Pediatrics

Question 1

Recommendations for tx of pediatric femoral shaft fractures

Answer 1

• children aged < 36 months should be evaluated for child abuse (grade A)
• tx w/ Pavlik harness or a spica cast is an option for infants ages < 6 months (grade C)
• early spica casting or traction w/ delayed spica casting for children aged 6 months to 5 yrs w/ < 2cm shortening (grade B)
• when spica cast is used in children aged 6 months to 5 yrs, altering the tx plan is an option when fx shortens > 2 cm (grade C)
• its an option to use flexible IM nailing to treat children aged 5-11 yrs (grade C)
• rigid trochanteric entry nailing, submuscular plating, and flexible IM nails are tx options for children 11yrs to skeletal maturity, but piriformis or near piriformis entry rigid nailing is NOT a tx option! (grade C)
• regional pain management is an option for pt comfort perioperatively (grade C)
• waterproof cast liners for spica casts are an option (grade C)

Question 2

Developmental dysplasia of the hip (DDH)

Answer 2

• spectrum of disorders of development of the hip that present in different forms at different ages
• common etiology is excessive laxity of the hip capsule w/ a failure to maintain the femoral head within the acetabulum
• the syndrome may manifest later during childhood or adolescence as a dislocated hip or during adolescence as a hip w/ poorly developed acetabular coverage (dysplasia of the hip)
• DDH evolves over time; chief reasons being fetal position and presentation at birth and laxity of the ligamentous structures around the hip joint
• DDH is used to denote both dislocation and dysplasia of the hip (dysplasia is the deficient development of the acetabulum)

Question 3

Predisposing factors for developmental dysplasia of the hip (DDH)

Answer 3

• ligamentous laxity (often inherited)
• breech position (especially footling)
• postnatal positioning (hips swaddled in extension)
• primary acetabular dysplasia (unlikely)
• always get a family hx!

Question 4

DDH most common’s

Answer 4

• females > males
• First born
• L hip > R hip (due to intrauterine position most frequently w/ L hip adducted against mother’s sacrum)
• whites/native Americans > blacks/asians

Question 5

Conditions associated w/ DDH

Answer 5

• Torticollis**
• Metatarsus adductus
• Oligohydramnios
• first-born white infants
• first-term hyperthyroidism

Question 6

Infantile Blount’s disease

Answer 6

• progressive pathologic genu varum (tibia vara) centered at the tibia
• children 2-5 yrs of age
• male > female
• bilateral in 50%
• likely multifactorial but related to mechanical overload in genetically susceptible individuals

Question 7

Differential diagnosis of genu varum

Answer 7

• Infantile blount’s disease
• persistent physiological varus
• rickets
• osteogenesis imperfecta
• MED, SED
• metaphyseal dysostosis (Schmidt, Jansen)
• focal fibrocartilaginous defect
• thrombocytopenia absent radius
• proximal tibia physeal injury (radiation, infection, trauma)

Question 8

physiologic genu varum

Answer 8

• genu varum (bowed legs) is normal in children less than 2 yrs
• genu varum migrates to a neutral at ~14 months
• continues on to a peak genu varum (knocked knees) at ~3 yrs of age
• genu valgum then migrates back to normal physiologic valgus at ~7 yrs of age

Question 9

classification of infantile blounts disease

Answer 9

• Langenskiold classification
• Type 1-6
• Type 1-4 consists of increasing medial metaphyseal beaking and sloping
• Type 5-6 have an epiphyseal-metaphyseal bony bridge (congenital bar across physis)
• stage 2 and 4 can exhibit spontaneous resolution

Question 10

LE deformity in infantile blounts disease

Answer 10

genu varum/flexion/IR deformity

Question 11

important measurement in Infantile Blounts disease

Answer 11

Metaphyseal-diaphyseal angle (Drennan)

• angle between line connecting metaphyseal beaks and a line perpendicular to the longitudinal axis of the tibia
• > 16% is considered abnormal and has a 95% change of progression
• <10% has a 95% chance of natural resolution of the bowing

Question 12

Treatment of Infantile Blounts disease

Answer 12

Non-op: brace tx w/ KAFO

• for stage I and II in children < 3 yrs
• bracing must continue for approx 2 yrs for resolution of bony changes
• if successful, improvement should occur within 1 yr

Operative: proximal tib/fib valgus osteotomy

• overcome the varus/flexion/IR deformity
• for stage I and II in children > 3 yrs
• stage III, IV, V, VI
• age > 4yrs (all stages)
• failure of brace tx (progressive deformity)
• metaphyseal-diaphyseal angles > 20 deg
• goals of correction include overcorrecting into 10-15 deg of valgus, and distal segment fixed in valgus, ER and lateral translation

Other operative tx options: growth modulation, physeal bar resection, hemiplateau elevation

Question 13

what is the age cutoff that determines tx in infantile blounts disease?

Answer 13

3

• before age 3 in stages I and II, treat w/ KAFO
• after age 3 treat w/ proximal tibia osteotomy
• evidence suggests that performing an osteotomy by age 4 decreases the risk of recurrence, and thus a deformity that has persisted beyond 3 yrs of age should undergo osteotomy before the age of 4 yrs

Question 14

when is a proximal tibial osteotomy indicated for tx of infantile blounts disease?

Answer 14

-children who have a progressive deformity, Langenskold III or greater, or older than age 3 yrs

Question 15

What measurement is used to distinguish Infantile Blounts disease from physiologic bowing?

Answer 15

metaphyseal-diaphyseal angle (Drennan angle)

Question 16

Note that evidence is mixed regarding the effectiveness of KAFO tx in children w/ infantile Blounts disease

Answer 16

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Question 17

Birch et al provides an update on current treatment of Blount’s disease. He suggests further radiographic evaluation in ambulatory infants with asymmetric varus deformity or varus deformity that persists after age 18 months. If these findings are present, radiographs are recommended. If the X-rays reveal metaphyseal-diaphyseal angle >16° on AP radiographs and confirm the diagnosis of infantile Blount disease, he recommends anti-varus long leg bracing during ambulation for patients aged <=3 years with progressive deformity, clear radiographic evidence of infantile Blount disease, or lateral thrust with ambulation.

Answer 17

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Question 18

Blount’s disease is a posteromedial proximal tibial physeal growth disturbance leading to varus, flexion, and internal rotation deformity of the tibia. When indicated, surgical goals include overcorrection of varus, flexion, and internal rotation deformities. MDA <9 are consistent with physiologic varus. MDA between 10-16 degrees is considered at risk for Blounts development and should be closely monitored. MDA >16 degrees indicate true infantile Blount’s with high likelihood of progression. Children who reach age 3 without correction of their varus should be considered for surgical intervention, as recurrence is high for children who are not corrected by the age of 4.

Answer 18

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Question 19

“Cover up test” for differentiating between physiologic and pathologic genu varum

Answer 19

The test is performed with the patient supine and lower extremities fully extended with the patellas pointing straight up. One hand is holding the ankle and the other is placed perpendicular to the long axis of the tibia to ‘cover-up’ the middle. Physiologic bowing is indicated by a valgus proximal tibia, while a Blount’s patient will have a neutral or varus proximal tibia.

Question 20

Hueter-Vokmann principle

Answer 20

increasing compression across a growth plate leads to decreasing growth and increasing tension stimulates growth

Question 21

rules of osteotomy as outlined by Paley

Answer 21

Rule 1: The axis of correction of angulation (ACA) can pass through the CORA (ACA-CORA). If the osteotomy passes through the ACA-CORA, correction produces pure angulation at the osteotomy site (no translation). Rule 2: If ACA passes through the CORA (ACA-CORA), but the osteotomy does NOT pass through the ACA-CORA, there will be angulation and translation of the bone ends at the osteotomy site. But the axis lines are collinear (no translation of axis). Rule 3: If the osteotomy passes through the ACA, but the CORA is at a different level, there will be angulation but no translation of bone ends. The axis lines will be parallel, but translated.

Question 22

When choosing rigid, locked, intramedullary nailing for treatment of pediatric femoral shaft fractures, the ideal starting point is where?

Answer 22

Lateral trochanteric starting point
-The lateral trochanter as an insertion site for rigid, locked intramedullary nailing has the lowest risk of AVN when treating pediatric femur fractures based on the current literature.