This document discusses Blount's disease, which is a progressive varus deformity of the proximal tibia. It can present as infantile or adolescent tibia vara. Risk factors include obesity, early walking, and family history. Radiographs may show widening of the physis, beaking of the epiphysis, and varus angulation. Non-operative treatment with a knee-ankle-foot orthosis can be effective for mild cases under age 3. For more severe cases, proximal tibial osteotomy is the main surgical treatment to correct alignment and deformity. Complications can include loss of correction, recurrence, and neurovascular injury if not performed carefully. The goal of treatment is to restore alignment and

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