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Pediatric Hip MCQs

Practice Set 94 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 1861

Topic: Pediatric Hip

What is the typical timeframe within which a positive Ortolani or Barlow sign should resolve spontaneously if DDH is not present?

. Within the first 24 hours of life
. By 2 weeks of age
. By 4-6 weeks of age
. By 3 months of age
. By 6 months of age

Correct Answer & Explanation

. By 4-6 weeks of age

Explanation

Many newborns exhibit a degree of transient hip laxity due to maternal hormones, which often resolves spontaneously. A positive Ortolani or Barlow test that is due to physiologic laxity (and not true DDH) typically resolves by 4-6 weeks of age. If instability persists beyond this point, it is more likely to represent true DDH and warrants further investigation and/or treatment. This is why initial observation is often recommended for stable but immature hips in the first few weeks of life.

Question 1862

Topic: Pediatric Hip

A 2-week-old female, born via spontaneous vaginal delivery, has an asymptomatic, stable hip on clinical exam. However, she was born breech. What is the most appropriate next step in her evaluation for DDH?

. No further action, as the clinical exam is negative.
. Repeat clinical exam at 6 weeks of age.
. Perform a hip ultrasound at 4-6 weeks of age.
. Initiate Pavlik harness treatment empirically.
. Order an AP pelvis radiograph immediately.

Correct Answer & Explanation

. Perform a hip ultrasound at 4-6 weeks of age.

Explanation

Despite a negative clinical exam, breech presentation is a significant risk factor for DDH, warranting imaging. However, due to the high rate of physiological laxity in the first few weeks of life that can spontaneously resolve, hip ultrasound is typically performed at 4-6 weeks of age for breech infants. This allows time for any transient laxity to resolve, reducing false positives, while still allowing for early diagnosis if true dysplasia is present. Immediate Pavlik is not indicated for a stable hip. Radiographs are not optimal before 4-6 months due to significant cartilage.

Question 1863

Topic: Pediatric Hip

Which of the following is considered a 'soft sign' of DDH, often necessitating further investigation, but not diagnostic on its own?

. Positive Ortolani sign
. Positive Barlow sign
. Limited hip abduction
. Asymmetric thigh folds
. Positive Galeazzi sign

Correct Answer & Explanation

. Asymmetric thigh folds

Explanation

Asymmetric thigh folds are considered a 'soft sign' of DDH. While suggestive, they are often seen in infants without DDH and can be present with normal hips. Therefore, they necessitate further investigation (e.g., ultrasound) but are not diagnostic on their own. Positive Ortolani and Barlow signs indicate hip instability and are considered 'hard signs.' Limited hip abduction and a positive Galeazzi sign are stronger indicators of DDH, particularly in older infants/toddlers.

Question 1864

Topic: Pediatric Hip

What is the primary goal of early diagnosis and treatment of developmental dysplasia of the hip?

. To prevent limb length discrepancy in adulthood.
. To avoid the need for reconstructive surgery later in life.
. To ensure normal development of the acetabulum and prevent future osteoarthritis.
. To correct a waddling gait in early childhood.
. To minimize the risk of avascular necrosis of the femoral head.

Correct Answer & Explanation

. To ensure normal development of the acetabulum and prevent future osteoarthritis.

Explanation

The primary goal of early diagnosis and treatment of DDH is to ensure normal development of the acetabulum and femoral head. This helps to prevent progressive acetabular dysplasia, femoral head deformity, and ultimately, the development of early-onset osteoarthritis in adulthood. While preventing the need for reconstructive surgery, correcting gait, and minimizing AVN are important outcomes, the fundamental aim is to achieve a stable, anatomically normal hip joint to prevent long-term sequelae.

Question 1865

Topic: Pediatric Hip

A 5-month-old infant has been in a Pavlik harness for 10 weeks for a dislocated hip. On follow-up, the hip remains dislocated and irreducible on clinical exam. What is the most appropriate next step in management?

. Increase the abduction in the Pavlik harness
. Discontinue the Pavlik harness and observe for spontaneous reduction
. Perform a closed reduction under anesthesia followed by spica casting
. Refer for open reduction and possible osteotomy
. Initiate traction therapy immediately

Correct Answer & Explanation

. Perform a closed reduction under anesthesia followed by spica casting

Explanation

If a Pavlik harness has failed to achieve reduction of a dislocated hip after an adequate trial (typically 3-6 weeks, and certainly after 10 weeks) and the hip remains irreducible, then a failed Pavlik harness indicates the need for more definitive intervention. At 5 months, if the hip is irreducible, the next step is typically a closed reduction under anesthesia followed by hip spica casting. Open reduction and possible osteotomy are considered if closed reduction fails, or for older children with highly unstable or chronically dislocated hips. Increasing abduction in a failed Pavlik is ineffective and risks AVN. Discontinuing treatment is inappropriate. Traction may be used as a preparatory step but not as the sole next step.

Question 1866

Topic: Pediatric Hip
Which type of DDH, according to Graf's classification, is most often managed with watchful waiting and considered a physiologically immature hip that may resolve spontaneously?
. Type Ia
. Type Ib
. Type IIa-
. Type IIc
. Type III

Correct Answer & Explanation

. Type IIa-

Explanation

Graf's Type IIa- hip, characterized by an alpha angle between 50-59 degrees and an age less than 3 months, is considered a physiologically immature hip. Many of these hips will mature spontaneously without intervention, making watchful waiting with a follow-up ultrasound the appropriate initial management. Type Ia and Ib are mature hips. Type IIc, III, and IV are dysplastic or decentered hips that generally require treatment.

Question 1867

Topic: Pediatric Hip

In a 2-year-old child presenting with a limp, what aspect of the physical exam is MOST helpful in differentiating DDH from transient synovitis?

. Presence of fever
. Limitation of hip abduction
. Pain with internal rotation of the hip
. WBC count and ESR/CRP levels
. History of recent viral illness

Correct Answer & Explanation

. Limitation of hip abduction

Explanation

While fever, pain with internal rotation, inflammatory markers, and a history of viral illness are all relevant for transient synovitis (acute, often painful, sometimes low-grade fever, mild inflammatory markers), a key differentiator for DDH (especially an undiagnosed late-presenting case) is the chronic limitation of hip abduction, often without acute pain or systemic signs. DDH manifests as a fixed contracture and structural abnormality. Transient synovitis, while painful, generally affects all ranges of motion and resolves. However, pain with internal rotation is also common in both, but DDH often has limited abduction, while transient synovitis often has more generalized limitations with pain. Limitation of abduction is a hallmark of DDH in older children.

Question 1868

Topic: Pediatric Hip
A 7-month-old presents with asymmetric abduction and a positive Galeazzi sign on the right. An AP pelvis radiograph reveals an increased acetabular index (right > left) and the right femoral head ossific nucleus is superior and lateral to Perkin's line. What is the most likely diagnosis?
. Legg-Calvé-Perthes disease
. Right transient synovitis
. Right developmental dysplasia of the hip
. Right septic arthritis
. Right coxa vara

Correct Answer & Explanation

. Right developmental dysplasia of the hip

Explanation

The clinical findings of asymmetric abduction and a positive Galeazzi sign, combined with radiographic findings of an increased acetabular index (acetabular hypoplasia) and superior/lateral displacement of the femoral head (subluxation/dislocation), are classic for developmental dysplasia of the hip. The age (7 months) makes radiographs the appropriate imaging. Perthes disease, transient synovitis, septic arthritis, and coxa vara would present with different clinical and/or radiographic features.

Question 1869

Topic: Pediatric Hip

What is the MOST common cause of a 'click' heard or felt in the hip of a newborn that is NOT indicative of DDH?

. Snapping of the iliopsoas tendon over the femoral head.
. Articular cartilage degeneration.
. Transient subluxation of the patella.
. Ligamentum teres rupture.
. Meniscal tear of the hip.

Correct Answer & Explanation

. Snapping of the iliopsoas tendon over the femoral head.

Explanation

A benign 'click' in a newborn's hip, in the absence of a positive Ortolani or Barlow sign, is most commonly due to the snapping of the iliopsoas tendon over the femoral head or the bony prominence. This is a common, normal variant and usually resolves spontaneously. Articular cartilage degeneration, patellar subluxation, ligamentum teres rupture, and meniscal tears are either extremely rare in newborns or not relevant to this benign clicking phenomenon.

Question 1870

Topic: Pediatric Hip
A 14-year-old female presents with chronic, insidious onset right hip pain, worse with activity. She has a subtle limp and limited internal rotation and abduction of the right hip. Radiographs are subtly abnormal, showing mild flattening of the superior acetabular rim and a slightly increased acetabular index. There is no evidence of avascular necrosis or slipped epiphysis. What is the most likely diagnosis?
. Legg-Calvé-Perthes disease
. Slipped capital femoral epiphysis (SCFE)
. Adolescent idiopathic scoliosis
. Developmental dysplasia of the hip (late presentation)
. Transient synovitis

Correct Answer & Explanation

. Developmental dysplasia of the hip (late presentation)

Explanation

This clinical picture, especially with the radiographic findings of mild acetabular dysplasia (flattening of the superior acetabular rim, increased acetabular index) in an adolescent, is highly suggestive of a late presentation of developmental dysplasia of the hip. Symptoms like chronic pain, limp, and limited motion are common as the dysplastic hip begins to fail. Perthes and SCFE are ruled out by the lack of characteristic radiographic findings. Adolescent idiopathic scoliosis is a spinal condition. Transient synovitis is acute and self-limiting, not chronic. The subtle radiographic findings are key to identifying this late-presenting DDH.

Question 1871

Topic: Pediatric Hip

A 13-year-old boy presents with severe groin pain and inability to bear weight. Radiographs demonstrate a severe slipped capital femoral epiphysis (SCFE) with a slip angle of 60 degrees. The surgeon performs an open surgical dislocation and a subcapital realignment (modified Dunn procedure). What is the primary blood supply at critical risk during the subcapital osteotomy, requiring the careful creation of a retinacular flap?

. Medial femoral circumflex artery
. Lateral femoral circumflex artery
. Obturator artery
. Inferior gluteal artery
. First perforating artery

Correct Answer & Explanation

. Medial femoral circumflex artery

Explanation

The deep branch of the medial femoral circumflex artery (MFCA) provides the primary blood supply to the femoral head. It is at significant risk during a Dunn osteotomy and must be meticulously protected by developing a retinacular flap.

Question 1872

Topic: Pediatric Hip
A 7-year-old boy with Legg-Calvé-Perthes disease demonstrates a 'hinge abduction' on dynamic arthrography, causing significant mechanical restriction and pain. Which of the following is the most appropriate surgical management?
. Continued observation with restricted weight-bearing
. Petrie casting in internal rotation and abduction
. Salter innominate osteotomy
. Valgus extension proximal femoral osteotomy
. Varus derotational proximal femoral osteotomy

Correct Answer & Explanation

. Valgus extension proximal femoral osteotomy

Explanation

Hinge abduction occurs when the extruded, deformed lateral femoral head impinges against the lateral acetabular margin. A valgus extension osteotomy repositions the deformed segment away from the margin, relieving the hinge effect and improving joint congruency.

Question 1873

Topic: Pediatric Hip

Which of the following pelvic osteotomies used for developmental dysplasia of the hip (DDH) is an incomplete, volume-reducing osteotomy that hinges on the triradiate cartilage?

. Salter osteotomy
. Pemberton osteotomy
. Chiari osteotomy
. Steel triple osteotomy
. Ganz periacetabular osteotomy

Correct Answer & Explanation

. Pemberton osteotomy

Explanation

The Pemberton osteotomy is an incomplete pericapsular osteotomy that hinges on the flexible triradiate cartilage. It changes the volume and shape of the acetabulum, making it ideal for a dysplastic, capacious acetabulum.

Question 1874

Topic: Pediatric Hip

A 12-year-old boy undergoes in situ pinning with a single screw for a stable slipped capital femoral epiphysis (SCFE). Two years later, he presents with limited hip internal rotation and a positive impingement test. The screw is radiographically extra-articular. What is the most likely cause of his symptoms?

. Avascular necrosis of the femoral head
. Chondrolysis from unrecognized joint penetration
. Anterior metaphyseal prominence leading to cam impingement
. Heterotopic ossification of the abductors
. Femoral neck nonunion

Correct Answer & Explanation

. Anterior metaphyseal prominence leading to cam impingement

Explanation

In situ pinning leaves the residual slippage uncorrected. The resulting anterior metaphyseal prominence frequently abuts the acetabular rim during flexion and internal rotation, causing secondary cam-type femoroacetabular impingement.

Question 1875

Topic: Pediatric Hip

During an open reduction and subcapital realignment (modified Dunn procedure) for a severe slipped capital femoral epiphysis (SCFE), how is the surgical approach optimized to protect the medial femoral circumflex artery (MFCA)?

. By utilizing a direct anterior (Smith-Petersen) approach
. By dissecting the periosteum off the anterior neck exclusively
. By performing a trochanteric flip osteotomy
. By temporarily ligating the lateral epiphyseal artery
. By dividing the ligamentum teres prior to dislocation

Correct Answer & Explanation

. By performing a trochanteric flip osteotomy

Explanation

The modified Dunn procedure utilizes a surgical hip dislocation via a trochanteric flip osteotomy. This extensile approach allows direct visualization and protection of the retinacular vessels, which are meticulously peeled back to preserve the MFCA.

Question 1876

Topic: Pediatric Hip

A 13-year-old obese boy presents with severe right hip pain and inability to bear weight after a minor fall 2 days ago. Radiographs confirm a slipped capital femoral epiphysis. According to the Loder classification, what is his primary risk for the most devastating complication of this specific type of slip?

. Chondrolysis
. Avascular necrosis (AVN) of the femoral head
. Coxa magna
. Femoroacetabular impingement
. Leg-length discrepancy

Correct Answer & Explanation

. Avascular necrosis (AVN) of the femoral head

Explanation

This is an unstable SCFE (defined by the inability to bear weight), which carries a high risk (up to 47%) of avascular necrosis (AVN). Stable slips have a much lower AVN risk but may lead to FAI or chondrolysis.

Question 1877

Topic: Pediatric Hip

An 8-year-old boy is diagnosed with Legg-Calve-Perthes disease. Radiographs show that 40% of the lateral pillar height is maintained. According to the Herring lateral pillar classification, what is his classification and associated prognosis?

. Group A; excellent prognosis without surgery
. Group B; good prognosis with containment surgery
. Group B; poor prognosis despite surgery
. Group C; poor prognosis regardless of treatment
. Group C; excellent prognosis with bracing

Correct Answer & Explanation

. Group C; poor prognosis regardless of treatment

Explanation

Herring Group C is defined by less than 50% maintenance of lateral pillar height. It carries a poor prognosis, and studies show little to no benefit from surgical containment in this group, particularly in older children.

Question 1878

Topic: Pediatric Hip

In a patient with Legg-Calve-Perthes disease, which of the following is considered a head at risk sign as described by Catterall?

. Gage sign
. Decreased medial joint space
. Intact lateral pillar
. Central calcification of the epiphysis
. Medial subluxation of the femoral head

Correct Answer & Explanation

. Gage sign

Explanation

Catterall's head-at-risk signs indicate a poorer prognosis in LCP disease. They include Gage sign (a V-shaped radiolucency in the lateral epiphysis/metaphysis), lateral subluxation, calcification lateral to the epiphysis, and a horizontal growth plate.

Question 1879

Topic: Pediatric Hip

According to the Loder classification, an unstable slipped capital femoral epiphysis (SCFE) is defined by which of the following criteria, and carries what primary complication risk?

. Inability to ambulate with or without crutches; high risk of chondrolysis
. Inability to ambulate with or without crutches; high risk of avascular necrosis
. Slip angle greater than 50 degrees; high risk of avascular necrosis
. Slip angle greater than 50 degrees; high risk of chondrolysis
. Duration of symptoms less than 3 weeks; high risk of delayed union

Correct Answer & Explanation

. Inability to ambulate with or without crutches; high risk of avascular necrosis

Explanation

The Loder classification defines an unstable SCFE by the patient's inability to ambulate, even with crutches. Unstable SCFE carries a significantly higher risk of avascular necrosis (up to nearly 50%) compared to stable SCFE.

Question 1880

Topic: Pediatric Hip
In the Herring lateral pillar classification for Legg-Calvé-Perthes disease, a Type B hip is characterized by:
. 100% preservation of the lateral pillar height
. Greater than 50% preservation of the lateral pillar height
. Less than 50% preservation of the lateral pillar height
. Complete collapse of the lateral pillar
. Central pillar collapse with lateral extrusion

Correct Answer & Explanation

. Greater than 50% preservation of the lateral pillar height

Explanation

In the Herring classification, Type B is defined by the preservation of >50% of the lateral pillar height. Type A has no lateral pillar involvement, and Type C has <50% of the lateral pillar maintained.

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