Menu

4. Pediatrics MCQs

Practice Set 115 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 2281

Topic: 4. Pediatrics

According to the Herring Lateral Pillar Classification for Legg-Calve-Perthes disease, a patient whose lateral pillar maintains 60% of its original height falls into which group, and what is the typical prognosis for an 8-year-old child in this group?

. Group A; excellent prognosis without surgery.
. Group B; fair prognosis, typically benefits from surgical containment.
. Group C; good prognosis with conservative care.
. Group B/C border; poor prognosis regardless of treatment.
. Group C; excellent prognosis with proximal femoral osteotomy.

Correct Answer & Explanation

. Group B; fair prognosis, typically benefits from surgical containment.

Explanation

Herring Group B indicates that the lateral pillar maintains between 50% and 100% of its original height. In an 8-year-old child, Group B (and B/C border) hips generally have a fair to poor prognosis with non-operative treatment but show significantly improved outcomes with surgical containment (such as a proximal femoral varus osteotomy or pelvic osteotomy). Group C (<50% height) generally has a poor prognosis.

Question 2282

Topic: Pediatric Hip

In a 12-year-old boy presenting with a unilateral slipped capital femoral epiphysis (SCFE), which of the following endocrine disorders is the strongest indication for prophylactic in situ pinning of the asymptomatic contralateral hip?

. Type 1 Diabetes Mellitus
. Hypothyroidism
. Hyperparathyroidism
. Cushing's syndrome
. Congenital adrenal hyperplasia

Correct Answer & Explanation

. Hypothyroidism

Explanation

Atypical SCFE occurs in patients with endocrine disorders (such as hypothyroidism, growth hormone deficiency, and panhypopituitarism) or in children outside the typical age range. These patients have a significantly higher rate of bilateral involvement, approaching 100% in some series for certain endocrinopathies. Hypothyroidism is a classic and strong indication for prophylactic pinning of the contralateral hip.

Question 2283

Topic: Pediatric Hip

A 3-month-old infant is being treated for developmental dysplasia of the hip (DDH) with a Pavlik harness. During a follow-up visit, the parents note that the infant is no longer actively extending the knee on the affected side. What is the most appropriate immediate management?

. Reassure the parents and observe while continuing the harness
. Adjust the anterior straps to increase hip flexion
. Adjust the posterior straps to decrease hip abduction
. Immediate cessation of the Pavlik harness
. Switch to a hip spica cast immediately

Correct Answer & Explanation

. Immediate cessation of the Pavlik harness

Explanation

Decreased active knee extension in an infant wearing a Pavlik harness is the classic presentation of a femoral nerve palsy, typically caused by excessive hip flexion. The standard of care is the immediate cessation of the Pavlik harness and observation. The palsy usually resolves within days to a couple of weeks, after which alternative bracing or casting can be considered.

Question 2284

Topic: Pediatric Hip

An 11-year-old boy presents with an acute-on-chronic slipped capital femoral epiphysis (SCFE) of the left hip. Prophylactic in situ pinning of the asymptomatic contralateral right hip is most strongly indicated in patients with which of the following clinical profiles?

. Age 13 years
. Male sex
. African American descent
. History of hypothyroidism or renal osteodystrophy
. Body Mass Index (BMI) > 95th percentile

Correct Answer & Explanation

. History of hypothyroidism or renal osteodystrophy

Explanation

Prophylactic pinning of the contralateral hip in a patient with a unilateral SCFE is highly recommended for patients with endocrine disorders (such as hypothyroidism, panhypopituitarism, or renal osteodystrophy), patients who have had prior radiation therapy, or patients who are relatively young (often defined as <10 years for girls and <11-12 years for boys) or have open triradiate cartilages. These factors significantly increase the risk of a subsequent contralateral slip.

Question 2285

Topic: 4. Pediatrics

Infantile tibia vara (Blount's disease) is a developmental condition resulting in progressive varus deformity. Which of the following combinations represents the most significant risk factors for the development of infantile Blount's disease?

. Late walking and low BMI
. Female gender and low birth weight
. Early walking and clinical obesity
. Caucasian descent and delayed milestones
. Vitamin D deficiency and strictly breastfed

Correct Answer & Explanation

. Early walking and clinical obesity

Explanation

Infantile tibia vara (Blount's disease) is characterized by an abnormal ossification of the medial aspect of the proximal tibial physis, leading to a progressive varus deformity. It is mechanically driven by excessive compressive forces on the medial physis. Early walking (before 1 year of age) and clinical obesity are the two most strongly associated risk factors, as they subject the immature medial physis to disproportionately high mechanical loads. It is also more common in children of African descent.

Question 2286

Topic: Pediatric Hip

A 6-week-old female is being treated with a Pavlik harness for developmental dysplasia of the hip. At a follow-up visit, the mother notes the infant is no longer actively kicking her affected leg. Physical examination reveals decreased active knee extension but normal sensation. Which of the following is the most likely cause?

. Transient synovitis
. Excessive hip flexion in the harness
. Excessive hip abduction in the harness
. Undiagnosed septic arthritis
. Slipped capital femoral epiphysis

Correct Answer & Explanation

. Excessive hip flexion in the harness

Explanation

Femoral nerve palsy is a known complication of Pavlik harness treatment and is caused by excessive hip flexion. The anterior strap should be adjusted to decrease flexion. Excessive abduction in the harness is classically associated with an increased risk of avascular necrosis (AVN) of the femoral head.

Question 2287

Topic: Pediatric Hip

A 12-year-old obese male presents with a left slipped capital femoral epiphysis (SCFE). Which of the following patient profiles most strongly indicates the need for prophylactic in situ pinning of the asymptomatic contralateral hip?

. Age greater than 14 years
. Presentation with a chronic slip
. Female gender
. Presence of an underlying endocrine disorder
. Slip angle less than 30 degrees

Correct Answer & Explanation

. Presence of an underlying endocrine disorder

Explanation

Prophylactic pinning of the contralateral hip in SCFE is generally recommended in patients with endocrine disorders (e.g., hypothyroidism, growth hormone deficiency, renal osteodystrophy) or prior radiation therapy due to a very high risk (often >50%) of developing a bilateral slip.

Question 2288

Topic: Pediatric Lower Extremity

During the Ponseti method for the conservative correction of idiopathic clubfoot (talipes equinovarus), the components of the deformity are addressed in a specific sequence. What is the very first component of the deformity that must be corrected during the initial casting phase?

. Equinus
. Varus of the hindfoot
. Cavus
. Adduction of the forefoot
. Tibial torsion

Correct Answer & Explanation

. Cavus

Explanation

The Ponseti method dictates a specific order of correction summarized by the acronym CAVE: Cavus, Adductus, Varus, Equinus. The first step is to correct the Cavus by elevating the first ray to align the forefoot with the hindfoot, establishing a solid lever arm for subsequent correction.

Question 2289

Topic: Pediatric Hip

A 3-month-old infant with developmental dysplasia of the hip (DDH) is being treated with a Pavlik harness. During a follow-up visit, the parents note decreased spontaneous movement of the affected leg. Examination reveals active toe movement but profound weakness in knee extension. What is the most likely cause of this complication?

. Excessive hip abduction in the harness
. Excessive hip adduction in the harness
. Excessive hip flexion in the harness
. Excessive hip extension in the harness
. Inadequate hip flexion in the harness

Correct Answer & Explanation

. Excessive hip flexion in the harness

Explanation

Femoral nerve palsy is a known complication of Pavlik harness treatment and is most commonly caused by excessive hip flexion, which stretches or compresses the femoral nerve against the inguinal ligament or pelvic brim. The clinical presentation is an absence of active knee extension. Treatment involves immediate adjustment of the harness or temporary removal until nerve function recovers. Excessive abduction, conversely, increases the risk of avascular necrosis (AVN) of the femoral head.

Question 2290

Topic: Pediatric Hip

A normal-weight 10-year-old girl presents with a unilateral slipped capital femoral epiphysis (SCFE). Given her atypical demographic profile for this condition, which underlying endocrine disorder is most commonly associated with SCFE and should prompt consideration for prophylactic pinning of the contralateral hip?

. Hyperthyroidism
. Hypothyroidism
. Type 1 Diabetes Mellitus
. Hyperparathyroidism
. Addison's disease

Correct Answer & Explanation

. Hypothyroidism

Explanation

While idiopathic SCFE typically occurs in overweight adolescents during their growth spurt (males 12-16, females 10-14), patients presenting outside of this typical age or weight demographic (e.g., <10 years old, or normal weight) have a high likelihood of an underlying endocrine or metabolic disorder. Hypothyroidism is the most common endocrine disorder associated with SCFE. Other conditions include renal osteodystrophy and growth hormone deficiency. These patients are at very high risk for contralateral disease, often necessitating prophylactic pinning.

Question 2291

Topic: Pediatric Upper Extremity & Spine

In the Lenke classification system for adolescent idiopathic scoliosis, a minor curve is defined as 'structural' (and therefore requires inclusion in the surgical fusion construct) if it meets which of the following criteria?

. The Cobb angle remains greater than or equal to 10 degrees on supine side-bending radiographs
. The Cobb angle remains greater than or equal to 25 degrees on supine side-bending radiographs
. Apical vertebral translation is greater than 1 cm
. Nash-Moe rotation is Grade 2 or higher
. The curve flexibility is less than 50% of the standing coronal Cobb angle

Correct Answer & Explanation

. The Cobb angle remains greater than or equal to 25 degrees on supine side-bending radiographs

Explanation

The Lenke classification defines a minor curve as structural if its Cobb angle remains at or above 25 degrees on maximal supine side-bending radiographs. Additionally, for thoracic curves, a regional kyphosis of +20 degrees or more (T2-T5 for proximal thoracic, T10-L2 for thoracolumbar/lumbar) also qualifies the curve as structural regardless of the side-bending coronal Cobb angle. Structural minor curves must be included in the arthrodesis.

Question 2292

Topic: Pediatric Hip

A 13-year-old obese male undergoes in-situ pinning for a stable Slipped Capital Femoral Epiphysis (SCFE). Four months postoperatively, he develops severe hip stiffness, worsening pain, and a 30-degree flexion contracture. Radiographs show a 50% reduction in the joint space globally compared to the contralateral hip. What is the most significant risk factor for this specific complication?

. Performing a base of neck capsulotomy
. Unrecognized hardware penetration into the articular joint
. Patient's elevated BMI
. Use of a single partially threaded screw instead of two
. Early postoperative weight bearing

Correct Answer & Explanation

. Unrecognized hardware penetration into the articular joint

Explanation

The clinical picture describes chondrolysis, a devastating complication of SCFE characterized by acute cartilage destruction and global joint space narrowing. The most strongly associated iatrogenic risk factor is unrecognized pin penetration into the hip joint during fixation. The use of live fluoroscopy (approach-withdraw technique) is critical to confirm the pin is completely within the femoral head.

Question 2293

Topic: Pediatric Hip

A 6-week-old infant is being treated with a Pavlik harness for Developmental Dysplasia of the Hip (DDH). After 3 weeks of treatment, the hip remains persistently dislocated. Which of the following ultrasonographic findings is the most significant anatomic predictor of harness failure?

. Alpha angle of 55 degrees
. Beta angle of 60 degrees
. Absence of the os acetabuli
. Interposed inverted limbus or pulvinar
. Graf Type IIa classification

Correct Answer & Explanation

. Interposed inverted limbus or pulvinar

Explanation

An interposed inverted limbus, thick pulvinar, contracted transverse acetabular ligament, or a tight iliopsoas tendon are intra-articular and extra-articular blocks to reduction. Their presence on imaging strongly predicts the failure of non-operative management (Pavlik harness) and often necessitates a closed or open reduction.

Question 2294

Topic: Pediatric Hip

A 6-week-old female infant is placed in a Pavlik harness for developmental dysplasia of the hip (DDH). One week later, the parents report that the infant is no longer actively kicking her right leg. On examination, there is an absence of active knee extension on the right side. Which of the following is the most likely cause of this complication?

. Obturator nerve palsy due to hyperabduction
. Femoral nerve palsy due to hyperflexion
. Sciatic nerve palsy due to extreme extension
. Superior gluteal nerve palsy due to internal rotation
. Lateral femoral cutaneous nerve palsy due to strap pressure

Correct Answer & Explanation

. Femoral nerve palsy due to hyperflexion

Explanation

Femoral nerve palsy is a known complication of the Pavlik harness, typically caused by excessive flexion of the hip. The hyperflexion causes the femoral nerve to become compressed against the inguinal ligament. Presentation includes loss of active quadriceps function (lack of active knee extension). The treatment is to temporarily remove or adjust the harness to reduce flexion, and the palsy almost always resolves spontaneously.

Question 2295

Topic: Pediatric Hip

When placing a single in situ screw for a slipped capital femoral epiphysis (SCFE), an incorrectly positioned starting point and trajectory can lead to catastrophic complications. Placement of the screw into which quadrant of the femoral head carries the highest risk of unrecognized joint penetration and damage to the primary blood supply, risking avascular necrosis (AVN)?

. Anterosuperior
. Anteroinferior
. Posterosuperior
. Posteroinferior
. Direct central

Correct Answer & Explanation

. Anterosuperior

Explanation

The anterosuperior quadrant of the femoral head is the 'danger zone' during SCFE pinning. Because the epiphysis slips posteriorly and inferiorly, the anterior and superior aspect of the metaphysis becomes prominent. A screw directed anterosuperiorly is likely to exit the metaphysis and penetrate the joint space unrecognized. Furthermore, the lateral epiphyseal vessels, which provide the primary blood supply to the femoral head, enter in this region; injuring them significantly increases the risk of AVN. Screws should ideally be placed in the center-center position.

Question 2296

Topic: Pediatric Hip

A 3-month-old infant in a Pavlik harness for developmental dysplasia of the hip (DDH) develops decreased active knee extension on the treated side. Which of the following harness positions is the most likely cause of this complication?

. Excessive abduction
. Excessive flexion
. Insufficient abduction
. Insufficient flexion
. Excessive external rotation

Correct Answer & Explanation

. Excessive flexion

Explanation

Femoral nerve palsy is a known complication of Pavlik harness treatment, presenting as decreased active quadriceps function (lack of active knee extension). It is typically caused by hyperflexion of the hip, which impinges the femoral nerve against the inguinal ligament. Treatment involves temporary removal of the harness or adjusting the anterior straps to decrease hip flexion. Excessive abduction is associated with avascular necrosis (AVN) of the femoral head.

Question 2297

Topic: Pediatric Hip

A 12-year-old obese male presents with left hip pain and an obligatory external rotation of the thigh during passive hip flexion. Radiographs confirm a mild, stable slipped capital femoral epiphysis (SCFE) on the left. His contralateral right hip is asymptomatic and radiographically normal. Which of the following is the strongest indication for prophylactic in situ pinning of the asymptomatic right hip?

. Patient's chronologic age of 12 years
. Body Mass Index (BMI) greater than the 95th percentile
. Presentation with an underlying endocrine disorder
. A slip angle of 30 degrees on the symptomatic side
. Male sex

Correct Answer & Explanation

. Presentation with an underlying endocrine disorder

Explanation

Prophylactic pinning of the contralateral asymptomatic hip in SCFE is generally indicated in patients with an underlying endocrinopathy (e.g., hypothyroidism, renal osteodystrophy, growth hormone deficiency), as they have a significantly higher risk of developing a bilateral slip, approaching 100% in some series. Other accepted indications include an inability to follow up and presentation at an atypically young age (<10 years).

Question 2298

Topic: Pediatric Hip

A 12-year-old obese male presents with left groin pain and an obligate external rotation of the hip during passive flexion. Radiographs confirm a stable slipped capital femoral epiphysis (SCFE). Which of the following accurately describes the anatomic displacement in SCFE?

. The epiphysis displaces anteriorly and laterally relative to the metaphysis.
. The metaphysis displaces anteriorly and externally rotates relative to the epiphysis.
. The epiphysis displaces superiorly and anteriorly.
. Klein's line intersects a larger portion of the epiphysis compared to the normal side.
. The metaphysis displaces posteriorly and medially.

Correct Answer & Explanation

. The metaphysis displaces anteriorly and externally rotates relative to the epiphysis.

Explanation

In SCFE, the femoral head (epiphysis) actually remains anatomically seated in the acetabulum. The deformity is created by the femoral neck (metaphysis) displacing anteriorly and externally rotating relative to the epiphysis. Consequently, it appears as though the epiphysis has slipped posteriorly and medially. Klein's line (drawn along the superior femoral neck) will intersect LESS of the epiphysis on the affected side.

Question 2299

Topic: Pediatric Hip

A 3-year-old girl is diagnosed with late-presenting developmental dysplasia of the hip (DDH). She undergoes an open reduction and a pelvic osteotomy. The surgeon performs a redirectional, complete innominate osteotomy that hinges on the pubic symphysis to provide anterolateral coverage of the femoral head. Which osteotomy was performed?

. Pemberton osteotomy
. Dega osteotomy
. Salter osteotomy
. Chiari osteotomy
. Steel triple osteotomy

Correct Answer & Explanation

. Salter osteotomy

Explanation

The Salter osteotomy is a complete, trans-iliac redirectional osteotomy that hinges on the pubic symphysis to provide primarily anterolateral coverage for DDH. The Pemberton is an incomplete osteotomy that hinges on the triradiate cartilage, reducing acetabular volume. The Dega is also incomplete, hinging on the triradiate, but focuses on lateral and posterior coverage. The Chiari is a salvage capsular interposition osteotomy. Steel is a triple osteotomy (ilium, ischium, pubis).

Question 2300

Topic: Pediatric Hip

A 4-month-old infant is being treated with a Pavlik harness for developmental dysplasia of the hip (DDH). The parents report that the child has stopped actively kicking the knee on the affected side. On examination, there is decreased active knee extension, but the patellar reflex is absent. Which of the following is the most likely cause of this complication?

. Excessive hip abduction
. Excessive hip flexion
. Inadequate hip flexion
. Excessive knee extension
. Direct pressure on the fibular head

Correct Answer & Explanation

. Excessive hip flexion

Explanation

Femoral nerve palsy is a known complication of the Pavlik harness, typically caused by excessive hip flexion causing compression of the femoral nerve against the inguinal ligament. It presents with decreased active knee extension. Treatment involves loosening the anterior straps or temporarily discontinuing the harness until nerve function recovers.

Test Yourself

Switch to an interactive, timed exam simulation to truly master this topic.

On this Page