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4. Pediatrics MCQs

Practice Set 82 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 1621

Topic: 4. Pediatrics

A 13-year-old boy has a radiographically mild, clinically stable slipped capital femoral epiphysis (SCFE). What is the most appropriate treatment? Review Topic

. Spica casting
. Open reduction and internal fixation
. Single screw in situ fixation of the epiphysis
. Two-screw in situ fixation of the epiphysis
. Crutches and no weight bearing for 6 weeks

Correct Answer & Explanation

. Single screw in situ fixation of the epiphysis

Explanation

The accepted treatment of a stable SCFE lesion involves fixation of the epiphysis in situ with a single screw that is perpendicular to the epiphysis and central in both the AP and lateral planes. Constructs such as the three-screw inverted triangle configuration have increased rates of penetration of the femoral head as well as femoral head osteonecrosis. Spica casting was once a popular treatment modality but is associated with a high incidence of chondrolysis and is no longer recommended. Closed reduction attempts increase the risk of osteonecrosis.(SBQ13PE.46) What developmental milestones are likely to be present in a 30-month-old child?Review TopicHand dominance establishedHops on one footHeel-to-toe walkPuts shoes on correct feetManages buttonsHand dominance is usually established in the third year of life.Normally, children younger than 2 years of age are ambidextrous. In some normal cases this persists after 2 years. Although there is some variability in this timing, strong hand preference in a younger child may be the result of a neurologic deficit.Frankenburg et al. used the Denver Developmental Screening Test (DDST) to evaluate 1036 Denver area children from 2 to 6.4 years. The ages at which 25, 50, 75 and 90 percent of children could perform tasks were calculated to establish norms for the sample. The authors stress that the DDST is not an intelligence test, but rather a screening test to be used in clinical practice to determine whether a child's development is within the normal range.IllustrationAshowstheDDST.Incorrect2:Normalfor

Question 1622

Topic: Pediatric Hip
Figures 39a and 39b show the current radiographs of an 8-year-old girl who has had pain in the left thigh for the past 3 months. She was recently diagnosed with hypothyroidism and started treatment 1 week ago. Examination reveals a mild abductor deficiency limp on the left side. She lacks 30 degrees of internal rotation on the left hip compared with the right hip. Management should consist of
. abductor muscle strengthening.
. a left 1-½ hip spica cast.
. closed reduction and pinning of the left hip.
. symptomatic treatment with crutch walking and nonsteroidal anti-inflammatory drugs.
. in situ pinning of both hips.

Correct Answer & Explanation

. in situ pinning of both hips.

Explanation

DISCUSSION: The radiographs confirm a slipped capital femoral epiphysis of the left hip, as well as a widened growth plate on the contralateral hip. This is considered a stable slip because the patient is able to walk. Treatment options for stable slips include in situ pinning, bone graft epiphysiodesis, and in some centers severe slips are treated with primary osteotomy and epiphyseal fixation. Percutaneous in situ fixation is the most popular and widely used method of treatment. This juvenile patient has an endocrine condition and a widened growth plate on the right side; therefore, strong consideration should be given to pinning the contralateral hip as a "pre-slip." Muscle strengthening, hip spica casting, and closed reduction have no place in the primary treatment of a stable slipped capital femoral epiphysis. REFERENCES: Loder RT, Richards BS, Shapiro PS, et al: Acute slipped capital femoral epiphysis: The importance of physeal stability. J Bone Joint Surg Am 1993;75:1134-1140. Loder R, Wittenberg B, DeSilva G: Slipped capital femoral epiphysis associated with endocrine disorders. J Pediatr Orthop 1995;15:349-356. Aronson DD, Carlson WE: Slipped capital femoral epiphysis: A prospective study of fixation with a single screw. J Bone Joint Surg Am 1992;74:810-819.

Question 1623

Topic: 4. Pediatrics
What is the primary limiting membrane and mechanical support for the periphery of the physis?
. Perichondrial ring of La Croix
. Groove of Ranvier
. Zone of provisional calcification
. Last intact transverse septum
. Primary spongiosa

Correct Answer & Explanation

. Perichondrial ring of La Croix

Explanation

The perichondrial fibrous ring of La Croix acts as a limiting membrane that provides mechanical support for the bone-cartilage junction of the growth plate. It is continuous with the ossification groove of Ranvier, which contributes chondrocytes for the increase in width of the growth plate.

Question 1624

Topic: Pediatric Hip

A 12-year-old boy has had left thigh pain for the past 4 months. Examination shows lack of internal rotation and abduction, and external rotation with hip flexion. A radiograph is shown in Figure 87. What is the most appropriate treatment? Review Topic

. Physical therapy
. In situ pinning
. Reduction and percutaneous pinning
. Surgical dislocation of the hip with reduction under direct vision
. Spica casting

Correct Answer & Explanation

. Physical therapy

Explanation

The patient has a stable slipped capital femoral epiphysis (SCFE). Preferred treatment of stable SCFE is in situ pinning. In situ fixation of stable SCFE has an extremely low rate of osteonecrosis. Gentle postural reduction with hip capsulotomy or surgical dislocation of the hip with reduction has been advocated for unstable SCFE.

Question 1625

Topic: Pediatric Lower Extremity

The CT scan shows the involvement area is approximately 30% of the posterior facet. What is the most appropriate treatment?

. Surgical resection
. Lateral column lengthening
. Coalition resection and lateral column lengthening
. Triple arthrodesis

Correct Answer & Explanation

. Surgical resection

Explanation

DISCUSSIONRadiographs reveal a talocalcaneal coalition. The incidence of tarsal coalition in the general population ranges between 2% and 13%. The incidence of tarsal coalition among patients with FGFR-related craniosynostosis syndromes is much higher than among the general population. Tarsal coalitions have been noted in FGFR-1-, FGFR-2-, and FGFR-3-related craniosynostosis syndromes of Apert, Pfeiffer, Crouzon, Jackson-Weiss, and Muenke, but not in Beare-Stevenson or Crouzonodermoskeletal syndromes. The FGFR genes are involved in cell proliferation, differentiation, migration, apoptosis, and pattern formation.Additionally, nonsyndromic familial coalitions have been described with autosomal-dominant patterns of inheritance.Cross-sectional imaging should always be obtained prior to resection of a radiographically evident coalition to define the extent of the coalition and determine the coexistence of an additional coalition. CT scan is the gold standard test; however, MRI can be helpful to define a suspected fibrous coalition if a CT scan is nondiagnostic. A bone scan may be useful if pain or history is atypical for a symptomatic coalition. Laboratory tests such as CBC, ESR, CRP, ANA, and RF may be indicated if the imaging evaluation does not confirm a tarsal coalition and if there is concern for malignancy, infection, or inflammatory arthritis.Investigators have suggested that larger talocalcaneal coalitions with surface areas larger than 33% to 50% of the size of the posterior facet are unsuitable for resection and primary arthrodesis should be considered. However, a study by Koshbin and associates found that with long-term follow-up, favorable functional outcomes were seen even with resections of large talocalcaneal coalitions occupying more than 50% of surface area.

Question 1626

Topic: 4. Pediatrics
What is the most likely area of injury in a distal femoral physeal fracture?
. Femoral attachment of the medial collateral ligament
. Tibial attachment of the medial collateral ligament
. Hypertrophic zone of the growth plate
. Proliferative zone of the growth plate

Correct Answer & Explanation

. Hypertrophic zone of the growth plate

Explanation

This patient likely has a physeal injury to the distal femoral physis. Stress radiographs or an MRI scan will most reliably reveal this diagnosis. The growth plate, when injured, is most commonly fractured through the hypertrophic zone of cartilage, its weakest point. This patient is optimally treated in a cylindrical or long-leg cast. Younger patients can be treated with a hip spica with a leg extension.

Question 1627

Topic: 4. Pediatrics
Examination of a 5-year-old boy with amyoplasia shows a flexion contracture of 70° of the right knee. The active arc of motion is from 70° to 90°, and the opposite knee has a flexion contracture of 10°. Both hips are dislocated with flexion contractures of 10°, passive hip motion is from 10° to 90° of flexion, and the feet are plantigrade and easily braceable. Despite a daily stretching program, the parents and physical therapists note that it is increasingly difficult for him to walk because of the flexion contracture of the right knee. Management of the knee flexion contracture should now include:
. intense physical therapy.
. an intramuscular injection of botulinum toxin A.
. radical posterior soft-tissue release.
. supracondylar femoral extension osteotomy.
. gradual correction with a circular ring external fixator.

Correct Answer & Explanation

. radical posterior soft-tissue release.

Explanation

DISCUSSION: Most children with amyoplasia are ambulatory and when a decrease in function occurs because of a severe contracture, it must be addressed. A radical posterior soft-tissue release, including the posterior knee capsule and often the collateral ligaments and the posterior cruciate ligament, is needed to obtain extension. After the age of 1 year, aggressive physical therapy will do little to correct a contracture. Botulinum toxin A is indicated for spasticity and is contraindicated with severe contractures. Supracondylar femoral extension osteotomy works well, but will remodel at an average rate of 1° per month, which is not considered ideal in a young patient. Gradual correction with a circular ring external fixator is an option, but a soft-tissue release will also most likely be needed for a contracture of this severity. REFERENCES: Sarwark JF, MacEwen GD, Scott CI Jr: Amyoplasia (a common form of arthrogryposis). J Bone Joint Surg Am 1990;72:465-469. DelBello DA, Watts HG: Distal femoral extension osteotomy for knee flexion contracture in patients with arthrogryposis. J Pediatr Orthop 1996;16:122-126. Sells JM, Jaffe KM, Hall JG: Amyoplasia, the most common type of arthrogryposis: The potential for good outcome. Pediatrics 1996;97:225-231.

Question 1628

Topic: 4. Pediatrics
Figure 45 shows the current radiograph of an 11-year-old girl who sustained a simple nondisplaced fracture of the distal radius 4 weeks ago. Management at the time of injury consisted of application of a short arm cast but no manipulation. What is the major concern at this time?
. Stiffness of the wrist joint
. Physeal growth arrest
. Physeal overgrowth
. Osteonecrosis of the metaphysis
. Posttraumatic arthritis

Correct Answer & Explanation

. Physeal growth arrest

Explanation

DISCUSSION: The fracture pattern represents a Peterson type I physeal injury, which is a comminuted metaphyseal fracture in which the fracture lines extend up to the physis. Because there is no displacement of the physis and the fracture lines do not cross the physis, there may be a tendency to dismiss this injury as a simple metaphyseal fracture with no significant sequelae. A small percentage of patients (3% in Peterson’s series) experience growth arrest. In this patient, a disabling ulnar plus deformity, defined as increased ulnar length in relationship to the distal radius, developed. REFERENCES: Peterson HA: Physeal fractures: Part 2. Two previously unclassified types. J Pediatr Orthop 1994;14:431-438. Peterson HA: Physeal and apophyseal injuries, in Rockwood CA Jr, Wilkins KE, Beaty JH (eds): Fractures in Children, ed 4. Philadelphia, PA, Lippincott-Raven, 1996, vol 3, pp 108-109.

Question 1629

Topic: 4. Pediatrics
Figure 39 shows the sagittal T1-weighted MRI scan of a 27-year-old man who twisted his knee 2 weeks ago. The arrow is pointing to:
. a physeal scar.
. a femoral stress fracture.
. a normal growth plate.
. Looser’s line.
. an abnormal growth plate.

Correct Answer & Explanation

. a physeal scar.

Explanation

DISCUSSION: The arrow identifies a transverse dark line that represents primary trabeculae of the physeal scar. A similar finding is seen in the proximal tibia. These lines may persist indefinitely. They do not represent ongoing growth, an abnormally open physeal plate, a stress fracture, or Looser’s line (fatigue fracture in osteomalacia). REFERENCE: El-Khoury G: MRI of the Musculoskeletal System. Philadelphia, PA, JB Lippincott, 1998, p 123.

Question 1630

Topic: Pediatric Hip
A 3-year-old child has refused to walk for the past 2 days. Examination in the emergency department reveals a temperature of 102.2 degrees F (39 degrees C) and limited range of motion of the left hip. An AP pelvic radiograph is normal. Laboratory studies show a WBC count of 9,000/mm3, an erythrocyte sedimentation rate (ESR) of 65 mm/h, and a C-reactive protein level of 10.5 mg/L (normal < 0.4). What is the next most appropriate step in management?
. Aspiration of the left hip
. Technetium Tc 99m bone scan
. Intravenous antibiotics
. Oral antibiotics
. CT of the hips

Correct Answer & Explanation

. Aspiration of the left hip

Explanation

DISCUSSION: Examination reveals an irritable hip, creating a differential diagnosis of transient synovitis versus pyogenic hip arthritis. Kocher and associates described four criteria to help predict the presence of infection: inability to bear weight, fever, ESR of more than 40 mm/h, and a peripheral WBC count of more than 12,000/mm3. This patient meets three of the four criteria, with a positive predictive value of 73% to 93% for joint infection. Therefore, aspiration of the hip is warranted, with a high likelihood that emergent hip arthrotomy will be indicated.

Question 1631

Topic: Pediatric Upper Extremity & Spine
The Risser sign is one of the most commonly used markers for skeletal maturation and growth potential in patients with adolescent idiopathic scoliosis. What Risser sign has been shown to correlate with the greatest velocity of skeletal linear growth?
. Risser 0
. Risser I
. Risser II
. Risser III
. Risser IV

Correct Answer & Explanation

. Risser 0

Explanation

There are two stages of life where the velocity of postnatal skeletal growth is most rapid: during the first year of life and puberty. Both correlate with a Risser sign of 0. Risser 0 covers the first 2/3 of the pubertal growth spurt and correlates with the greatest velocity of skeletal linear growth. Risser grades range from 0 to V and are a measure of the progression of ossification in the pelvis. The Risser sign is usually referenced in clinical decision-making regarding adolescent idiopathic scoliosis. Biondi et al. examined 111 patients to determine the relationship between the accuracy of the Risser sign and bone age determinations. They found that the iliac crest apophysis maturation correlated with skeletal age assessment. They suggest that Risser sign is a reliable method for assessing skeletal bone age.

Question 1632

Topic: 4. Pediatrics

What genetic defect is responsible for achondroplasia? Review Topic

. Trisomy of chromosome 21
. Defect in collagen, type 1, alpha 1 (COL1A1)
. Defect in fibroblast growth factor 3 (FGF-3)
. Defect in fibroblast growth factor receptor 3 (FGFR-3)

Correct Answer & Explanation

. Defect in fibroblast growth factor receptor 3 (FGFR-3)

Explanation

In achondroplasia the defect is always in the same location on this gene (a defect in FGFR-3), and most children share a very similar clinical phenotype. Achondroplasia is not caused by a defect in the gene for FGF-3, the growth factor itself, but rather the gene coding for the receptor. Trisomy of chromosome 21 is responsible for Down syndrome. Defects in the COL1A1 gene are found in some types of osteogenesis imperfecta. Unlike achondroplasia, the defects occur throughout the gene, with more than 200 mutation sites reported.

Question 1633

Topic: 4. Pediatrics

A 12-year-old child with L4 myelomeningocele who is schedules for foot surgery has a functioning ventriculoperitoneal shunt and has no history of allergies. Management should include

. Use of regional rather than general anesthesia
. Observation of a latex-avoidance protocol
. Latex skin allergen testing
. Premedication with corticosteroids and antihistamines
. Avoidance of prophylactic antibiotics derived from penicillin

Correct Answer & Explanation

. Observation of a latex-avoidance protocol

Explanation

The high prevalence of latex allergy in patients with myelomeningocoele is thought to result from a heavy degree of latex exposure throughout life, including closure of the spinal defect, multiple orthopedic, urologic, and neurologic procedures, and repeat bladder catheterization. As many as 50% of these patients may have the allergy. Appropriate perioperative management includes utilization of a latexfree protocol.

Question 1634

Topic: Pediatric Lower Extremity
Figure 16 shows the clinical photograph of a 3-month-old infant with a foot deformity that has been nonprogressive since birth. Examination reveals that the deformity corrects actively and with passive manipulation. There is no associated equinus. Management should consist of
. serial casting.
. UCBL orthotics.
. abductor hallucis lengthening.
. observation and parental reassurance.
. corrective shoes.

Correct Answer & Explanation

. observation and parental reassurance.

Explanation

The patient has bilateral metatarsus adductus deformities. Deformities that are passively correctable spontaneously resolve and no treatment is required. Therefore, observation is the management of choice for passively correctable deformities.

Question 1635

Topic: Pediatric Upper Extremity & Spine

A 7-year-old boy is seen in the emergency department with an isolated and displaced supracondylar humerus fracture and absent radial and ulnar pulses. Despite a moderately painful attempt at realignment, examination reveals that his hand remains pulseless. What is the next most appropriate step in management? Review Topic

. Order an urgent angiogram and then proceed to the OR
. Repeat the reduction in the emergency department and reassess.
. Perform open reduction through an anterior approach.
. Perform closed reduction and pinning in the OR and reassess the vascular status.
. Perform arterial repair and then stabilize the fracture.

Correct Answer & Explanation

. Perform closed reduction and pinning in the OR and reassess the vascular status.

Explanation

Displaced supracondylar humerus fractures in children may have associated vascular compromise. Decreased blood flow may be due to vessel injury, entrapment within the fracture site, kinking from fracture displacement, or from vessel spasm. Optimal initial treatment in the emergency department includes gentle realignment of the limband vascular assessment. Angiography is not required in isolated injuries as the level of the vessel compromise is always at the site of the fracture. When blood flow is not restored, the next best step in treatment is to proceed urgently to the operating room. A formal closed reduction and pinning is performed, and then the vascular status is reassessed. Exploration and vascular repair is required if the hand is cool, white, and without pulses.

Question 1636

Topic: 4. Pediatrics
The mother of a 3-month-old infant states that she has difficulty positioning the infant’s legs during diaper changes. Examination reveals limited abduction of both hips and a negative Ortolani sign. A radiograph reveals bilaterally dislocated hips. Initial management consists of guided reduction in a Pavlik harness, with weekly follow-up. Figures 57a and 57b show the radiograph and CT scan obtained after 6 weeks in the harness. Management should now consist of
. placement of the hips in wider abduction and continued use of the harness.
. increased flexion of the hips and continued use of the harness.
. removal of the harness and application of an Ilfeld splint.
. removal of the harness and application of a von Rosen splint.
. removal of the harness, followed by closed or open reduction.

Correct Answer & Explanation

. removal of the harness, followed by closed or open reduction.

Explanation

DISCUSSION: In an infant younger than age 6 months with a complete dislocation of the hip that is not initially reducible, the Pavlik harness may be used for a trial of guided reduction. When the harness is used in these patients, the infant should be followed at weekly intervals to see if reduction has been achieved. If the hip does not reduce after 3 to 4 weeks of harness wear, the harness should be discontinued, and closed or open reduction should be considered to avoid secondary deformation of the posterolateral acetabulum, also known as Pavlik harness pathology. Changing to other abduction braces is not indicated.

Question 1637

Topic: 4. Pediatrics
A nonambulatory verbal 6-year-old child with spastic quadriplegic cerebral palsy has progressive bilateral hip subluxation of more than 50%. There is no pain with range of motion, but abduction is limited to 20 degrees maximum. An AP radiograph is seen in Figure 34. Management should consist of
. percutaneous bilateral adductor tenotomy.
. oral baclofen.
. phenol injection into the obturator nerve.
. open adductor tenotomy with neurectomy of the anterior branch of the obturator nerve.
. open adductor tenotomy with release of the iliopsoas and bilateral proximal femoral varus derotation osteotomy.

Correct Answer & Explanation

. open adductor tenotomy with release of the iliopsoas and bilateral proximal femoral varus derotation osteotomy.

Explanation

DISCUSSION: The natural history of the patient’s hips, if left untreated, is gradual progression to dislocation. To prevent future pain, prevention of dislocation is often helpful. The patient is too old for soft-tissue releases alone. Therefore, the treatment of choice is medial release of both hips to obtain 45 degrees or better of hip abduction in conjunction with psoas tenotomy and bilateral femoral varus osteotomies.

Question 1638

Topic: 4. Pediatrics
  • Acondroplasia and other chondrodysplasias are caused by mutations in the receptors of which of the following families of growth factors?
. Insulin-like growth factor (IGF-1)
. Fibroblast growth factor (FGF-1)
. Platelet-derived growth factor (PDGF)
. Transforming growth factor beta (TGF-B)
. Bone morphogenetic proteins (BMP)

Correct Answer & Explanation

. Insulin-like growth factor (IGF-1)

Explanation

"The gene responsible for achondroplasia has been mapped to chromosome 4p16.3 (ref 7,8); the gentic interval encompassing the disease gene contains a member of the fibroblast growth factor receptor (FGFR3) family which is expressed in articular chondrocytes.

Question 1639

Topic: Pediatric Upper Extremity & Spine

A 21-year-old right hand-dominant male collegiate swimmer reports painful clicking in the right shoulder. He states that he can occasionally feel his shoulder “slip out” when he is working out. AP, true AP, and axillary radiographs are shown in Figures 39a through 39c. What is the next most appropriate step in management? Review Topic

. Echocardiography
. Abdominal ultrasound
. Skeletal survey
. Glenoid osteotomy
. Physical therapy

Correct Answer & Explanation

. Echocardiography

Explanation

The radiographs show glenoid hypoplasia. The common radiographic findings of glenoid hypoplasia include an inferior and posterior glenoid deficiency, enlargement of the distal end of the clavicle, and sometimes an indentation in the glenoid. It is usually bilateral and rarely associated with other syndromes; therefore, an echocardiogram, abdominal ultrasound, or a skeletal survey is unnecessary unless the patient has stigmata of a syndrome such as Holt-Oram or Apert’s. Although posterior instability has been reported, the results of glenoid osteotomy have been variable and should not be considered initially. Physical therapy is the mainstay of initial management, but the patient should be counseled that this may be a recurrent problem with early osteoarthritis developing in many patients. Radiographs of the contralateral side should be obtained because this is usually bilateral.

Question 1640

Topic: 4. Pediatrics

A 9-year-old boy is injured while playing soccer. His examination reveals painful range of motion between 5° and 75°. There is tenderness on the medial side of his knee. There is no effusion, a grade 1A Lachman test, and severe pain over the medial epicondyle of the knee. Varus stress is negative and pain is elicited with valgus stress. Initial radiographs were negative for abnormality. What is the next diagnostic step?

. Repeat radiographs while the patient is weight bearing
. Ultrasonography of the lower extremity and calf
. Stress radiographs
. CT scan

Correct Answer & Explanation

. Repeat radiographs while the patient is weight bearing

Explanation

This patient likely has a physeal injury to the distal femoral physis. Stress radiographs or an MRI scan will most reliably reveal this diagnosis. The growth plate, when injured, is most commonly fractured through the hypertrophic zone of cartilage, its weakest point. This patient is optimally treated in acylindrical or long-leg cast.

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