This practice set contains high-yield board review questions covering key concepts in Pediatric Upper Extremity & Spine. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.
Question 361
Topic: Pediatric Upper Extremity & Spine
In the evaluation of Adolescent Idiopathic Scoliosis (AIS), the Lenke classification system utilizes the flexibility of curves on side-bending radiographs to determine fusion levels. A minor thoracic curve is considered "structural" if the Cobb angle on the side-bending radiograph fails to reduce below what specific threshold?
Correct Answer & Explanation
. 10 degrees
Explanation
In the Lenke classification for AIS, a minor curve is considered structural if it remains 25 degrees or greater on lateral side-bending radiographs, or if there is local kyphosis >20 degrees.
Question 362
Topic: Pediatric Upper Extremity & Spine
A 13-year-old girl with adolescent idiopathic scoliosis (AIS) has a right thoracic curve of 55 degrees. She is Risser 0. Pulmonary function testing demonstrates a forced vital capacity (FVC) of 55% of predicted. What is the most appropriate surgical approach?
Correct Answer & Explanation
. Anterior spinal fusion
Explanation
Posterior spinal fusion is the standard of care for large thoracic curves in AIS. Anterior approaches are generally contraindicated in patients with diminished pulmonary function (FVC < 60% to 70% predicted) due to the risk of postoperative pulmonary decline.
Question 363
Topic: Pediatric Upper Extremity & Spine
A 12-year-old premenarchal female presents for scoliosis evaluation. Radiographs demonstrate a right thoracic curve of 32 degrees. Her Risser stage is 0. What is the most appropriate next step in management?
Correct Answer & Explanation
. Observation with repeat radiographs in 6 months
Explanation
Full-time bracing with a TLSO is indicated for skeletally immature patients (Risser 0-2, premenarchal) with an idiopathic scoliosis curve between 25 and 45 degrees to halt curve progression.
Question 364
Topic: Pediatric Upper Extremity & Spine
A 13-year-old premenarchal female (Risser 0) presents with a right thoracic adolescent idiopathic scoliosis. Standing radiographs demonstrate a primary thoracic curve of 35 degrees. What is the most appropriate management?
Correct Answer & Explanation
. Observation with repeat radiographs in 6 months
Explanation
Bracing is indicated for skeletally immature patients (Risser 0-2, premenarchal) with progressive curves between 25 and 45 degrees. A TLSO worn for 16 to 23 hours daily has been proven to significantly reduce the progression of curves to surgical thresholds.
Question 365
Topic: Pediatric Upper Extremity & Spine
A patient presents with high median nerve neuropathy causing weakness in wrist flexion, forearm pronation, and thumb IP flexion. If the site of compression is the ligament of Struthers, this anatomic structure connects the medial epicondyle to what landmark?
Correct Answer & Explanation
. Supracondylar process of the humerus
Explanation
The ligament of Struthers is an anomalous band present in about 1% of the population, connecting the supracondylar process to the medial epicondyle. Compression here causes high median neuropathy, unlike compression at the Arcade of Struthers, which affects the ulnar nerve.
Question 366
Topic: Pediatric Upper Extremity & Spine
According to the Lenke classification for adolescent idiopathic scoliosis, which of the following radiographic criteria defines a minor curve as "structural" and necessitates its inclusion in the fusion construct?
Correct Answer & Explanation
. Cobb angle > 15 degrees on standing PA radiographs
Explanation
In the Lenke classification, a minor curve is considered structural if it fails to bend out to less than 25 degrees on side-bending radiographs, or if there is a regional kyphosis of ≥ 20 degrees. Structural curves must be included in the operative fusion.
Question 367
Topic: Pediatric Upper Extremity & Spine
In the surgical planning for adolescent idiopathic scoliosis, a Lenke Type 1 curve is defined by which of the following structural characteristics?
Correct Answer & Explanation
. Structural proximal thoracic curve and structural main thoracic curve
Explanation
A Lenke Type 1 curve (Main Thoracic) dictates that the main thoracic curve is structural, while both the proximal thoracic and thoracolumbar/lumbar curves are nonstructural (they bend out to less than 25 degrees on side-bending radiographs).
Question 368
Topic: Pediatric Upper Extremity & Spine
A 14-year-old female with adolescent idiopathic scoliosis (AIS) has a main thoracic curve of 55 degrees and a lumbar curve of 40 degrees. On side-bending films, the lumbar curve corrects to 20 degrees. The center sacral vertical line (CSVL) lies completely medial to the medial border of the apical lumbar vertebra. According to the Lenke classification, what is the correct lumbar modifier for this curve pattern?
Correct Answer & Explanation
. Modifier A
Explanation
In the Lenke classification, a lumbar modifier C is assigned when the CSVL falls completely medial to the pedicles of the apical lumbar vertebra. Modifier A means the CSVL lies between the pedicles, and B means it touches the medial border.
Question 369
Topic: Pediatric Upper Extremity & Spine
A 7-year-old boy presents with a Gartland Type II supracondylar humerus fracture. Radiographs show posterior displacement with an intact anterior humeral line. He has a strong radial pulse and good capillary refill. Sensory function is normal. What is the MOST appropriate management?
Correct Answer & Explanation
. Long arm cast immobilization in 90 degrees of flexion
Explanation
A Gartland Type II supracondylar humerus fracture is characterized by displacement with an intact posterior cortex and an intact anterior humeral line. While some sources might suggest closed reduction and casting for stable Type II fractures, the prevailing consensus for displaced Type II and all Type III fractures is closed reduction and percutaneous pinning (CRPP). This provides stable fixation, allowing for earlier mobilization and minimizing the risk of re-displacement, which is a common complication with casting alone. Cast immobilization in 90 degrees of flexion without pinning is generally reserved for non-displaced (Type I) or minimally displaced fractures. ORIF is usually reserved for open fractures, neurovascular compromise that doesn't resolve after reduction, or failed closed reduction. Observation is for Type I. Skeletal traction is largely historical for this injury.
Question 370
Topic: Pediatric Upper Extremity & Spine
A 6-year-old boy falls from a playground structure and sustains a Gartland type III extension-type supracondylar humerus fracture. Radiographs demonstrate posterolateral displacement of the distal fracture fragment. Based on the displacement pattern of the proximal fragment, which neurovascular structure is at the HIGHEST risk of injury, and what corresponding clinical finding should the examiner specifically evaluate?
Correct Answer & Explanation
. Radial nerve; inability to actively extend the wrist and digits
Explanation
In a Gartland type III extension-type supracondylar humerus fracture with posterolateral displacement of the distal fragment, the proximal shaft fragment is driven anteromedially. This anteromedial proximal spike places the structures in the anterior/medial aspect of the elbow—specifically the brachial artery, the median nerve, and its anterior interosseous nerve (AIN) branch—at the highest risk of injury. The AIN is the most commonly injured nerve in extension-type supracondylar humerus fractures overall, particularly with this posterolateral displacement pattern. An AIN palsy presents with loss of motor function to the flexor pollicis longus (FPL) and the flexor digitorum profundus (FDP) of the index finger, resulting in an inability to form the 'OK' sign. Conversely, posteromedial displacement of the distal fragment drives the proximal fragment anterolaterally, risking the radial nerve.
Question 371
Topic: Pediatric Upper Extremity & Spine
A 6-year-old boy presents with a completely displaced, extension-type supracondylar humerus fracture (Gartland Type III). On initial examination, the hand is pink but the radial pulse is non-palpable. The patient is taken emergently to the operating room. After closed reduction and percutaneous pinning, the fracture is anatomically aligned. The hand remains pink with brisk capillary refill, but the radial pulse remains absent. What is the most appropriate next step in management?
Correct Answer & Explanation
. Immediate open exploration of the brachial artery
Explanation
The scenario describes a 'pink, pulseless' hand following reduction and pinning of a pediatric supracondylar humerus fracture. The current standard of care dictates that if the hand is well-perfused (pink, warm, brisk capillary refill <2 seconds, detectable pulse oximetry waveform) after fracture reduction, even in the absence of a palpable radial pulse, the appropriate management is close observation and monitoring. Open exploration is indicated only if the hand is 'white and pulseless' (ischemic) after reduction.
Question 372
Topic: Pediatric Upper Extremity & Spine
A 6-year-old boy presents with a completely displaced, extension-type supracondylar humerus fracture (Gartland Type III). He exhibits weakness with active flexion of the thumb interphalangeal joint and the distal interphalangeal joint of the index finger. Which of the following nerve injuries is most likely present?
Correct Answer & Explanation
. Radial nerve
Explanation
The anterior interosseous nerve (AIN), a motor branch of the median nerve, is the most commonly injured nerve in extension-type pediatric supracondylar humerus fractures. The AIN innervates the flexor pollicis longus (FPL), the lateral half of the flexor digitorum profundus (FDP), and the pronator quadratus. An AIN neuropraxia results in the inability to actively flex the thumb interphalangeal (IP) joint and the index finger distal interphalangeal (DIP) joint, classically leading to an abnormal 'OK' sign (creating a pinch rather than an O). The radial nerve is the second most commonly injured nerve, often seen with posteromedial fracture displacement.
Question 373
Topic: Pediatric Upper Extremity & Spine
A lateral approach to the distal femur is utilized for plating a supracondylar femur fracture. As the vastus lateralis is elevated from the lateral intermuscular septum, robust vessels are encountered piercing the septum. These perforating vessels are primarily branches of which artery?
Correct Answer & Explanation
. Profunda femoris artery
Explanation
The perforating arteries encountered at the lateral intermuscular septum during a lateral femoral approach are branches of the profunda femoris artery. They must be carefully identified and coagulated to prevent postoperative hematoma.
Question 374
Topic: Pediatric Upper Extremity & Spine
A 6-year-old boy falls from the monkey bars and sustains a widely displaced Gartland type III supracondylar humerus fracture. On arrival at the emergency department, his hand is pink but the radial pulse is not palpable. Closed reduction and percutaneous pinning are performed. After pinning, the hand remains well-perfused and pink, but the radial pulse is still absent on palpation and Doppler. What is the most appropriate next step in management?
Correct Answer & Explanation
. Observation and admission for 24 to 48 hours
Explanation
The management of a 'pink, pulseless' hand following an acceptable reduction and pinning of a supracondylar humerus fracture is observation. Collateral circulation in the pediatric elbow is robust, providing adequate perfusion to the hand even if the brachial artery is in spasm or sustains a localized intimal injury. Current AAOS guidelines support observation; the pulse typically returns within 24 to 48 hours. Vascular exploration is strictly indicated if the hand is white, cold, and poorly perfused (ischemic) after reduction.
Question 375
Topic: Pediatric Upper Extremity & Spine
A 6-year-old girl is brought to the emergency department after falling from monkey bars. She sustains a severely displaced Gartland type III supracondylar humerus fracture. On initial examination, her hand is pink and well-perfused, but the radial pulse is absent. She is taken to the operating room for urgent closed reduction and percutaneous pinning. Following stable anatomic reduction and pinning, the hand remains pink with brisk capillary refill (< 2 seconds), but the radial pulse remains nonpalpable by Doppler. What is the most appropriate next step in management?
Correct Answer & Explanation
. Observation with close clinical monitoring for 24 to 48 hours
Explanation
The management of the "pink, pulseless hand" following adequate reduction and percutaneous pinning of a pediatric supracondylar humerus fracture is observation. Studies have consistently shown that if the hand remains well-perfused (warm, pink, capillary refill < 2 seconds) despite an absent palpable or Dopplerable pulse, collateral circulation is adequate. Routine vascular exploration or advanced imaging (CTA) is not indicated in this scenario, as the pulse often returns within a few days to weeks, and long-term functional outcomes are excellent. If the hand were "white and pulseless" post-reduction, immediate exploration of the brachial artery would be warranted.
Question 376
Topic: Pediatric Upper Extremity & Spine
A 5-year-old boy falls from monkey bars and presents to the emergency department. Radiographs reveal a completely displaced, extension-type supracondylar humerus fracture. On examination, his hand is pink and warm, but the radial pulse is not palpable. Capillary refill is brisk (< 2 seconds). He is unable to make an 'OK' sign, but finger extension is intact. What is the most appropriate initial management?
Correct Answer & Explanation
. Urgent closed reduction and percutaneous pinning, followed by observation of perfusion
Explanation
The clinical presentation is a 'pulseless, pink hand' associated with a completely displaced supracondylar humerus fracture, along with an anterior interosseous nerve (AIN) palsy (unable to make an OK sign). The initial management for a well-perfused, pulseless hand in this setting is urgent closed reduction and percutaneous pinning (CRPP). Often, the pulse returns following reduction as the kinked or compressed brachial artery is relieved. If the hand remains pink and well-perfused with brisk capillary refill after stabilization, continued observation is appropriate without immediate vascular exploration. Vascular exploration is indicated if the hand is poorly perfused (pale, cold, pulseless) before reduction and remains so after reduction, or if it becomes poorly perfused after reduction.
Question 377
Topic: Pediatric Upper Extremity & Spine
A 6-year-old boy sustains a completely displaced Gartland type III supracondylar humerus fracture. He undergoes prompt closed reduction and percutaneous pinning. Postoperatively, the radial pulse remains unpalpable, but the hand is warm with a brisk capillary refill of less than 2 seconds. Pulse oximetry on the index finger shows a strong waveform and 99% oxygen saturation.
What is the most appropriate next step in management?
Correct Answer & Explanation
. Observation and hospital admission for monitoring
Explanation
In the setting of a supracondylar humerus fracture with a "pulseless but pink" hand following satisfactory closed reduction and pinning, the standard of care is observation and admission for serial clinical examinations. The collateral circulation in pediatric patients is typically robust enough to maintain adequate perfusion even if the brachial artery is in spasm, contused, or tethered. Arterial exploration is strictly indicated if the hand is persistently ischemic (white, cool, lack of capillary refill) after reduction.
Question 378
Topic: Pediatric Upper Extremity & Spine
A 10-year-old premenarcheal girl is incidentally found to have a right thoracic adolescent idiopathic scoliosis (AIS). Upright standing radiographs demonstrate a Cobb angle of 26 degrees. Her Risser stage is 0. Based on standard prognostic criteria (Lonstein and Carlson), what is the approximate risk that this curve will progress to a surgical or bracing threshold (>50 degrees or requiring intervention)?
Correct Answer & Explanation
. 65 - 70%
Explanation
The Lonstein and Carlson progression factor evaluates the risk of curve progression in AIS based on the Cobb angle, Risser stage, and chronological age. A young, premenarcheal patient (Risser 0 or 1) presenting with a curve between 20 and 29 degrees has a high risk of progression, calculated to be approximately 68%. This patient clearly meets the indications for bracing (curve > 25 degrees in an immature patient).
Question 379
Topic: Pediatric Upper Extremity & Spine
A 5-year-old boy sustains a completely displaced supracondylar humerus fracture (Gartland Type III). Upon presentation, his hand is pink, but the radial pulse is absent. He undergoes urgent closed reduction and percutaneous pinning.
In the recovery room, the fracture is well-reduced, the hand remains pink and warm with a capillary refill of less than 2 seconds, and oxygen saturation on the index finger is 99%; however, the radial pulse remains nonpalpable. What is the most appropriate next step in management?
Correct Answer & Explanation
. Observation and hospital admission for neurovascular monitoring
Explanation
The 'pulseless, pink, perfused' hand after adequate closed reduction and percutaneous pinning of a supracondylar humerus fracture is a well-recognized clinical entity. Because the hand is well perfused (capillary refill <2 seconds, good warmth, and normal pulse oximetry), collateral circulation is adequate. The standard of care is admission for 24 to 48 hours for close neurovascular monitoring. Operative exploration of the brachial artery is only indicated if the hand becomes dysvascular (pulseless, pale, cold) after reduction, or if there is impending compartment syndrome.
Question 380
Topic: Pediatric Upper Extremity & Spine
A 12-year-old girl presents for evaluation of a spinal deformity. Standing posteroanterior radiographs demonstrate a right thoracic adolescent idiopathic scoliosis (AIS) with a Cobb angle of 22 degrees.
Which of the following parameters indicates that the patient is currently in the period of maximum risk for rapid curve progression?
Correct Answer & Explanation
. Peak height velocity
Explanation
The risk of progression in adolescent idiopathic scoliosis (AIS) is most strongly correlated with the patient's remaining growth potential. The period of maximum growth—and thus maximum curve progression risk—is during peak height velocity (PHV). PHV typically occurs before menarche, before the closure of the triradiate cartilage, and at Risser stage 0 (typically Sanders stage 3). Risser stage 4, post-menarche status, and Sanders stage 7 all indicate advanced skeletal maturity and a significantly lower risk of curve progression.
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