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Pediatric Hip MCQs

Practice Set 65 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 1281

Topic: Pediatric Hip

In addition to the short and thick tubular bones seen in the radiograph below, what other skeletal anomaly is frequently associated with this syndrome?




. Absence of clavicles
. Scapular winging
. Atlantoaxial instability
. Coxa vara

Correct Answer & Explanation

. Absence of clavicles

Explanation

Correct Answer: Absence of claviclesEllis-van Creveld's syndrome is associated with several other skeletal and systemic anomalies, including the absence of clavicles, a narrow chest, and a hypoplastic maxilla.

Question 1282

Topic: Pediatric Hip

A 12-year-old girl with end-stage renal disease presents with bilateral hip pain. Radiographs demonstrate a "rugger jersey" spine and a slipped capital femoral epiphysis. Her PTH is markedly elevated. What is the primary mechanism driving her skeletal disease?

. Decreased renal excretion of calcium
. Increased 1-alpha-hydroxylase activity
. Phosphate retention and decreased calcitriol production
. Primary hyperparathyroidism
. Increased renal excretion of phosphate

Correct Answer & Explanation

. Phosphate retention and decreased calcitriol production

Explanation

In renal osteodystrophy, failing kidneys retain phosphate and lose 1-alpha-hydroxylase activity, decreasing active Vitamin D (calcitriol) production. This leads to hypocalcemia, secondary hyperparathyroidism, and resultant skeletal lesions like SCFE and osteitis fibrosa cystica.

Question 1283

Topic: Pediatric Hip

A 10-year-old girl with cleidocranial dysplasia presents with a progressively waddling gait.

Based on the typical pelvic pathology of this condition, what is the most likely diagnosis?

. Developmental dysplasia of the hip (DDH)
. Slipped capital femoral epiphysis (SCFE)
. Coxa vara
. Coxa valga
. Avascular necrosis of the femoral head

Correct Answer & Explanation

. Coxa vara

Explanation

Cleidocranial dysplasia is frequently associated with developmental coxa vara due to a primary ossification defect in the femoral neck. Progressive coxa vara results in a waddling gait and positive Trendelenburg sign.

Question 1284

Topic: Pediatric Hip

A 9-year-old girl with cleidocranial dysplasia presents for follow-up.

She has bilateral coxa vara with a neck-shaft angle of 95 degrees and a Hilgenreiner epiphyseal angle (HEA) of 65 degrees. What is the most appropriate management for her hips?

. Observation and annual radiographs
. Bilateral spica casting
. Valgus-producing proximal femoral osteotomies
. In situ single screw pinning of the hips
. Bilateral pelvic support osteotomies

Correct Answer & Explanation

. Valgus-producing proximal femoral osteotomies

Explanation

Coxa vara is a common orthopedic issue in cleidocranial dysplasia. Surgical correction via valgus proximal femoral osteotomy is indicated when the neck-shaft angle is less than 110-120 degrees or the HEA is greater than 60 degrees, due to a high risk of progression and pseudoarthrosis.

Question 1285

Topic: Pediatric Hip

A 7-year-old girl is evaluated for delayed eruption of secondary dentition and an unusual ability to appose her shoulders anteriorly. Radiographs confirm absent clavicles.

Which of the following orthopaedic manifestations is most commonly associated with this genetic syndrome?

. Coxa vara
. Slipped capital femoral epiphysis
. Acetabular protrusio
. Bilateral hip dislocation
. Avascular necrosis of the femoral head

Correct Answer & Explanation

. Coxa vara

Explanation

Cleidocranial dysplasia (RUNX2 gene mutation) classically presents with delayed ossification of the skull, aplastic or hypoplastic clavicles, and pelvic abnormalities. Coxa vara and a widened pubic symphysis are the most common associated hip/pelvic manifestations.

Question 1286

Topic: Pediatric Hip

A 2-week-old neonate presents with pseudoparalysis of the right lower extremity and crying upon diaper changes. Ultrasound confirms a significant hip effusion.

What is the most appropriate next step in management?

. Observation and repeat ultrasound in 1 week
. Pavlik harness application
. Intravenous antibiotics followed by MRI
. Immediate joint aspiration, arthrotomy, and irrigation
. Closed reduction and spica casting

Correct Answer & Explanation

. Immediate joint aspiration, arthrotomy, and irrigation

Explanation

Neonatal septic arthritis ('coxitis') is a surgical emergency that can rapidly destroy the cartilaginous femoral head. Immediate joint aspiration and urgent open arthrotomy with irrigation is required to prevent permanent joint destruction.

Question 1287

Topic: Pediatric Hip

A 3-week-old neonate presents with fever, irritability, and a pseudoparalysis of the right lower extremity. Ultrasound reveals a hip joint effusion.

What is the most appropriate next step in management?

. Pavlik harness application
. Urgent hip aspiration and surgical drainage
. Intravenous antibiotics and observation
. Closed reduction and spica casting
. MRI of the bilateral hips

Correct Answer & Explanation

. Urgent hip aspiration and surgical drainage

Explanation

Neonatal septic arthritis of the hip is a surgical emergency. Delay in decompression can lead to rapid destruction of the unossified femoral head (Tom Smith arthritis).

Question 1288

Topic: Pediatric Hip



A 3-week-old neonate presents with pseudoparalysis of the right leg and crying with diaper changes. There is no fever, but CRP is significantly elevated. Ultrasound reveals a hip effusion. If this neonatal septic arthritis (coxitis) is diagnosed late and untreated, what is the most severe classical long-term orthopedic complication?

. Slipped capital femoral epiphysis
. Resorption of the femoral head and neck (Tom Smith arthritis)
. Legg-Calve-Perthes disease
. Development of an aneurysmal bone cyst
. Progressive tibia vara

Correct Answer & Explanation

. Resorption of the femoral head and neck (Tom Smith arthritis)

Explanation

Neonatal septic arthritis of the hip often lacks classic systemic signs like high fever. Delayed diagnosis and treatment lead to rapid cartilaginous destruction and complete resorption of the proximal femur, a devastating sequela known as Tom Smith arthritis.

Question 1289

Topic: Pediatric Hip

A 12-year-old obese boy presents with a left slipped capital femoral epiphysis (SCFE). Which of the following is an absolute indication for prophylactic in situ pinning of the contralateral, asymptomatic hip?

. Age greater than 14 years
. Presence of an underlying endocrine disorder
. Presence of a large effusion on the symptomatic side
. Male gender
. Mild slip angle (less than 30 degrees)

Correct Answer & Explanation

. Presence of an underlying endocrine disorder

Explanation

Prophylactic pinning of the contralateral hip in SCFE is strongly recommended in patients with endocrine disorders (e.g., hypothyroidism, renal osteodystrophy) due to the very high risk of bilateral involvement.

Question 1290

Topic: Pediatric Hip
In Legg-Calvé-Perthes disease, the Herring Lateral Pillar classification is most reliably applied at what stage of the disease to predict the ultimate deformity?
. Initial (ischemic) stage
. Early fragmentation stage
. Reossification stage
. Residual stage
. Pre-ischemic stage

Correct Answer & Explanation

. Early fragmentation stage

Explanation

The Herring Lateral Pillar classification assesses the structural height of the lateral pillar of the femoral head. It is most accurately determined during the early to mid fragmentation stage before reossification begins.

Question 1291

Topic: Pediatric Hip

A 45-year-old female with Crowe IV developmental dysplasia of the hip (DDH) is undergoing a total hip arthroplasty. The surgeon plans to place the acetabular component at the true anatomic hip center and perform a subtrochanteric shortening osteotomy. Which of the following is the primary rationale for performing the shortening osteotomy in this specific scenario?

. To prevent superior gluteal nerve palsy
. To prevent sciatic nerve palsy
. To increase the offset of the femoral component
. To allow for the use of a larger acetabular component
. To correct excessive femoral retroversion

Correct Answer & Explanation

. To prevent sciatic nerve palsy

Explanation

Correct Answer: To prevent sciatic nerve palsyCrowe IV DDH is characterized by a high hip dislocation with greater than 100% subluxation. The native acetabulum is hypoplastic, and a false acetabulum forms superiorly. When performing a THA in these patients, placing the cup in the true anatomic hip center provides the best biomechanical advantage and longevity. However, bringing the femur down to the true hip center requires significant lengthening of the limb. Lengthening the limb by more than 4 cm poses a high risk of stretch-induced sciatic nerve palsy. To safely place the cup at the true center without overstretching the sciatic nerve, a subtrochanteric shortening osteotomy of the femur is routinely performed.

Question 1292

Topic: Pediatric Hip

A 40-year-old female with severe unilateral developmental dysplasia of the hip (Crowe type IV) undergoes a complex THA requiring significant leg lengthening. Postoperatively, she is unable to actively dorsiflex her foot or extend her great toe, and has numbness over the dorsum of her foot. What is the most common intraoperative mechanism for this specific neurologic complication?

. Direct laceration of the tibial nerve
. Retractor compression of the femoral nerve
. Excessive limb lengthening causing stretch injury to the peroneal division of the sciatic nerve
. Thermal injury from bone cement escaping anteriorly
. Ligation of the internal iliac artery causing ischemic neuropathy

Correct Answer & Explanation

. Excessive limb lengthening causing stretch injury to the peroneal division of the sciatic nerve

Explanation

The peroneal division of the sciatic nerve is particularly vulnerable to stretch injury during THA, especially in cases requiring limb lengthening >4 cm (such as Crowe IV DDH). It is tethered at the fibular head, making it mechanically more susceptible to tension than the tibial division.

Question 1293

Topic: Pediatric Hip
In a patient with Crowe Type III developmental dysplasia of the hip undergoing THA, the surgeon opts to place the acetabular component in the native true acetabulum rather than a high hip center. Which of the following surgical maneuvers is most commonly required to successfully reduce the hip and protect the neurovascular structures?
. Ischial osteotomy
. Subtrochanteric shortening osteotomy
. Hamstring release
. Anterior capsulorrhaphy
. Distal femoral lengthening osteotomy

Correct Answer & Explanation

. Subtrochanteric shortening osteotomy

Explanation

Placing the cup in the true, anatomic acetabulum in severe DDH requires bringing the femur down significantly. A subtrochanteric shortening osteotomy is typically required to allow joint reduction without placing excessive, dangerous tension on the sciatic nerve.

Question 1294

Topic: Pediatric Hip

A 40-year-old female with Crowe IV developmental dysplasia of the hip is undergoing a total hip arthroplasty. The surgeon plans to place the acetabular component at the level of the true anatomic acetabulum. What additional procedural step is most likely required to safely accomplish this reduction?

. Greater trochanteric advancement
. Proximal femoral replacement
. Subtrochanteric shortening osteotomy
. Hamstring tendon lengthening
. Proximal femoral valgus osteotomy

Correct Answer & Explanation

. Subtrochanteric shortening osteotomy

Explanation

In Crowe IV DDH, the femur is highly migrated. Placing the cup in the true, anatomic acetabulum requires significant distal translation of the femur to achieve reduction. A subtrochanteric shortening osteotomy is typically necessary to allow reduction and prevent devastating traction injury to the sciatic nerve.

Question 1295

Topic: Pediatric Hip

A newborn with Down syndrome undergoes a pelvic radiograph for hip screening. Which of the following classic radiographic findings is typically seen in the pelvis of infants with Trisomy 21?

. Increased acetabular index and steep acetabular roofs
. Decreased iliac index with flattened acetabular roofs and flared iliac wings
. Protrusio acetabuli with medial joint space narrowing
. Coxa vara with a fragmented proximal femoral epiphysis
. A shallow acetabulum with a sharply angled sourcil

Correct Answer & Explanation

. Decreased iliac index with flattened acetabular roofs and flared iliac wings

Explanation

The classic pelvic radiographic appearance in Down syndrome includes flared iliac wings and flattened acetabular roofs, resulting in a decreased iliac index. This contrasts with developmental dysplasia of the hip (DDH), which shows an increased acetabular index.

Question 1296

Topic: Pediatric Hip

A 10-year-old male with Down syndrome presents with a 3-week history of a limp and poorly localized knee pain. Radiographs confirm a slipped capital femoral epiphysis (SCFE). Compared to an idiopathic SCFE in a neurotypical child, this patient is at an increased risk for which of the following?

. Chondrolysis requiring joint arthrodesis
. Femoral nerve palsy
. Development of a subtrochanteric fracture
. Bilateral involvement
. Malignant transformation

Correct Answer & Explanation

. Bilateral involvement

Explanation

Patients with Down syndrome have a higher incidence of SCFE and a significantly higher rate of bilateral involvement compared to the idiopathic population. They often present younger and require careful evaluation of the contralateral hip.

Question 1297

Topic: Pediatric Hip
A 10-year-old boy with Down syndrome presents with a 2-month history of a limp and poorly localized thigh pain. Exam reveals obligate external rotation of the hip during passive flexion. Which of the following is the most likely diagnosis?
. Legg-Calvé-Perthes disease
. Transient synovitis
. Slipped capital femoral epiphysis (SCFE)
. Developmental dysplasia of the hip (DDH)
. Septic arthritis

Correct Answer & Explanation

. Slipped capital femoral epiphysis (SCFE)

Explanation

Children with Down syndrome are at increased risk for SCFE, frequently due to underlying endocrine issues (e.g., hypothyroidism). Obligate external rotation with hip flexion is the classic physical exam finding for SCFE.

Question 1298

Topic: Pediatric Hip
A 6-year-old boy presents with bilateral hip pain and a waddling gait. Radiographs reveal bilateral, symmetric fragmentation and flattening of the femoral capital epiphyses, with normal acetabuli and normal spine radiographs. His father had similar early-onset arthritis. Which of the following best differentiates this condition from Legg-Calvé-Perthes disease?
. Unilateral involvement is typical in MED
. Symmetric, bilateral involvement and autosomal dominant inheritance favor MED
. Presence of platyspondyly favors MED
. Elevated inflammatory markers favor MED
. Scoliosis is a hallmark of MED

Correct Answer & Explanation

. Symmetric, bilateral involvement and autosomal dominant inheritance favor MED

Explanation

Multiple Epiphyseal Dysplasia (MED) usually presents with symmetric, bilateral epiphyseal changes and has an autosomal dominant inheritance. Legg-Calvé-Perthes disease is predominantly unilateral and lacks a strong inherited pattern.

Question 1299

Topic: Pediatric Hip

A 2-week-old neonate presents with asymmetric hip creases, fever, and pseudoparalysis of the right lower extremity. Ultrasound confirms a large hip effusion, and emergent surgical drainage is performed. The clinical image below demonstrates severe sequelae of a missed diagnosis in a similar patient.

What is the most devastating long-term complication of delayed diagnosis of neonatal septic arthritis of the hip?

. Coxa magna with joint space widening
. Complete avascular destruction of the femoral head and neck with hip subluxation
. Slipped capital femoral epiphysis
. Legg-Calve-Perthes disease
. Isolated acetabular dysplasia without femoral head involvement

Correct Answer & Explanation

. Complete avascular destruction of the femoral head and neck with hip subluxation

Explanation

Delay in treating neonatal septic arthritis of the hip results in catastrophic destruction of the cartilaginous femoral head and neck due to infection and increased intra-articular pressure compromising the vascular supply. This results in the classic Choi type IV sequelae (destruction of head and neck).

Question 1300

Topic: Pediatric Hip
A 10-year-old boy presents with bilateral knee and hip pain, and a waddling gait. Radiographs show delayed, irregular, and fragmented ossification centers of the capital femoral epiphyses. Lateral knee radiographs demonstrate a "double-layer" patella. Spinal radiographs are entirely normal. What is the most likely diagnosis?
. Spondyloepiphyseal dysplasia congenita
. Multiple epiphyseal dysplasia
. Legg-Calvé-Perthes disease
. Pseudoachondroplasia
. Mucopolysaccharidosis

Correct Answer & Explanation

. Multiple epiphyseal dysplasia

Explanation

Multiple epiphyseal dysplasia (MED) presents with delayed and irregular ossification of multiple epiphyses leading to early osteoarthritis, but uniquely leaves the spine relatively spared (differentiating it from SED). A "double-layer" patella is a classic radiographic sign.

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