Lower Extremity Deformity/Deficiencies Flashcards
For LLD, which hip is less covered in the tab: the short or long leg?
Long leg - pelvis tilts towards the short side leaving the long side less covered
For LLD, which side is a resulting scoliosis more likely to develop on: the short or long leg?
Short leg
What age does growth stop for boys and girls
B: 16yo
G: 14yo
During the last 4 years of growth, what is the contribution of the physes in the femur and tibia (in order)?
Prox fem: 3mm Dist fem: 9mm Prox tib: 6mm Dist tib: 3mm Use these + age left to skeletal maturity to calculate total LLD (remember to convert to cm!)
If a patient has LLD from hemihypertrophy, what other screening test should they have done until 6yo?
Abd US - screen for embryonal cancers (Wilms tumor, etc)
How do congenital LLD progress over time?
Absolute discrepancy increases
Percentage remains constant - short limb will be 70% of the long side at birth and at skeletal maturity
What is the amount of LLD you need to meet surgical threshold?
> 2cm
What is Blount’s disease? What are the 2 types?
Genu varum
Infantile: osteochondrosis of the prox tib physis + adjacent epiphysis -> physeal bar
Adolescent: varus force on knee inhibits medial physeal growth (Hueter Volkmann principle: compression decreases growth at physis)
RF infantile Blounts
Obese
Early walkers
African American
More often bilateral
What metaphyseal diaphyseal angle has a 95% chance of progressive bowing in Blounts?
16%
<10% - likely to self resolve
What is the normal progression of LE alignment as children grow?
Varus normal until 2yo
Max valgus 3-4yo (up to 20deg)
Should be straight by 7yo
Classification system for Blounts. What are the early vs late changes on imaging?
Langenskiold
Early: metaphyseal beaking/sloping
Late: medial physeal closure
What additional procedure should be considered during Blount’s osteotomy to prevent complications
Anterior fasciotomy
When is ideal surgery for infantile Blounts
If done <4yo, lower risk recurrence
Where should you modulate growth for Blounts
Proximal lateral tibia
Name causes of genu valgum
Rickets
Physeal injury
Cozen frx (prox tib metaphyseal)
Benign tumors (fibrous dysplasia, etc)
How much valgus is pathologic in kids >7yo
> 12deg
>10yo and the limb mechanical axis falls in outer quadrant of the plateau
Treat genu valgum
No bracing
Cozen frx self resolves
Skel immature: guided growth
Skel mature: osteotomy
What additional procedure is done during genu valgum osteotomy to prevent complication?
IT band release / peroneal nerve release
Name 3 causes of intoeing + measurements
Babies: metatarsus adductus - heel bisector line
Toddlers: internal tibial torsion - TPA >10deg IR
Older (4+yo): femoral anteversion - IR>70, ER<20
What does femoral anteversion mean?
Neck is anteverted relative to the transcondylar axis
Therefore, you IR femur to compensate and get the TCA to neutral
Most often presents as patellar medial maltracking/pain
What are the physical exam parts for intoeing/rotational profile
Foot progression angle during gait
Thigh foot angle prone
Max hip IR/ER
What is the trochanteric prominence angle test
How much hip IR needed to make GT most prominent laterally
Measure of fem AV
What is threshold to treat fem AV surgically? How would you do this?
> 8yo (basically watch all intoers until this age for spont resolve)
Unacceptable gait/pain
<10deg hip ER
Derotational osteotomy @ subtroch level
