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4. Pediatrics MCQs

Practice Set 77 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 1521

Topic: 4. Pediatrics
Hamstring lengthening and posterior transfer of the rectus femoris will be most successful in a patient with cerebral palsy who has which of the following gait abnormalities?
. Excessive knee flexion through stance, stiff knee during swing, and rectus femoris activity in swing
. Excessive knee flexion through stance and continuous quadricep activity in stance and swing
. Excessive knee flexion through stance, short stride length, and continuous hamstring activity in swing
. Knee hyperextension in stance, knee extension during swing, and rectus femoris activity in swing
. Knee hyperextension in stance, continuous rectus femoris activity in stance and swing, and drop foot

Correct Answer & Explanation

. Excessive knee flexion through stance, stiff knee during swing, and rectus femoris activity in swing

Explanation

DISCUSSION: Children with cerebral palsy typically ambulate with a crouched gait characterized by excessive flexion of the hips and knees during stance. Many patients exhibit co-contracture of the quadriceps and hamstrings, causing a stiff-knee gait. Normally, the rectus femoris fires at the initiation of swing and in terminal swing through initial contact. Prolonged activity of the rectus femoris throughout the swing phase interferes with normal knee flexion. This contributes to a stiff knee during swing phase and prevents clearance of the foot. Lengthening of the hamstrings alone will not improve foot clearance. Hamstring lengthening is contraindicated when there is hyperextension during stance. Transfer of the rectus femoris to one of the knee flexors has been shown to improve knee flexion during swing by an average of 15°. This allows improved foot clearance.

Question 1522

Topic: 4. Pediatrics
The mother of a 2-year-old boy reports that he had pain in the right hip all night and refuses to walk on the leg this morning. He is afebrile. Examination reveals pain on hip extension and adduction, but he is able to internally and externally rotate the hip approximately 20 degrees in each direction without pain. Laboratory studies reveal a WBC count of 7,400/mm3, with 62% polymorphonuclear neutrophil leukocytes. The AP radiograph shown in Figure 15 reveals a left teardrop distance of 8 mm, while the right side measures 10 mm. Which of the following diagnostic studies will best help confirm the diagnosis?
. Technetium Tc 99m bone scan
. Ultrasound of the hips
. CT of the pelvis
. MRI of the pelvis
. Aspiration of the hip joint

Correct Answer & Explanation

. Aspiration of the hip joint

Explanation

DISCUSSION: The differential diagnosis includes septic hip and transient synovitis. Both disorders may present with a joint effusion. The increased teardrop distance and loss of range of motion implies that there is excess fluid in the joint. While the other tests can confirm this, only aspiration can characterize the fluid further, thereby indicating the etiology of the effusion. Provided there is enough fluid obtained at aspiration, the joint fluid should be sent for Gram stain, culture, cell count, glucose, and protein studies. REFERENCE: Tachdjian MO: Pediatric Orthopedics, ed 2. Philadelphia, PA, WB Saunders, 1990, pp 1415-1435.

Question 1523

Topic: 4. Pediatrics

03 An 18 month old child has bilateral “corner fractures” of the distal femoral metaphyses of unknown origin. Following a skeletal survey, the first step in management should consist of

. notification of child protection services
. bilateral long leg casts and discharge
. bilateral percutaneous pinning, long leg casts, and discharge
. hospital admission and Bryant’s traction. 5- Hospital admission and modified Bryant’s traction Question 65.03

Correct Answer & Explanation

. notification of child protection services

Explanation

The key to this question consists in realizing that corner fractures are highly diagnostic for battered children. Thus, the first step in management is to notify protective services. The cited references however remind us that any broken bone could be indicative of child abuse.back to this question next question

Question 1524

Topic: 4. Pediatrics
  • Which of the following radiographic findings would be characteristic of the knee joints of a patient with neuropathic osteoarthropathy of the knee?
. Fragmentation and subluxation of the normal joint articulation
. Varus deformity with medial subchondral sclerosis
. Preferential narrowing of the medial tibiofemoral compartment
. Narrowing of the medial, lateral, and patellofemoral compartments
. Bone proliferation at the patellar tendon and ligament insertion sites

Correct Answer & Explanation

. Fragmentation and subluxation of the normal joint articulation

Explanation

Neuropathic osteoarthropathy (a.k.a. Charcot joint) develops most often in weight-bearing joints. The most likely cause is diabetes mellitus, but it is also associated with syphilis, leprosy, yaws, congenital insensitivity to pain, spina bifida, myelomeningocele, syringomyelia, aerodystrophic neuropathy, amyloid neuropathy, peripheral neuropathy of alcoholism, spinal cord injury, peripheral nerve injury, post-transplant neuropathy, and intraarticular steroid injections.The loss of sensation to the joint is followed by severe degenerative changes, osteophyte formation, articular and subchondral fractures, and often calcification of surrounding soft tissues. In the knee, this is a tricompartmental disease and will not selectively affect one compartment over another.

Question 1525

Topic: 4. Pediatrics

Figures 31a and 31b show the radiograph and MRI scan of an otherwise normal 3-month-old infant who has a spinal deformity. MRI reveals no intraspinal anomalies. What is the next step in management? Review Topic

. Posterior spinal fusion with instrumentation
. Anterior-posterior hemiepiphysiodesis
. Brace management
. Cardiac and renal evaluation
. Hemivertebrectomy and fusion

Correct Answer & Explanation

. Posterior spinal fusion with instrumentation

Explanation

Congenital scoliosis in an infant warrants evaluation of the renal, cardiac, and neurologic systems because frequently there is concurrent pathology. Progression in this instance is possible but not certain; therefore, progression must be documented prior to any surgical intervention. Close observation with serial radiographs every 4 to 6 months is appropriate. All of the surgical options listed may be reasonable choices in the future, but cardiac evaluation is the most important issue at this time.

Question 1526

Topic: 4. Pediatrics
  • A 12 month old infant has congenital complete absence of the tibia. Examination reveals that the femur in the abnormal limb is 3 cm short, with a normal ipsilateral hip. The patient has an intact fibula, an equinovarus foot with four rays, and moderate popliteal skin webbing. Management should consist of
. Syme’s amputation
. Arthrodesis of the knee
. Disarticulation of the knee
. Centralization of the fibula
. Prosthetic fitting to accommodate the present deformity

Correct Answer & Explanation

. Syme’s amputation

Explanation

Congenital longitudinal deficiency of the tibia (tibial hemimelia) is a rare anomaly. It is characterized by leg length inequality, malrotation of the extremity, and an equinovarus position of the foot. Currently, the primary treatment option is disarticulation at the knee. Centralization of the fibula has been performed in the past with poor long term results, which have required reoperations leading to amputations. The Syme amputation and prosthetic fitting of the present deformity has led to poor results.

Question 1527

Topic: 4. Pediatrics
Figure 11a shows the clinical photograph of a 46-year-old woman who reports a 3-week history of pain and a “lump” at the base of her neck. She is otherwise in good health and denies any trauma. A 3-D reconstruction CT is shown in Figure 11b. What is the most likely diagnosis?
. Unreduced posterior sternoclavicular dislocation
. Congenital hypoplasia of the medial clavicle
. Postmenopausal arthritis of the sternoclavicular joint
. Sternoclavicular hyperostosis
. Spontaneous subluxation of the right sternoclavicular joint

Correct Answer & Explanation

. Spontaneous subluxation of the right sternoclavicular joint

Explanation

DISCUSSION: Spontaneous subluxation of the sternoclavicular joint occurs without any significant trauma. It is usually accentuated by placing the extremity in an overhead position. Discomfort usually resolves within 4 to 6 weeks with nonsurgical management.

Question 1528

Topic: 4. Pediatrics
In a longitudinal study of children with spastic diplegia, analysis of long-term function will most likely reveal
. a deterioration of gait stability and an increase in double support time.
. a deterioration of gait stability and a decrease in double support time.
. improved excursion about the knee, ankle, and pelvis.
. improvement in the popliteal angle.
. increases in single support time.

Correct Answer & Explanation

. a deterioration of gait stability and an increase in double support time.

Explanation

DISCUSSION: In a longitudinal study of 18 patients with spastic diplegia over a period of 32 months, three-dimensional gait analysis revealed a deterioration of gait stability with increases in double support time and decreases in single support time. Kinematic data also identified a loss of excursion about the knee, ankle, and pelvis. Interestingly, the static examination of the children showed a decrease in the popliteal angle over time. The authors concluded that ambulatory ability tends to worsen over time in children with spastic diplegia. REFERENCE: Johnson DC, Damiano DL, Abel MF: The evolution of gait in childhood and adolescent cerebral palsy. J Pediatr Orthop 1997;17:392-396.

Question 1529

Topic: Pediatric Hip
  • Figures 43a and 43b show the radiographs of an 8-year-old boy who was referred by his gym teacher because of an awkward running pattern. The patient denies any pain in his hips. Examination reveals a mild Trendelenberg gait and decreased internal rotation of the left hip to 25 degrees compared to 40 degrees on the right. What is the most likely diagnosis?

. SCFE
. MED
. Perthes disease
. Hypothyroidism
. Chondrolysis

Correct Answer & Explanation

. SCFE

Explanation

The referenced article is a current concept review on the treatment of Legg-Calve-Perthes Disease and does not specifically mention diagnosis. Self limited non-inflammatory deformity of the weight-bearing portion of the femur, likely due to osteonecrosis. Usually seen in 4-8 year old males with delayed skeletal maturity. Family history, low birth weight, and abnormal birth presentation.Symptoms include-pain, effusion (from synovitis), and a limp, decreased ROM especially Abduction internal rotation. Trendelenburg stance is common.The key in this question is the age, decreased ROM, Trendelenburg gait. The prognosis is directly related to the age at presentation, after 8 years old the prognosis is poor. SCFE(Slipped Capital Femoral Epiphysis)-Usually seen in obese adolescent boys with a family history. African American more common. Often related to endocrine abnormalities, presenting with externally rotated gait, decreased internal rotation, thigh atrophy, with hip or knee pain, symptoms vary with the acuteness of the slip.Hypothyroidism is often a finding with patients presenting with SCFE and chondrolysis is a known complication of SCFE.

Question 1530

Topic: 4. Pediatrics
Figure 3a shows the preoperative radiograph of a 5-year-old girl who achieved complete correction with valgus osteotomies. Figure 3b shows a radiograph obtained 2 years later. What is the cause of the recurrent deformity on the right side?
. Inadequate restoration of the weight-bearing axis
. Partial growth arrest of the medial tibial physis
. Age older than 3 years
. Obesity (greater than the 95th percentile)
. A metaphyseal-diaphyseal angle of greater than 20 degrees

Correct Answer & Explanation

. Partial growth arrest of the medial tibial physis

Explanation

Although inadequate correction, obesity, patient age of older than 5 years and an increased metaphyseal-diaphyseal angle are all associated with a poorer outcome, the radiographs show a growth arrest of the medial tibial physis. If not recognized and treated with early surgery, progressive genu varum will occur with continued growth of the lateral physis. In addition to repeat osteotomy, options for treating the arrest include physeal bar resection or, as necessary, completion of the growth arrest by epiphyseodesis of the lateral physes, followed by a limb equalization procedure at a later date.

Question 1531

Topic: 4. Pediatrics

A 7-year-old boy is seen for follow-up for a scoliotic deformity. His parents are concerned because his deformity seems to have increased. He has no pain and is neurologically intact. A radiograph is shown in Figure 94, and measurement of his curve reveals that it has increased 10 degrees. What is the most appropriate recommendation for this patient at this time? Review Topic

. Observation
. Bracing
. A "growing rod"
. Distraction instrumentation and posterior arthrodesis
. Hemivertebra excision and limited fusion

Correct Answer & Explanation

. Observation

Explanation

Nakamura and associates have reported good results in patients with resection for hemivertebra-related congenital scoliosis who have a progression of their deformity. Because of the progression, observation is not appropriate for this patient's deformity. Bracing has not been shown to alter the progression of congenital scoliosis. The "growing rod" technique is also not effective in preventing progression related to hemivertebra. Distraction instrumentation carries an increased risk of neurologic complications in children with congenital spine deformities. Progression after posterior arthrodesis alone can occur through the so-called "crankshaft phenomenon."

Question 1532

Topic: Pediatric Hip
A 9-year-old girl reports the immediate onset of severe groin pain and the inability to walk after tripping on a curb. Examination reveals marked hip pain with passive range of motion. A radiograph is shown in Figure 21. Regardless of treatment, what is the most common complication following this injury?
. Chondrolysis
. Osteochondritis dissecans of the femoral head
. Osteonecrosis of the femoral head
. Nonunion
. Coxa magna

Correct Answer & Explanation

. Osteonecrosis of the femoral head

Explanation

DISCUSSION: The patient has an unstable slipped capital femoral epiphysis (SCFE). According to the classification system based on physeal stability, an unstable SCFE is one in which the patient is unable to walk, even with crutches. Ischemic necrosis, or osteonecrosis, of the femoral head is the most devastating complication of SCFE. One study found a 47% incidence of ischemic necrosis following unstable slips. This complication is most likely the result of vascular injury associated with initial femoral head displacement rather than the result of either tamponade from joint effusion or gentle repositioning prior to stabilization. Chondrolysis is a relatively uncommon complication following treatment of SCFE. This complication has been associated with persistent penetration of the hip joint with screws or pins used to stabilize the femoral head or with spica cast immobilization. There are no reports to suggest that osteochondritis dissecans, nonunion, or coxa magna follows treatment of SCFE. REFERENCES: Loder RT, Richards BS, Shapiro PS, et al: Acute slipped capital epiphysis: The importance of physeal stability. J Bone Joint Surg Am 1993;75:1134-1140. Rhoad RC, Davidson RS, Heyman S, et al: Pretreatment bone scan in SCFE: A predictor of ischemia and avascular necrosis. J Pediatr Orthop 1999;19:164-168.

Question 1533

Topic: 4. Pediatrics
Figure 39 shows the radiograph of a 4-month-old infant who has been undergoing weekly casting since birth for a congenital equinovarus deformity. Management should now consist of
. surgical correction.
. continued casting.
. botulinum toxin injection into the gastrocnemius-soleus complex.
. an ankle-foot orthosis.
. observation with no further treatment.

Correct Answer & Explanation

. surgical correction.

Explanation

DISCUSSION: The radiograph shows the development of a rocker-bottom foot deformity. A rocker-bottom foot occurs in the treatment of clubfoot when casting is continued in the presence of a very tight gastrocnemius-soleus complex and an uncorrected hindfoot. While there are some preliminary reports on using Botox injection and continued casting for the equinus deformity, most authors recommend posterior or posterior medial release. Percutaneous tenotomy has been recently recommended with the resurgence of the Ponseti technique.

Question 1534

Topic: 4. Pediatrics
Figure 6 shows the clinical photograph of a 3-year-old boy who started to walk at the age of 10 months and has a gait that is appropriate for his age. His height is in the 40th percentile for his age. Management should consist of:
. Follow-up in six months.
. AP and lateral radiographs.
. AP and lateral radiographs, and a bone scan.
. AP and lateral radiographs, and serum levels for calcium, phosphate, and creatinine.
. AP and lateral radiographs, blood serum levels for calcium, phosphate, and creatinine, and a 24-hour urine collection for vitamin D metabolites.

Correct Answer & Explanation

. Follow-up in six months.

Explanation

The diagnosis is Developmental Genu Valgum. There are several clues in the question that suggest that this is a benign process. First, they tell you that the child walked at 10 months of age (within normal limits) which helps rule out several neuromuscular disorders. Second, the child is three years of age. A moderate amount of “knock knees” is considered physiologic up to six years of life. Third, the child is in the 40th percentile for his height (again within normal limits). The correct treatment for children with physiologic genu valgum up to six years of life is OBSERVATION; if the condition persists past six years, standing AP radiographs and a metabolic work-up are indicated. Because response (0) is the only answer not including x-rays, this is the one you should have selected.

Question 1535

Topic: 4. Pediatrics

A 10-month-old infant has no flexion at the elbows, mild flexion contractures at the wrist, a rigid clubfoot deformity on the left foot, and a rigid rocker bottom deformity on the right foot. Examination of the patient's hips reveals limited

. Preliminary skin traction followed by closed reduction under general anesthesia
. Immediate closed reduction under anesthesia
. Preliminary skeletal traction followed by closed reduction under general anesthesia
. Bilateral open reduction performed through a medial approach
. Bilateral open reduction performed through an anterior approach

Correct Answer & Explanation

. Preliminary skin traction followed by closed reduction under general anesthesia

Explanation

The patient has arthrogryposis. Szoke and associates performed open reduction through a medial approach on 40 hip dislocations in 26 patients with this condition and reported good results in 80% and fair results in 12%. Due to the stiffness associated with this disorder, closed reduction with or without skin or skeletal traction is not feasible. Open reduction through an anterior approach is reserved for older children.

Question 1536

Topic: Pediatric Hip
An obese 10-year-old boy has had left groin pain and a limp for the past 2 months. Examination reveals decreased abduction and internal rotation. Laboratory studies show normal renal function and an elevated thyroid-stimulating hormone (TSH) level. AP and frog lateral radiographs of the pelvis are shown in Figures 30a and 30b. What is the best course of action?
. Traction followed by reduction and pinning
. In situ pinning of the left hip
. In situ pinning of both hips
. No weight bearing on the left side and nonsteroidal anti-inflammatory drugs
. Femoral realignment osteotomy

Correct Answer & Explanation

. In situ pinning of both hips

Explanation

The radiographs show a grade I slipped capital femoral epiphysis (SCFE) that is classified as stable because the child is able to bear weight. The elevated TSH level indicates possible hypothyroidism. SCFE usually occurs in boys age 12 to 14 years. Because of the patient’s young age and hypothyroidism, he is at increased risk for slippage of the contralateral hip; therefore, prophylactic pinning of the uninvolved side also should be considered. Because of the risk of slip progression, crutch treatment and nonsteroidal anti-inflammatory drugs are not indicated. Realignment osteotomy is not indicated for grade I SCFE. Traction to reduce the slip, followed by pinning, has been advocated for unstable slips but is not indicated here.

Question 1537

Topic: 4. Pediatrics
An 8-year-old sustains the injury shown in Figures A and B. Postoperative radiographs are shown in Figures C and D. After cast removal and in-office K-wire removal, elbow range of motion is found to be between 20-80 degrees of flexion. How soon after surgery is range of motion expected to be >90% of normal?
. 2 months after surgery
. 3 months after surgery
. 6 months after surgery
. 9 months after surgery
. 12 months after surgery

Correct Answer & Explanation

. 6 months after surgery

Explanation

After closed reduction and percutaneous pinning of a displaced pediatric supracondylar fracture, it will take an average of 6 months for 94% of normal elbow range of motion to return. Displaced pediatric supracondylar elbow fractures are often treated with closed reduction and percutaneous pinning. Risk of stiffness is low considering the extra-articular nature of the injury. Utility of physical therapy to improve range of motion after operative treatment of this injury is not supported in the literature. Zionts et al. retrospectively evaluated elbow stiffness after treatment for pediatric supracondylar fractures. Ninety-four percent of normal range of motion was restored by 6 months after the operative procedure. Further improvement occurs up to one-year postoperatively.

Question 1538

Topic: 4. Pediatrics

-Figures 10a and 10b are the sagittal and coronal MRI scans of a 5-year-old boy who noticed “clicking” in his right knee. His family denied any trauma, but admitted that the child was active and fell frequently.Birth and developmental history were unremarkable, and specifically negative for other musculoskeletal conditions. On physical examination, there was no warmth, tenderness, or erythema, or effusion. The child had an audible and palpable clunk when the knee was taken from a position of extreme flexion to full extension. There was no anterior, posterior, medial, or lateral instability on examination or medial or lateral joint line tenderness. The child had not been systemically ill. Radiographs were unrevealing.What is the most likely diagnosis?

. Discoid lateral meniscus
. Congenital absence of the anterior cruciate ligament
. Torn medial meniscus
. Osteomyelitis of the distal femurDISCUSSION A discoid lateral meniscus is probably the most common cause of a symptomatic clicking or clunking in the knee in a young child. This is a congenital problem that can become symptomatic as soon as a child ambulates, or the condition may remain asymptomatic for several years. The meniscus develops from a cartilaginous anlage and at no point in its development is it discoid. The MRI scans reveal a band of meniscal tissue filling the joint’s lateral compartment on both sagittal and coronal images. Amedial meniscal tear is usually accompanied by a history of injury and an effusion, which are not present in this child. There is also no joint line tenderness, which makes this diagnosis less likely. Congenital absence of the anterior cruciate ligament may be found in children born with congenital knee hyperextension, which is ruled out in this case by normal history and examination findings.Children with osteomyelitis are often systemically ill. On examination, they may have warmth and tenderness. MRI scans will often show an area of increased signal on T1-weighted images.

Correct Answer & Explanation

. Discoid lateral meniscus

Explanation

Question 1539

Topic: 4. Pediatrics
A 12-year-old boy with an ankle fracture undergoes closed reduction under sedation in the emergency department. Figure 27 shows a lateral radiograph of the ankle after two attempts at closed reduction. Based on these findings, treatment should now consist of
. at least two more attempts at closed reduction in the emergency department before the patient’s sedation wears off.
. at least two attempts at closed reduction in the operating room under general anesthesia with muscle relaxation.
. acceptance of the reduction because the alignment is satisfactory and growth problems are rare with Salter-Harris type I fractures.
. open reduction, extraction of any interposed periosteum, and smooth wire fixation to prevent nonunion.
. open reduction, extraction of any interposed periosteum, and smooth wire fixation to decrease the chance of premature physeal closure.

Correct Answer & Explanation

. open reduction, extraction of any interposed periosteum, and smooth wire fixation to decrease the chance of premature physeal closure.

Explanation

The widening of the physis associated with incomplete reduction of this fracture suggests that periosteum is interposed at the fracture site. Clinical and animal study findings suggest that the interposed periosteum may lead to premature physeal closure. Repeated forceful attempts at reduction may subject the physis to further injury and should be avoided. Growth problems are common in children with Salter-Harris type I fractures of the lower extremities. Nonunions are rare in children with Salter-Harris type I fractures.

Question 1540

Topic: 4. Pediatrics
A 10-year-old child with cerebral palsy undergoes bilateral hamstring lengthening for severe knee flexion contractures, and knee immobilizers are applied postoperatively. Examination at the initial postoperative check 2 hours after surgery reveals that she can dorsiflex her toes on the right foot, but not on the left foot. The physician should now
. repeat the examination in a few hours.
. remove the left knee immobilizer and flex the knee.
. apply long leg casts that include the feet.
. obtain an electromyogram and nerve conduction velocity studies.
. perform peroneal nerve exploration.

Correct Answer & Explanation

. remove the left knee immobilizer and flex the knee.

Explanation

DISCUSSION: Children with cerebral palsy are often difficult to examine. However, this patient clearly has a peroneal nerve deficit, most likely from the acute stretch after the hamstring lengthening. The nerve has the best chance of recovery if it is relaxed by flexing the knee. Once the nerve has recovered, gradual knee extension can be accomplished.

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