blounts disease by dr. mayur jejurikar

1. WELCOME TO SHORT
NOTE DISCUSSION
Presented by:
Dr. Mayur .R. Jejurikar
Resident, Phase – B,
Dept. of Orthopaedic Surgery,
BSMMU.

2. TOPIC OF DISCUSSION:
o Tibia vara
o Osteochondrosis deformans tibiae
o Erlacher’s disease
BLOUNT’S DISEASE
Synonyms:

3. HISTORICAL BACKGROUND:
o Erlacher is credited with the first description of tibia vara & internal tibial torsion in
1922.
o But, it was Walter Blount’s article in 1937, that prompted recognition of this disorder.
o Later in 1952, Langenskiold described radiographic changes & stages of the disease
in the Scandinavian population.

4. INTRODUCTION:
o Tibia vara/ Blount’s disease is a
developmental condition.
o It is characterised by a disturbance of
enchondral ossification at the upper end of
tibia, affecting the medial portion of the
growth plate, mainly in its posteromedial
aspect & the medial portion of the
epiphyseal ossification center.
o As a result, an abrupt varus angulation
develops at the proximal portion of the
metaphysis while the diaphysis remains
straight.

5. INTRODUCTION:
o Secondary effects include internal torsion
of the tibia, insufficient ossification of the
medial portion of the medial tibial condyle
& stretched lateral collateral ligament.
o Blount described tibia vara as “an
osteochondrosis similar to coxa plana &
Madelung deformity but located at the
medial side of the proximal tibial
epiphysis”.

6. RELEVANT ANATOMY:

7. CONTD:

8. CONTD:

9. CONTD:

10. CONTD:

11. ETIOLOGY:
o The exact cause is unknown & the condition is idiopathic.
o Enchondral ossification seems to be altered.
o Suggested causative factors include infection, trauma, osteonecrosis & a latent form
of rickets, although none of these have been proved.
o A combination of hereditary & developmental factors is most likely cause.
o Weight bearing must be necessary for its development bcoz it doesn’t occur in non-
ambulatory patients.
o Relationship of early walking & obesity with Blount's disease has been clearly
documented.
o Neither sex seems predisposed.
o Children of negroid descent, particularly in the West Indies & in West Africa, appear
to be affected more frequently than the others.

12. PATHOLOGY:
o The cartilage over the medial side of the epiphyseal growth plate, particularly in the
area of the ‘beak’, is grossly disorganized.
o As a result of disordered endochondral ossification, the medial portion of the
ossification zone of the metaphysis forms a step-like unossified defect within which
there are intermingled islands of bone and abnormal cartilage.
o The osteocartilagenous tissue extends medially from the metaphysis as an
outgrowth about a bony beak.
o The intra-articular pathology consists of:
 enlargement & hypermobility of the medial meniscus,
 depression of the anterior aspect of the medial femoral condyle &
depression of the posteromedial plateau of the tibia.

13. TYPES OF TIBIA VARA:
o According to the age, Blount described two types of tibia vara:
Infantile : begins before 8 years of age
Adolescent : begins after 8 years of age but before skeletal maturity.
Further subdivided into:
1) occurring between 8 & 13 years caused by partial closure of
the physis after trauma or infection.
2) occurring between 8 & 13 years in black & obese children
without a distinct cause.

14. CLINICAL PRESENTATION:
INFANTILE TYPE
o It is bilateral & symmetrical in approximately 60% of
affected children .
o The bowleg deformity becomes apparent when the infant
starts to stand & walk.
o It is impossible to differentiate it from the physiological
bowing before 2 years of age.
o Later as the age increases the deformity worsens which is
not the case with physiological bowing.
o The components of the deformity include a sharp medial
angulation of the tibia at the metaphysis, more evident in
the weight-bearing position.

15. CONTD:
o Internal tibial torsion & pes planovalgus develop
secondarily.
o In compensation there is hypertrophy of the medial
femoral condyle.
o A bony, hard, non-tender prominence is palpable on the
medial epiphysiometaphyseal junction.
o SIFFERT KATZ sign: As the extended knee is slightly
flexed, the medial femoral condyle loosely engages the
depression in the medial tibial plateau & posteromedial
rocking is demonstrable.
o The deformity worsens progressively & an increasingly
sharp, usually bilateral, bowleg angulation & waddling
gait become pronounced.

16. CONTD:
o In long standing cases, there is slight flexion deformity &
the collateral ligaments become lax & joint becomes
unstable.
o Limb length discrepancy is usually not seen as it is
bilateral.

17. CONTD:
ADOLESCENT TYPE
o Not as common as infantile type.
o Develops between 8-13 years of age.
o The deformity is unilateral, is generally mild to moderate,
rarely exceeds 20 degrees.
o It is never associated with a medial osteocartilagenous
prominence.
o Secondary internal tibial torsion & pes planovalgus do
not develop.
o The leg shortening may be appreciable.
o The patient is usually obese.

18. RADIOGRAPHY:
o X-ray is the most commonly done investigation for
the diagnosis.
o Characteristically the medial half of the epiphysis
appears short, thin & wedged.
o Physis is irregular in contour & slopes medially.
o The medial portion of the metaphysis displays a
beak-like projection extending medially &
surrounded by multiple radiolucent areas (cartilage).

19. CONTD:
• This projection present medially is often
palpable, but this projection is not diagnostic of
tibia vara.
• Medial metaphyseal fragmentation is
pathognomic for the development of a
progressive tibia vara.
• The angular deformity occurs just distal to this
projection.

20. CONTD:

21. CONTD:
• Langenskiold noted progression of
epiphyseal changes & the
deformity through six stages with
growth & development.
• At stage VI, the medial portion of
the epiphysis fuses at a 90 degree
downward angle.

22. CONTD:
o Various angles of the femur &
tibia at the knee can be
determined on the
radiographs, when the
deformity is present.

23. CONTD:
o Normally, tibiofemoral angle
progresses from pronounced varus
before the age of 1 year to valgus
between ages 1.5 & 3 years.
o Several authors have suggested that
deviation from normal tibiofemoral
angle development indicates Blount
disease, & the metaphyseal-diaphyseal
angle is an early indicator of Blount's
disease.
o This measurement is not an absolute
prognosticator of Blount’s disease, but
a metaphyseal-diaphyseal angle of >
11 degrees warrants close observation.

24. CONTD:
o Most authors agree that
mechanical axis of the limb, as it
relates to the tibiofemoral angle
on the radiographs, should be the
most functional measurement of
the amount of deformity present.
o The intra-articular pathology is
defined by double-contrast
arthrography & by arthroscopy.
o These will delineate the defects of
the articular surfaces as well as
the state of the medial meniscus.

25. HISTOLOGICAL FINDINGS:
o In the infantile type, bone changes include delayed ossification of the
medial epiphysis & metaphysis of the proximal tibia.
o These changes include cell hypertrophy & dense cellularity, fibrocartilage
islands & abnormally large group of capillaries.

26. DIFFERENTIAL DIAGNOSIS:
o Congenital bowing of the tibia.
o Vitamin-D resistant rickets.
o Deformity of the medial tibial condyle due to gonadal dysgenesis.

27. TREATMENT:
o Depends upon the age of the child &
severity of the varus deformity.
 Non-operative treatment:
o Generally, observation or a trial of
bracing is indicated for children between
ages 2-5 years.
o Ambulatory bracing with an above-the-
knee orthosis is effective.
o If the disease continues to progress with
brace treatment, it will no longer be
effective.

28. CONTD:
 Operative treatment:
o Progressive deformity usually requires osteotomy.
o Recurrence of the deformity is not as frequent after osteotomy at an early age as after
osteotomy when the child is older, with recurrence rates of about 80% reported in
older children compared with less than 20% in younger children.
o One cause of recurrence after osteotomy is a physeal bar.
o Greene listed the following criteria for determining tomographically whether bony bar
is present or not preoperatively:
1) Age > 5 years.
2) Medial physeal slope of 50-70 degrees.
3) Langenskiold grade IV radiographic changes.
4) Body wt. > 95th percentile.
5) Black girls who meet the previous criteria.

29. OPERATIVE GUIDELINES:
o In children above the age of 9 years with more severe involvement, osteotomy
alone, with bony bar resection, or with epiphysiodesis of the lateral tibial & fibular
physes may be indicated.
o Medial physeal bar resection alone has been reported to be effective when
premature closure of the physes is evident, but significant angular deformity would
not be corrected by bar resection alone.
o Lateral tibial epiphysiodesis can be done, with/without osteotomy, after the age of 9
years but before skeletal maturity.
o In unilateral involvement, epiphysiodesis of the uninvolved leg may be indicated to
correct leg-length discrepancy.
o For older patients in whom bracing & tibial osteotomy have failed, & when the risk
of abnormal spontaneous medial epiphysiodesis is high, intraepiphyseal osteotomy
& valgus metaphyseal osteotomy to correct severe joint instability & varus
angulation respectively may be indicated.
o The Ilizarov technique is effective for correction of deformity & lengthening if
needed in an adolescent patients.

30. OSTEOTOMIES:
o Metaphyseal / oblique osteotomy by Rab technique:

31. CONTD:
o Opening-closing Chevron osteotomy by Greene technique.
Modification of dome osteotomy.

32. CONTD:
o Epiphyseal & Metaphyseal osteotomy by Ingram, Canale & Beaty
technique.

33. CONTD:
o Intraepiphyseal osteotomy by Siffert, Storen & Johnson technique

34. CONTD:
o Hemielevation of the epiphysis osteotomy with leg lengthening using an Ilizarov
frame by Jones & Hefney technique

35. CONTD:
o Hemicondylar tibial osteotomy by Zayer technique

36. CONTD:
o External fixation, including the Taylor spatial frame, may be indicated to achieve
stability after osteotomy & immediate correction & seems to be an excellent
method of treating an extremely obese pt. for whom unilateral or bilateral casting
is impractical.

37. COMPLICATIONS OF HIGH TIBIAL OSTEOTOMY:
o Neurovascular complications after an osteotomy result most commonly
from vascular occlusion or common peroneal nerve palsy.
o Stretching of the anterior tibial artery occurs at the interosseous
membrane with varus correction (as for genu valgum), & compression of
the artery occurs with valgus correction (as for genu varum).
o Decrease in dorsiflexion & severe pain on plantar flexion of the toes are
the most common clinical signs of occlusion of the artery or of an anterior
compartment syndrome.
o Matsen & Staheli outlined the appropriate management for each of them.

38. FOLLOW-UP:
o Follow-up & post-operative weight bearing is specific to the procedure
performed.
o In general, osteotomies heal in approximately 6-8 weeks.
o In general, external fixation remains in place for 12 weeks postoperatively.
o Continuing follow-up care after initial surgical correction is necessary because
of the risk of recurrence.

39. OUTCOME & PROGNOSIS:
o The prognosis in the infantile form of Blount disease must be considered
separately from that in the adolescent form.
o Infantile tibia vara has a good prognosis, and recurrence rates of
deformity are low when treated at a young age and early stage.
o In the late-onset form of the disease, regression does not occur and the
varus deformity may worsen over time.