Orthopedic Pediatric Review | Dr Hutaif Pediatric Ortho -...

Question 1

A 6-week-old female is being treated with a Pavlik harness for Developmental Dysplasia of the Hip (DDH).

At her 2-week follow-up, the parents report she is not kicking her left leg as much. On examination, she has decreased active extension of the left knee, though passive range of motion is normal. What is the most likely cause of this finding?

Explanation

Hyperflexion of the hips in a Pavlik harness can cause compression of the femoral nerve, leading to a transient femoral nerve palsy. This presents clinically as decreased active extension of the knee. Treatment involves adjusting the anterior straps to decrease the degree of hip flexion or temporarily discontinuing the harness until function returns.

Question 2

A 13-year-old obese male with a stable left Slipped Capital Femoral Epiphysis (SCFE) undergoes in situ pinning with a single cannulated screw.

Six months postoperatively, he develops severe, constant hip pain and a significantly restricted range of motion in all planes. Radiographs demonstrate concentric joint space narrowing without hardware failure. What is the most likely diagnosis?

Explanation

Chondrolysis is a severe complication of SCFE, highly associated with unrecognized intra-articular screw penetration. It presents with pain, global stiffness, and diffuse, concentric joint space narrowing on radiographs. Avascular necrosis typically presents with subchondral collapse and sclerosis rather than global joint space narrowing.

Question 3

An infant with idiopathic clubfoot is being treated with the Ponseti method of serial casting.

The forefoot has been successfully abducted to 60 degrees, and the heel is in valgus. However, the foot remains in 20 degrees of equinus. What is the most appropriate next step in management?

Explanation

In the Ponseti method (CAVE: Cavus, Adductus, Varus, Equinus), equinus is the final deformity to be corrected. Once the forefoot reaches roughly 60 degrees of abduction and the heel varus is corrected to valgus, a percutaneous Achilles tenotomy is indicated if ankle dorsiflexion is less than 15 degrees. Forcing dorsiflexion in a cast against a tight Achilles can cause a midfoot rocker-bottom deformity.

Question 4

A 5-year-old boy presents with an extension-type Gartland III supracondylar humerus fracture after a fall.

On examination, his hand is well-perfused (pink) with brisk capillary refill, but the radial pulse is absent. What is the most appropriate initial management?

Explanation

The presentation of a 'pink, pulseless' hand with a displaced supracondylar fracture dictates urgent closed reduction and percutaneous pinning (CRPP) as the initial step. Often, the pulse returns after reduction removes the tethering or kinking of the brachial artery. If the hand remains pink and well-perfused after CRPP, observation is appropriate even if the pulse remains absent. Open exploration is indicated for a 'white, pulseless' hand that does not improve after reduction.

Question 5

A 4-year-old child sustains a mildly displaced (<2mm) lateral condyle fracture of the humerus, which is treated non-operatively in a long arm cast. Three months later, radiographs reveal a frank nonunion of the lateral condyle. If left untreated, what late neurological complication is most characteristic of this condition?

Explanation

Nonunion of a lateral condyle fracture typically results in progressive cubitus valgus deformity. Over time, the valgus deformity progressively stretches the ulnar nerve behind the medial epicondyle, leading to a delayed neuropathy known as 'tardy ulnar nerve palsy', which can present years or even decades after the initial injury.

Question 6

A 7-year-old boy is diagnosed with Legg-Calvé-Perthes disease. Anteroposterior radiographs of the pelvis demonstrate that exactly 50% of the lateral pillar height is maintained on the affected side. According to the Herring lateral pillar classification, into which group does this patient fall?

Explanation

The Herring Lateral Pillar classification is a strong prognostic indicator in LCP. Group A has 100% height maintenance; Group B has >50% height; Group C has <50% height. Group B/C is a distinct, intermediate category where exactly 50% of the pillar height is maintained or the pillar is very narrow (2-3 mm). Patients in Group B/C have outcomes worse than Group B but better than Group C.

Question 7

A 4-year-old boy presents to the emergency department with acute right hip pain, a severe limp, and a refusal to bear weight. His temperature is 38.6°C. Laboratory workup reveals a WBC count of 13,500/mm³ and an ESR of 45 mm/hr. According to the Kocher criteria, what is the approximate statistical probability that this child has septic arthritis of the hip?

Explanation

The Kocher criteria for differentiating septic arthritis from transient synovitis include four predictors: fever >38.5°C, non-weight bearing status, ESR >40 mm/hr, and WBC >12,000/mm³. This patient has all 4 criteria. According to the original study, the probability of septic arthritis is approximately: 1 criterion = 3%, 2 criteria = 40%, 3 criteria = 93%, and 4 criteria = 99%.

Question 8

A newborn is diagnosed with congenital scoliosis secondary to a fully segmented hemivertebra at T8.

Which of the following is the most appropriate routine screening protocol to order next to evaluate for frequently associated anomalies?

Explanation

Congenital scoliosis is highly associated with VACTERL anomalies. Genitourinary anomalies (e.g., unilateral renal agenesis) occur in 20-30% of patients, and congenital heart defects occur in 10-15%. Therefore, a renal ultrasound and an echocardiogram are mandatory screening tests. An MRI of the entire spine is also indicated to rule out intraspinal anomalies (e.g., tethered cord), but an MRI of the brain is not.

Question 9

In a 6-year-old child with spastic quadriplegic cerebral palsy (GMFCS Level V), routine hip surveillance is indicated. What is the most important, standardized radiographic parameter used to monitor the progression of hip displacement in this population?

Explanation

Reimer's migration percentage (MP) is the gold standard measurement for monitoring hip displacement in children with cerebral palsy. It quantifies the percentage of the ossified femoral head that is displaced outside the lateral margin of the acetabulum (Perkin's line). An MP > 30% indicates subluxation and generally warrants increased surveillance or orthopedic intervention.

Question 10

A 3-year-old girl, who is at the 95th percentile for weight and began walking at 9 months of age, presents with progressive bilateral genu varum.

Radiographs reveal an abrupt medial beaking of the proximal tibial metaphysis and a metaphyseal-diaphyseal angle (Drennan's angle) of 18 degrees. What is the most likely diagnosis?

Explanation

Infantile Blount disease (tibia vara) classicly affects overweight children who are early walkers. Radiographs show varus centered at the proximal tibia with medial metaphyseal beaking. A metaphyseal-diaphyseal angle > 16 degrees has a high predictive value for progression to true Blount disease, differentiating it from physiologic bowing, which usually has an angle < 11 degrees.

Question 11

A 5-year-old boy with blue sclerae, multiple previous fractures, and mild short stature is diagnosed with Osteogenesis Imperfecta Type I. Which of the following gene mutations is most commonly responsible for this condition?

Explanation

Osteogenesis Imperfecta (OI) is a disorder of type I collagen, the major structural protein in bone. Over 90% of OI cases are caused by mutations in either the COL1A1 or COL1A2 genes. Type I OI is generally the mildest and most common form, typically resulting from a null mutation leading to a quantitative deficiency of structurally normal type I collagen.

Question 12

A 3-year-old boy presents with progressive bowing of the lower extremities, short stature, and a waddling gait. Laboratory studies reveal a normal serum calcium, profoundly low serum phosphate, elevated alkaline phosphatase, and normal parathyroid hormone levels. What is the primary pathophysiology underlying his condition?

Explanation

The clinical presentation and laboratory findings (normal Ca, very low PO4, normal PTH) are diagnostic of X-linked hypophosphatemic rickets (familial hypophosphatemic rickets). This is caused by a mutation in the PHEX gene, which leads to an overproduction of Fibroblast Growth Factor 23 (FGF23). FGF23 causes profound renal phosphate wasting and inhibits 1-alpha-hydroxylase.

Question 13

A 13-year-old girl sustains an ankle injury during a soccer match. Radiographs reveal an isolated Salter-Harris III fracture of the anterolateral distal tibial epiphysis (Tillaux fracture). Which of the following describes the anatomical sequence of distal tibial physeal closure that predisposes adolescents to this specific fracture pattern?

Explanation

The distal tibial physis begins to close around 12-14 years of age. The sequence of closure begins centrally, proceeds medially, and finishes laterally (the anterolateral quadrant is the last to close). Because the anterolateral physis remains open while the rest is fused, it is vulnerable to avulsion by the anterior inferior tibiofibular ligament during an external rotation injury, resulting in a Tillaux fracture.

Question 14

A 14-year-old boy complains of a painful, rigid flatfoot and a history of recurrent ankle sprains. Physical examination demonstrates severe restriction of subtalar motion and peroneal spasticity. A 45-degree internal oblique radiograph of the foot reveals an 'anteater nose' sign. Which of the following is the most likely diagnosis?

Explanation

The 'anteater nose' sign is pathognomonic for a calcaneonavicular coalition. It is best visualized on a 45-degree internal oblique radiograph and represents an elongated anterior process of the calcaneus extending toward the navicular. Talocalcaneal coalitions are more likely to present with a 'C-sign' on a lateral radiograph.

Question 15

A 12-year-old elite Little League pitcher complains of progressively worsening pain in his throwing shoulder during the late cocking phase. Radiographs show widening and sclerosis of the proximal humeral physis. What is the primary pathophysiology of this condition (Little League Shoulder)?

Explanation

Little League shoulder is an overuse injury characterized by a stress reaction or a Salter-Harris type I stress fracture of the proximal humeral physis. It is caused by repetitive torsional stresses during the throwing motion. Treatment primarily consists of rest and cessation of throwing until symptoms resolve and the physis appears normal radiographically.

Question 16

An 8-year-old Japanese girl presents with a painless, palpable 'clunk' on the lateral side of her left knee during terminal extension. MRI confirms a discoid lateral meniscus. Which specific variant of a discoid meniscus is characterized by an absent posterior meniscotibial attachment, leading to hypermobility and snapping?

Explanation

The Wrisberg ligament variant of a discoid meniscus lacks normal posterior meniscotibial (coronary ligament) attachments. Its only posterior attachment is to the meniscofemoral ligament of Wrisberg. This lack of peripheral stability allows the meniscus to hypermobilize into the joint during extension, causing a mechanical 'clunk' or 'snap' even in the absence of a meniscal tear.

Question 17

A 3-year-old boy sustains a closed, isolated, midshaft femur fracture after a fall from a playground structure.

Radiographs show 1.5 cm of overriding. What is the most widely accepted definitive management for this patient?

Explanation

The standard of care for isolated, closed femur fractures in children aged 6 months to 5 years (with <2 cm of shortening) is early spica casting. The Pavlik harness is indicated for infants under 6 months. Flexible intramedullary nailing is typically indicated for school-aged children (5 to 11 years).

Question 18

A 15-year-old female gymnast presents with persistent lower back pain. Lateral radiographs of the lumbar spine reveal a pars interarticularis defect at L5 and a forward translation of L5 on S1. The superior endplate of S1 is divided into four equal parts, and the posterior cortex of L5 sits over the second quartile. According to the Meyerding classification, what is the grade of this spondylolisthesis?

Explanation

The Meyerding classification grades spondylolisthesis based on the percentage of forward slip of the superior vertebral body over the inferior one. Grade I is 0-25%; Grade II is 26-50%; Grade III is 51-75%; Grade IV is 76-100%; Grade V is >100% (spondyloptosis). A slip in the second quartile (26-50%) is Grade II.

Question 19

A 7-year-old boy undergoes closed reduction and percutaneous pinning of a displaced supracondylar humerus fracture.

Six hours postoperatively, he is crying uncontrollably on the ward and requires escalating doses of IV opioids. Which of the following is the most reliable early clinical indicator of compartment syndrome in this pediatric patient?

Explanation

In pediatric patients, classic signs like paresthesia and pain out of proportion are difficult to assess. The '3 As' (Anxiety, Agitation, and Increasing Analgesic requirement) are considered the earliest, most sensitive, and most reliable indicators of developing compartment syndrome in children. Pulselessness, pallor, and paresis are very late, often irreversible signs.

Question 20

An 8-month-old infant with homozygous achondroplasia presents with witnessed episodes of central sleep apnea, hyperreflexia, and generalized hypotonia. What is the most likely anatomic cause of these severe neurological symptoms?

Explanation

Foramen magnum stenosis is a critical and potentially lethal complication in infants with achondroplasia, caused by defective endochondral ossification of the skull base. It leads to cervicomedullary compression, which presents clinically as central sleep apnea, brisk deep tendon reflexes, hypotonia, and motor delays. Urgent neurosurgical decompression is indicated in symptomatic patients.

Question 21

A 12-year-old obese male presents with severe left hip pain and is completely unable to bear weight, even with the assistance of crutches. Radiographs confirm a severe left Slipped Capital Femoral Epiphysis (SCFE). Which of the following best describes his classification and the associated risk of the most catastrophic complication?

Explanation

According to the Loder classification, an unstable SCFE is defined by the inability to bear weight, with or without crutches. Unstable SCFE carries a significantly higher risk of avascular necrosis (AVN), occurring in up to 50% of cases.

Question 22

An 18-month-old female with late-presenting Developmental Dysplasia of the Hip (DDH) undergoes closed reduction and spica casting in the operating room. To minimize the risk of iatrogenic avascular necrosis (AVN) of the femoral head, which of the following extreme positions must be strictly avoided during casting?

Explanation

Extreme abduction places excessive pressure on the cartilaginous femoral head and compresses the medial circumflex femoral artery. This is the most significant risk factor for iatrogenic AVN following closed reduction and spica casting for DDH.

Question 23

A 9-year-old boy is diagnosed with Legg-Calvé-Perthes disease. Radiographs demonstrate that less than 50% of the lateral pillar height is maintained. Based on the Herring Lateral Pillar Classification, which of the following is true regarding his prognosis and management?

Explanation

Herring Lateral Pillar Type C is defined by <50% maintenance of the lateral pillar height and carries the poorest prognosis. In children over 8 years old with severe involvement, while surgical containment (femoral or pelvic osteotomy) may be attempted, the long-term outcome remains guarded.

Question 24

A 4-year-old boy previously treated for idiopathic clubfoot with the Ponseti method presents with a relapsed deformity. Gait analysis reveals dynamic supination of the foot during the swing phase. Passive range of motion demonstrates a fully correctable deformity. What is the most appropriate definitive management?

Explanation

Dynamic supination during the swing phase in a relapsed clubfoot is typically caused by an overactive tibialis anterior. If the foot is passively correctable, a full tibialis anterior tendon transfer (TATT) to the lateral (third) cuneiform is the treatment of choice.

Question 25

A 3-year-old female presents with progressive unilateral genu varum. Standing lower extremity radiographs are obtained. Measurement of the metaphyseal-diaphyseal angle (Drennan's angle) is most predictive of progression to infantile Blount's disease when it exceeds what threshold?

Explanation

The metaphyseal-diaphyseal angle (Drennan's angle) is used to differentiate physiologic bowing from infantile Blount's disease. An angle greater than 16 degrees has a high predictive value for progression to Blount's disease.

Question 26

A 6-year-old boy sustains a completely displaced, extension-type supracondylar humerus fracture (Gartland Type III). Upon presentation, his hand is pale and pulseless. Following closed reduction and percutaneous pinning in the operating room, the hand becomes warm and pink with a capillary refill of 2 seconds, but the radial pulse remains unpalpable. What is the most appropriate next step in management?

Explanation

A "pink, pulseless" hand after reduction of a supracondylar humerus fracture indicates adequate collateral perfusion. The standard of care is close observation and admission, as the pulse frequently returns within a few days.

Question 27

A 7-year-old non-ambulatory child with spastic quadriplegic cerebral palsy presents for a routine evaluation. Pelvic radiographs demonstrate a Reimers Migration Percentage of 45% bilaterally. He is currently painless. What is the most appropriate treatment recommendation?

Explanation

In children with cerebral palsy, a Reimers Migration Percentage >40% indicates significant hip subluxation with a high risk of progression to dislocation. Comprehensive bony reconstruction with VDRO and a volume-reducing pelvic osteotomy (e.g., Dega) is indicated.

Question 28

A newborn is evaluated for congenital scoliosis. Which of the following radiographic vertebral anomalies carries the highest risk for rapid, unrelenting curve progression and typically requires early in situ spinal fusion?

Explanation

A unilateral unsegmented bar with a contralateral hemivertebra at the same level provides a severe growth tether on one side and excessive growth potential on the convex side. This combination has nearly a 100% chance of rapid progression and requires early surgical fusion.

Question 29

A 3-year-old presents with a 2-day history of right hip pain, refusal to bear weight, and a temperature of 38.8°C. According to the updated Kocher criteria by Caird et al., which laboratory value was added as a strong independent predictor for septic arthritis of the hip?

Explanation

Caird et al. modified the original Kocher criteria by adding a C-reactive protein (CRP) level > 2.0 mg/dL. The presence of all five predictors yields a >97% probability of septic arthritis.

Question 30

A 13-year-old male presents with recurrent ankle sprains and a rigid, painful flatfoot. Radiographs show an elongated anterior process of the calcaneus resembling an "anteater's nose" on the lateral view. What is the most likely diagnosis?

Explanation

The "anteater nose" sign on a lateral radiograph is highly indicative of a calcaneonavicular coalition, representing an elongated anterior process of the calcaneus approaching the navicular. Talocalcaneal coalitions are typically associated with the "C-sign."

Question 31

A 5-year-old boy with Osteogenesis Imperfecta (Type III) is being treated with intravenous bisphosphonates. By what specific mechanism do bisphosphonates decrease the fracture rate in these patients?

Explanation

Bisphosphonates are analogues of inorganic pyrophosphate that bind to hydroxyapatite crystals in bone. They are ingested by osteoclasts during resorption, which disrupts their intracellular metabolism and induces apoptosis, thereby increasing bone density.

Question 32

An 8-year-old, 35 kg boy sustains a transverse midshaft fracture of the right femur. He is treated with titanium elastic nails (TENs). What is the most common complication associated with this surgical treatment?

Explanation

The most common complication of flexible intramedullary nailing (TENs) for pediatric femur fractures is soft tissue irritation and pain at the distal entry sites. This often necessitates hardware removal once the fracture has healed.

Question 33

A 13-year-old female sustains a fracture of the anterolateral aspect of her distal tibial epiphysis after an external rotation injury. This fracture pattern (Tillaux fracture) occurs specifically due to the asymmetrical closure of the distal tibial physis. In what sequence does the normal distal tibial physis close?

Explanation

The distal tibial physis closes in a characteristic sequence: first centrally, then anteromedially, followed by posteromedially, and finally laterally. Because the anterolateral physis is the last to close, it is susceptible to avulsion by the anterior inferior tibiofibular ligament (Tillaux fracture).

Question 34

An 8-year-old girl presents with a painless "clunking" in her lateral knee during flexion and extension. MRI demonstrates a Wrisberg-variant discoid lateral meniscus. What anatomical structure is characteristically absent in this variant?

Explanation

The Wrisberg variant of a discoid meniscus lacks normal posterior meniscotibial (coronary) ligament attachments, making it hypermobile. It attaches only via the posterior meniscofemoral ligament (Wrisberg), leading to a snapping sensation as it subluxates during knee motion.

Question 35

A 4-year-old boy presents with profound bilateral genu varum, frontal bossing, and short stature. Laboratory evaluation reveals a normal serum calcium, significantly decreased serum phosphate, elevated alkaline phosphatase, and normal parathyroid hormone levels. A mutation in the PHEX gene is confirmed. What is the primary pathophysiologic defect in this disorder?

Explanation

The presentation and lab findings are classic for X-linked hypophosphatemic rickets (mutated PHEX gene). This mutation leads to elevated levels of Fibroblast Growth Factor 23 (FGF23), which inhibits renal phosphate reabsorption and decreases phosphate levels, causing rickets.

Question 36

A 5-year-old child sustains a minimally displaced (<2 mm) lateral condyle fracture of the humerus. If left completely untreated and progressing to a nonunion, what is the most likely long-term complication?

Explanation

A nonunion of a lateral condyle fracture leads to progressive superior migration of the lateral condyle, resulting in a progressive cubitus valgus deformity. Over time, this stretches the ulnar nerve, classically leading to a tardy ulnar nerve palsy.

Question 37

An 18-month-old male is evaluated for congenital pseudarthrosis of the tibia (CPT). Examination reveals anterolateral bowing of the affected leg. Which genetic condition is most strongly associated with this finding?

Explanation

Anterolateral bowing of the tibia and congenital pseudarthrosis of the tibia are classic musculoskeletal manifestations of Neurofibromatosis Type 1 (NF-1). Approximately 50% of patients with CPT have an underlying diagnosis of NF-1.

Question 38

A 9-year-old male presents with acute shoulder pain after throwing a baseball. Radiographs reveal a pathologic fracture through a centrally located, lytic, expansile bone lesion in the proximal humeral metaphysis. A "fallen leaf" sign is noted. What is the most appropriate initial management?

Explanation

The clinical presentation and "fallen leaf" sign are pathognomonic for a Unicameral Bone Cyst (UBC). When a pathologic fracture occurs through a UBC, initial treatment is immobilization to allow the fracture to heal, which occasionally leads to spontaneous cyst resolution.

Question 39

A newborn is diagnosed with achondroplasia. Which zone of the epiphyseal physis (growth plate) is primarily affected by the genetic mutation underlying this condition?

Explanation

Achondroplasia is caused by an activating mutation in the Fibroblast Growth Factor Receptor 3 (FGFR3) gene. This mutation primarily inhibits chondrocyte proliferation, thus affecting the proliferative zone of the physis and leading to rhizomelic dwarfism.

Question 40

A 9-year-old boy presents with a limp and groin pain. Radiographs demonstrate Legg-Calvé-Perthes disease classified as Lateral Pillar B. He has maintained good range of motion. What is the most appropriate surgical treatment to prevent femoral head deformation in this patient?

Explanation

For patients older than 8 years with Lateral Pillar B or B/C border Legg-Calvé-Perthes disease, surgical containment yields better outcomes than nonoperative management. A varus derotation osteotomy (VDRO) centers the femoral head within the acetabulum to allow spherical remodeling.

Question 41

A 6-year-old boy falls from monkey bars and sustains a widely displaced posterolateral Gartland type III supracondylar humerus fracture. Which of the following neurologic deficits is most likely to be observed on physical examination?

Explanation

Posterolateral displacement in supracondylar humerus fractures places the anterior interosseous nerve (AIN) at the greatest risk. AIN palsy presents with an inability to flex the interphalangeal joint of the thumb and the distal interphalangeal joint of the index finger (the "OK" sign).

Question 42

A 4-year-old girl is evaluated for severe bowing of her left leg. Radiographs reveal a prominent physeal step-off with depression of the medial tibial plateau, consistent with Langenskiöld stage IV infantile Blount's disease. What is the most appropriate management?

Explanation

Bracing for infantile Blount's disease is generally ineffective after 3 years of age or in advanced stages (Langenskiöld III and above). A proximal tibial osteotomy is required to correct the severe multiplanar deformity and restore normal joint mechanics.

Question 43

A 5-year-old boy presents with a 2-day history of right hip pain and inability to bear weight. His temperature is 38.8°C (101.8°F), WBC count is 14,000/mm3, ESR is 55 mm/hr, and CRP is 3.5 mg/dL. Radiographs of the hip are normal. What is the most appropriate next step in management?

Explanation

This patient meets all four Kocher criteria (fever, non-weight-bearing, ESR >40, WBC >12,000), giving him a >93% probability of septic arthritis. The definitive diagnostic next step is an ultrasound-guided hip aspiration to confirm the diagnosis before proceeding to surgical washout.

Question 44

A 12-year-old boy with a BMI in the 99th percentile presents with left knee pain and an inability to bear weight on his left leg. Radiographs confirm a severe Slipped Capital Femoral Epiphysis (SCFE). Which of the following factors is the greatest predictor for the development of avascular necrosis (AVN) in this patient?

Explanation

The inability to bear weight defines an unstable SCFE, which carries a significantly higher risk of avascular necrosis (up to 47%) compared to stable slips. Slip severity or chronicity does not predict AVN as strongly as clinical stability.

Question 45

A 6-week-old female undergoes a screening hip ultrasound for breech presentation. The alpha angle is 45 degrees, and the beta angle is 80 degrees. According to the Graf classification, what is the most appropriate initial management?

Explanation

An alpha angle of <50 degrees corresponds to a Graf Type III or severe Type IIc hip, indicating significant developmental dysplasia of the hip (DDH). The gold standard initial treatment for a child <6 months of age with DDH is a Pavlik harness.

Question 46

A 4-year-old boy with a history of idiopathic clubfoot treated successfully with the Ponseti method presents with a relapsed deformity. Gait analysis shows dynamic supination of the foot during the swing phase. Passive range of motion demonstrates a fully correctable deformity. What is the most appropriate surgical intervention?

Explanation

Dynamic supination during the swing phase in a relapsed, fully correctable clubfoot is best treated with a full tibialis anterior tendon transfer (TATT) to the lateral cuneiform. This balances the forefoot forces; a SPLATT is contraindicated in Ponseti relapses as it does not sufficiently address the deforming force.

Question 47

A 3-year-old boy sustains an isolated midshaft femur fracture. Radiographs demonstrate 1.5 cm of shortening and 10 degrees of varus angulation. What is the most appropriate definitive management?

Explanation

For children aged 6 months to 5 years with a diaphyseal femur fracture and acceptable shortening (<2 cm), closed reduction and spica casting is the standard of care. Flexible nails are generally reserved for children aged 5 to 11 years or heavier children (>50 lbs).

Question 48

A 13-year-old girl sustains an ankle injury during a soccer game. Radiographs reveal a Salter-Harris type III fracture of the anterolateral aspect of the distal tibial epiphysis (Tillaux fracture). This fracture pattern is primarily caused by an avulsion of which of the following structures?

Explanation

A juvenile Tillaux fracture is an avulsion of the anterolateral distal tibial epiphysis caused by tension from the anterior inferior tibiofibular ligament (AITFL) during an external rotation injury. It occurs as the distal tibial physis closes from central to anterolateral.

Question 49

A 12-year-old boy presents with a history of recurrent ankle sprains and a rigid, painful flatfoot. Radiographs demonstrate an "anteater nose" sign.

Which radiographic view is most sensitive for confirming the exact location of the most likely coalition?

Explanation

The "anteater nose" sign on a lateral radiograph is pathognomonic for a calcaneonavicular coalition. The 45-degree internal oblique view of the foot optimally profiles the calcaneonavicular interval to confirm the diagnosis.

Question 50

A 10-year-old boy with known Legg-Calvé-Perthes disease presents with increasing hip pain and stiffness. An arthrogram demonstrates "hinge abduction" with lateral subluxation of the femoral head against the acetabular rim during hip abduction. What is the most appropriate surgical treatment?

Explanation

Hinge abduction occurs when an enlarged, deformed femoral head impinges on the lateral acetabular margin, preventing spherical containment. A valgus extension osteotomy redirects the head, moves the impingement away from the acetabular rim, and improves congruency.

Question 51

A newborn infant is noted to have severe anterolateral bowing of the right tibia. There are no fractures present on initial radiographs. The infant is at highest risk for developing congenital pseudarthrosis of the tibia (CPT). Which of the following genetic conditions is most strongly associated with this finding?

Explanation

Anterolateral bowing of the tibia is highly associated with congenital pseudarthrosis of the tibia (CPT). Approximately 50% of patients with CPT have a diagnosis of Neurofibromatosis type 1 (NF1), linked to chromosome 17q.

Question 52

A 14-year-old elite baseball pitcher complains of insidious onset right shoulder pain during the cocking phase of throwing. Radiographs reveal widening and irregularity of the proximal humeral physis. What is the most appropriate initial management?

Explanation

Little Leaguer's shoulder (proximal humeral epiphysiolysis) is a stress fracture of the proximal humeral physis due to repetitive rotational forces. The gold standard treatment is complete cessation of throwing for typically 3 months, followed by a gradual return-to-throwing program.

Question 53

A 5-year-old boy is brought to the emergency department after a low-speed motor vehicle collision. He is neurologically intact with no neck pain. Lateral cervical spine radiographs show 3 mm of anterior translation of C2 on C3. The Swischuk line passes 1 mm anterior to the anterior aspect of the posterior arch of C3. What is the most appropriate management?

Explanation

This scenario describes physiologic pseudosubluxation of C2 on C3, which is common in children under 8 years. A Swischuk line passing within 2 mm of the anterior aspect of the posterior arch of C3 confirms this is a normal variant requiring no intervention.

Question 54

An 11-year-old boy complains of intermittent left knee pain after playing basketball. MRI reveals a 1.5 cm stable osteochondritis dissecans (OCD) lesion on the lateral aspect of the medial femoral condyle. What is the most important factor predicting successful non-operative healing of this lesion?

Explanation

The status of the physes is the most critical prognostic factor for the healing of an OCD lesion. Patients with open physes (juvenile OCD) have a significantly higher rate of spontaneous healing with non-operative management compared to those with closed physes.

Question 55

A 6-year-old girl presents with a painless "clunking" in her right knee. She has no history of trauma. MRI confirms the presence of a Wrisberg variant discoid lateral meniscus. This specific variant is characterized by the absence of which of the following structures?

Explanation

The Wrisberg variant of a discoid meniscus lacks the normal posterior meniscotibial (coronary) ligament attachments. Its only posterior tether is the meniscofemoral ligament of Wrisberg, making it highly hypermobile and prone to snapping.

Question 56

A 7-year-old child with spastic quadriplegic cerebral palsy is evaluated during routine hip surveillance. Radiographs demonstrate a Reimers Migration Percentage of 45% in the right hip. The patient is non-ambulatory (GMFCS Level V) but experiences pain with diapering. What is the most recommended treatment?

Explanation

In cerebral palsy, a migration percentage >40% typically indicates impending or true hip subluxation that will not resolve with soft-tissue release alone. Bony reconstruction with a varus derotation osteotomy (VDRO), often combined with a pelvic osteotomy, is required.

Question 57

A 2-month-old infant is diagnosed with congenital muscular torticollis, presenting with a right sternocleidomastoid mass and the chin rotated to the left. Which of the following screening evaluations is strictly recommended for this infant?

Explanation

Congenital muscular torticollis has a known association with Developmental Dysplasia of the Hip (DDH), with co-occurrence rates reported up to 20%. Therefore, an ultrasound of the hips is routinely recommended for early detection of DDH.

Question 58

A 4-year-old boy with blue sclerae has sustained six fractures over the past two years with minimal trauma. Genetic testing confirms Osteogenesis Imperfecta (OI). The fundamental pathophysiology of his disease involves a defect in the synthesis of which of the following?

Explanation

Osteogenesis Imperfecta is primarily caused by autosomal dominant mutations in the COL1A1 or COL1A2 genes, which lead to quantitative or qualitative defects in Type I collagen, the major structural protein of bone.

Question 59

A 5-year-old girl undergoes closed reduction and percutaneous pinning for a Gartland type III supracondylar humerus fracture. Postoperatively, the radial pulse is completely absent, but her hand is warm, pink, and demonstrates brisk capillary refill (<2 seconds). What is the most appropriate management?

Explanation

A "pink, pulseless" hand after anatomic reduction and stabilization of a supracondylar humerus fracture indicates adequate collateral circulation. The standard of care is close clinical observation, as the pulse typically returns within a few days due to resolution of vasospasm.

Question 60

A 12-year-old boy presents with a 3-week history of right hip pain and a limp. He is unable to bear weight on the right leg, even with crutches. Radiographs confirm a Slipped Capital Femoral Epiphysis (SCFE). According to the Loder classification, what is the most significant prognostic factor associated with this specific presentation?

Explanation

The inability to bear weight defines an unstable SCFE according to the Loder classification. Unstable slips carry a significantly higher risk of developing avascular necrosis (up to 47%) compared to stable slips.

Question 61

An 8-year-old boy is diagnosed with Legg-Calve-Perthes disease. Radiographs show greater than 50% collapse of the lateral pillar of the femoral head. According to the Herring lateral pillar classification, what is his stage and expected prognosis?

Explanation

Herring Lateral Pillar Group C is defined by >50% loss of lateral pillar height. It is associated with a poor prognosis, particularly in children over 8 years of age, and often leads to a poorly spherical femoral head regardless of intervention.

Question 62

A 4-week-old female with an irreducible but dilatable left developmental dysplasia of the hip (DDH) is placed in a Pavlik harness. After 4 weeks of strictly compliant wear, dynamic ultrasound shows the hip remains completely dislocated. What is the most appropriate next step in management?

Explanation

Continuing a Pavlik harness for a hip that remains dislocated after 3-4 weeks is contraindicated because it can cause 'Pavlik harness disease' due to posterior acetabular wear. The harness must be abandoned in favor of a rigid orthosis or closed reduction and spica casting.

Question 63

A 3-year-old girl presents with progressive bilateral genu varum. Radiographs reveal a prominent medial metaphyseal beak and a sharp diaphyseal-metaphyseal angle. Which of the following is the most accurate statement regarding the suspected underlying pathology?

Explanation

Infantile Blount disease is characterized by disordered ossification of the medial aspect of the proximal tibial physis, causing varus, procurvatum, and internal rotation. Risk factors include obesity, African-American descent, and early walking.

Question 64

A 6-year-old boy sustains a severe extension-type supracondylar humerus fracture. On examination, the hand is pink and warm with normal capillary refill, but the radial pulse is not palpable.

What is the most appropriate initial management?

Explanation

For a 'pulseless, pink hand' associated with a supracondylar humerus fracture, the standard of care is urgent closed reduction and percutaneous pinning (CRPP). If the hand remains pink and well-perfused post-reduction, routine vascular exploration is unnecessary.

Question 65

An infant born with idiopathic clubfoot is treated with the Ponseti method. After successful sequential casting and a percutaneous Achilles tenotomy, the foot is placed in a foot abduction orthosis. The parents ask what the most common cause of future deformity recurrence is. What is the correct response?

Explanation

The vast majority of clubfoot relapses following successful Ponseti casting and tenotomy are directly attributed to poor parental adherence to the foot abduction orthosis (Denis Browne splint) bracing protocol. Strict compliance significantly minimizes relapse rates.

Question 66

A 4-year-old child with a history of multiple low-energy fractures, distinct blue sclerae, and dentinogenesis imperfecta is evaluated in the orthopedic clinic. Genetic testing reveals an autosomal dominant mutation. This systemic condition is primarily caused by a quantitative or qualitative defect in which of the following?

Explanation

Osteogenesis imperfecta (OI) is most commonly caused by autosomal dominant mutations in the COL1A1 or COL1A2 genes, leading to defective Type I collagen synthesis. This affects bone, sclera, and dentin, producing the classic clinical triad.

Question 67

A 4-year-old boy previously treated for idiopathic clubfoot with the Ponseti method presents with a dynamic supination deformity during the swing phase of gait. Passive ankle dorsiflexion is 15 degrees. What is the most appropriate surgical management?

Explanation

Dynamic supination during the swing phase in a relapsed clubfoot, when passive dorsiflexion is adequate, is treated with a tibialis anterior tendon transfer to the lateral cuneiform.

Question 68

An 8-year-old boy is diagnosed with Legg-Calvé-Perthes disease. Anteroposterior radiographs demonstrate greater than 50% loss of the lateral pillar height. According to the Herring classification, which group does this represent and what is the expected outcome?

Explanation

Herring Group C is characterized by >50% collapse of the lateral pillar height. This group is associated with poor prognostic outcomes and a high rate of aspherical femoral heads at maturity.

Question 69

A 10-year-old girl with spastic diplegic cerebral palsy is found to have a Reimers migration percentage of 55% bilaterally. She is asymptomatic but has progressive subluxation. What is the most appropriate surgical intervention?

Explanation

In older children with cerebral palsy and a Reimers migration index >50%, soft tissue release alone is insufficient. Bony reconstruction with VDRO and a pelvic osteotomy is the standard of care to achieve stable coverage.

Question 70

A 14-year-old obese male presents with a stable slipped capital femoral epiphysis (SCFE) of the left hip. He undergoes in situ pinning. Which of the following conditions represents the strongest indication for prophylactic pinning of the asymptomatic contralateral hip?

Explanation

Endocrine disorders, such as hypothyroidism or panhypopituitarism, and renal osteodystrophy significantly increase the risk of bilateral SCFE, making prophylactic contralateral pinning highly recommended.

Question 71

A 3-year-old boy presents with persistent bowing of the legs. Radiographs reveal medial metaphyseal beaking and a metaphyseal-diaphyseal angle of 18 degrees. What is the most appropriate initial management for this patient?

Explanation

A metaphyseal-diaphyseal angle >16 degrees is highly suggestive of infantile Blount disease. Initial treatment in a 3-year-old (Langenskiöld stage I or II) typically involves a trial of bracing with a KAFO.

Question 72

A 2.5-year-old girl presents with a limp. Clinical examination and radiographs confirm a unilaterally dislocated left hip (Developmental Dysplasia of the Hip). What is the most appropriate definitive management?

Explanation

In children older than 18-24 months with an untreated DDH, open reduction is generally required, often combined with a pelvic osteotomy to address acetabular dysplasia, and occasionally a femoral shortening osteotomy.

Question 73

A 7-year-old boy sustains a completely displaced extension-type supracondylar humerus fracture. On neurological examination, he is unable to flex the interphalangeal joint of the thumb and the distal interphalangeal joint of the index finger. Which nerve is injured?

Explanation

The anterior interosseous nerve (AIN) is the most commonly injured nerve in extension-type pediatric supracondylar humerus fractures, resulting in the inability to form the 'A-OK' sign.

Pediatric Orthopaedics: Comprehensive MCQ Question Bank & Exam Prep

Orthopedic Pediatric Review | Dr Hutaif Pediatric Ortho -...

Key Takeaway

Orthopedic Pediatric Review | Dr Hutaif Pediatric Ortho -...

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