral to the epiphysis

Explanation

Catterall's 'head-at-risk' signs for Legg-Calvé-Perthes disease identify patients with a poorer prognosis and a higher likelihood of significant femoral head deformity. These signs include: calcification lateral to the epiphysis, Gage sign (a V-shaped radiolucency in the lateral portion of the epiphysis/metaphysis), lateral subluxation of the femoral head, horizontal orientation of the growth plate, and metaphyseal cysts.

Question 3194

Topic: Pediatric Lower Extremity

A 2-week-old infant with idiopathic bilateral clubfoot is undergoing serial casting using the Ponseti method. After correcting the cavus, adductus, and varus deformities, the foot demonstrates 15 degrees of residual equinus. What is the next most appropriate step?

. Continue serial weekly casting until the equinus is fully corrected
. Perform a complete posteromedial release
. Perform a percutaneous Achilles tenotomy
. Transfer the anterior tibial tendon to the lateral cuneiform
. Discontinue casting and prescribe a Denis Browne bar immediately

Correct Answer & Explanation

. Perform a percutaneous Achilles tenotomy

Explanation

In the Ponseti method for treating clubfoot, deformities are corrected in the sequence of Cavus, Adductus, Varus, and finally Equinus (CAVE). Once the midfoot and forefoot are appropriately abducted and the heel is in valgus, the residual equinus is addressed. The vast majority of infants (over 80-90%) require a percutaneous Achilles tenotomy to achieve dorsiflexion, followed by a final cast applied for 3 weeks.

Question 3195

Topic: Pediatric Upper Extremity & Spine

A 12-year-old premenarchal female (Risser stage 0) presents with adolescent idiopathic scoliosis. Standing posteroanterior radiographs reveal a primary right thoracic curve measuring 32 degrees and a compensatory left lumbar curve of 20 degrees. What is the most appropriate management recommendation?

. Observation with repeat standing radiographs in 6 months
. Full-time wear of a nighttime bending brace
. Posterior spinal fusion with pedicle screw instrumentation
. Full-time wear of a thoracolumbosacral orthosis (TLSO)
. Intensive physical therapy and core strengthening program

Correct Answer & Explanation

. Full-time wear of a thoracolumbosacral orthosis (TLSO)

Explanation

The indications for bracing in Adolescent Idiopathic Scoliosis (AIS) are a growing child (Risser 0-2, premenarchal or < 1 year postmenarchal) with a curve between 25 and 40 degrees, or curve progression of > 5 degrees over 6 months in a curve initially measuring 20-29 degrees. Because this patient is Risser 0 with significant growth remaining and a 32-degree curve, full-time bracing with a TLSO (typically prescribed for 16-23 hours/day) is indicated. The BrAIST trial confirmed full-time bracing decreases the risk of curve progression to surgical magnitude.

Question 3196

Topic: 4. Pediatrics
A 3-year-old obese female presents with progressive bilateral bowing of her legs. Radiographs reveal an abrupt varus deformity at the proximal tibial metaphyses with a metaphyseal-diaphyseal angle (Drennan's angle) of 20 degrees bilaterally. Beaking of the medial metaphysis is also noted. What is the most appropriate initial management for this patient?
. Reassurance and annual observation
. Bilateral proximal tibial valgus osteotomies
. Guided growth with lateral tension band plates
. Bilateral knee-ankle-foot orthoses (KAFOs)
. Bilateral epiphysiodesis of the lateral proximal tibia

Correct Answer & Explanation

. Bilateral knee-ankle-foot orthoses (KAFOs)

Explanation

This presentation is classic for infantile Blount disease (tibia vara), supported by the patient's age, obesity, metaphyseal beaking, and a metaphyseal-diaphyseal angle greater than 16 degrees. For children younger than 3-4 years old with Langenskiöld stage I or II disease, the initial treatment of choice is nonoperative management with bilateral KAFOs (worn either full-time or during weight-bearing activities). Surgery (valgus producing osteotomy) is reserved for older children, those who fail brace treatment, or higher Langenskiöld stages.

Question 3197

Topic: 4. Pediatrics

A 5-year-old girl with spastic quadriplegic cerebral palsy (GMFCS level V) undergoes routine hip surveillance. Radiographs demonstrate a migration percentage of 45% in the right hip. Clinical examination reveals 20 degrees of hip abduction bilaterally with a positive Thomas test. Which of the following is the most appropriate management?

. Observation with repeat radiographs in 1 year
. Botulinum toxin injection to the adductors
. Isolated adductor and iliopsoas tenotomies
. Varus derotational osteotomy (VDRO) with or without pelvic osteotomy
. Total hip arthroplasty

Correct Answer & Explanation

. Varus derotational osteotomy (VDRO) with or without pelvic osteotomy

Explanation

In children with severe cerebral palsy (GMFCS IV or V) and a hip migration percentage greater than 40-50%, soft tissue releases alone (e.g., adductor tenotomies) have an unacceptably high failure rate. Bony reconstruction with a proximal femoral varus derotational osteotomy (VDRO), often combined with a pelvic osteotomy, is the standard of care to achieve and maintain hip reduction.

Question 3198

Topic: 4. Pediatrics

A 6-week-old female infant is placed in a Pavlik harness for treatment of developmental dysplasia of the hip. At the 1-week follow-up, the parents note that she is no longer kicking her left leg. On examination, the infant lacks active knee extension on the left and the patellar reflex is absent. Which of the following harness configurations is the most likely cause of this complication?

. Excessive flexion of the hip
. Excessive abduction of the hip
. Excessive extension of the hip
. Excessive adduction of the hip
. Inadequate sizing of the chest strap

Correct Answer & Explanation

. Excessive flexion of the hip

Explanation

Femoral nerve palsy is a well-known complication of Pavlik harness treatment and typically presents with decreased active knee extension and an absent patellar reflex. It is caused by excessive flexion of the hip. Treatment involves temporarily discontinuing or adjusting the harness to decrease hip flexion, which usually leads to spontaneous resolution. In contrast, excessive abduction places the infant at high risk for avascular necrosis (AVN).

Question 3199

Topic: Pediatric Hip

A 12-year-old boy with a BMI in the 99th percentile undergoes in situ pinning of a severe left slipped capital femoral epiphysis (SCFE). Which of the following factors most strongly indicates the need for prophylactic pinning of the contralateral, asymptomatic right hip?

. Age 12 years at presentation
. Severe slip angle on the index side
. Presence of an underlying endocrine disorder (e.g., hypothyroidism)
. Male gender and elevated BMI
. Family history of SCFE

Correct Answer & Explanation

. Presence of an underlying endocrine disorder (e.g., hypothyroidism)

Explanation

Prophylactic pinning of the contralateral hip in SCFE is controversial for idiopathic cases but is universally recommended for patients with an underlying endocrinopathy (such as hypothyroidism, renal osteodystrophy, or growth hormone deficiency) due to the exceedingly high risk of bilateral involvement. Age <10 years or the inability to follow up reliably are also relative indications, whereas severity of the primary slip and BMI are not independent absolute indications.

Question 3200

Topic: 4. Pediatrics
A 3-year-old girl is evaluated for bilateral bowlegs. Clinical examination reveals a lateral thrust during gait and a prominent medial metaphyseal beak of the proximal tibia. Radiographs demonstrate a metaphyseal-diaphyseal angle of 20 degrees bilaterally. Based on her age and radiographic findings, what is the most appropriate initial management?
. Reassurance and observation for spontaneous resolution
. Vitamin D supplementation
. Knee-ankle-foot orthoses (KAFOs)
. Proximal tibial valgus-producing osteotomy
. Guided growth (hemiepiphysiodesis) of the lateral proximal tibia

Correct Answer & Explanation

. Knee-ankle-foot orthoses (KAFOs)

Explanation

The patient exhibits classic signs of infantile Blount's disease (age < 4 years, pronounced medial metaphyseal beak, metaphyseal-diaphyseal angle > 16 degrees). For children under 3-4 years of age with early Langenskiöld stages (I or II), non-operative treatment with daytime bracing using KAFOs is the standard initial management. Surgery is indicated if bracing fails or if the child presents at an older age with advanced disease.

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