This practice set contains high-yield board review questions covering key concepts in 4. Pediatrics. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.
Question 901
Topic: Pediatric Hip
An obese 13-year-old boy presents with right knee pain and a limp. Examination shows obligatory external rotation of the right hip during passive flexion. What is the most appropriate definitive management?
Correct Answer & Explanation
. In situ single screw fixation
Explanation
The presentation is classic for a Slipped Capital Femoral Epiphysis (SCFE). The standard of care is in situ stabilization with a single, partially threaded cannulated screw to prevent further slippage.
Question 902
Topic: 4. Pediatrics
According to the Ponseti method for congenital talipes equinovarus (clubfoot), which component of the deformity is typically corrected last?
Correct Answer & Explanation
. Equinus
Explanation
The Ponseti sequence of correction is represented by the acronym CAVE: Cavus, Adductus, Varus, and Equinus. Equinus is corrected last and often requires a percutaneous Achilles tenotomy.
Question 903
Topic: 4. Pediatrics
A 13-year-old obese male presents with a 3-week history of groin pain and a limp. On examination, there is obligatory external rotation of the hip during passive hip flexion. The pathology of this condition occurs primarily through which zone of the physis?
Correct Answer & Explanation
. Hypertrophic zone
Explanation
The patient has a slipped capital femoral epiphysis (SCFE), characterized by groin pain and obligatory external rotation during hip flexion. The mechanical failure and slippage occur through the hypertrophic zone of the physis.
Question 904
Topic: Pediatric Hip
A 6-month-old female is referred for asymmetric thigh folds and limited hip abduction. Which imaging modality is most appropriate to evaluate for developmental dysplasia of the hip (DDH) at this age?
Correct Answer & Explanation
. AP Pelvis radiograph
Explanation
While ultrasound is the modality of choice for infants under 4 to 6 months, plain AP pelvis radiographs become more reliable at 6 months of age. This is due to the progressive ossification of the femoral head (ossific nucleus).
Question 905
Topic: Pediatric Hip
A 12-year-old boy presents with left hip pain and an obligate external rotation of the hip with flexion. Radiographs confirm a mild left slipped capital femoral epiphysis (SCFE). Which of the following is the strongest indication for prophylactic pinning of the contralateral asymptomatic hip?
Prophylactic pinning of the contralateral hip in SCFE is strongly recommended for patients with underlying endocrinopathies, radiation therapy, or renal failure. These systemic conditions present an exceptionally high risk for bilateral involvement.
Question 906
Topic: 4. Pediatrics
A 2-week-old infant is being treated for idiopathic congenital talipes equinovarus using the Ponseti method. After sequential correction of the cavus, adductus, and varus deformities over several weeks, the foot remains in significant equinus. What is the next appropriate step in management?
Correct Answer & Explanation
. Percutaneous Achilles tendon tenotomy
Explanation
In the Ponseti method, after correcting cavus, adductus, and varus, residual equinus deformity requires a percutaneous Achilles tenotomy prior to the final cast. Forceful dorsiflexion against a tight Achilles must be avoided as it causes a rocker-bottom deformity.
Question 907
Topic: Pediatric Hip
A 13-year-old obese male presents with a 4-week history of right groin pain and a worsening limp. Physical examination reveals an obligate external rotation of the hip during passive flexion. Radiographs demonstrate posterior and inferior displacement of the proximal femoral epiphysis. What is the standard of care for this condition?
Correct Answer & Explanation
. In situ percutaneous pinning
Explanation
The standard of care for a stable Slipped Capital Femoral Epiphysis (SCFE) is in situ fixation, typically utilizing a single cannulated screw. Attempting a closed reduction significantly increases the risk of avascular necrosis of the femoral head.
Question 908
Topic: 4. Pediatrics
A 21-year-old man presents for evaluation of high arches, which have been present his entire life. C urrently, he is experiencing some discomfort with running activities. His brother and mother have high arches. He does not recall any trauma as a child, or any other pertinent childhood musculoskeletal problems. C linical examination reveals a rigid deformity bilaterally. The most common cause for his high arches is:
Correct Answer & Explanation
. Hereditary sensorimotor neuropathy
Explanation
The most common cause of familial cavovarus foot deformity is hereditary sensorimotor neuropathy (C harcot-Marie-Tooth disease). This is an autosomal dominant condition with variable penetrance. Idiopathic cavus foot is common, but not familial, nor is it associated with this extensive deformity.
Question 909
Topic: 4. Pediatrics
A 6-year-old child sustains a completely displaced supracondylar humerus fracture. After closed reduction and percutaneous pinning, the fracture heals. However, at 1-year follow-up, the child has a noticeable cubitus varus deformity. What is the most common cause of this specific deformity?
Correct Answer & Explanation
. Malunion
Explanation
Cubitus varus is the most common long-term complication of supracondylar humerus fractures. It is almost exclusively caused by malunion, specifically from inadequate correction of medial comminution and internal rotation malalignment.
Question 910
Topic: Pediatric Hip
A 13-year-old obese boy presents with a 3-week history of right groin pain and an obligatory external rotation of the hip when the hip is flexed. What is the most appropriate initial treatment?
Correct Answer & Explanation
. In situ pinning with a single cannulated screw
Explanation
The presentation is classic for a slipped capital femoral epiphysis (SCFE). The standard of care is immediate in situ pinning with a single, centrally placed cannulated screw to prevent further slippage.
Question 911
Topic: Pediatric Hip
A 13-year-old obese boy presents with left thigh pain and an obligatory external rotation of the hip during flexion. Radiographs confirm a slipped capital femoral epiphysis (SCFE). Which of the following is the most significant risk factor for the development of chondrolysis in this patient?
Correct Answer & Explanation
. Unrecognized joint penetration by the hardware
Explanation
Unrecognized intra-articular hardware penetration is a well-documented and highly significant risk factor for chondrolysis following SCFE fixation. Proper fluoroscopic evaluation using the approach-withdrawal technique is crucial to avoid this complication.
Question 912
Topic: Pediatric Hip
A 6-week-old female infant is undergoing treatment for developmental dysplasia of the hip (DDH) with a Pavlik harness. During a follow-up visit, the mother notes that the infant is no longer actively extending her knee on the affected side. What is the most appropriate next step in management?
Correct Answer & Explanation
. Loosen or remove the harness temporarily
Explanation
The infant is demonstrating signs of a femoral nerve palsy, a known complication of hyperflexion in a Pavlik harness. The most appropriate immediate management is to loosen the anterior straps or temporarily remove the harness until nerve function recovers.
Question 913
Topic: Pediatric Hip
A 12-year-old obese boy presents with a stable slipped capital femoral epiphysis (SCFE) of the left hip. The surgeon plans in situ fixation with a single partially threaded cannulated screw. To avoid the most common complication leading to chondrolysis, which of the following is the most sensitive intraoperative imaging technique to ensure the screw has not penetrated the joint?
Correct Answer & Explanation
. Approach-withdrawal technique on fluoroscopy
Explanation
The approach-withdrawal technique using live fluoroscopy while rotating the hip is the most sensitive method to detect unrecognized screw penetration in SCFE fixation. Standard orthogonal views possess blind spots that can obscure a prominent screw tip.
Question 914
Topic: Pediatric Hip
A 13-year-old obese male presents with progressive left groin and knee pain. On physical examination, as his left hip is passively flexed, it obligatorily deviates into external rotation. What is the most likely diagnosis?
Correct Answer & Explanation
. Slipped capital femoral epiphysis
Explanation
Obligatory external rotation with passive hip flexion is a hallmark clinical sign of slipped capital femoral epiphysis (SCFE). The disorder is most common in overweight, adolescent males.
Question 915
Topic: 4. Pediatrics
What is the most common neurological deficit associated with a severely displaced extension-type supracondylar humerus fracture in a pediatric patient?
Correct Answer & Explanation
. Anterior interosseous nerve (AIN) palsy
Explanation
The anterior interosseous nerve (AIN) is the most commonly injured nerve in extension-type supracondylar fractures. It is evaluated clinically by testing the patient's ability to make an 'OK' sign.
Question 916
Topic: Pediatric Hip
A 13-year-old obese male presents with a 2-month history of groin pain and an obligatory external rotation of the thigh during passive hip flexion. Following fixation of the affected hip, which of the following is the most robust indication for prophylactic pinning of the contralateral hip?
Correct Answer & Explanation
. A low modified Oxford bone age score indicating skeletal immaturity
Explanation
The patient has a Slipped Capital Femoral Epiphysis (SCFE). Prophylactic pinning of the contralateral hip is heavily considered in patients at high risk for a subsequent slip, which includes skeletal immaturity (low modified Oxford bone age score) and endocrine disorders.
Question 917
Topic: Pediatric Hip
A 13-year-old obese male presents with left thigh pain and a limp for 3 weeks. An AP pelvis radiograph is evaluated.
On physical examination, what is the most likely finding when the affected hip is passively flexed?
Correct Answer & Explanation
. Obligatory external rotation
Explanation
Slipped Capital Femoral Epiphysis (SCFE) classically presents with obligatory external rotation of the thigh during passive hip flexion. This occurs due to the relative posterior and inferior displacement of the proximal femoral epiphysis.
Question 918
Topic: 4. Pediatrics
A 14-year-old male, Tanner Stage IV, presents with a complex distal tibial physeal fracture after a soccer injury. His history includes seven years of single-sport specialization, training 18+ hours/week, and recent vague, deep-seated distal tibial pain. Which of the following statements best describes the most likely underlying pathophysiology contributing to this patient's acute injury?
Correct Answer & Explanation
. Single-sport specialization led to chronic microtrauma, causing a pre-existing stress reaction that weakened the metaphyseal bone.
Explanation
Correct Answer: CThe case explicitly states that the patient's history of single-sport specialization, high training volume, and prodromal symptoms (vague, deep-seated pain in the distal tibia) strongly suggest a pre-existing stress reaction or stress fracture of the distal tibial metaphysis. This chronic microtrauma disrupts normal bone remodeling, leading to microscopic trabecular failure and structural compromise. When a sudden, high-energy torsional force is applied to this already weakened bone, it fails catastrophically, often involving the partially closed physis, as seen in this complex triplane fracture. This highlights the long-term impact of single-sport specialization and inadequate recovery.Option A is incorrect because Tanner Stage IV indicates partial physeal closure, specifically the transitional period where the physis is uniquely vulnerable to these types of fractures (Tillaux and triplane). Complete closure would make a physeal fracture impossible. Option B is incorrect as the mechanism described is a twisting sensation with a planted foot, characteristic of an external rotation injury, not a direct impact. Option D is incorrect; while avulsion fractures of the anterior inferior tibiofibular ligament (Chaput tubercle) are seen in this age group (Tillaux fracture), the underlying pathophysiology of chronic stress reaction due to specialization is a more fundamental contributing factor to the complexity of this specific injury. Option E is incorrect; while a 'pop' can occur with ligamentous injuries, the severe pain, rapid swelling, and inability to bear weight, especially in the context of prodromal symptoms and the described mechanism, are highly suggestive of a significant bony injury, which was confirmed to be a complex physeal fracture.
Question 919
Topic: 4. Pediatrics
A 14-year-old male, Tanner Stage IV, sustains a distal tibial physeal fracture. The distal tibial physis contributes approximately 45% of the total longitudinal growth of the tibia. Understanding the chronological and spatial sequence of physeal closure is critical for managing such injuries. Which of the following statements accurately describes the typical pattern of distal tibial physeal closure?
Correct Answer & Explanation
. Closure begins centrally, proceeds medially, and the anterolateral physis is the final segment to fuse.
Explanation
The case explicitly states that the closure pattern of the distal tibial physis is highly predictable and asymmetric. It initiates in the central portion (often referred to as Kump bump) and proceeds medially. The lateral and anterolateral portions of the physis are the final segments to fuse. This asymmetrical closure creates a unique biomechanical vulnerability during the transitional period, leading to fracture patterns like the juvenile Tillaux and triplane fractures. Option A is incorrect as it reverses the correct closure pattern. Option C is incorrect because the closure is distinctly asymmetrical, not symmetrical. Option D is incorrect as the primary description focuses on medial-to-lateral and central-to-peripheral progression, not posterior-to-anterior. Option E is incorrect; the distal tibial physis typically begins to close around age 14-15 in males, corresponding precisely with Tanner Stage IV development, making physeal fractures, particularly transitional ones, common in this stage.
Question 920
Topic: 4. Pediatrics
Following successful reduction of the triplane fracture, the surgeon proceeds with internal fixation using partially threaded cannulated screws. The patient is Tanner Stage IV and nearing skeletal maturity. When placing the screws for definitive fixation, which principle is most critical to prioritize in this specific patient?
Correct Answer & Explanation
. Prioritize anatomic articular congruity, even if it means crossing the physis with a smooth screw shaft.
Explanation
Correct Answer: CThe case states: 'If the patient is Tanner Stage IV and nearing skeletal maturity, the risk of clinically significant growth arrest from crossing the physis with a smooth screw shaft is negligible compared to the catastrophic risk of articular incongruity.' Therefore, prioritizing anatomic articular congruity is paramount in this age group, even if it necessitates crossing the physis with a smooth screw shaft, as the risk of growth arrest is low and the risk of post-traumatic arthritis from incongruity is high.Option A is incorrect because, while generally desirable, in older adolescents nearing skeletal maturity, the risk-benefit analysis shifts, and articular congruity takes precedence over strictly avoiding physeal violation. Option B is incorrect; partially threaded screws are typically used to achieve lag compression across the fracture fragments, and fully threaded screws might not provide the desired compression. Option D is incorrect; K-wires are used for provisional fixation, but definitive fixation for displaced intra-articular fractures typically requires screws for stable compression. Option E is incorrect; screw placement trajectory is dictated by fracture morphology and optimal fixation, not solely by nerve avoidance, although nerve protection is always critical during the approach.
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