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 981
Topic: 4. Pediatrics
A 14-year-old male sustains an ankle injury while skateboarding. Radiographs demonstrate a Salter-Harris III fracture of the anterolateral aspect of the distal tibial epiphysis (Tillaux fracture). Which of the following ligaments is responsible for the avulsion of this fracture fragment?
Correct Answer & Explanation
. Anterior inferior tibiofibular ligament (AITFL)
Explanation
A juvenile Tillaux fracture is a Salter-Harris III fracture of the anterolateral distal tibia. It is caused by an external rotation force leading to avulsion of the bony fragment via the anterior inferior tibiofibular ligament (AITFL) as the medial physis closes last.
Question 982
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?
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 983
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?
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 984
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?
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 985
Topic: 4. Pediatrics
In a pediatric patient with spondylolysis (pars defect without slip) who is asymptomatic, what is the recommended management?
Correct Answer & Explanation
. Observation with activity as tolerated and repeat imaging in 1 year
Explanation
Correct Answer: CFor asymptomatic spondylolysis without slip, the primary recommendation is observation with activity as tolerated. Most pars defects remain stable and asymptomatic. Surgical intervention is reserved for symptomatic, failed conservative cases. Bracing or activity restriction might be considered for symptomatic spondylolysis to promote healing, but not for asymptomatic lesions. Physical therapy is more relevant for symptomatic individuals.
Question 986
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?
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 987
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?
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 988
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?
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 989
Topic: 4. Pediatrics
A 5-year-old child sustains a Gartland type III extension-type supracondylar humerus fracture. After successful closed reduction and percutaneous pinning, the hand remains pink but the radial pulse is absent on Doppler ultrasound. Capillary refill is 2 seconds. What is the most appropriate next step?
Correct Answer & Explanation
. Observation with close neurovascular monitoring
Explanation
A 'pink, pulseless' hand following adequate reduction and stabilization of a pediatric supracondylar humerus fracture indicates sufficient collateral perfusion. The standard of care is close clinical observation, as vascular exploration is generally reserved for a 'white, pulseless' hand.
Question 990
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?
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 991
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?
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 992
Topic: 4. Pediatrics
A 6-year-old boy sustains a completely displaced extension-type supracondylar humerus fracture. Examination reveals a "puckered" appearance of the anterior antecubital skin and an absent radial pulse. The hand remains warm and pink. What is the next best step?
Correct Answer & Explanation
. Urgent closed reduction and percutaneous pinning
Explanation
A pink, pulseless hand in the setting of a displaced pediatric supracondylar humerus fracture is an indication for urgent closed reduction and percutaneous pinning. The pulse often returns immediately after anatomical fracture reduction.
Question 993
Topic: 4. Pediatrics
A 6-year-old child sustains a distal femur fracture (33-M/3.1) that requires open reduction and internal fixation with a plate. The plate must cross the distal femoral physis to achieve stable fixation. Which of the following describes a common indication for plate removal in children that is less common in adults?
Correct Answer & Explanation
. Arrest of physeal growth due to plate impingement.
Explanation
Correct Answer: CIn children, the presence of growth plates (physes) means that plates applied across or near these structures can impinge upon or damage the physis, leading to growth arrest or angular deformities. Therefore, plates are often removed once healing is complete or if they are crossing a physis and significant growth remains, to prevent or correct growth disturbances. While symptomatic prominence (Option A), refracture (Option B), infection (Option D), and non-union (Option E) can occur in both children and adults, physeal arrest is a unique and critical consideration for pediatric patients, making implant removal often necessary to preserve normal growth. The image clearly shows a plate crossing the physis, highlighting this specific risk.
Question 994
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?
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 995
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?
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 996
Topic: 4. Pediatrics
A 12-year-old obese African American male presents with progressive right knee varus deformity. He reports no pain but notes difficulty participating in sports due to his bowing. Physical examination reveals a noticeable varus thrust with ambulation. Standing full-length AP radiographs show a right Medial Proximal Tibial Angle (MPTA) of 72 degrees, a Mechanical Axis Deviation (MAD) of 35 mm medial to the center of the knee, and open physes. Left hand and wrist radiograph indicates a skeletal age of 11 years. Which of the following is the most appropriate initial surgical management for this patient?
Correct Answer: DThe patient presents with severe adolescent Blount disease, characterized by an MPTA of 72 degrees and a MAD of 35 mm medial to the center of the knee. According to the case content, lateral hemiepiphysiodesis is indicated for mild to moderate angular deformities, typically with an MPTA between 75-85 degrees and MAD generally less than 20-30 mm. Severe deformities, defined as MAD > 30-40 mm or MPTA < 70 degrees, are a contraindication for hemiepiphysiodesis because the remaining growth potential is unlikely to achieve full correction within a reasonable timeframe, or a rapid, definitive correction is required. In such severe cases, especially in older patients or those with significant deformity, an acute correction osteotomy (proximal tibial varus-producing osteotomy) is the definitive solution. While the patient has open physes, the severity of the deformity outweighs the benefits of guided growth in this scenario. Observation and bracing are typically for milder, non-progressive cases or younger children. Medial hemiepiphysiodesis would worsen the varus. Distal femoral hemiepiphysiodesis would address femoral varus, but the primary pathology here is tibial.
Question 997
Topic: 4. Pediatrics
During a lateral proximal tibial hemiepiphysiodesis, a surgeon is performing the dissection to expose the lateral cortex of the proximal tibia. Which neurovascular structure is at highest risk of iatrogenic injury if deep or misguided retractors are used, and where is it typically located relative to the surgical site?
Correct Answer & Explanation
. Common peroneal nerve, coursing superficially around the fibular neck, approximately 3-5 cm distal to the proximal tibial physis.
Explanation
Correct Answer: CThe case explicitly states under the 'Neurovascular Structures' section that the 'Common Peroneal Nerve courses superficially around the fibular neck, approximately 3-5 cm distal to the proximal tibial physis. Extreme care must be taken to avoid injury during lateral dissection and especially with any hardware placed deep and distal.' This makes it the structure at highest risk with deep or misguided retractors in this specific surgical approach. The popliteal artery and vein are located posteriorly, but less directly at risk with a lateral approach to the tibia. The anterior tibial artery passes through the interosseous membrane anteriorly. The saphenous nerve is medial, and the posterior tibial artery is deep in the posterior compartment, making them less vulnerable during a lateral proximal tibial approach.
Question 998
Topic: 4. Pediatrics
A 7-year-old patient with progressive infantile Blount disease (Langenskiรถld Stage III) undergoes lateral proximal tibial hemiepiphysiodesis. The biomechanical principle primarily responsible for the gradual correction of the varus deformity in this procedure is:
Correct Answer & Explanation
. The Hueter-Volkmann law, where reduced compressive forces on the medial physis stimulate growth, while the tethered lateral physis grows slower.
Explanation
The case clearly outlines the biomechanical basis for hemiepiphysiodesis. Hemiepiphysiodesis operates on fundamental biomechanical principles governed by the Hueter-Volkmann law and the concept of guided growth. The Hueter-Volkmann law states that increased compressive forces across a physis inhibit growth, while decreased compressive forces stimulate growth. In lateral hemiepiphysiodesis, the lateral side of the physis is tethered, which effectively increases compressive forces or restricts growth on that side. This allows the medial physis, which was previously subjected to excessive compressive forces due to varus, to experience relatively decreased compressive forces (or simply grow uninhibitedly), thereby stimulating its growth and correcting the varus deformity. The plate acts as a hinge, not an active compressor of the physis itself, but rather guides differential growth.
Question 999
Topic: 4. Pediatrics
A 5-year-old child is being evaluated for progressive infantile Blount disease. Which of the following radiographic views is considered most crucial for a comprehensive assessment of overall lower limb alignment, identification of the deformity's apex, and accurate measurement of the Mechanical Axis Deviation (MAD)?
Correct Answer & Explanation
. Standing full-length Anteroposterior (AP) radiograph (Mechanical Axis View) from femoral head to ankle.
Explanation
Correct Answer: CUnder 'Radiographic Evaluation' in the 'Pre-Operative Planning' section, the case states: 'Standing Full-Length AP Radiographs (Mechanical Axis Views): Crucial for comprehensive assessment of overall limb alignment. These films extend from the femoral head to the ankle joint and are used to: Determine the Mechanical Axis Deviation (MAD)... Measure the Medial Distal Femoral Angle (mLDFA)... Measure the Joint Line Convergence Angle (JLCA)... Identify any significant Leg Length Discrepancy (LLD).' While other views provide important information (e.g., knee AP for MPTA, lateral for procurvatum, MRI for physeal integrity), the standing full-length AP radiograph is uniquely essential for assessing the overall mechanical axis and identifying the true extent and location of the deformity in the entire limb.
Question 1000
Topic: 4. Pediatrics
During lateral proximal tibial hemiepiphysiodesis using an eight-plate, the most critical technical step to ensure effective guided growth and prevent physeal damage is:
Correct Answer & Explanation
. Inserting the screws perpendicular to the long axis of the bone, ensuring they are entirely within either the epiphyseal or metaphyseal bone, and parallel to the physis.
Explanation
Correct Answer: CThe 'Detailed Surgical Approach / Technique' section emphasizes the critical nature of screw insertion. It states: 'The screws should be inserted parallel to the physis and perpendicular to the long axis of the bone segment. This ensures that the growth plate is not compressed or damaged, but rather 'tethered' by the plate.' It further clarifies: 'Crucially, verify that no screw has crossed or damaged the physis. The screw threads should be entirely within either the epiphyseal or metaphyseal bone. The smooth shaft of the screw should pass through the physis, allowing translation.' While bicortical purchase is generally aimed for stability (especially in the metaphysis), unicortical in the epiphysis is often acceptable. The plate should sit flush, but not necessarily be 'tightly compressed' in a way that would impede the hinge effect. Placing the plate too far anteriorly or using an oversized drill bit are not the most critical aspects for guided growth efficacy and physeal protection.
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