Menu

4. Pediatrics MCQs

Practice Set 111 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 2201

Topic: Pediatric Hip

An infant is being treated with a Pavlik harness for developmental dysplasia of the hip (DDH). The harness is adjusted, but the anterior straps are inadvertently pulled too tight, placing the hips in excessive flexion (greater than 120 degrees). What is the most likely neurologic complication resulting from this specific positioning error?

. Sciatic nerve palsy
. Femoral nerve palsy
. Obturator nerve palsy
. Avascular necrosis of the femoral head
. Superior gluteal nerve palsy

Correct Answer & Explanation

. Femoral nerve palsy

Explanation

The Pavlik harness must be carefully adjusted. Excessive flexion of the hips (anterior straps too tight, >120 degrees of flexion) compresses the femoral nerve against the inguinal ligament, leading to an iatrogenic femoral nerve palsy. The clinical sign is an absence of active knee extension. Avascular necrosis (AVN) is the most devastating complication overall and is associated with excessive abduction (posterior straps too tight). Sciatic nerve palsy is rare in this context.

Question 2202

Topic: Pediatric Hip

During in situ pinning of a slipped capital femoral epiphysis (SCFE), unrecognized pin penetration into the hip joint space is most directly associated with which of the following postoperative complications?

. Avascular necrosis
. Chondrolysis
. Coxa vara
. Femoroacetabular impingement
. Premature osteoarthritis

Correct Answer & Explanation

. Chondrolysis

Explanation

Unrecognized pin penetration into the hip joint during in situ fixation of a SCFE is the most common cause of chondrolysis. It causes rapid loss of articular cartilage, leading to severe stiffness, pain, and a narrowed joint space on radiographs.

Question 2203

Topic: Pediatric Hip

In the ultrasonographic evaluation of developmental dysplasia of the hip (DDH) using the Graf method, the alpha angle is used to assess acetabular development. Which of the following anatomical landmarks are used to measure the alpha angle?

. The bony roof of the acetabulum and the straight portion of the iliac bone
. The cartilaginous roof of the acetabulum and the iliac bone
. The triradiate cartilage and the labrum
. The femoral head and the iliac bone
. The labrum and the joint capsule

Correct Answer & Explanation

. The bony roof of the acetabulum and the straight portion of the iliac bone

Explanation

In the Graf method for DDH, the alpha angle measures the concavity of the bony roof. It is formed by the intersection of the baseline (drawn along the straight portion of the ilium) and the bony roof line (drawn from the lower edge of the iliac bone at the triradiate cartilage tangent to the osseous rim). A normal alpha angle is greater than or equal to 60 degrees.

Question 2204

Topic: Pediatric Upper Extremity & Spine
A 6-year-old boy sustains a completely displaced (Gartland Type III) supracondylar humerus fracture. On initial presentation in the emergency department, his hand is warm and well-perfused (pink), but the radial pulse is absent on palpation and Doppler ultrasound. What is the most appropriate next step in management?
. Immediate surgical exploration of the brachial artery
. CT angiography of the upper extremity
. Urgent closed reduction and percutaneous pinning
. Application of a long arm cast in 90 degrees of flexion
. Observation and elevation for 24 hours

Correct Answer & Explanation

. Urgent closed reduction and percutaneous pinning

Explanation

The standard of care for a 'pulseless, pink' hand in the setting of a displaced pediatric supracondylar humerus fracture is urgent closed reduction and percutaneous pinning (CRPP). Realigning the fracture relieves the tethering, kinking, or spasm of the brachial artery over the proximal fragment, often restoring the pulse. Vascular exploration is indicated if the hand is 'pulseless and pale' (ischemic) before or after reduction.

Question 2205

Topic: Pediatric Hip

A 14-year-old boy with an acute-on-chronic Slipped Capital Femoral Epiphysis (SCFE) is treated with in-situ single screw fixation. Six months later, he presents with severe hip stiffness, pain, and loss of all hip motion. Radiographs demonstrate uniform narrowing of the joint space to less than 3 mm. Which of the following is the most established primary risk factor for this specific complication?

. Unrecognized screw penetration into the joint
. Unstable slip classification at presentation
. Body Mass Index greater than the 95th percentile
. Underlying undiagnosed hypothyroidism
. Failure to perform prophylactic pinning of the contralateral hip

Correct Answer & Explanation

. Unrecognized screw penetration into the joint

Explanation

The clinical presentation describes chondrolysis, a devastating complication of SCFE characterized by acute loss of articular cartilage and severe stiffness. The most strongly associated risk factor for chondrolysis following SCFE fixation is unrecognized pin/screw penetration into the joint space. An unstable slip is a risk factor for avascular necrosis (AVN), not primarily chondrolysis.

Question 2206

Topic: Pediatric Upper Extremity & Spine
A 6-year-old boy presents with a Gartland Type III extension-type supracondylar humerus fracture. On initial exam, the hand is pink but lacks a palpable radial pulse. Following emergent closed reduction and percutaneous pinning in the operating room, the hand remains pink and pulseless, but capillary refill is brisk (<2 seconds). What is the most appropriate next step in management?
. Immediate removal of pins and transition to open reduction
. Emergent anterior approach for brachial artery exploration
. Observation and admission for 24-48 hours
. Doppler ultrasound of the radial artery in the PACU
. Formal angiography of the upper extremity

Correct Answer & Explanation

. Observation and admission for 24-48 hours

Explanation

The management of a 'pink, pulseless' hand after satisfactory reduction and pinning of a pediatric supracondylar humerus fracture is observation. The brisk capillary refill indicates adequate collateral perfusion. Vascular exploration is strictly indicated if the hand is 'white and pulseless' (ischemic) after reduction.

Question 2207

Topic: 4. Pediatrics

The Ponseti method relies on a precise, sequential manipulation and casting technique to treat idiopathic congenital talipes equinovarus (clubfoot). Which of the following represents the correct anatomical order of deformity correction dictated by this method?

. Cavus, Adductus, Varus, Equinus
. Equinus, Varus, Adductus, Cavus
. Adductus, Cavus, Varus, Equinus
. Cavus, Varus, Adductus, Equinus
. Varus, Adductus, Cavus, Equinus

Correct Answer & Explanation

. Cavus, Varus, Adductus, Equinus

Explanation

The correct sequence of correction in the Ponseti method is easily remembered by the mnemonic CAVE: Cavus (corrected by supinating the forefoot and elevating the first ray), Adductus, Varus (adductus and varus correct together as the forefoot is abducted around the fulcrum of the talar head), and finally Equinus (which often requires a percutaneous Achilles tenotomy as the final step).

Question 2208

Topic: Pediatric Lower Extremity

A 2-week-old infant with idiopathic clubfoot is undergoing correction via the Ponseti method. The treating physician applies the first cast. According to Ponseti principles, what is the primary goal of the very first cast application?

. Correction of the cavus deformity by elevating the first ray
. Correction of the forefoot adductus by manipulating the metatarsals
. Correction of the hindfoot varus by abducting the foot
. Correction of the hindfoot equinus by dorsiflexing the ankle
. Correction of internal tibial torsion

Correct Answer & Explanation

. Correction of the cavus deformity by elevating the first ray

Explanation

The Ponseti method corrects the components of clubfoot in a specific sequence: Cavus, Adductus, Varus, and Equinus (CAVE). The first step requires elevation of the first ray (dorsiflexion of the first metatarsal) to correct the forefoot cavus. This aligns the forefoot with the hindfoot, allowing the foot to be treated as a single unit during subsequent abduction.

Question 2209

Topic: Pediatric Hip

An 8-week-old female infant is undergoing treatment for developmental dysplasia of the hip (DDH) with a Pavlik harness. During a routine clinical check, the orthopedic surgeon notes that the infant has decreased active extension of the knee on the affected side, and the patellar reflex is diminished. What is the most likely cause of this finding and the appropriate harness adjustment?

. Femoral nerve palsy from excessive hip flexion; loosen the anterior straps
. Sciatic nerve palsy from excessive hip flexion; tighten the posterior straps
. Obturator nerve palsy from excessive hip abduction; loosen the posterior straps
. Avascular necrosis of the femoral head from excessive hip abduction; discontinue the harness
. Normal variant of Pavlik harness use; maintain current strap settings

Correct Answer & Explanation

. Femoral nerve palsy from excessive hip flexion; loosen the anterior straps

Explanation

The clinical findings of decreased active knee extension and a diminished patellar reflex indicate a femoral nerve palsy. In the setting of a Pavlik harness, this is almost always caused by hyperflexion of the hips compressing the nerve. The appropriate management is to loosen the anterior straps to reduce the degree of hip flexion, which usually leads to complete resolution of the palsy.

Question 2210

Topic: Pediatric Hip

A 12-year-old obese male presents with a left-sided Slipped Capital Femoral Epiphysis (SCFE). In which of the following scenarios is prophylactic in situ pinning of the contralateral asymptomatic right hip most strongly indicated?

. Male gender without other comorbidities
. Age greater than 14 years at initial presentation
. Initial presentation with a chronic slip
. Presence of an endocrine disorder such as hypothyroidism
. Slip angle less than 30 degrees on the affected side

Correct Answer & Explanation

. Presence of an endocrine disorder such as hypothyroidism

Explanation

Prophylactic pinning of the contralateral hip in SCFE is strongly considered in patients with metabolic or endocrine disorders (e.g., hypothyroidism, renal osteodystrophy, growth hormone deficiency), as these conditions present a high risk for bilateral involvement. It is also considered in patients presenting at a younger age (males <12, females <10) or those with prior radiation therapy.

Question 2211

Topic: 4. Pediatrics

In a pediatric patient with a lateral condyle fracture of the humerus, the Milch classification differentiates between two types based on the fracture anatomy. Where does the fracture line exit the articular surface in a Milch Type II fracture?

. Capitellotrochlear groove
. Lateral to the capitellum
. Medial to the trochlea apex
. Through the trochlear groove
. Radiocapitellar joint

Correct Answer & Explanation

. Capitellotrochlear groove

Explanation

According to the Milch classification for lateral condyle fractures, a Milch Type I fracture line exits laterally through the capitellotrochlear groove (Salter-Harris IV equivalent), leaving the lateral trochlear ridge intact to stabilize the elbow. Milch Type II fractures exit medially through the trochlear groove (Salter-Harris II equivalent), violating the lateral trochlear ridge and resulting in a structurally unstable joint.

Question 2212

Topic: Pediatric Lower Extremity

When treating congenital idiopathic clubfoot (talipes equinovarus) using the Ponseti method, what is the correct sequence of deformity correction during serial casting?

. Equinus, Varus, Adductus, Cavus
. Cavus, Adductus, Varus, Equinus
. Varus, Cavus, Equinus, Adductus
. Adductus, Cavus, Equinus, Varus
. Equinus, Adductus, Varus, Cavus

Correct Answer & Explanation

. Cavus, Adductus, Varus, Equinus

Explanation

The Ponseti method involves sequential correction of the clubfoot deformities using the mnemonic CAVE: Cavus (corrected first by elevating the first ray), Adductus, Varus, and finally Equinus. The equinus deformity is corrected last, often requiring a percutaneous Achilles tenotomy if dorsiflexion remains limited after the other deformities have been corrected.

Question 2213

Topic: Pediatric Hip

An 8-year-old boy, who is in the 10th percentile for height and 90th percentile for weight, presents with an idiopathic unilateral slipped capital femoral epiphysis (SCFE). Given his young age, an underlying endocrinopathy is highly suspected. Which of the following laboratory profiles is most classically associated with the most common endocrine cause of SCFE in this age group?

. Elevated free T4 and low TSH
. Decreased free T4 and elevated TSH
. Elevated growth hormone and IGF-1
. Elevated serum calcium and decreased PTH
. Decreased testosterone and elevated FSH

Correct Answer & Explanation

. Decreased free T4 and elevated TSH

Explanation

SCFE in children under the age of 10 or those with atypical presentations should prompt an evaluation for an underlying endocrine disorder. Hypothyroidism is the most common endocrinopathy associated with SCFE, characterized by a low free T4 and an elevated TSH.

Question 2214

Topic: Pediatric Lower Extremity

The Ponseti method is the recognized gold standard for the conservative treatment of idiopathic clubfoot. According to this protocol, what is the very first component of the deformity that must be corrected during the initial casting phase?

. Adductus
. Equinus
. Varus
. Cavus
. Internal tibial torsion

Correct Answer & Explanation

. Cavus

Explanation

The Ponseti method follows the CAVE mnemonic for the order of correction: Cavus, Adductus, Varus, Equinus. The very first step involves correcting the high arch (cavus) by elevating the first ray to align the forefoot with the hindfoot, which provides a solid lever arm to subsequently correct the adductus and varus.

Question 2215

Topic: Pediatric Hip

An 8-week-old infant with developmental dysplasia of the hip (DDH) is being treated with a Pavlik harness. During a routine follow-up, the parents note that the child is no longer actively kicking the leg on the affected side. Upon physical examination, there is an absent patellar reflex and decreased active knee extension. Which of the following errors in harness application is the most likely cause of this complication?

. Excessive flexion of the hip
. Excessive abduction of the hip
. Excessive adduction of the hip
. Placement of the chest strap too high
. Inadequate tension on the posterior straps

Correct Answer & Explanation

. Excessive flexion of the hip

Explanation

Femoral nerve palsy is a known complication of Pavlik harness treatment, typically resulting from hyperflexion of the hips, which compresses the femoral nerve against the inguinal ligament. Excessive abduction is associated with avascular necrosis (AVN) of the femoral head.

Question 2216

Topic: Pediatric Hip

In a patient presenting with a slipped capital femoral epiphysis (SCFE), which of the following is the strongest indication for prophylactic in situ pinning of the asymptomatic contralateral hip?

. Age older than 15 years at the time of presentation
. Male gender
. Obesity (BMI > 95th percentile)
. Presence of an underlying endocrine disorder (e.g., hypothyroidism)
. Moderate-to-severe slip angle (>30 degrees) on the affected side

Correct Answer & Explanation

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

Explanation

While contralateral pinning is debated in idiopathic SCFE, there is broad consensus that patients with an underlying endocrinopathy (such as hypothyroidism, renal osteodystrophy, or growth hormone deficiency) have an exceptionally high risk of bilateral involvement (up to 100% in some series). Therefore, prophylactic contralateral pinning is strongly indicated in these patients. Other indications include an inability to reliably follow up or an age at presentation of less than 10 years.

Question 2217

Topic: Pediatric Lower Extremity

In the Ponseti method for the treatment of idiopathic clubfoot, the sequence of deformity correction is critical for a successful outcome. Which of the following represents the correct first step in the manipulation and casting process?

. Dorsiflexion of the ankle to correct equinus
. Abduction of the forefoot to correct adductus
. Pronation of the forefoot to correct varus
. Elevation of the first ray to correct cavus
. Eversion of the calcaneus to correct hindfoot varus

Correct Answer & Explanation

. Elevation of the first ray to correct cavus

Explanation

The sequence of correction in the Ponseti method follows the acronym CAVE: Cavus, Adductus, Varus, Equinus. The very first step must be the correction of the cavus deformity. This is achieved by elevating the first ray (supinating the forefoot), which aligns the forefoot with the hindfoot. Pronating the forefoot, a common error, worsens the cavus deformity.

Question 2218

Topic: 4. Pediatrics

An infant with developmental dysplasia of the hip (DDH) is being treated with a Pavlik harness. During a 2-week follow-up visit, the mother notes that the infant is no longer actively kicking the right leg. Physical examination reveals decreased active knee extension on the right side, with an absent patellar reflex, but normal active ankle and toe motion. Which of the following harness adjustments is the most appropriate next step to resolve this complication?

. Decrease the abduction angle of the posterior straps
. Increase the flexion angle of the anterior straps
. Decrease the flexion angle of the anterior straps
. Discontinue the harness entirely and place the child in a spica cast
. Add an anti-rotation strap to the affected side

Correct Answer & Explanation

. Decrease the flexion angle of the anterior straps

Explanation

The infant has developed a femoral nerve palsy, which is the most common nerve palsy associated with Pavlik harness use. It is caused by excessive hyperflexion of the hip, which compresses the femoral nerve against the inguinal ligament. The appropriate management is to decrease the flexion angle of the anterior straps. If the palsy does not resolve within a few days to a week after adjustment, the harness should be temporarily discontinued. Excessive abduction (posterior straps) is associated with a vascular complication—avascular necrosis (AVN) of the femoral head.

Question 2219

Topic: Pediatric Hip

In the evaluation of developmental dysplasia of the hip (DDH) in a 6-month-old child, the ossific nucleus of the femoral head is delayed. Which radiographic landmark combination correctly defines the normal anatomical position of the proximal femur?

. Superior to Hilgenreiner's line and medial to Perkin's line
. Inferior to Hilgenreiner's line and medial to Perkin's line
. Inferior to Hilgenreiner's line and lateral to Perkin's line
. Superior to Hilgenreiner's line and lateral to Perkin's line
. Medial to the teardrop and superior to Hilgenreiner's line

Correct Answer & Explanation

. Inferior to Hilgenreiner's line and medial to Perkin's line

Explanation

On an AP pelvis radiograph, the normal femoral head (or its expected unossified cartilaginous analogue) should reside in the inferomedial quadrant formed by the intersection of Hilgenreiner's line (horizontal through the triradiate cartilages) and Perkin's line (vertical descending from the lateral margin of the ossified acetabulum).

Question 2220

Topic: Pediatric Hip

A 12-year-old obese boy is diagnosed with a stable slipped capital femoral epiphysis (SCFE) and undergoes in-situ percutaneous screw fixation. If a prominent anterior metaphyseal bump remains, what is the most common long-term complication associated with the natural history of his hip?

. Avascular necrosis of the femoral head
. Chondrolysis
. Femoroacetabular impingement (cam-type)
. Premature osteoarthritis due to pincer impingement
. Leg length discrepancy > 3 cm

Correct Answer & Explanation

. Femoroacetabular impingement (cam-type)

Explanation

Following SCFE, the persistent retroverted orientation of the femoral head relative to the neck leaves a prominent anterior metaphyseal bump. This altered anatomy classically leads to cam-type femoroacetabular impingement (FAI) during hip flexion, which is the most common cause of premature secondary osteoarthritis in these patients.

Test Yourself

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

On this Page