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Pediatric Hip MCQs

Practice Set 15 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 281

Topic: Pediatric Hip
A 7-year-old boy presents with a 3-week history of right hip pain and a limp. He denies trauma. On examination, he has decreased internal rotation and abduction of the right hip. Radiographs show increased density of the right femoral epiphysis and a flattened appearance. What is the most likely diagnosis?
. Septic arthritis of the hip
. Transient synovitis of the hip
. Slipped capital femoral epiphysis (SCFE)
. Legg-Calvé-Perthes disease
. Developmental dysplasia of the hip (DDH)

Correct Answer & Explanation

. Legg-Calvé-Perthes disease

Explanation

The clinical presentation of a 7-year-old boy with hip pain, limp, and decreased hip motion (especially internal rotation and abduction), combined with radiographic findings of increased density (sclerosis) and flattening (fragmentation) of the femoral epiphysis, is classic for Legg-Calvé-Perthes disease. Septic arthritis would present acutely with systemic signs and extreme pain, transient synovitis is usually self-limiting with normal radiographs after a few days, SCFE typically occurs in older, often obese adolescents, and DDH is usually diagnosed in infancy or early childhood.

Question 282

Topic: Pediatric Hip

In the treatment of a young patient with an acute, unstable slipped capital femoral epiphysis (SCFE), what is the most significant iatrogenic risk associated with performing a forceful closed reduction prior to percutaneous pinning?

. Chondrolysis
. Avascular necrosis of the femoral head
. Ipsilateral femoral neck fracture
. Premature physeal closure
. Labral tear

Correct Answer & Explanation

. Avascular necrosis of the femoral head

Explanation

Forceful or aggressive closed reduction of an unstable SCFE disrupts the already tenuous retinacular blood supply, dramatically increasing the risk of avascular necrosis (AVN). Incidental pinning in situ or gentle reduction is preferred.

Question 283

Topic: Pediatric Hip

A 12-year-old obese male presents with acute-on-chronic left knee pain and inability to bear weight for the past 2 days. Examination reveals obligate external rotation of the left hip with passive flexion. Radiographs confirm a slipped capital femoral epiphysis (SCFE). Which of the following is the most significant risk factor for developing avascular necrosis (AVN) in this patient?

. Obesity
. The slip being unstable
. Prophylactic pinning of the contralateral hip
. Use of a single cannulated screw for fixation
. Capsulotomy performed at the time of surgery

Correct Answer & Explanation

. The slip being unstable

Explanation

The clinical instability of a SCFE, defined as the inability to bear weight with or without crutches, is the most significant predictor for the development of AVN. The rate of AVN is markedly higher in unstable slips compared to stable slips.

Question 284

Topic: Pediatric Hip

A 6-month-old female with developmental dysplasia of the hip (DDH) has failed 6 weeks of treatment in a Pavlik harness, with persistent dislocation of the left hip. What is the most appropriate next step in management?

. Continue Pavlik harness for an additional 6 weeks
. Transition to a rigid abduction orthosis (e.g., Ilfeld brace)
. Closed reduction and spica casting under general anesthesia
. Open reduction via an anterior approach and pelvic osteotomy
. Femoral derotational osteotomy

Correct Answer & Explanation

. Closed reduction and spica casting under general anesthesia

Explanation

If a Pavlik harness fails to achieve reduction after 3-4 weeks in a young infant, it should be discontinued to avoid "Pavlik disease" (posterior acetabular wear). The next appropriate step is closed reduction and spica casting, often preceded by an arthrogram.

Question 285

Topic: Pediatric Hip

A 12-year-old obese boy presents with acute left groin pain and an inability to bear weight after a minor twisting injury. Radiographs confirm a slipped capital femoral epiphysis (SCFE). Which of the following defines this as an "unstable" SCFE?

. Slip angle greater than 50 degrees
. Presence of an effusion on ultrasound
. Inability to ambulate with or without crutches
. Physeal widening on the lateral radiograph
. Associated endocrine abnormality

Correct Answer & Explanation

. Inability to ambulate with or without crutches

Explanation

The Loder classification defines an unstable SCFE based strictly on clinical presentation: the patient's inability to ambulate on the affected limb, even with the use of crutches. Unstable SCFE carries a significantly higher risk of avascular necrosis (up to 50%).

Question 286

Topic: Pediatric Hip
A 6-year-old boy is diagnosed with Legg-Calvé-Perthes disease. According to the modified lateral pillar classification (Herring), which of the following radiographic findings indicates the worst prognosis (Group C)?
. No involvement of the lateral pillar
. Greater than 50% maintenance of the lateral pillar height
. Less than 50% maintenance of the lateral pillar height
. Presence of a metaphyseal cyst
. Subchondral fracture line (Crescent sign) involving half of the epiphysis

Correct Answer & Explanation

. Less than 50% maintenance of the lateral pillar height

Explanation

In the Herring lateral pillar classification, Group C is defined as greater than 50% collapse (or less than 50% maintenance) of the lateral pillar height. This group has the highest risk of long-term deformity and poorest clinical outcomes.

Question 287

Topic: Pediatric Hip

A 13-year-old male with a BMI of 35 presents with chronic left knee pain and an obligate external rotation of the hip during active flexion. An AP pelvis radiograph confirms a stable slipped capital femoral epiphysis (SCFE). Which of the following describes the most appropriate surgical intervention?

. In situ pinning with a single cannulated screw
. Open reduction and internal fixation
. Prophylactic pinning of the contralateral hip routinely
. Proximal femoral osteotomy
. Spica cast application

Correct Answer & Explanation

. In situ pinning with a single cannulated screw

Explanation

The standard of care for a stable SCFE is in situ pinning with a single, central cannulated screw. This provides stability to prevent further slip while minimizing the risk of avascular necrosis.

Question 288

Topic: Pediatric Hip

A 6-year-old male is diagnosed with Legg-Calve-Perthes disease. Radiographs show involvement of the entire epiphysis, but the lateral pillar maintains greater than 50% of its height. Which of the following is the most important prognostic factor for the development of late degenerative joint disease in this patient?

. Age at onset of symptoms
. Gender of the patient
. Use of non-weight-bearing crutches
. Body mass index
. Family history

Correct Answer & Explanation

. Age at onset of symptoms

Explanation

The most critical prognostic factor in Legg-Calve-Perthes disease is the age at the onset of symptoms, with children under 8 generally having a better prognosis due to greater remodeling potential. Lateral pillar classification is also important but secondary to age in overall long-term prognosis.

Question 289

Topic: Pediatric Hip

A 6-year-old boy is diagnosed with Legg-Calve-Perthes disease. Radiographs reveal fragmentation of the femoral head with the lateral pillar maintaining 60% of its original height. According to the Herring Lateral Pillar Classification, what is the classification and typical prognosis?

. Group A; excellent prognosis without surgery
. Group B; guarded prognosis, may benefit from containment surgery
. Group C; poor prognosis, universal early osteoarthritis
. Group B/C; indicated for immediate total hip arthroplasty
. Group A; requires immediate femoral varus osteotomy

Correct Answer & Explanation

. Group B; guarded prognosis, may benefit from containment surgery

Explanation

In the Herring Lateral Pillar Classification, Group B denotes >50% lateral pillar height maintained. Children in Group B have a guarded prognosis and often benefit from containment surgery (like a femoral or pelvic osteotomy) to preserve sphericity, especially if older than 8.

Question 290

Topic: Pediatric Hip

A 13-year-old obese male presents with acute left groin pain and an inability to bear weight on the affected extremity, even with the use of crutches. Radiographs confirm a slipped capital femoral epiphysis (SCFE). Which of the following factors most strongly predicts the development of avascular necrosis (AVN) in this patient?

. Age at presentation
. Degree of radiographic slip angle
. Inability to bear weight
. Delay in presentation greater than 3 weeks
. Presence of a significant hip effusion

Correct Answer & Explanation

. Inability to bear weight

Explanation

The inability to bear weight defines an unstable SCFE, which is the most significant predictor of avascular necrosis (AVN), with reported rates up to 50%. Stable SCFEs, where the patient can bear weight, have an AVN rate approaching 0%.

Question 291

Topic: Pediatric Hip

A 6-week-old female is currently being treated with a Pavlik harness for developmental dysplasia of the hip (DDH). The parents bring her to the clinic noting a decrease in spontaneous movement of the affected leg over the past two days. On examination, the infant lacks active knee extension, though ankle and toe movements are normal. What is the most likely cause of this clinical finding?

. Excessive hip abduction in the harness
. Excessive hip flexion in the harness
. Inadequate hip flexion in the harness
. Excessive hip adduction in the harness
. Acute vascular compromise of the femoral artery

Correct Answer & Explanation

. Excessive hip flexion in the harness

Explanation

Femoral nerve palsy is a known complication of Pavlik harness treatment and presents as decreased active knee extension. It is caused by hyperflexion of the hip, requiring immediate adjustment or temporary discontinuation of the harness until function returns.

Question 292

Topic: Pediatric Hip

A 6-month-old infant is diagnosed with a dislocatable hip on the Ortolani maneuver. Radiographs show a dislocated left hip with an acetabular index of 35 degrees. What is the most appropriate initial treatment?

. Pavlik harness
. Spica cast
. Closed reduction under general anesthesia
. Open reduction with capsulorrhaphy
. Traction followed by closed reduction

Correct Answer & Explanation

. Pavlik harness

Explanation

Correct Answer: AFor an infant aged 0-6 months (and often up to 9 months) with a dislocatable or reducible dislocated hip (Developmental Dysplasia of the Hip - DDH), the Pavlik harness is the gold standard initial treatment. It maintains the hips in gentle flexion and abduction, promoting concentric reduction and encouraging normal acetabular development. Closed reduction under general anesthesia and spica casting are typically reserved for older infants or failures of Pavlik harness treatment. Open reduction is indicated for irreducible dislocations.

Question 293

Topic: Pediatric Hip

A 12-year-old obese male presents with an acute-on-chronic unstable slipped capital femoral epiphysis (SCFE). Which of the following intraoperative maneuvers or surgical decisions carries the highest risk for inducing avascular necrosis (AVN) of the femoral head?

. Use of a single fully threaded screw
. Incidental penetration of the articular surface with the drill
. Anatomic closed reduction of the slip prior to fixation
. Perform an open capsulotomy
. Use of a prophylactic screw in the contralateral hip

Correct Answer & Explanation

. Anatomic closed reduction of the slip prior to fixation

Explanation

Forceful or anatomic closed reduction of an unstable SCFE significantly increases the risk of avascular necrosis due to further disruption of the already compromised retinacular vessels. Current guidelines advocate for in situ fixation or controlled open reduction techniques like the modified Dunn procedure.

Question 294

Topic: Pediatric Hip

A 13-year-old obese male presents with left groin pain and an inability to bear weight on the left leg for the past 24 hours. Radiographs confirm a severe left slipped capital femoral epiphysis (SCFE). Which of the following management strategies carries the lowest risk of avascular necrosis (AVN) while addressing the pathology?

. Immediate forceful closed reduction and pinning
. Urgent in-situ pinning with joint decompression
. Observation with strict bed rest for 6 weeks
. Subtrochanteric derotational osteotomy
. Skeletal traction for 2 weeks followed by pinning

Correct Answer & Explanation

. Urgent in-situ pinning with joint decompression

Explanation

This is an unstable SCFE (inability to bear weight), which has a high rate of AVN. Urgent gentle in-situ pinning, often accompanied by intracapsular decompression to lower tamponade pressure, is the standard of care. Forceful reduction significantly increases AVN risk.

Question 295

Topic: Pediatric Hip

A 6-month-old female with developmental dysplasia of the hip (DDH) has failed a 4-week trial of a Pavlik harness for a dislocated left hip. Ultrasound confirms the hip remains dislocated. What is the most appropriate next step in management?

. Continue the Pavlik harness for an additional 4 weeks
. Transition to a rigid abduction orthosis (e.g., Ilfeld splint)
. Closed reduction and spica casting under general anesthesia
. Open reduction with femoral shortening osteotomy
. Observation until skeletal maturity

Correct Answer & Explanation

. Closed reduction and spica casting under general anesthesia

Explanation

If a Pavlik harness fails to achieve reduction within 3-4 weeks, it must be discontinued to avoid "Pavlik harness disease" (posterior acetabular wear and AVN). The next appropriate step is an examination under anesthesia, arthrogram, and closed reduction with spica casting.

Question 296

Topic: Pediatric Hip

A 13-year-old obese male presents with a sudden inability to bear weight on his right leg after a minor fall. Radiographs demonstrate a severe slipped capital femoral epiphysis (SCFE). Which of the following complications is he at the highest risk of developing compared to a patient who can bear weight?

. Chondrolysis
. Avascular necrosis
. Femoral nerve palsy
. Osteomyelitis
. Premature osteoarthritis of the knee

Correct Answer & Explanation

. Avascular necrosis

Explanation

An unstable SCFE, defined clinically by the inability to bear weight, is associated with a significantly higher risk of avascular necrosis of the femoral head compared to a stable SCFE.

Question 297

Topic: Pediatric Hip

A 12-year-old obese male presents with a two-week history of a limp and poorly localized thigh and knee pain. Radiographs reveal a slipped capital femoral epiphysis (SCFE). Which of the following represents the primary blood supply to the femoral head that is at risk of disruption in this condition?

. Lateral femoral circumflex artery
. Artery of the ligamentum teres
. Medial femoral circumflex artery
. Inferior gluteal artery
. Superior gluteal artery

Correct Answer & Explanation

. Medial femoral circumflex artery

Explanation

The medial femoral circumflex artery (MFCA) provides the primary blood supply to the femoral head in older children and adults. Disruption of the MFCA during a severe or unstable SCFE (or its treatment) can lead to avascular necrosis.

Question 298

Topic: Pediatric Hip

A 7-month-old infant is undergoing treatment with a Pavlik harness for developmental dysplasia of the hip (DDH). The mother notes the child is no longer actively extending the knee on the affected side. Upon examination, the quadriceps reflex is absent. Which nerve is most likely compressed by the harness?

. Sciatic nerve
. Femoral nerve
. Obturator nerve
. Lateral femoral cutaneous nerve
. Tibial nerve

Correct Answer & Explanation

. Femoral nerve

Explanation

Hyperflexion of the hip in a Pavlik harness can lead to compression of the femoral nerve against the pelvic brim. This presents as a femoral nerve palsy, characterized by decreased active knee extension and loss of the patellar reflex.

Question 299

Topic: Pediatric Hip

During shoulder arthroscopy for recurrent anterior instability, the labrocapsular complex is found to be avulsed from the anterior glenoid rim and displaced medially, having healed onto the anterior neck of the glenoid. Which of the following acronyms describes this specific lesion?

. GLAD
. HAGL
. ALPSA
. Perthes
. SLAP

Correct Answer & Explanation

. ALPSA

Explanation

An ALPSA (Anterior Labroligamentous Periosteal Sleeve Avulsion) lesion occurs when the anterior labrum is avulsed but the periosteum remains intact, allowing it to displace medially and heal abnormally. It must be mobilized laterally for anatomical repair.

Question 300

Topic: Pediatric Hip

The patient's clinical presentation included insidious onset of progressive groin and lateral thigh pain, mechanical catching, and morning stiffness lasting 45 minutes. Radiographs showed severe tricompartmental joint space narrowing, subchondral sclerosis, extensive osteophytes, and subchondral cysts. Inflammatory markers (ESR, CRP) were normal.

Considering these findings, which of the following conditions is least likely to be the primary diagnosis?

. Primary osteoarthritis of the hip.
. Avascular necrosis (AVN) of the femoral head.
. Rheumatoid arthritis (RA).
. Post-traumatic osteoarthritis.
. Developmental dysplasia of the hip (DDH) leading to secondary OA.

Correct Answer & Explanation

. Rheumatoid arthritis (RA).

Explanation

Correct Answer: CRheumatoid arthritis (RA) is least likely to be the primary diagnosis. The patient's presentation with mechanical pain, morning stiffness lasting 45 minutes (typical for OA, RA is usually >1 hour), and radiographic findings of osteophytes, subchondral sclerosis, and cysts are classic for osteoarthritis. RA typically presents with inflammatory pain (worse with rest), symmetric polyarthritis, and radiographic features of concentric joint space narrowing, erosions, and juxta-articular osteopenia, with an absence of osteophytes. Furthermore, inflammatory markers (ESR, CRP) would typically be elevated in active RA, which were normal in this patient. Primary osteoarthritis (A) is the most likely diagnosis. AVN (B) can cause similar pain but has distinct radiographic features (crescent sign, patchy sclerosis/lucency) and MRI is diagnostic. Post-traumatic OA (D) and DDH leading to secondary OA (E) are forms of osteoarthritis and would present with similar clinical and radiographic features to primary OA, making them plausible differential diagnoses for thetypeof OA, but not fundamentally different conditions like RA.

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