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Pediatric Hip MCQs

Practice Set 33 of 104

This practice set contains high-yield board review questions covering key concepts in Pediatric Hip. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 641

Topic: Pediatric Hip

In the management of Slipped Capital Femoral Epiphysis (SCFE), prophylactic in situ pinning of the contralateral hip is most strongly indicated in a patient presenting with which of the following underlying characteristics?

. Hypothyroidism
. Obesity (>95th percentile)
. Male gender
. Age greater than 14 years at presentation
. African American descent

Correct Answer & Explanation

. Age greater than 14 years at presentation

Explanation

Prophylactic pinning of the contralateral hip in SCFE is highly recommended in patients with underlying endocrinopathies (e.g., hypothyroidism, renal osteodystrophy, growth hormone deficiency) and in those presenting at a particularly young age (girls <10, boys <12) due to the significantly elevated risk of developing a subsequent contralateral slip.

Question 642

Topic: Pediatric Hip
A 6-week-old female infant is evaluated for Developmental Dysplasia of the Hip (DDH). Coronal ultrasound demonstrates an alpha angle of 48 degrees and a beta angle of 65 degrees. According to Graf's classification and standard clinical guidelines, what is the most appropriate initial management?
. Observation and repeat ultrasound in 4 weeks
. Application of a Pavlik harness
. Closed reduction and spica casting under anesthesia
. Open reduction and capsulorrhaphy
. Varus derotational osteotomy

Correct Answer & Explanation

. Application of a Pavlik harness

Explanation

An alpha angle of < 60 degrees (in this case, 48 degrees) indicates a shallow, dysplastic acetabulum (Graf Type III or worse). The gold standard initial treatment for a child under 6 months of age with a dysplastic, subluxated, or reducible dislocated hip is the application of a Pavlik harness to maintain flexion and abduction, promoting physiologic remodeling of the acetabulum.

Question 643

Topic: Pediatric Hip

Prophylactic in situ pinning of the contralateral asymptomatic hip in a patient with a Slipped Capital Femoral Epiphysis (SCFE) is most strongly indicated in which of the following clinical profiles?

. A 14-year-old boy with a normal body mass index
. A 12-year-old boy with renal osteodystrophy
. A 13-year-old girl with an acute-on-chronic SCFE
. A 15-year-old boy who sustained a mechanical fall
. A 10-year-old girl with a completely normal endocrine workup

Correct Answer & Explanation

. A 12-year-old boy with renal osteodystrophy

Explanation

Prophylactic pinning of the contralateral hip in SCFE is controversial but is strongly recommended in patients with endocrine or metabolic disorders (such as renal osteodystrophy, hypothyroidism, or panhypopituitarism) due to the exceptionally high rate of bilateral involvement (up to 100% in some metabolic conditions). It is also commonly considered in patients presenting at a very young age (< 10 years).

Question 644

Topic: Pediatric Hip

An 8-year-old girl is diagnosed with bilateral slipped capital femoral epiphysis (SCFE). On examination, her height and weight are both below the 5th percentile for her age. Which of the following is the most likely underlying etiology and the most appropriate screening test?

. Hypothyroidism; Thyroid-stimulating hormone (TSH) and Free T4
. Renal osteodystrophy; Parathyroid hormone (PTH) and basic metabolic panel
. Growth hormone deficiency; Insulin-like growth factor 1 (IGF-1)
. Panhypopituitarism; Serum prolactin and cortisol levels
. Hyperthyroidism; Total T3 and T4 levels

Correct Answer & Explanation

. Hypothyroidism; Thyroid-stimulating hormone (TSH) and Free T4

Explanation

SCFE occurring in a child under 10 years of age or presenting bilaterally is highly suspicious for an underlying endocrine or metabolic disorder. Hypothyroidism is the most common endocrine disorder associated with SCFE, often presenting with short stature, delayed bone age, and weight gain, though generalized growth restriction can occur. Screening with TSH and Free T4 is the most appropriate initial step.

Question 645

Topic: Pediatric Hip

A 4-month-old infant is being treated for developmental dysplasia of the hip (DDH) with a Pavlik harness. During a follow-up visit, the orthopedist notices an absence of active knee extension on the affected side. This complication is most directly related to which of the following harness fitting errors?

. Excessive abduction of the hips
. Insufficient abduction of the hips
. Excessive flexion of the hips
. Insufficient flexion of the hips
. Excessive internal rotation of the hips

Correct Answer & Explanation

. Excessive flexion of the hips

Explanation

Femoral nerve palsy is a known complication of the Pavlik harness and presents as an inability to actively extend the knee. It is caused by excessive flexion of the hip (typically > 120 degrees), which compresses the femoral nerve against the rim of the pelvis or the inguinal ligament. Excessive abduction is associated with avascular necrosis of the femoral head.

Question 646

Topic: Pediatric Hip

A 12-year-old boy is diagnosed with a unilateral slipped capital femoral epiphysis (SCFE) of the left hip. The orthopaedic surgeon recommends prophylactic in situ pinning of the contralateral right hip due to a high risk of subsequent slip. Which of the following underlying conditions most strongly warrants prophylactic contralateral pinning in SCFE?

. Obesity with BMI > 95th percentile
. Hypothyroidism
. Attention Deficit Hyperactivity Disorder (ADHD)
. Vitamin D deficiency rickets
. Mild renal osteodystrophy

Correct Answer & Explanation

. Hypothyroidism

Explanation

While idiopathic SCFE is common in obese adolescents, endocrinopathies are strong indications for prophylactic contralateral pinning due to the exceedingly high risk of bilateral involvement. Hypothyroidism, panhypopituitarism, and growth hormone deficiency are the most common endocrine disorders associated with atypical or early/late presentation of SCFE, and prophylactic pinning of the asymptomatic hip is strongly recommended in these patients.

Question 647

Topic: Pediatric Hip

The primary blood supply to the femoral head in an adolescent with a slipped capital femoral epiphysis (SCFE) is derived from the:

. Lateral epiphyseal branches of the medial circumflex femoral artery
. Medial epiphyseal branches of the obturator artery
. Artery of the ligamentum teres
. Inferior gluteal artery
. Ascending branch of the lateral circumflex femoral artery

Correct Answer & Explanation

. Lateral epiphyseal branches of the medial circumflex femoral artery

Explanation

The lateral epiphyseal artery, a terminal branch of the medial circumflex femoral artery (MCFA), provides the predominant blood supply to the femoral head in older children and adolescents. Disruption of these retinacular vessels during a SCFE or its surgical treatment can lead to avascular necrosis.

Question 648

Topic: Pediatric Hip

Chondrolysis is a devastating complication following the surgical treatment of Slipped Capital Femoral Epiphysis (SCFE). The development of chondrolysis is most strongly associated with which of the following factors?

. Unrecognized intra-articular penetration of the fixation hardware
. Female sex and early menarche
. Delay in surgical intervention greater than 24 hours
. Use of a single 7.3 mm cannulated screw instead of two
. Concomitant prophylactic pinning of the contralateral hip

Correct Answer & Explanation

. Unrecognized intra-articular penetration of the fixation hardware

Explanation

Unrecognized intra-articular hardware penetration is the most common iatrogenic cause of chondrolysis in SCFE treatment. It causes severe mechanical damage to the articular cartilage, leading to rapid joint space narrowing, stiffness, and pain.

Question 649

Topic: Pediatric Hip

A 12-year-old obese boy presents with acute right groin pain and an inability to bear weight on his right leg, even with crutches. Radiographs confirm a severe Slipped Capital Femoral Epiphysis (SCFE). According to the Loder classification, what is the primary determinant of this patient's high risk for avascular necrosis (AVN)?

. Slip angle > 50 degrees
. Inability to ambulate with or without crutches
. Duration of symptoms < 3 weeks
. Open triradiate cartilage
. Metaphyseal blanch sign of Steel

Correct Answer & Explanation

. Inability to ambulate with or without crutches

Explanation

The Loder classification defines SCFE as 'stable' or 'unstable' strictly based on the patient's ability to bear weight (ambulate) with or without crutches. Unstable slips (inability to bear weight) carry a significantly higher risk of avascular necrosis (up to 47%) compared to stable slips.

Question 650

Topic: Pediatric Hip
A 6-week-old female infant undergoes a screening ultrasound for developmental dysplasia of the hip (DDH). The standard coronal view yields an alpha angle of 35 degrees and a beta angle of 85 degrees. According to the Graf classification, what is the diagnosis and the most appropriate next step in management?
. Normal hip (Type I); parental reassurance
. Physiologic immaturity (Type IIa); repeat ultrasound in 4 weeks
. Subluxated hip (Type III); initiate Pavlik harness treatment
. Dislocated hip (Type IV); proceed to closed reduction and spica casting
. Dysplastic hip (Type IIb); immediate open reduction

Correct Answer & Explanation

. Subluxated hip (Type III); initiate Pavlik harness treatment

Explanation

An alpha angle of < 43 degrees with a beta angle > 77 degrees correlates with a Graf Type III hip, which represents a decentered (subluxated) hip with a measurable cartilage roof. The appropriate initial management for a subluxated hip in an infant under 6 months of age is reduction and stabilization utilizing a Pavlik harness.

Question 651

Topic: Pediatric Hip

A 7-year-old boy presents with a painless limp and is diagnosed with Legg-Calve-Perthes disease in the fragmentation stage. Radiographs reveal that exactly 60% of the lateral pillar of the femoral head maintains its normal radiolucent height. According to the Herring Lateral Pillar Classification, what group is this hip, and what is its prognosis without intervention?

. Group A; excellent prognosis
. Group B; good prognosis given his age is < 8 years
. Group B/C border; poor prognosis requiring surgery
. Group C; poor prognosis requiring immediate containment
. Group C; excellent prognosis with simple bracing

Correct Answer & Explanation

. Group B; good prognosis given his age is < 8 years

Explanation

Herring's Lateral Pillar Classification assesses the height of the lateral aspect of the femoral head. Group A has >100% (no involvement), Group B maintains >50% of lateral pillar height, and Group C maintains <50%. With 60% preserved, this is Group B. Patients in Group B who are under 8 years of age at the onset of the disease generally have a good prognosis and often do well with conservative management.

Question 652

Topic: Pediatric Hip

A 4-month-old female is being treated with a Pavlik harness for developmental dysplasia of the hip (DDH). At her 2-week follow-up, the mother reports that the infant has stopped actively extending her knee on the treated side. Upon examination, the hip is well-reduced. Which of the following is the most appropriate management regarding the harness?

. Tighten the anterior straps to maintain reduction
. Loosen the anterior straps to reduce hip flexion
. Tighten the posterior straps to increase abduction
. Loosen the posterior straps to decrease abduction
. Discontinue the harness immediately and schedule a closed reduction

Correct Answer & Explanation

. Loosen the anterior straps to reduce hip flexion

Explanation

Decreased active knee extension in an infant treated with a Pavlik harness is highly suspicious for a femoral nerve palsy. This complication is typically caused by excessive hip flexion, which compresses the femoral nerve against the inguinal ligament. The correct management is to immediately loosen the anterior flexion straps. Once the nerve function returns, the straps can be cautiously readjusted. Femoral nerve palsy in this setting usually resolves completely if addressed promptly.

Question 653

Topic: Pediatric Hip

A 9-year-old male presents with a slipped capital femoral epiphysis (SCFE) of the right hip. Under which of the following conditions is prophylactic in situ pinning of the contralateral asymptomatic left hip most strongly indicated?

. The patient has a BMI > 95th percentile
. The patient has a diagnosis of renal osteodystrophy
. The slip is classified as unstable
. The slip angle on the right is greater than 50 degrees
. The patient is male

Correct Answer & Explanation

. The patient has a diagnosis of renal osteodystrophy

Explanation

Prophylactic pinning of the contralateral hip in SCFE is controversial but is strictly indicated in patients who have a high likelihood of a subsequent contralateral slip. Absolute or strong indications include underlying endocrine disorders (such as hypothyroidism or growth hormone deficiency), metabolic bone disease (such as renal osteodystrophy), prior radiation therapy to the pelvis, and very young age (typically females <10 and males <12). Obesity or slip severity on the affected side are not absolute indications on their own.

Question 654

Topic: Pediatric Hip
A 6-year-old boy is diagnosed with Legg-Calvรฉ-Perthes disease. During the fragmentation stage, an AP radiograph of his pelvis is used to determine his prognosis according to the Herring lateral pillar classification. To be classified as Group C (which carries the worst prognosis), the lateral pillar of the femoral head must demonstrate what percentage of maintained height compared to the contralateral normal hip?
. Less than 50%
. 50% to 100%
. Greater than 75%
. Complete collapse (0%) only
. Maintains 100% height but with extensive sclerosis

Correct Answer & Explanation

. Less than 50%

Explanation

The Herring lateral pillar classification is assessed on an AP radiograph during the fragmentation phase of Legg-Calvรฉ-Perthes disease. It is based on the height of the lateral third (pillar) of the capital femoral epiphysis. Group A: 100% of the lateral pillar height is maintained. Group B: >50% of the lateral pillar height is maintained. Group C: <50% of the lateral pillar height is maintained. Patients in Group C have the poorest outcomes, often developing aspherical incongruency and early osteoarthritis.

Question 655

Topic: Pediatric Hip

In which of the following scenarios is prophylactic in situ pinning of the contralateral, asymptomatic hip most strongly indicated in a patient presenting with a unilateral slipped capital femoral epiphysis (SCFE)?

. A 13-year-old male with a BMI in the 95th percentile
. A 12-year-old female with primary hyperparathyroidism
. A 14-year-old male with an acute, unstable SCFE
. An 11-year-old female with a chronic, stable SCFE
. A 15-year-old male with a positive family history of SCFE

Correct Answer & Explanation

. A 12-year-old female with primary hyperparathyroidism

Explanation

Prophylactic pinning of the contralateral hip in SCFE is controversial for idiopathic cases but is highly recommended in patients with endocrine disorders (e.g., hypothyroidism, renal osteodystrophy, hyperparathyroidism, growth hormone deficiency) or prior radiation therapy. These patients have a significantly higher risk (up to 100% in some metabolic conditions) of developing a contralateral slip compared to those with idiopathic SCFE.

Question 656

Topic: Pediatric Hip

An 11-year-old obese boy is diagnosed with a unilateral, stable slipped capital femoral epiphysis (SCFE). Prophylactic pinning of the contralateral asymptomatic hip is being considered. Which of the following factors most strongly increases the risk of a contralateral slip and supports the decision for prophylactic pinning?

. Male gender
. African American race
. Age greater than 14 years at presentation
. Open triradiate cartilage at the time of presentation
. Presence of a metaphyseal blanch sign of Steel

Correct Answer & Explanation

. Open triradiate cartilage at the time of presentation

Explanation

Patients with an initial SCFE have a significant risk of contralateral slip (up to 20-60%). The risk is highest in patients with endocrine disorders (e.g., hypothyroidism) and those with significant remaining growth. An open triradiate cartilage indicates significant skeletal immaturity and remaining growth, representing a strong predictor for subsequent contralateral slip, thus often serving as a relative indication for prophylactic pinning.

Question 657

Topic: Pediatric Hip

A 12-year-old boy presents with an acute-on-chronic slipped capital femoral epiphysis (SCFE) of the left hip. Under which of the following conditions is prophylactic pinning of the asymptomatic contralateral hip most strongly indicated?

. Age greater than 14 years
. Female gender
. Presence of an endocrine disorder such as hypothyroidism
. Grade I slip on the affected side
. BMI less than 85th percentile

Correct Answer & Explanation

. Presence of an endocrine disorder such as hypothyroidism

Explanation

Prophylactic pinning of the contralateral hip in SCFE is highly recommended in patients with endocrine disorders (e.g., hypothyroidism, growth hormone deficiency, renal osteodystrophy) due to the high risk of bilateral involvement (up to 100% in some endocrine conditions). Other risk factors include age <10 years (or open triradiate cartilage) and prior radiation therapy.

Question 658

Topic: Pediatric Hip

An 8-week-old female infant is treated with a Pavlik harness for Developmental Dysplasia of the Hip (DDH). During a follow-up visit, the mother notes that the infant is no longer kicking her leg on the affected side. Examination reveals an absent patellar reflex and inability to actively extend the knee. What positioning error in the Pavlik harness most likely caused this complication?

. Excessive hip flexion
. Inadequate hip flexion
. Excessive hip abduction
. Inadequate hip abduction
. Excessive internal rotation

Correct Answer & Explanation

. Excessive hip flexion

Explanation

The clinical picture describes a femoral nerve palsy, a known complication of the Pavlik harness. It is typically caused by excessive hip flexion (often >120 degrees), which compresses the femoral nerve against the inguinal ligament. Excessive hip abduction, conversely, places the patient at a higher risk for avascular necrosis (AVN) of the femoral head.

Question 659

Topic: Pediatric Hip

A 7-year-old boy is diagnosed with Legg-Calve-Perthes disease. According to the Herring Lateral Pillar Classification, which of the following describes a Group B hip, and what is its prognostic significance?

. No lucency in the lateral pillar; uniformly good prognosis
. Less than 50% loss of lateral pillar height; variable prognosis depending on age
. Greater than 50% loss of lateral pillar height; uniformly poor prognosis
. Complete collapse of the lateral pillar; invariably requires salvage surgery
. Central pillar collapse with an intact lateral pillar; uniformly good prognosis

Correct Answer & Explanation

. Less than 50% loss of lateral pillar height; variable prognosis depending on age

Explanation

The Herring Lateral Pillar Classification assesses the height of the lateral pillar of the femoral head on an AP radiograph during the fragmentation stage. Group A has no loss of height; Group B has >50% maintained (i.e., <50% loss of height); Group C has <50% of the height maintained. Group B hips generally have a good outcome in patients <8 years old but a less predictable/worse outcome in older patients.

Question 660

Topic: Pediatric Hip

A 12-year-old boy presents with a left-sided severe slipped capital femoral epiphysis (SCFE). Which of the following factors provides the strongest indication for prophylactic pinning of the asymptomatic contralateral hip?

. Male gender
. Obesity (BMI > 95th percentile)
. Presence of an underlying endocrine disorder
. Age greater than 14 years at presentation
. African American ethnicity

Correct Answer & Explanation

. Presence of an underlying endocrine disorder

Explanation

Prophylactic pinning of the contralateral hip in SCFE is heavily debated, but there is broad consensus that patients with underlying endocrine disorders (e.g., hypothyroidism, growth hormone deficiency, renal osteodystrophy) or previous radiation therapy are at a remarkably high risk of developing a contralateral slip. Thus, prophylactic pinning is strongly indicated in these populations.

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