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Pediatric Hip MCQs

Practice Set 66 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 1301

Topic: Pediatric Hip

A 13-year-old boy with a BMI of 32 presents with acute-on-chronic left hip pain and an inability to bear weight. Radiographs confirm a severe Slipped Capital Femoral Epiphysis (SCFE). Which of the following is a recognized indication for prophylactic in situ pinning of the contralateral asymptomatic hip?

. Patient age > 14 years
. Endocrine disorder such as hypothyroidism
. Male sex
. Acute presentation < 3 weeks
. Unilateral slip angle > 50 degrees

Correct Answer & Explanation

. Endocrine disorder such as hypothyroidism

Explanation

Prophylactic pinning of the contralateral hip in SCFE is generally recommended for patients with underlying metabolic or endocrine disorders (e.g., hypothyroidism, renal osteodystrophy), prior radiation therapy, or an age outside the typical range (e.g., < 10 years).

Question 1302

Topic: Pediatric Hip

A 13-year-old obese male presents with right hip pain, an antalgic gait, and an obligate external rotation of the hip upon flexion. Radiographs demonstrate a slipped capital femoral epiphysis (SCFE). Relative to the femoral neck, in which anatomical direction does the epiphysis translate in a typical SCFE?

. Anterior and superior
. Anterior and inferior
. Posterior and superior
. Posterior and inferior
. Directly posterior

Correct Answer & Explanation

. Posterior and inferior

Explanation

In a slipped capital femoral epiphysis (SCFE), the epiphysis typically remains within the acetabulum while the femoral neck displaces anteriorly and superiorly. Therefore, relative to the femoral neck, the epiphysis displaces posteriorly and inferiorly. This creates the classic 'ice cream slipping off the cone' radiographic appearance on the lateral view.

Question 1303

Topic: Pediatric Hip
A 14-year-old obese male presents to the emergency department with a 2-day history of severe left hip pain and inability to bear weight after twisting his leg. He reports a 3-month history of intermittent mild hip discomfort. On exam, the left lower extremity is held in external rotation and he has severe pain with any attempt at passive motion. Radiographs demonstrate an unstable Slipped Capital Femoral Epiphysis (SCFE) with significant posterior and inferior displacement (Grade III). What is the most appropriate immediate management to minimize the risk of avascular necrosis (AVN)?
. Emergent open reduction and internal fixation.
. In situ pinning with a single screw, without any manipulation or reduction attempt.
. Gentle closed reduction under anesthesia, followed by in situ pinning.
. Traction for 24-48 hours followed by in situ pinning.
. Modified Dunn procedure (subcapital osteotomy) and internal fixation.

Correct Answer & Explanation

. In situ pinning with a single screw, without any manipulation or reduction attempt.

Explanation

For unstable SCFE, the most critical complication is avascular necrosis (AVN) of the femoral head. Any attempts at reduction, even gentle ones, significantly increase the risk of AVN due to disruption of the retinacular vessels. Therefore, in situ pinning without manipulation is generally considered the safest immediate management to minimize AVN and stabilize the epiphysis. While some surgeons might consider a very gentle reduction for extreme displacements, the highest priority is typically placed on avoiding AVN, making no manipulation the safest initial approach. Open reduction carries a very high risk of AVN. Gentle closed reduction also has a significant risk of AVN and is controversial. Traction is not a definitive treatment. The Modified Dunn procedure is an osteotomy used for severe chronic deformities or failed pinning, not for acute unstable SCFE.

Question 1304

Topic: Pediatric Hip

A 7-year-old boy is diagnosed with Legg-Calve-Perthes disease (LCPD) of the left hip. Radiographs show significant femoral head collapse and fragmentation (Herring Lateral Pillar B/C border). He has limited abduction and internal rotation. What is the primary goal of treatment for LCPD, particularly in this age group and severity?

. Pain control and activity modification.
. Maintaining containment of the femoral head within the acetabulum.
. Promoting revascularization of the femoral head.
. Accelerating ossification of the femoral head.
. Preventing slipped capital femoral epiphysis.

Correct Answer & Explanation

. Maintaining containment of the femoral head within the acetabulum.

Explanation

For Legg-Calve-Perthes disease (LCPD), especially in older children (typically 6-8+ years) and more severe cases (such as Herring Lateral Pillar B/C border), the primary goal of treatment is 'containment' of the femoral head within the acetabulum. The acetabulum acts as a natural mold, helping to maintain the spherical shape of the femoral head as it undergoes revascularization and reossification. This minimizes deformity, prevents incongruity, and reduces the risk of early degenerative arthritis. Containment can be achieved through non-surgical methods (e.g., abduction orthoses) or surgically (e.g., varus osteotomy of the femur or Salter innominate osteotomy). While pain control (Option A) is important, it's a symptomatic treatment, not the primary goal for long-term hip health. Promoting revascularization (Option C) is the body's natural process during LCPD, and treatment aims to protect the femoral head during this phase. Accelerating ossification (Option D) is not a treatment goal. Preventing slipped capital femoral epiphysis (Option E) is incorrect, as SCFE is a distinct hip condition.

Question 1305

Topic: Pediatric Hip
A 14-year-old obese male presents with sudden onset of severe right hip pain and inability to bear weight. X-rays show a severe slipped capital femoral epiphysis (SCFE) with >60 degrees posterior slip. Which of the following is the most appropriate initial management strategy?
. Percutaneous in situ pinning without reduction
. Gentle closed reduction followed by in situ pinning
. Open reduction with surgical dislocation and pinning
. Spica casting without surgery
. Traction followed by delayed pinning

Correct Answer & Explanation

. Open reduction with surgical dislocation and pinning

Explanation

For severe unstable SCFE (often defined as >60 degrees slip or inability to bear weight), forceful closed reduction is contraindicated due to a high risk of avascular necrosis (AVN) of the femoral head and chondrolysis. Open reduction, typically via a surgical dislocation approach, allows for controlled reduction of the epiphysis under direct visualization while preserving the vascular supply, followed by stable fixation with pins. Percutaneous in situ pinning without reduction is for stable SCFE. Gentle closed reduction might be considered for less severe unstable slips, but >60 degrees indicates a high risk. Spica casting and traction are not definitive treatments for SCFE.

Question 1306

Topic: Pediatric Hip

A 13-year-old male presents with right knee pain and an antalgic gait. Physical exam reveals obligatory external rotation with hip flexion. Radiographs demonstrate posterior and inferior slippage of the right proximal femoral epiphysis. Which of the following is considered a definitive indication for prophylactic in-situ pinning of the contralateral asymptomatic hip in this condition?

. Male sex
. Endocrine disorder such as hypothyroidism
. Slip angle greater than 50 degrees
. Age greater than 14 years
. Duration of symptoms less than 3 weeks

Correct Answer & Explanation

. Endocrine disorder such as hypothyroidism

Explanation

Slipped Capital Femoral Epiphysis (SCFE) frequently occurs bilaterally. Prophylactic pinning of the contralateral hip is indicated in patients with underlying endocrinopathies (e.g., hypothyroidism, renal osteodystrophy) or in very young patients (under 10 years old), due to the exceptionally high risk of bilateral involvement in these cohorts.

Question 1307

Topic: Pediatric Hip

An 8-week-old female is being treated with a Pavlik harness for developmental dysplasia of the hip (DDH). During follow-up, the mother notes that the infant is no longer kicking her right leg. Examination reveals decreased active knee extension on the right. What is the most likely cause of this finding?

. Excessive hip abduction in the harness
. Hyperflexion of the hip in the harness
. Ischemic necrosis of the proximal femoral epiphysis
. Brachial plexus traction injury
. Deep infection of the hip joint

Correct Answer & Explanation

. Hyperflexion of the hip in the harness

Explanation

The infant has developed a femoral nerve palsy, a known complication of Pavlik harness treatment. It is caused by excessive hyperflexion of the hip, which compresses the femoral nerve against the inguinal ligament. Treatment involves adjusting the anterior straps to decrease hip flexion. Excessive hip abduction, by contrast, risks avascular necrosis (AVN) of the femoral head.

Question 1308

Topic: Pediatric Hip

When planning a proximal femoral osteotomy for a severe coxa vara deformity using Paley principles, placing the hinge lateral to the CORA along the transverse bisector line will result in:

. An opening wedge correction
. A closing wedge correction
. A neutral wedge correction
. Pure translation without angular correction
. Creation of an iatrogenic rotational deformity

Correct Answer & Explanation

. An opening wedge correction

Explanation

Placing the hinge on the convex side of the deformity (lateral in coxa vara) along the bisector line results in an opening wedge correction. This lengthens the bone while simultaneously correcting the angulation.

Question 1309

Topic: Pediatric Hip

The SUPERhip procedure developed by Dr. Paley for Congenital Femoral Deficiency primarily aims to surgically reconstruct which of the following combined pathomorphologies?

. Anterior dislocation of the hip with a normal femur
. Acetabular dysplasia, severe coxa vara, and femoral retroversion
. Isolated symptomatic coxa valga
. Slipped capital femoral epiphysis with impingement
. Avascular necrosis secondary to Legg-Calve-Perthes disease

Correct Answer & Explanation

. Acetabular dysplasia, severe coxa vara, and femoral retroversion

Explanation

The SUPERhip procedure systematically reconstructs the complex soft tissue and bony deformities inherent to severe CFD. This primarily includes correction of severe coxa vara, femoral retroversion, flexion contractures, and associated acetabular dysplasia.

Question 1310

Topic: Pediatric Hip

In evaluating a patient with severe coxa vara, you note a negative articulotrochanteric distance (ATD). What is the primary biomechanical consequence of this anatomic alignment?

. Increased tension in the hip abductors leading to an antalgic gait
. Decreased mechanical advantage of the abductors leading to a Trendelenburg gait
. Increased lateral offset of the femoral shaft leading to IT band syndrome
. Excessive femoral anteversion causing in-toeing
. Impingement of the lesser trochanter on the ischium

Correct Answer & Explanation

. Decreased mechanical advantage of the abductors leading to a Trendelenburg gait

Explanation

A negative ATD indicates the tip of the greater trochanter is above the center of the femoral head, which severely shortens the lever arm of the hip abductors. This functional weakness results in a classic Trendelenburg lurch.

Question 1311

Topic: Pediatric Hip

A 14-year-old patient presents with developmental coxa vara. A proximal femoral osteotomy is planned. According to Paley's Rule 1 of deformity correction, to achieve angular correction and realign the mechanical axis without creating a secondary translation deformity, where must the osteotomy and correction hinge be placed relative to the center of rotation of angulation (CORA)?

. Osteotomy proximal to the CORA, hinge at the CORA
. Osteotomy distal to the CORA, hinge proximal to the CORA
. Osteotomy and hinge exactly at the CORA
. Osteotomy in the diaphysis, hinge at the CORA
. Osteotomy and hinge at the level of the lesser trochanter regardless of the CORA

Correct Answer & Explanation

. Osteotomy and hinge exactly at the CORA

Explanation

Paley's Rule 1 states that if the osteotomy and the correction hinge are both placed at the CORA, pure angulation occurs. This corrects the deformity and flawlessly realigns the mechanical axis without introducing any translational displacement.

Question 1312

Topic: Pediatric Hip

A 12-year-old with developmental coxa vara has a neck-shaft angle of 90 degrees and significant relative trochanteric overgrowth resulting in a Trendelenburg gait. A valgus-producing intertrochanteric osteotomy is planned. According to Paley's principles, where should the osteotomy hinge be positioned to optimally correct the varus, relatively distalize the greater trochanter, and maximize neck length?

. At the mechanical axis of the entire femur
. At the medial cortex of the lesser trochanter
. At the lateral cortex of the proximal femur
. Exactly at the medullary center of the intertrochanteric line
. On the transverse bisector line medial to the primary CORA

Correct Answer & Explanation

. At the lateral cortex of the proximal femur

Explanation

Placing the hinge on the convex side (lateral cortex) creates a medial opening wedge osteotomy. This corrects the varus angle, adds femoral neck length, and functionally distalizes the greater trochanter to restore abductor mechanics.

Question 1313

Topic: Pediatric Hip

A 14-year-old patient with severe coxa vara is undergoing a proximal femoral osteotomy. Radiographic analysis reveals the Center of Rotation of Angulation (CORA) is located in the center of the femoral head. If the osteotomy is performed at the intertrochanteric level and the hinge is placed precisely at the CORA, what is the anticipated geometric outcome according to Paley's principles?

. The mechanical and anatomical axes will remain malaligned.
. The mechanical axis will be corrected with collinear axes, but translation will occur at the osteotomy site.
. The mechanical axis will be corrected with no translation at the osteotomy site.
. The anatomical axes will become parallel but not collinear, creating a secondary translational deformity.
. The correction will induce an unintended limb length discrepancy without correcting angulation.

Correct Answer & Explanation

. The mechanical axis will be corrected with collinear axes, but translation will occur at the osteotomy site.

Explanation

According to Paley's Rule 2, when the osteotomy is performed at a different level than the CORA but the hinge is placed at the CORA, the mechanical axes become collinear. However, this necessitates translation at the osteotomy site.

Question 1314

Topic: Pediatric Hip
During the application of an articulated hinged distractor for the treatment of severe Legg-Calvรฉ-Perthes disease, precise hinge placement is critical. To avoid iatrogenic cartilage destruction during hip range of motion, the mechanical hinge of the external fixator must perfectly overlie which anatomical landmark?
. The tip of the greater trochanter
. The center of rotation of the femoral head
. The anterior inferior iliac spine (AIIS)
. The piriformis fossa
. The mechanical lateral distal femoral angle (mLDFA)

Correct Answer & Explanation

. The center of rotation of the femoral head

Explanation

An articulated hip distractor must have its mechanical axis perfectly collinear with the anatomical center of rotation of the femoral head. Any mismatch creates a cam effect, leading to severe joint compression and cartilage damage during motion.

Question 1315

Topic: Pediatric Hip

A 5-year-old child with Schmid metaphyseal chondrodysplasia is evaluated for a waddling gait. Radiographs of the pelvis and lower extremities are most likely to demonstrate which of the following characteristic findings?

. Coxa valga and genu valgum with narrow physes
. Coxa vara and genu varum with widened, irregular physes
. Slipped capital femoral epiphysis with normal metaphyseal bone
. Fragmented, stippled epiphyses of the proximal femur
. Dense, sclerotic metaphyseal bands

Correct Answer & Explanation

. Coxa vara and genu varum with widened, irregular physes

Explanation

Correct Answer: Coxa vara and genu varum with widened, irregular physesSchmid metaphyseal chondrodysplasia is characterized radiographically by abnormalities confined primarily to the metaphyses, while the epiphyses remain normal (distinguishing it from epiphyseal dysplasias). The classic radiographic findings include coxa vara (decreased neck-shaft angle), genu varum, and widened, irregular, and cupped physes (metaphyseal flaring). The waddling gait is a direct clinical consequence of the coxa vara and resulting abductor mechanical disadvantage. Stippled epiphyses are seen in chondrodysplasia punctata, and dense sclerotic bands are seen in heavy metal poisoning or bisphosphonate use.

Question 1316

Topic: Pediatric Hip

A 5-year-old boy presents with short stature, a waddling gait, and progressive bowing of the lower extremities. Radiographs reveal coxa vara, genu varum, and flaring of the metaphyses, but the spine and epiphyses are entirely normal. Genetic testing is most likely to reveal a mutation in the gene encoding for which of the following proteins?

. Type II collagen
. Type IX collagen
. Type X collagen
. Fibroblast growth factor receptor 3
. Cartilage oligomeric matrix protein

Correct Answer & Explanation

. Type X collagen

Explanation

Correct Answer: Type X collagenThe patient's presentation of metaphyseal flaring, coxa vara, and genu varum with normal epiphyses and spine is characteristic of Schmid type metaphyseal chondrodysplasia. This condition is inherited in an autosomal dominant pattern and is caused by mutations in theCOL10A1gene, which encodes for Type X collagen. Type X collagen is primarily expressed by hypertrophic chondrocytes in the growth plate.

Question 1317

Topic: Pediatric Hip

Which of the following combined lower extremity deformities is the most characteristic clinical hallmark of Schmid metaphyseal chondrodysplasia?

. Genu valgum with a normal femoral neck angle
. Coxa vara and genu varum
. Coxa valga and genu recurvatum
. Anterolateral tibial bowing
. Posteromedial tibial bowing

Correct Answer & Explanation

. Coxa vara and genu varum

Explanation

Patients with Schmid metaphyseal chondrodysplasia classically present with significant coxa vara and progressive genu varum. This leads to the characteristic waddling gait often observed when they begin walking.

Question 1318

Topic: Pediatric Hip

A 7-year-old boy with known Schmid metaphyseal chondrodysplasia presents with a worsening waddling gait. Pelvic radiographs demonstrate bilateral coxa vara with a Hilgenreiner-epiphyseal (HE) angle of 75 degrees. What is the most appropriate management?

. Observation with annual radiographs
. Bilateral spica casting
. Bilateral valgus-producing proximal femoral osteotomies
. Epiphysiodesis of the greater trochanters
. Bisphosphonate infusions

Correct Answer & Explanation

. Bilateral valgus-producing proximal femoral osteotomies

Explanation

In Schmid metaphyseal chondrodysplasia, progressive coxa vara with a Hilgenreiner-epiphyseal (HE) angle greater than 60 degrees carries a high risk of pseudarthrosis and progressive deformity. Valgus-producing proximal femoral osteotomies are indicated to correct the mechanical axis and shear forces.

Question 1319

Topic: Pediatric Hip

A 10-year-old child presents with bilateral hip pain and a waddling gait. Radiographs reveal flattened, fragmented capital femoral epiphyses bilaterally, but normal spine morphology. Which of the following best differentiates this condition from bilateral Legg-Calve-Perthes disease?

. Elevated inflammatory markers
. Involvement of the vertebral bodies
. Positive family history with an autosomal dominant inheritance
. Association with blue sclerae
. Unilateral presentation initially

Correct Answer & Explanation

. Positive family history with an autosomal dominant inheritance

Explanation

Multiple Epiphyseal Dysplasia (MED) mimics bilateral Legg-Calve-Perthes disease but is distinguished by symmetric bilateral involvement, an autosomal dominant inheritance, and normal spine morphology (which differentiates it from spondyloepiphyseal dysplasia).

Question 1320

Topic: Pediatric Hip

A 28-year-old female with a known history of an inherited chondrodysplasia presents with hip pain and a waddling gait. Review the provided radiograph. Which of the following proximal femoral deformities is most commonly associated with this condition in adulthood?



. Coxa valga
. Coxa vara
. Slipped capital femoral epiphysis
. Femoral retroversion
. Cam impingement

Correct Answer & Explanation

. Coxa vara

Explanation

Correct Answer: Coxa varaThe radiograph shows retarded ossification of the proximal femur, which is usually accompanied by coxa vara in the adult period for patients with Spondyloepiphyseal Dysplasia. This deformity contributes to the waddling gait and hip pain.

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