Blounts; Paeds

1. Blount’s Disease
Sarbdev Singh

2. Introduction
• Symmetrical genu varum before the age of 2 years is rarely
pathological

3. When is Genu Varum Pathological?
• Most likely if:
• Present after 2 years of age
• Progressive deformity beyond age of 2
• Unilateral
• Short stature
• Severe
• In a child with obesity
• Early walker (before age of 1)
• Mild deformities after the age of 2 years may resolve spontaneously
and probably represent extreme variants of physiological bowing

4. What causes
Genu Varum?
• Injury of proximal tibial physis (infection,
radiation, or trauma)
• Metabolic Diseases – Rickets, OI
• Blount’s disease – infantile and adolescent
• Generalized or focal osteochondrodysplasia, eg
hereditary multiple exostoses, achondroplasia,
focal fibrocartilaginous dysplasia
• Tibia hemimelia
• MED, SED

5. • Family history of bow legs should raise suspicions of
• Hypophosphatemic rickets
• Hereditary multiple exostoses
• Bone/cartilage dysplasia

6. Tibia vara / Blount’s Disease
• A progressive pathologic varus deformity of the proximal tibia
• Disease is centered at the medial aspect of proximal tibial physis
• Aetiology – unknown
• Thought to be an overload phenomenon on proximal medial tibial physis –
supraphysiological compressive forces from severe obesity
• Tends to produce VARUS + FLEXION + INTERNAL ROTATION deformity
(3-D)
1. Infantile tibia vara (Blount disease) : < 3 years, common
2. Adolescent tibia vara : >10 years old

9. • Clinical features
• obese
• Lateral thrust gait
• Deformity
• Genu varum - acute proximal
• Internal tibial torsion
• Procurvatum (flexion deformity)
• Unilateral or bilateral
• LLD (mostly unilateral)
• Cover up test (infantile)
• Patient supine & lower extremities fully extended with the
patella up.
• Physiologic bowing is indicated by a valgus proximal tibia,
while a Blount's patient will have a neutral or varus proximal
tibia.
*A toddler may appear bow-legged if both knees and hips are flexed
when walking; a gentle repositioning of the hips and knees with patella
facing up will correct it (NEVER COMMENT ON ANGLE IF FFD PRESENT)

10. When are radiographs
required?
• Most children referred DO NOT require
• Unilateral bowing
• Features not associated with physiological
bowing (as mentioned before)
• Varus progresses
*Radiographic features are only present in
Blount’s after age 18months (*Staheli)

11. • Imaging
• Long limb standing view
• Tibia AP and lateral views
*Patella facing forward
• Findings
• Sharp varus angulation in metaphysis
• Widening and irregular physeal line medially
• Medially slopped & irregular ossified epiphysis
• Prominent beaking of medial epiphysis with lucent cartilage island within
beak
• Lateral subluxation of proximal end tibia

12. *problem – lack of reproducibility and that it was not intended for use in determining the prognosis
or type of treatment, as pointed out by the author. (*Staheli)

13. II
III IV V VI

15. • Drennan metaphyseal-diaphyseal angle (MDA)
• Angle between
• Line connecting metaphyseal beak and
• Line perpendicular to the longitudinal axis of the
tibia
• Meeting at most prominent lateral point
• >16’ abnormal, 95% chance progression
• >10 : Diagnosis of Blount’s in Probable (Staheli)
• <10’ : 95% chance of resolution
• Tibiofemoral angle
• Mechanical axis

16. What indicates progression is likely?
• Severity of the deformity at presentation
• Obesity – BMI >22
*BMI > 22 + MDA > 10 --- Strongly suggestive of progression
OR
MDA > 16
*Selvadurai Nayagam

17. What problems need to be managed?
• Tibial Deformity
• Varus + Internal Tibial Torsion + Flexion
• Joint Deformity
• Medial tibial hemiplateau depression
• Mostly in late stage
• Results in recurrence & early degenerative
joint disease (DJD)
• Physeal Bar
• LLD
• Mainly in unilateral with significant physeal
growth retardation
• Limb lengthening not a great option with
underlying joint instability & deformity
• Close f/up for ideal chance for an
epiphysiodesis of opposite extremity.
• Recurrence
• Obesity, Ligament laxity, Langenskiold stage IV
above, presence of bone bar and
undercorrection (Staheli)
• Hence why DIAGNOSE EARLY & INTERVENE!!
• Neurovascular complications
• High risk of compartment syndrome & peroneal
nerve palsy
• Anterior compartment release recommended
during index procedure
*Randall Loder

18. Our Aim of treatment?
1. Restore normal tibial alignment
2. Restore normal mechanical axis
3. Correct joint deformity
• If articular surface is defective – need to correct
4. Equalize limb length
• Differing knee levels predisposes to early DJD
5. Maintain correction, prevent recurrence
• Best chance of avoiding recurrence – early correction of deformity!
6. Prevent neurovascular complications
*Randall Loder

19. Treatment Options (Non-operative)
• Mainstay treatment for infantile blount’s of
L’skiold stage I & II
• Above knee non articulated KAFO – custom
moulded to provide 3 point fixation
• Takes ~ 12-18months of use to resolve with
success rates of 90% (when presenting
deformity is mild to moderate)
• If fail by age of 4 OR progresses to L’skiold
stage III --- immediate tibial osteotomy is
indicated (Randall Loder)
*Selvadurai
• No data to confirm effectiveness
• Only for younger than 3 & Stage I or II
• Multiple problems associated :
• Use during daytime can be difficult &
uncomfortable leading to poor compliance
• Moulding is difficult & corrective force
over knee may not be tolerated
• Locks knee in extension – unphysiological
& uncomfortable & stretches ligaments
• May affect sleep patterns causing irritable
child/behavior changes
*Staheli

21. Proximal Tibial Osteotomy
• Most widely used surgery
• Infantile Blount’s – MUST be below tibial tuberosity
1. Acute corrective
• With internal fixator
• Kwiring in younger
• Plating in older
• With external fixator –preferred for ability to fine tune deformity
post op.
• Often with prophylactic anterior compartment fasciotomy
2. Gradual corrective
• With external fixator
• Less risk of compartment syndrome

23. Physeal elevating osteotomy
• Significant depression of medial tibial epiphysis - Langenskiöld V / VI
• Sparing physis
• When child approaching
skeletal maturity
• Evidence of premature
physeal arrest

24. *Medial Plateau Elevation
• Tilted ‘pitched roof’ appearance of the tibial Joint line --- misleading
• Could be an unossified cartilage appearing as incomplete medial tibial
condyle
• MRI or arthrogram will show true joint level
*comparison of xray of knee taken in supine & weight bearing!
• In true underdeveloped medial tibial condyle --- clinically significant
laxity to valgus stressing can be exhibited
*Selvadurai

25. Physeal Bar Resection
• Young patients who has developed physeal bar – resection can be
considered along with repeat osteotomy
• Results are often disappointing
• In patients with at least 4 years of growth remaining (Orthobullets)
• Interpositional material - fat

26. Growth modulating
• Proximal lateral tibia
hemiepiphyseodesis
• ≥ 2 years of growth remaining
• 2 types
I. Temporary
• Extraperiosteal 8 plate or staples
• Slight overcorrection to valgus to
account for rebound growth upon
removal
II. Permanent
• Timing is crucial

29. Complications
• Proximal tibial recurvatum
• injury to proximal tibial physis at level of tibial tubercle  hyperextension instability of knee
• Anterior tibial artery injury
• Proximal tibial osteotomy must be performed distal to tibial tubercle, near the level of trifurcation of popliteal
artery
• 29% injured in osteotomy procedure
• Compartment syndrome
• Prophylactic fasciotomy of all compartment should be performed during all osteotomy procedures
• Postop neurovascular surveillance for 1st 48H
• Peroneal nerve palsy
• Infections
• Iatrogenic fractures
• Loss of correction
• Recurrence
• Progression

30. Thank you