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Pediatric Upper Extremity & Spine MCQs

Practice Set 7 of 33

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 121

Topic: Pediatric Upper Extremity & Spine

A 13-year-old premenarchal female with adolescent idiopathic scoliosis (AIS) is evaluated. She has a right thoracic curve of 32 degrees. Risser stage is 1.

What is the most appropriate next step in management?

. Observation with serial radiographs every 6 months
. Thoracolumbosacral orthosis (TLSO) bracing for 18 hours daily
. Posterior spinal fusion
. Anterior tethering procedure
. Nighttime-only bending brace

Correct Answer & Explanation

. Thoracolumbosacral orthosis (TLSO) bracing for 18 hours daily

Explanation

In a growing child (premenarchal, Risser 0-2) with an AIS curve between 25 and 44 degrees, full-time bracing (TLSO) is indicated. The BrAIST trial demonstrated that wearing a brace for at least 18 hours a day significantly decreases the risk of curve progression to surgical magnitude.

Question 122

Topic: Pediatric Upper Extremity & Spine
A 14-year-old female with adolescent idiopathic scoliosis (AIS) has a 32-degree main thoracic curve. She is premenarchal with a Risser stage of 0. Which of the following is the most appropriate evidence-based management?
. Observation with full-spine radiographs in 6 months
. Physical therapy emphasizing core strengthening and Schroth methods
. Thoracolumbosacral orthosis (TLSO) wear for 18 hours daily
. Nighttime-only Providence bracing
. Posterior spinal fusion

Correct Answer & Explanation

. Thoracolumbosacral orthosis (TLSO) wear for 18 hours daily

Explanation

The BRAIST trial demonstrated that bracing for at least 18 hours per day significantly decreases the progression of curves in skeletally immature patients (Risser 0-2) with a Cobb angle of 25 to 40 degrees.

Question 123

Topic: Pediatric Upper Extremity & Spine

A 13-year-old premenarchal female with Adolescent Idiopathic Scoliosis (AIS) presents with a 32-degree right thoracic curve. Her Risser stage is 0. What is the most appropriate next step in management?

. Observation with radiographs in 6 months
. Thoracolumbosacral orthosis (TLSO) bracing
. Posterior spinal fusion
. Anterior vertebral body tethering
. Physical therapy focusing on core strengthening

Correct Answer & Explanation

. Thoracolumbosacral orthosis (TLSO) bracing

Explanation

TLSO bracing is indicated for growing children (Risser 0-2, premenarchal) with curves between 25 and 45 degrees to prevent curve progression.

Question 124

Topic: Pediatric Upper Extremity & Spine

A 15-year-old female with AIS has a main thoracic curve of 50 degrees, a proximal thoracic curve of 20 degrees (which corrects to 10 degrees on side-bending), and a lumbar curve of 35 degrees (which corrects to 15 degrees on side-bending). According to the Lenke classification, what is her curve type?

. Lenke Type 1
. Lenke Type 2
. Lenke Type 3
. Lenke Type 4
. Lenke Type 5

Correct Answer & Explanation

. Lenke Type 1

Explanation

Lenke Type 1 curves have a structural main thoracic curve, while the proximal thoracic and lumbar curves are non-structural (bend out to <25 degrees).

Question 125

Topic: Pediatric Upper Extremity & Spine
A 13-year-old premenarchal female with adolescent idiopathic scoliosis (AIS) presents with a right thoracic curve. Radiographs show a Cobb angle of 32 degrees and a Risser stage of 0. Which of the following is the most appropriate management, and what is the optimal duration of daily treatment to prevent curve progression?
. Observation with radiographs every 6 months
. Thoracolumbosacral orthosis (TLSO) bracing for 8-12 hours daily
. Thoracolumbosacral orthosis (TLSO) bracing for at least 18 hours daily
. Posterior spinal fusion with pedicle screw instrumentation
. Physical therapy focusing on core strengthening and Schroth exercises

Correct Answer & Explanation

. Thoracolumbosacral orthosis (TLSO) bracing for at least 18 hours daily

Explanation

For a growing child (Risser 0-2) with an AIS curve between 25 and 45 degrees, bracing is the standard of care. The BRAIST study demonstrated a dose-response relationship, showing that wearing a brace for at least 18 hours a day significantly decreases the risk of curve progression to the surgical threshold.

Question 126

Topic: Pediatric Upper Extremity & Spine

According to the Lenke Classification system for adolescent idiopathic scoliosis, which of the following criteria defines a 'structural' minor curve that must be included in the fusion construct?

. A Cobb angle greater than 40 degrees on standing radiographs
. A Cobb angle that fails to correct to less than 25 degrees on side-bending radiographs
. Apical vertebral rotation of grade II or higher on the Nash-Moe scale
. A curve with an apical vertebra above T4
. A curve associated with a thoracic kyphosis greater than 20 degrees

Correct Answer & Explanation

. A Cobb angle that fails to correct to less than 25 degrees on side-bending radiographs

Explanation

In the Lenke classification, a minor curve is considered structural (and therefore typically requires inclusion in the fusion) if it does not bend out to less than 25 degrees on supine maximum side-bending radiographs, or if there is regional kyphosis > 20 degrees.

Question 127

Topic: Pediatric Upper Extremity & Spine
A 6-year-old boy falls from monkey bars and presents with a Gartland Type III supracondylar humerus fracture. On exam, the hand is pink but the radial pulse is absent. After emergent closed reduction and percutaneous pinning in the operating room, the hand remains pink, capillary refill is brisk, but the radial pulse is still absent on Doppler. What is the most appropriate next step in management?
. Immediate exploration of the brachial artery
. Perform a CT angiogram of the upper extremity
. Remove the pins and open the fracture anteriorly
. Close observation with pulse oximetry and serial exams
. Perform a prophylactic forearm fasciotomy

Correct Answer & Explanation

. Close observation with pulse oximetry and serial exams

Explanation

For a 'pulseless but pink' hand after anatomic reduction and stabilization of a pediatric supracondylar humerus fracture, the standard of care is close clinical observation. The collateral circulation is sufficient for hand viability, and the radial pulse often returns over time.

Question 128

Topic: Pediatric Upper Extremity & Spine

A 6-year-old boy sustains a completely displaced extension-type supracondylar humerus fracture. On presentation, the radial pulse is absent, but the hand is warm and pink with brisk capillary refill. What is the most appropriate initial management?

. Immediate open vascular exploration
. Urgent closed reduction and percutaneous pinning
. CT angiography of the upper extremity
. Observation and casting in 90 degrees of flexion
. Fasciotomy of the forearm

Correct Answer & Explanation

. Urgent closed reduction and percutaneous pinning

Explanation

For a pulseless but well-perfused ('pink') hand associated with a completely displaced supracondylar humerus fracture, the standard of care is urgent closed reduction and percutaneous pinning. Vascular exploration is reserved for limbs that remain under-perfused (pale/white) after reduction.

Question 129

Topic: Pediatric Upper Extremity & Spine
A 1-year-old boy with a Blauth Type IV thumb hypoplasia is being evaluated for pollicization. He is noted to have short stature and café-au-lait spots. Which of the following laboratory tests is mandatory before proceeding with elective surgery?
. Sweat chloride test
. Hemoglobin electrophoresis
. Diepoxybutane (DEB) chromosomal breakage test
. Flow cytometry for CD18
. Serum ceruloplasmin

Correct Answer & Explanation

. Diepoxybutane (DEB) chromosomal breakage test

Explanation

The patient's presentation suggests Fanconi anemia, an autosomal recessive disorder associated with radial longitudinal deficiency and aplastic anemia. The diagnosis is confirmed by demonstrating increased chromosomal breakage in the presence of clastogenic agents like diepoxybutane (DEB).

Question 130

Topic: Pediatric Upper Extremity & Spine

A neonate is evaluated in the nursery for bilateral upper extremity anomalies. Examination reveals bilateral absent radii, but the thumbs are present and appear normal. What systemic hematologic abnormality is classically associated with this specific presentation?

. Macrocytic anemia
. Thrombocytopenia
. Pancytopenia with hypocellular marrow
. Leukopenia
. Polycythemia

Correct Answer & Explanation

. Thrombocytopenia

Explanation

Thrombocytopenia Absent Radius (TAR) syndrome is uniquely characterized by the absence of the radius with the preservation of the thumb. This distinguishes it from Fanconi anemia or Holt-Oram syndrome, where the thumb is typically hypoplastic or absent.

Question 131

Topic: Pediatric Upper Extremity & Spine

A 6-year-old boy presents with a completely displaced, extension-type Gartland III supracondylar humerus fracture. Which of the following neurologic deficits is most commonly associated with this specific injury pattern?

. Anterior interosseous nerve palsy
. Radial nerve palsy
. Ulnar nerve palsy
. Posterior interosseous nerve palsy
. Axillary nerve palsy

Correct Answer & Explanation

. Anterior interosseous nerve palsy

Explanation

The anterior interosseous nerve (AIN) is the most commonly injured nerve in extension-type supracondylar humerus fractures. It is typically assessed by asking the patient to make an "OK" sign to test the flexor pollicis longus and flexor digitorum profundus to the index finger.

Question 132

Topic: Pediatric Upper Extremity & Spine

A 14-year-old female with adolescent idiopathic scoliosis (AIS) is evaluated. She is pre-menarcheal and Risser 0. Standing radiographs reveal a right thoracic curve measuring 35 degrees. What is the most appropriate management plan?

. Observation with radiographs every 6 months
. Thoracolumbosacral orthosis (TLSO) bracing for 16-23 hours daily
. Nighttime bending brace only
. Posterior spinal fusion with pedicle screws
. Anterior tethering procedure

Correct Answer & Explanation

. Thoracolumbosacral orthosis (TLSO) bracing for 16-23 hours daily

Explanation

In a skeletally immature patient (Risser 0-2, pre-menarcheal) with an AIS curve between 25 and 45 degrees, bracing is indicated to halt progression. A dose-response relationship exists, with >18 hours of daily wear showing the greatest benefit.

Question 133

Topic: Pediatric Upper Extremity & Spine
A 6-year-old boy undergoes closed reduction and percutaneous pinning of a Gartland type III extension-type supracondylar humerus fracture. Post-operatively, he is unable to flex the interphalangeal joint of the thumb and the distal interphalangeal joint of the index finger. Which iatrogenic or traumatic nerve injury has likely occurred?
. Ulnar nerve injury from medial pin placement
. Radial nerve injury from lateral pin placement
. Anterior interosseous nerve injury during displacement or reduction
. Posterior interosseous nerve injury from lateral pin placement
. Median nerve injury from cubitus varus

Correct Answer & Explanation

. Anterior interosseous nerve injury during displacement or reduction

Explanation

The anterior interosseous nerve (AIN) is the most commonly injured nerve in extension-type pediatric supracondylar humerus fractures. It innervates the flexor pollicis longus and the flexor digitorum profundus to the index finger, resulting in the inability to form an 'OK' sign.

Question 134

Topic: Pediatric Upper Extremity & Spine

A 6-year-old boy undergoes closed reduction and percutaneous pinning for a completely displaced supracondylar humerus fracture. Post-operatively, the hand is pink and well-perfused with a brisk capillary refill, but the radial pulse remains unpalpable. What is the most appropriate next step in management?

. Immediate exploration of the brachial artery.
. Removal of the pins and placement in a long arm cast.
. Observation and hospital admission for 24 hours.
. Performance of a local sympathetic block.
. Immediate CT angiography of the upper extremity.

Correct Answer & Explanation

. Observation and hospital admission for 24 hours.

Explanation

A 'pink, pulseless' hand following reduction of a supracondylar humerus fracture indicates adequate collateral circulation. The standard of care is close observation, as the pulse often returns within 24 to 48 hours without surgical intervention.

Question 135

Topic: Pediatric Upper Extremity & Spine

A 25-year-old patient, who underwent a single-level Milch osteotomy in childhood for septic hip sequelae, now presents with severe lateral knee instability and early-onset medial compartment osteoarthritis of the knee. The orthopedic surgeon attributes these long-term complications primarily to:

. A. Inadequate tensioning of the hip abductor muscles, leading to persistent Trendelenburg gait.
. B. The creation of a severe valgus deformity at the knee due to lateral translation of the distal femur and medial mechanical axis deviation.
. C. Residual hip flexion contracture that was not addressed by the single osteotomy.
. D. The inability of the Milch osteotomy to provide sufficient pelvic support, leading to chronic pelvic obliquity.
. E. Overcorrection of the leg length discrepancy, causing contralateral limb overload.

Correct Answer & Explanation

. B. The creation of a severe valgus deformity at the knee due to lateral translation of the distal femur and medial mechanical axis deviation.

Explanation

Correct Answer: BThe case explicitly details the pitfalls of the Milch osteotomy: 'The severe valgus angulation at the proximal femur translated the entire distal femur laterally. This created a catastrophic valgus deformity at the knee and shifted the mechanical axis far outside the lateral compartment. This single-level approach led to severe patellar instability, rapid lateral compartment arthritis, and an unacceptable cosmetic deformity.' The question describes medial compartment osteoarthritis, which is a direct result of the varus moment induced by the mechanical axis shiftingmedialto the knee, causing medial compartment overload, despite the overall limb appearing valgus. The text states: 'The load-bearing line now falls far medial to the center of the knee, a condition known as Mechanical Axis Deviation (MAD)... This chronic varus force is devastating to the knee joint, leading to... Medial Compartment Overload... Degenerative Arthritis: The combination of ligamentous laxity and asymmetric cartilage overload inevitably precipitates early-onset medial compartment osteoarthritis of the knee.'Option A is incorrectbecause the Milch osteotomy was often successful in eliminating the Trendelenburg limp by providing pelvic support, even if at a cost.Option C is incorrectbecause while flexion contractures can be present, the primary knee complications described are due to the mechanical axis deviation, not directly from an uncorrected flexion contracture.Option D is incorrectbecause the Milch osteotomy's primary goal, and often its success, was in providing pelvic support, even with its other drawbacks.Option E is incorrectbecause the Milch osteotomy does not inherently address LLD, and overcorrection of LLD is not cited as its primary pitfall leading to these specific knee complications.

Question 136

Topic: Pediatric Upper Extremity & Spine

When predicting the timing of epiphysiodesis utilizing the Green-Anderson growth remaining method, which assessment tool is strictly required to ensure accuracy?

. The multiplier method coefficient tables
. Greulich and Pyle atlas of skeletal development
. Mose concentric circles
. Tanner-Whitehouse sexual maturity grading
. Risser staging of the iliac apophysis

Correct Answer & Explanation

. Greulich and Pyle atlas of skeletal development

Explanation

The Green-Anderson method relies heavily on skeletal age (bone age), not chronological age. The Greulich and Pyle atlas of left hand/wrist radiographs is the standard tool used to determine this parameter.

Question 137

Topic: Pediatric Upper Extremity & Spine

A 55-year-old patient undergoes a full-length standing radiograph, similar to , for chronic knee pain. The mechanical axis is found to pass 15 mm lateral to the center of the knee joint. Based on Paley's principles, what does this finding indicate, and what is the most likely associated clinical presentation?

. A. Varus deformity; "bow-legged" appearance.
. B. Valgus deformity; "knock-kneed" appearance.
. C. Neutral alignment; no significant deformity.
. D. Proximal femoral varus; hip pain.
. E. Distal tibial valgus; ankle instability.

Correct Answer & Explanation

. B. Valgus deformity; "knock-kneed" appearance.

Explanation

Correct Answer: BAccording to Paley's principles, the normal mechanical axis passes slightly medial to the exact center of the knee joint, typically 8 to 10 millimeters medial to the tibial spine. A lateral deviation of the mechanical axis from the knee center indicates a valgus deformity, which is clinically known as a "knock-kneed" appearance. A deviation of 15 mm lateral is a significant valgus deformity.Option Ais incorrect because a varus deformity is indicated by a medial deviation of the mechanical axis from the knee center, leading to a "bow-legged" appearance.Option Cis incorrect as neutral alignment would have the mechanical axis passing 8-10mm medial to the tibial spine, not 15mm lateral.Options D and Eare incorrect as the mechanical axis deviation primarily describes overall limb alignment at the knee, not specific deformities at the hip or ankle without further angular analysis.

Question 138

Topic: Pediatric Upper Extremity & Spine

A surgeon is planning a deformity correction using an external fixator. During the planning phase, the surgeon inadvertently places the Axis of Correction of Angulation (ACA) significantly distal to the true Center of Rotation of Angulation (CORA) of the deformity. What is the most likely iatrogenic deformity that will result from this mismatch during gradual correction?

. A. Pure angulation without translation.
. B. Pure translation without angulation.
. C. Angulation with unwanted translation.
. D. Unwanted limb lengthening.
. E. Unwanted limb shortening.

Correct Answer & Explanation

. C. Angulation with unwanted translation.

Explanation

Correct Answer: CThe text explicitly states, "A misunderstanding of the relationship between the bone's geometric pivot point—the Center of Rotation of Angulation (CORA)—and the hardware's mechanical pivot point—the Axis of Correction of Angulation (ACA)—is the root cause of surgical failure. Ignoring these rules inevitably leads to iatrogenic deformities, such as unwanted translation, rotation, or unexpected changes in limb length." When the ACA is not coincident with the CORA, angulation correction will inevitably introduce unwanted translation of the bone segments relative to each other. While limb length changes or rotation can also occur, unwanted translation is the most direct and common consequence of an ACA-CORA mismatch during angulation correction.Option Ais incorrect because a mismatch between ACA and CORA prevents pure angulation; translation will occur.Option Bis incorrect; while translation occurs, it is in conjunction with the intended angulation, not as a pure translation.Options D and Eare possible iatrogenic deformities, but unwanted translation is the most direct and common consequence of an ACA-CORA mismatch specifically for angulation correction, as the bone segments are forced to rotate around a point different from their true deformity apex.

Question 139

Topic: Pediatric Upper Extremity & Spine

A 30-year-old male presents with a complex femoral deformity. A preoperative radiograph, as shown in , is obtained to assess the distal femoral alignment. According to Paley's principles, what is the normal physiologic range for the Mechanical Lateral Distal Femoral Angle (mLDFA), and what does it measure?

. A. 75°-80°; measures proximal femoral alignment.
. B. 80°-85°; measures overall limb alignment.
. C. 85°-90°; measures distal femoral alignment.
. D. 90°-95°; measures distal tibial alignment.
. E. 95°-100°; measures knee joint obliquity.

Correct Answer & Explanation

. C. 85°-90°; measures distal femoral alignment.

Explanation

Correct Answer: CThe provided table in the text clearly states that the Mechanical Lateral Distal Femoral Angle (mLDFA) has a normal physiologic range of 85° to 90° (average 87°) and measures distal femoral alignment. This angle is critical for identifying the source of angular deformities in the distal femur.Option Ais incorrect as the range is too low, and it measures distal, not proximal, femoral alignment.Option Bis incorrect as mLDFA measures a specific segment's alignment, not overall limb alignment (which is primarily assessed by MAD).Option Dis incorrect as mLDFA pertains to the femur, not the tibia.Option Eis incorrect as the range is too high, and while it relates to knee alignment, its primary measure is distal femoral alignment.

Question 140

Topic: Pediatric Upper Extremity & Spine

A 48-year-old patient with severe medial compartment osteoarthritis and a significant varus deformity (Mechanical Axis Deviation 25mm medial to knee center) is scheduled for a high tibial osteotomy. What is the primary objective of this realignment surgery concerning the Mechanical Axis Deviation (MAD)?

. A. To shift the MAD to 20mm lateral to the knee center to offload the medial compartment.
. B. To restore the MAD to a neutral, physiologic position (typically 8-10mm medial to the tibial spine).
. C. To achieve a MAD of 0mm, passing directly through the center of the knee joint.
. D. To increase the overall limb length by at least 10mm.
. E. To correct only the angular deformity without considering translation.

Correct Answer & Explanation

. B. To restore the MAD to a neutral, physiologic position (typically 8-10mm medial to the tibial spine).

Explanation

Correct Answer: BThe text states, "The primary objective of nearly all lower extremity realignment surgery is to restore the MAD to a neutral, physiologic position. This normalizes load distribution across the articular cartilage of the hip, knee, and ankle, directly alleviating pain, improving gait efficiency, and preventing the onset of premature degenerative joint disease." The normal physiologic position is typically 8 to 10 millimeters medial to the tibial spine.Option Ais incorrect. While some surgeons may aim for slight overcorrection in specific cases of medial compartment osteoarthritis, the primary goal described by Paley is restoration to a neutral physiologic position, not an arbitrary significant lateral shift.Option Cis incorrect. A MAD of 0mm (passing directly through the center of the knee) is not considered the normal physiologic alignment; a slight medial deviation is normal.Option Dis incorrect; limb lengthening is a separate goal and not the primary objective of correcting MAD in this context.Option Eis incorrect; MAD correction inherently involves addressing both angular and potentially translational components to achieve proper alignment.

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