Menu

4. Pediatrics MCQs

Practice Set 135 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 2681

Topic: Pediatric Hip

An 18-month-old girl is diagnosed with residual acetabular dysplasia following successful closed reduction of DDH. Her current acetabular index (AI) is 38 degrees. What is considered the upper limit of normal for the acetabular index at this age?

. 15 degrees
. 20 degrees
. 25 degrees
. 30 degrees
. 35 degrees

Correct Answer & Explanation

. 15 degrees

Explanation

In children older than 1 year, an acetabular index greater than 25 degrees is generally considered abnormal and indicative of dysplasia. Persistent elevation may necessitate a pelvic osteotomy.

Question 2682

Topic: 4. Pediatrics
A 13-year-old girl sustains an ankle injury. Radiographs show a Salter-Harris III fracture of the anterolateral aspect of the distal tibial epiphysis. What is the pathomechanics of this specific fracture?
. Avulsion by the anterior inferior tibiofibular ligament (AITFL) due to external rotation
. Impaction of the talus into the tibial plafond
. Avulsion by the posterior inferior tibiofibular ligament
. Plantarflexion and inversion injury
. Direct blow to the lateral malleolus

Correct Answer & Explanation

. Avulsion by the anterior inferior tibiofibular ligament (AITFL) due to external rotation

Explanation

A juvenile Tillaux fracture is an avulsion of the anterolateral distal tibial epiphysis by the AITFL, caused by an external rotation force. This occurs because the distal tibial physis closes from medial to lateral, leaving the lateral portion vulnerable.

Question 2683

Topic: 4. Pediatrics

A 9-month-old infant is brought to the emergency department with a spiral fracture of the midshaft femur. The parents report the child caught his leg in the crib slats. What is the most appropriate next step in management?

. Immediate spica casting and discharge
. Flexible intramedullary nailing
. Full skeletal survey and child protection team consultation
. Application of a Pavlik harness
. External fixation

Correct Answer & Explanation

. Immediate spica casting and discharge

Explanation

A femur fracture in a non-ambulatory infant is highly suspicious for non-accidental trauma. A skeletal survey and consultation with child protective services must be initiated before definitive discharge or care.

Question 2684

Topic: Pediatric Upper Extremity & Spine

A 13-year-old premenarcheal girl (Risser 0) presents with adolescent idiopathic scoliosis. Radiographs demonstrate a right thoracic curve of 32 degrees. What is the most appropriate treatment recommendation?

. Observation with repeat radiographs in 6 months
. Physical therapy and core strengthening
. TLSO bracing for 16-23 hours per day
. Nighttime-only bending brace
. Posterior spinal fusion

Correct Answer & Explanation

. Observation with repeat radiographs in 6 months

Explanation

Bracing is indicated for skeletally immature patients (Risser 0-2) with a curve between 25 and 40 degrees. A TLSO worn for 16 to 23 hours a day is the most effective nonsurgical method to halt curve progression.

Question 2685

Topic: Pediatric Hip

A newborn with arthrogryposis multiplex congenita is found to have bilateral rigid, dislocated hips. Which of the following statements regarding the management of these hips is most accurate?

. Pavlik harness treatment is highly successful.
. Closed reduction is typically achievable by 3 months of age.
. Bilateral dislocations are often left untreated due to a high risk of stiffness and recurrence.
. Early open reduction is mandatory to achieve ambulation.
. Femoral shortening is contraindicated in arthrogrypotic hips.

Correct Answer & Explanation

. Pavlik harness treatment is highly successful.

Explanation

Teratologic hip dislocations in arthrogryposis are extremely rigid. Bilateral dislocations are frequently left untreated because surgical intervention carries a high risk of severe stiffness, while unreduced bilateral hips still permit functional ambulation.

Question 2686

Topic: Pediatric Hip

Following closed reduction and spica casting for DDH, a 1-year-old child's radiograph demonstrates failure of the ossific nucleus to appear within 1 year post-reduction. The femoral head appears broad and the neck is short. This presentation is most consistent with which complication?

. Residual acetabular dysplasia
. Avascular necrosis (AVN) of the femoral head
. Coxa magna
. Slipped capital femoral epiphysis
. Septic arthritis

Correct Answer & Explanation

. Residual acetabular dysplasia

Explanation

Failure of the ossific nucleus to appear within 1 year, or early signs of a broad head and short neck (coxa brevis), are classic radiographic indicators of avascular necrosis following DDH treatment. It is primarily associated with extreme abduction in the spica cast.

Question 2687

Topic: 4. Pediatrics

A 6-week-old female infant born breech is evaluated for DDH. Ultrasound examination using the Graf method reveals an alpha angle of 65 degrees and a beta angle of 45 degrees. What is the most appropriate management?

. Immediate Pavlik harness application
. Rigid abduction orthosis
. Reassurance and routine pediatric follow-up
. Closed reduction and spica casting
. Repeat ultrasound in 6 weeks

Correct Answer & Explanation

. Immediate Pavlik harness application

Explanation

According to the Graf ultrasound classification for DDH, an alpha angle greater than 60 degrees and a beta angle less than 55 degrees represent a normal, mature infant hip (Type I). No intervention is necessary.

Question 2688

Topic: Pediatric Upper Extremity & Spine

A 12-year-old girl with adolescent idiopathic scoliosis (AIS) presents with a right thoracic curve. She is premenarcheal, Risser 0, and her curve measures 35 degrees on standing PA radiograph. Which of the following is the most appropriate next step in management?

. Observation with clinical follow-up in 6 months
. Thoracolumbosacral orthosis (TLSO) bracing for 16-23 hours per day
. Nighttime only bending brace
. Posterior spinal fusion
. Physical therapy and core strengthening

Correct Answer & Explanation

. Observation with clinical follow-up in 6 months

Explanation

Bracing is indicated for skeletally immature patients (Risser 0-2) with AIS curves between 25 and 45 degrees. A TLSO worn for 16-23 hours daily has been shown to significantly decrease the risk of curve progression to the surgical threshold.

Question 2689

Topic: Pediatric Hip

A 6-week-old female infant, born in the breech presentation, is evaluated for developmental dysplasia of the hip (DDH). Ultrasound reveals an alpha angle of 48 degrees and a beta angle of 80 degrees on the left hip. The hip is stable on clinical exam. What is the most appropriate management?

. Observation and repeat ultrasound in 1 month
. Application of a Pavlik harness
. Rigid abduction bracing
. Closed reduction and spica casting
. Open reduction

Correct Answer & Explanation

. Observation and repeat ultrasound in 1 month

Explanation

An alpha angle of less than 60 degrees indicates acetabular dysplasia (Graf type II or worse). In a 6-week-old infant with dysplasia, a Pavlik harness is the gold standard initial treatment to promote normal acetabular development.

Question 2690

Topic: Pediatric Hip

A 3-year-old child presents with a neglected right developmental dysplasia of the hip (DDH). She undergoes an open reduction, pelvic osteotomy, and femoral shortening osteotomy. Which of the following is the most devastating complication specific to the surgical treatment of DDH?

. Chondrolysis
. Avascular necrosis (AVN) of the femoral head
. Sciatic nerve palsy
. Leg length discrepancy
. Heterotopic ossification

Correct Answer & Explanation

. Chondrolysis

Explanation

Avascular necrosis of the femoral head is the most severe and specific complication of DDH treatment, often resulting from excessive pressure on the femoral head or disruption of the medial circumflex femoral artery during reduction.

Question 2691

Topic: 4. Pediatrics
A 13-year-old boy presents with ankle pain following a fall. Radiographs demonstrate a Salter-Harris III fracture of the anterolateral aspect of the distal tibial epiphysis. What is the deforming force and the structure responsible for this avulsion fracture?
. Plantar flexion; anterior talofibular ligament
. External rotation; anterior inferior tibiofibular ligament (AITFL)
. Inversion; calcaneofibular ligament
. External rotation; deltoid ligament
. Eversion; posterior inferior tibiofibular ligament

Correct Answer & Explanation

. External rotation; anterior inferior tibiofibular ligament (AITFL)

Explanation

This describes a Tillaux fracture, which occurs due to an external rotation force. The anterior inferior tibiofibular ligament (AITFL) avulses the anterolateral distal tibial epiphysis, which is the last portion of the physis to close.

Question 2692

Topic: Pediatric Hip

A 5-month-old infant with developmental dysplasia of the hip has been treated in a Pavlik harness for 4 weeks. Repeat ultrasound reveals that the left hip remains persistently dislocated. What is the most appropriate next step in management?

. Continue the Pavlik harness for another 4 weeks
. Transition to a rigid abduction orthosis (e.g., Ilfeld brace)
. Closed reduction and spica casting under general anesthesia
. Open reduction and pelvic osteotomy
. Femoral varus derotational osteotomy

Correct Answer & Explanation

. Continue the Pavlik harness for another 4 weeks

Explanation

Failure to achieve reduction in a Pavlik harness after 3-4 weeks requires abandonment of the harness to prevent "Pavlik harness disease" (damage to the posterior acetabular wall). The next step is closed reduction and spica casting under anesthesia.

Question 2693

Topic: 4. Pediatrics

A neonate with arthrogryposis multiplex congenita is found to have bilateral teratologic hip dislocations. The hips are stiff and cannot be reduced on physical examination. What is the standard recommendation for management?

. Immediate application of a Pavlik harness
. Immediate closed reduction and spica casting
. Delay surgical intervention until the child is 6-12 months old for bilateral open reductions
. Bilateral femoral shortening osteotomies at 3 months of age
. No intervention is indicated as ambulation is not possible

Correct Answer & Explanation

. Immediate application of a Pavlik harness

Explanation

Teratologic hip dislocations are stiff and irreducible by conservative means (Pavlik harness or simple closed reduction is contraindicated/ineffective). Treatment typically involves open reduction when the infant is older (6-12 months) to allow adequate size for surgery.

Question 2694

Topic: Pediatric Hip

During the radiographic evaluation of a 2-year-old child for developmental dysplasia of the hip (DDH), the orthopedist draws a horizontal line connecting the bilateral triradiate cartilages. What is the name of this reference line?

. Perkin's line
. Hilgenreiner's line
. Shenton's line
. Wiberg's angle
. Klein's line

Correct Answer & Explanation

. Perkin's line

Explanation

Hilgenreiner's line is a horizontal line drawn through the bilateral triradiate cartilages. Perkin's line is drawn perpendicular to Hilgenreiner's line at the lateral edge of the acetabulum, creating quadrants to locate the ossific nucleus of the femoral head.

Question 2695

Topic: Pediatric Hip

A 6-week-old female is being treated with a Pavlik harness for developmental dysplasia of the hip (DDH). At her 1-week follow-up, the mother notes that the child has stopped extending the knee on the affected side. On examination, the quadriceps are flaccid. What is the most appropriate next step in management?

. Continue the Pavlik harness and reassure the mother
. Discontinue the Pavlik harness and observe for neurologic recovery
. Adjust the anterior strap to increase hip flexion
. Adjust the posterior strap to decrease hip abduction
. Transition immediately to a rigid hip abduction orthosis

Correct Answer & Explanation

. Continue the Pavlik harness and reassure the mother

Explanation

Femoral nerve palsy is a known complication of excessive hip flexion in a Pavlik harness. The harness must be discontinued to allow for nerve recovery before resuming any abduction treatment.

Question 2696

Topic: 4. Pediatrics

A 9-month-old child with DDH is undergoing closed reduction and spica casting. According to Ramsey, the safe zone for positioning the hip to minimize the risk of avascular necrosis while maintaining reduction is defined by the arc between which two positions?

. Maximum flexion and maximum extension
. Maximum abduction and maximum adduction
. Maximum abduction and the angle of redislocation in adduction
. Maximum flexion and the angle of redislocation in extension
. Maximum internal rotation and maximum external rotation

Correct Answer & Explanation

. Maximum flexion and maximum extension

Explanation

Ramsey's safe zone is the arc between maximum abduction and the angle at which the hip redislocates in adduction. Forcing the hip into extreme abduction outside this zone significantly increases the risk of avascular necrosis.

Question 2697

Topic: Pediatric Hip

An 18-month-old requires open reduction for a chronically dislocated hip due to DDH. Which of the following anatomical structures is considered an intra-articular obstacle to successful closed reduction?

. Iliopsoas tendon
. Adductor longus muscle
. Transverse acetabular ligament
. Anterior joint capsule
. Reflected head of the rectus femoris

Correct Answer & Explanation

. Iliopsoas tendon

Explanation

Intra-articular obstacles to reduction in DDH include the transverse acetabular ligament, ligamentum teres, pulvinar, and an inverted limbus. Extra-articular obstacles include the iliopsoas, adductors, and an hourglass constriction of the capsule.

Question 2698

Topic: Pediatric Hip

A 4-week-old female born breech undergoes an ultrasound screening for DDH. The report notes an alpha angle of 45 degrees and a beta angle of 65 degrees. According to Graf's classification, what does the alpha angle represent?

. Cartilaginous roof coverage
. Bony roof coverage
. Femoral head sphericity
. Acetabular anteversion
. Femoral neck-shaft angle

Correct Answer & Explanation

. Cartilaginous roof coverage

Explanation

In the Graf ultrasound method, the alpha angle measures the bony roof of the acetabulum (normal is > 60 degrees). The beta angle measures the cartilaginous roof.

Question 2699

Topic: Pediatric Hip

A 6-month-old infant was treated with a Pavlik harness for 3 months. Recent radiographs reveal fragmentation and delayed ossification of the left femoral head. Excessive positioning in which direction during treatment is most strongly associated with this complication?

. Flexion
. Extension
. Abduction
. Adduction
. Internal rotation

Correct Answer & Explanation

. Flexion

Explanation

Avascular necrosis (AVN) of the femoral head in DDH treatment is most commonly caused by excessive abduction. This position compresses the medial circumflex femoral artery, compromising blood flow to the epiphysis.

Question 2700

Topic: Pediatric Hip

A 13-year-old obese male presents with left groin and knee pain. On physical examination, which finding is considered the classic pathognomonic sign during passive flexion of the affected hip?

. Obligate internal rotation
. Obligate external rotation
. Severe limitation of hip abduction
. Severe limitation of hip adduction
. A positive Trendelenburg sign

Correct Answer & Explanation

. Obligate internal rotation

Explanation

Obligate external rotation during passive hip flexion is the classic physical examination finding in Slipped Capital Femoral Epiphysis (SCFE). This occurs due to the anterior and superior translation of the femoral neck relative to the epiphysis.

Test Yourself

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

On this Page