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4. Pediatrics MCQs

Practice Set 290 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 5781

Topic: Pediatric Lower Extremity

A 16-year-old male presents with chronic anterior knee pain, exacerbated by kneeling and direct pressure. Examination reveals swelling and tenderness directly over the patellar tendon insertion on the tibial tubercle. Radiographs show fragmentation and irregularity of the tibial tubercle. What is the most likely diagnosis?

. Patellofemoral pain syndrome
. Sinding-Larsen-Johansson syndrome
. Osgood-Schlatter disease
. Patellar tendinopathy
. Chondromalacia patellae

Correct Answer & Explanation

. Osgood-Schlatter disease

Explanation

The clinical picture of anterior knee pain, swelling, and tenderness over the tibial tubercle, along with radiographic fragmentation/irregularity of the tibial tubercle in an adolescent male, is classic for Osgood-Schlatter disease. This is an apophysitis (traction apophysitis) of the tibial tubercle due to repetitive stress from the quadriceps tendon pulling on the developing bone. Sinding-Larsen-Johansson syndrome is similar but affects the inferior pole of the patella. Patellofemoral pain syndrome and chondromalacia patellae involve the patellofemoral joint. Patellar tendinopathy (jumper's knee) affects the patellar tendon, usually in older adolescents or adults, without tibial tubercle fragmentation.

Question 5782

Topic: Pediatric Upper Extremity & Spine

Which of the following is the most effective bracing technique for an adolescent with idiopathic scoliosis with a Cobb angle of 28 degrees and Risser 0-1 (skeletally immature)?

. Soft thoracolumbosacral orthosis (TLSO)
. Dynamic scoliosis brace (e.g., SpineCor)
. Milwaukee brace (cervicothoracolumbosacral orthosis)
. Nighttime-only bracing with a rigid TLSO
. Observation only

Correct Answer & Explanation

. Nighttime-only bracing with a rigid TLSO

Explanation

For skeletally immature adolescents with idiopathic scoliosis (Risser 0-1) and a Cobb angle between 20-40 degrees, bracing is indicated to prevent curve progression. While full-time rigid TLSOs are traditional, recent evidence and guidelines support the efficacy of nighttime-only bracing with a rigid TLSO for similar outcomes, improving patient compliance and quality of life. Soft braces or dynamic braces have not shown superior efficacy. The Milwaukee brace is rarely used now due to its bulkiness and cosmetic issues, reserved for very high thoracic curves. Observation only is inappropriate for a progressive curve in an immature patient.

Question 5783

Topic: 4. Pediatrics
A 6-month-old infant presents with a 'clicky' hip on examination, but the Ortolani and Barlow tests are negative. Ultrasound reveals an alpha angle of 55 degrees and a beta angle of 65 degrees. What is the most appropriate next step in management?
. Pavlik harness application.
. Referral for open reduction.
. Observation and repeat ultrasound in 3 months.
. Double diapering.
. Hip spica cast application.

Correct Answer & Explanation

. Observation and repeat ultrasound in 3 months.

Explanation

The Graf ultrasound classification for DDH uses alpha and beta angles. An alpha angle of 55 degrees (normal > 60 degrees) indicates a dysplastic acetabulum, and a beta angle of 65 degrees (normal < 55 degrees) indicates an unossified cartilaginous roof. This combination suggests a Graf Type IIa hip, which is considered 'immature' but not frankly dysplastic or dislocated in an infant under 3 months. However, for a 6-month-old, an alpha angle of 55 degrees is considered abnormal. Given the negative Ortolani/Barlow tests, and the age, this is likely a mild dysplasia. The most appropriate next step is observation with close follow-up and repeat ultrasound in 3 months. Intervention with a Pavlik harness is typically for dislocated or dislocatable hips (Graf types III/IV or IIc/IId/III/IV in older infants), or if the hip has not matured by 3 months. Open reduction is for failed conservative management. Double diapering is not an effective treatment. Spica cast is for older or more severe cases.

Question 5784

Topic: Pediatric Hip

An obese 12-year-old boy presents with left hip pain and the radiograph shown. He is diagnosed with a slipped capital femoral epiphysis (SCFE). Which of the following treatments is contraindicated due to its association with a high risk of osteonecrosis?

. Percutaneous pinning in situ
. Closed reduction prior to pinning
. Prophylactic pinning of the contralateral hip
. Open subtrochanteric osteotomy
. Spica cast immobilization

Correct Answer & Explanation

. Closed reduction prior to pinning

Explanation

Correct Answer: BForceful closed reduction of a slipped capital femoral epiphysis is contraindicated because it significantly increases the risk of osteonecrosis (avascular necrosis) of the femoral head by disrupting the already tenuous retinacular blood supply. The standard of care is in situ fixation. Spica casting is generally not used as primary treatment due to poor control and stiffness, but closed reduction is the most dangerous intervention listed.

Question 5785

Topic: Pediatric Hip

A 32-year-old woman presents with right hip pain and the radiograph shown, demonstrating developmental dysplasia of the hip (DDH) with a high acetabular index. A Bernese (Ganz) periacetabular osteotomy is planned. Which of the following is a primary biomechanical goal of this procedure?

. Medialization of the hip joint center
. Lateralization of the hip joint center
. Increasing the femoral neck-shaft angle
. Decreasing the femoral anteversion
. Proximalization of the greater trochanter

Correct Answer & Explanation

. Medialization of the hip joint center

Explanation

Correct Answer: AThe Bernese periacetabular osteotomy (PAO) is designed to reorient the acetabulum to improve femoral head coverage. A key biomechanical goal and advantage of the PAO is the ability to medialize the hip joint center, which decreases the joint reactive forces by reducing the lever arm of the body weight, thereby improving the mechanical environment of the dysplastic hip.

Question 5786

Topic: Pediatric Hip
A 38-year-old runner presents with right hip pain. Imaging reveals a well-circumscribed, radiolucent lesion with a sclerotic margin in the anterosuperior aspect of the femoral neck. This lesion, known as a synovial herniation pit, is most frequently associated with which of the following underlying conditions?
. Legg-Calvé-Perthes disease
. Slipped capital femoral epiphysis
. Femoroacetabular impingement
. Developmental dysplasia of the hip
. Avascular necrosis of the femoral head

Correct Answer & Explanation

. Femoroacetabular impingement

Explanation

Synovial herniation pits (Pitt's pits) are benign, often incidental, radiolucent lesions with sclerotic margins typically located in the anterosuperior femoral neck. They are thought to result from mechanical abrasion and herniation of synovium into the bone. They are highly associated with cam-type femoroacetabular impingement (FAI), where the abnormal femoral head-neck junction abuts the acetabular rim.

Question 5787

Topic: Pediatric Hip
A 7-year-old boy with a history of a painless limp is diagnosed with Legg-Calvé-Perthes disease. An arthrogram is performed to evaluate joint congruency. The maximum abduction/internal rotation view is shown in Figure A, and the abduction view is shown in Figure B. The failure of the lateral epiphysis to slide under the acetabular edge with abduction, accompanied by medial dye pooling, is pathognomonic for which of the following conditions?
. Cam impingement
. Hinge abduction
. Pincer impingement
. Coxa magna
. Slipped capital femoral epiphysis

Correct Answer & Explanation

. Hinge abduction

Explanation

The arthrogram images demonstrate classic hinge abduction, a critical finding in severe Legg-Calvé-Perthes disease. Hinge abduction occurs when the enlarged, deformed lateral portion of the femoral head extrudes and impinges against the lateral margin of the acetabulum during abduction. Instead of gliding smoothly into the acetabulum, the femoral head hinges on the acetabular rim, causing the medial joint space to widen (distract), which is visualized as medial dye pooling on the arthrogram. Persistent hinge abduction prevents normal spherical remodeling of the femoral head and is an indication for surgical intervention to restore congruency.

Question 5788

Topic: Pediatric Hip

A 32-year-old woman presents with chronic right hip pain. The AP pelvis radiograph demonstrates developmental dysplasia of the hip with a high acetabular index (27 degrees) and anterior undercoverage. Assuming the joint space is well-preserved and there is no advanced osteoarthritis, which of the following is the most appropriate surgical intervention?

. Total hip arthroplasty
. Hip arthrodesis
. Bernese (Ganz) periacetabular osteotomy
. Proximal femoral derotational osteotomy
. Surgical hip dislocation and osteochondroplasty

Correct Answer & Explanation

. Bernese (Ganz) periacetabular osteotomy

Explanation

Correct Answer: Bernese (Ganz) periacetabular osteotomyThe radiograph shows symptomatic developmental dysplasia of the hip (DDH) with significant anterolateral undercoverage. In a young, active patient with preserved joint space and symptomatic dysplasia, a redirectional pelvic osteotomy is indicated to improve femoral head coverage and biomechanics, thereby delaying or preventing the onset of osteoarthritis. The Bernese (Ganz) periacetabular osteotomy is the most widely accepted procedure for this indication in adults, as it allows for multiplanar correction while maintaining the integrity of the posterior column.

Question 5789

Topic: Pediatric Hip
A 7-year-old boy with a history of a painless limp undergoes an arthrogram of the hip, as shown in the provided images. The failure of the lateral epiphysis to slide under the acetabular edge during abduction is diagnostic of which of the following?
. Cam impingement
. Pincer impingement
. Hinge abduction
. Slipped capital femoral epiphysis
. Coxa vara

Correct Answer & Explanation

. Hinge abduction

Explanation

The arthrogram demonstrates hinge abduction, a severe complication of Legg-Calvé-Perthes disease where the deformed, extruded lateral portion of the femoral head hinges against the lateral acetabular margin during abduction, preventing concentric reduction. This persistent hinge abduction prevents femoral head remodeling by the acetabulum.

Question 5790

Topic: Pediatric Hip

An obese 12-year-old boy presents with left hip pain and an antalgic gait. A radiograph is provided. Which of the following complications is most strongly associated with attempts at closed reduction of this condition?

. Chondrolysis
. Osteonecrosis of the femoral head
. Femoroacetabular impingement
. Premature physeal closure
. Slipped capital femoral epiphysis of the contralateral hip

Correct Answer & Explanation

. Osteonecrosis of the femoral head

Explanation

Correct Answer: Osteonecrosis of the femoral headThe radiograph shows a slipped capital femoral epiphysis (SCFE). Closed reduction of a SCFE is contraindicated because it significantly increases the risk of osteonecrosis (avascular necrosis) of the femoral head. The recommended treatment is percutaneous pinning in situ.

Question 5791

Topic: Pediatric Hip

A 32-year-old woman presents with chronic right hip pain. A radiograph is provided, demonstrating developmental dysplasia of the hip with a high acetabular index. Which of the following is the primary biomechanical goal of the most appropriate joint-preserving surgery for this patient?

. Medialization of the hip center of rotation and improvement of anterior and lateral femoral head coverage
. Lateralization of the hip center of rotation to increase abductor moment arm
. Creation of a fibrous hinge to prevent superior migration
. Resection of the cam lesion to prevent impingement
. Proximalization of the greater trochanter

Correct Answer & Explanation

. Medialization of the hip center of rotation and improvement of anterior and lateral femoral head coverage

Explanation

Correct Answer: Medialization of the hip center of rotation and improvement of anterior and lateral femoral head coverageThe radiograph shows developmental dysplasia of the hip (DDH). The Bernese (Ganz) periacetabular osteotomy is the treatment of choice for symptomatic dysplasia with preserved joint space. Its biomechanical goals include improving anterior and lateral coverage of the femoral head and medializing the hip center of rotation to decrease joint contact forces.

Question 5792

Topic: Pediatric Hip

A 7-year-old boy with a history of a painless limp presents with limited abduction and spasm on internal rotation. Radiographs obtained during an arthrogram are shown. The failure of the lateral epiphysis to slide under the acetabular edge during abduction is diagnostic of which of the following?

. Cam-type femoroacetabular impingement
. Hinge abduction
. Pincer-type femoroacetabular impingement
. Slipped capital femoral epiphysis
. Chondrolysis

Correct Answer & Explanation

. Hinge abduction

Explanation

Correct Answer: BThe radiographs demonstrate classic hinge abduction in a patient with Legg-Calve-Perthes disease. Hinge abduction occurs when the enlarged, deformed lateral portion of the femoral head impinges on the lateral acetabular margin during abduction, preventing the head from sliding concentrically into the acetabulum. The arthrogram shows medial dye pooling due to distraction of the joint. Persistent hinge abduction prevents proper femoral head remodeling and is an indication for surgical intervention.

Question 5793

Topic: Pediatric Hip

An obese 12-year-old boy presents with left hip pain and an obligatory external rotation during hip flexion. An AP pelvis radiograph is shown. Which of the following is the most appropriate definitive management for the left hip?

. Spica cast immobilization
. Closed reduction and internal fixation
. Percutaneous pinning in situ
. Proximal femoral osteotomy
. Observation and non-weight bearing

Correct Answer & Explanation

. Percutaneous pinning in situ

Explanation

Correct Answer: CThe radiograph demonstrates a slipped capital femoral epiphysis (SCFE) of the left hip. The standard of care for a stable SCFE is percutaneous pinning in situ with a single cannulated screw to prevent further slippage and promote physeal closure. Closed reduction is contraindicated as it significantly increases the risk of osteonecrosis. Spica casting and observation are not appropriate definitive treatments.

Question 5794

Topic: Pediatric Hip

A 32-year-old woman presents with right hip pain that has failed conservative management. An AP pelvis radiograph is shown, demonstrating a high acetabular index and anterolateral undercoverage of the femoral head with preserved joint space. Which of the following surgical interventions is most appropriate?

. Total hip arthroplasty
. Hip arthrodesis
. Bernese (Ganz) periacetabular osteotomy
. Proximal femoral varus osteotomy
. Arthroscopic labral debridement

Correct Answer & Explanation

. Bernese (Ganz) periacetabular osteotomy

Explanation

Correct Answer: CThe radiograph reveals developmental dysplasia of the hip (DDH) with significant anterolateral undercoverage but preserved joint space. In a young, active patient with symptomatic DDH and minimal osteoarthritis, a Bernese (Ganz) periacetabular osteotomy is the procedure of choice. It reorients the acetabulum to improve femoral head coverage and biomechanics, delaying or preventing the need for total hip arthroplasty.

Question 5795

Topic: Pediatric Hip

A 7-year-old boy with a known history of Legg-Calve-Perthes disease presents with worsening pain and a limp. An AP radiograph in maximum abduction is shown. The failure of the lateral epiphysis to slide under the acetabular edge with abduction is known as hinge abduction. This biomechanical phenomenon is most likely to result in which of the following?

. Spontaneous resolution of the deformity
. Prevention of femoral head remodeling by the acetabulum
. Medial subluxation of the femoral head
. Overgrowth of the greater trochanter
. Avascular necrosis of the acetabulum

Correct Answer & Explanation

. Prevention of femoral head remodeling by the acetabulum

Explanation

Correct Answer: BThe radiograph demonstrates hinge abduction, where the extruded, enlarged lateral portion of the femoral head hinges against the lateral acetabular margin during abduction. This prevents the femoral head from seating concentrically in the acetabulum, thereby preventing the acetabulum from acting as a spherical mold to remodel the femoral head during the healing phase of Legg-Calve-Perthes disease.

Question 5796

Topic: 4. Pediatrics

An 8-month-old infant is noted to have a congenital spinal deformity as shown in the clinical photograph. Neurologic examination is normal. Which of the following screening tests is most highly recommended to identify the most common associated extraspinal anomaly in this patient?

. Echocardiogram
. Renal ultrasound
. MRI of the brain
. Pulmonary function tests
. Barium swallow

Correct Answer & Explanation

. Renal ultrasound

Explanation

Correct Answer: BThe patient has congenital scoliosis. Approximately 60% of patients with congenital vertebral anomalies have associated abnormalities in other organ systems. The most common associated extraspinal anomalies are genitourinary (occurring in up to 37% of patients), such as renal agenesis, duplication, or ectopia. Therefore, a renal ultrasound is the most appropriate and least invasive initial screening test.

Question 5797

Topic: Pediatric Hip

A 13-year-old boy presents with an acute, unstable slipped capital femoral epiphysis (SCFE) and cannot bear weight. He undergoes urgent single-screw in situ fixation. Which of the following complications has the highest incidence specifically associated with the unstable nature of this slip?

. Chondrolysis
. Avascular necrosis (AVN)
. Femoroacetabular impingement
. Contralateral slip
. Implant failure

Correct Answer & Explanation

. Avascular necrosis (AVN)

Explanation

Unstable SCFE is defined by the inability to bear weight and carries a significantly higher risk of avascular necrosis (AVN), ranging from 10% to 50%. The disruption of the retinacular vessels during the acute displacement is the primary cause.

Question 5798

Topic: Pediatric Hip

A 13-year-old obese male presents with acute-on-chronic thigh pain and is unable to bear weight. Examination reveals an obligatory external rotation with passive hip flexion. Radiographs confirm a severe, unstable Slipped Capital Femoral Epiphysis (SCFE). During closed reduction and pinning, which of the following vascular structures is most at risk of injury, potentially causing avascular necrosis?

. Lateral femoral circumflex artery
. Medial femoral circumflex artery
. Obturator artery
. Inferior gluteal artery
. First perforating branch of the profunda femoris

Correct Answer & Explanation

. Medial femoral circumflex artery

Explanation

The medial femoral circumflex artery (specifically its posterosuperior retinacular branches) provides the dominant blood supply to the capital femoral epiphysis. Forceful or non-anatomic reduction of an unstable SCFE places this vessel at high risk of tension and thrombosis, leading to avascular necrosis.

Question 5799

Topic: Pediatric Upper Extremity & Spine
A 5-year-old girl sustains a Gartland type III extension-type supracondylar humerus fracture with posterolateral displacement of the distal fragment. Upon evaluation, she cannot make a forceful 'A-OK' sign. Which nerve is most likely injured?
. Ulnar nerve
. Radial nerve
. Anterior interosseous nerve
. Musculocutaneous nerve
. Posterior interosseous nerve

Correct Answer & Explanation

. Anterior interosseous nerve

Explanation

Posterolateral displacement of the distal fragment in an extension-type supracondylar humerus fracture places the medial structures at risk, specifically the median nerve and its anterior interosseous nerve (AIN) branch. The AIN innervates the FPL and FDP to the index finger, required to make the 'A-OK' sign.

Question 5800

Topic: Pediatric Hip

A 12-year-old obese male presents with a left-sided Slipped Capital Femoral Epiphysis (SCFE) and undergoes in situ pinning. Prophylactic pinning of the contralateral hip would be most strongly indicated if the patient had which of the following concomitant conditions?

. Type 1 Diabetes Mellitus
. Asthma
. Hypothyroidism
. Attention Deficit Hyperactivity Disorder
. Scoliosis

Correct Answer & Explanation

. Hypothyroidism

Explanation

Prophylactic contralateral pinning in SCFE is strongly indicated in patients with underlying endocrine disorders (such as hypothyroidism or renal osteodystrophy) or in children presenting at an age less than 10 years, due to the exceptionally high risk of bilateral involvement.

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