Blounts Disease

By Dr Harsimranjeet Singh Sidhu

Chairperson- Dr Rupa Kumar C.S

History

• Erlacher was the first to describe tibia vara and internal tibial torsion- 1922.

• Blount- 1937- His Article prompted the diagnosis of this disorder

• Langenskiold in 1952 came up with classification for this disorder

Dr Blount Description

• “an osteocondrosis similar to Coxa Plana and Madelung deformity but located at the medial side of the proximal tibialepiphysis”

Introduction• It is a developmental condition

characterised by a disturbance of orderly sequence of enchondralossification at the upper end of the tibia, affecting the medial portion of growth plate, mainly in its posteromedial aspect and medial portion of the epiphyseal ossification centre.

• Resulting in abrupt varusangulation at proximal portion oFtibial metaphysis , while diaphysisremains straight.

Etiology- What Causes It.

• Current concept – tibia vara is an acquired disease of proximal tibial metaphysis of unknown cause.

• Enchondral ossification is most likely altered.

Suggested causative factors

• Infection

• Trauma

• Osteonecrosis

• Latent form of rickets

ALTHOUGH NONE HAVE BEEN PROVED

Combination of developmental and hereditary factors is most likely the cause

• The Relationship of early walking and obesity with Blount disease has been clearly documented.

• Rarely seen in non ambulatory children.

ETIOLOGY contd

• Familial occurance reported by several authors…..but as noted by Langenskiold and Riska, because radiographic features of infantile tibia vara have never been seen in patients younger than 1 year and rarely before 2 years..this condition should be consider congenital one.

PATHOLOGYHistologic evaluation of affected growth plates and

corresponding part of metaphysis shows :-

1. Islands of densely packed cartilage cells displaying greater hypertrophy than expected from their position in growth plate.

2. Island of nearly acellular cartilage.

3. exceptionally large clusters of capillary vessels.

Pathophysiology

• The physeal cell collumns become irregular and disordered in arrangement and normal endochondral ossification is disrupted , both in the medial aspect of metaphysis and in corresponding part of physis.

• Varus deformity progresses as long as ossification is defective and growth continues laterally on lateral part of physis.

• In later stages , an actual bony bridge may tether the medial growth , and the medial tibialplateau may apear deficient posteromedialy.

• Ligamentous laxity on lateral side of knee frequently develops in a neglected or recurrent deformity .

Classification

• Blount distinguished it as :-

Infantile-

Less than 8 years of age

bilateral in 60 %

Adolescent :-

more than 8 years to skeletal fusion.

with a cause- black, obese.

Langenskoild classification (1952)Depending on degree of

metaphysial epiphysial changes-6 progressive stages with increasing age

• Stage I- Irregular metaphysealossification combined with medial and distal protrusion of the metaphysis.

• Stage II,III, IV - evolves from mild depression of the medial metaphysis to a step- off of the medial metaphysis.

Langenskoild classification (1952)

Stage V- Increased slope of medial articularsurface and a cleft separating the medial and lateral epicondyle.

• Stage VI- Bony Bridge across the physis.

• Bowleg deformity first becomes apparent when infant starts to stand and walk.

• Obese child.

• DEFORMITY

Sharp medial angulation of tibia at metaphysis.

Deformity more evident in weight bearing position

Internal tibial torsion

Clinical Picture

• To compensate for the tibial varus , the medial femoral condyle hypertrophies.

• Over the medial aspect of epiphyseometaphysealjunction , a bony , hard , non tender prominence is palpable( reffered as BEAK on xrays )

• In long standing neglected cases –

slight flexion deformity is added to varus deformity.

collateral ligaments become lax- joint unstable.

medial tibial condyle becomes severely depressed and OA develops within medial compartment of knee.

Radiological examination• Standing AP view from hip to ankle.

FEATURES :-

Varus angulation at the epiphysealmetaphyseal junction.

Widened and irregular physeal line medially.

Medially sloped and irregular ossified epiphysis, sometimes triangular.

Prominent beaking of the medial metaphysis with lucent cartilage islands within the beak.

Lateral subluxaton of the proximal end of tibia.

Metaphyseal Beak

Tibia Femoral Angle• Normally progresses from

pronounced varus before age of 1 year to valgus between the ages 1.5 to 3 years…

• any deviation from normal tibiofemoral angle development indicates Blountsdisease.

Metaphysio diaphyseal Angle

• Levin And Drennan

• If angle > 11 degree- mostly blount lesions

• If angle < or = 11 degree….mostly resolves.

Further Work Up

• No specific blood markers.

• TESTS to rule out Rickets, ViTamin D deficiency

• Ct scan is indicated to detect physeal bar in children above 5 years of age.

Diffrential Diagnosis

• Physiologic Genu Varum

• Skeletal dysplasias

• Metabolic diseases ( renal osteodystrophy, vit d resistant rickets )

• post traumatic deformity

• Post infective sequelae

Developmental (physiological) bowing:

Developmental bowing Blount disease

Disappear after 2 years. Progressive.

Bilateral and symmetric. Unilateral or bilateral asymmetric.

Metaphyseal diaphysealangle < 11

Metaphyseal diaphysealangle > 11

TREATMENT

• Treatment choices and prognosis greatly depends upon on the age of the patient and radiographic stage of the disease

ORTHOTICS• INDICATIONS

Child younger than 3 years of age

Lesions not greater than langenskiold stage 1 and 2.

Especially if unilateral involvement.

KNEE ANKLE FOOT ORTHOSIS(KAFO)• Rainley.et all Prefferred LOCKED

KAFO that produced valgus force by 3 points pressure.

• Recommended 23 hrs /day.

• Full weight bearing.

RISKS of failure:-

Ligamentous laxity.

Patient weight above 90 percentile.

Late initiation of bracing.

ELASTIC BLOUNT BRACE• 1987

• A medial upright design that uses a wide elastic band just distal to the knee joint.

• Excusively used

ease of fabrication

Smaller profile

Corrective Osteotomy Options

METAPHYSEAL

EPIPHYSEAL- METAPHYSEAL

INTRA EPIPHYSEAL

Rx – CORRECTIVE OSTEOTOMY• In children older than 9 years with more severe

involvement , osteotomy alone , with bony bar resection , or with epiphysiodesis of lateral tibialand fibular physis is indicated.

• For older Children in whom bracing and tibialosteotomy have failed to prevent progressive deformity , Ingram , Siffert and others have suggested an intraepiphyseal osteotomy to correct severe joint instability and a valgus metaphysealosteotomy to correct the varus angulation

CORRECTIVE OSTEOTOMY Rx

• Schoenecker et al- elevation of medial tibialplateau along with metaphyseaal wedge osteotomy

• Gregosiewics – Double elevating osteotomies; intraepiphyseal and metaphyseal.

• Zeyer – hemicondylar tibial osteotomy through the epiphysis into the tibial intercondylar notch.

• Bell, Coogan- Recommended illizarov technique.

Metaphyseal oblique osteotomy

• George .T.Rab

• Advantage-

• single plane oblique cut allows simultaneous correction of varus and internal rotation .

• permits postoperative cast wedging if necessary to obtain appropriate position.

• Post-operatively

Cast is changed at 4 weeks

Weight bearing allowed if callus evident over radiographs

Cast worn till 8 weeks/ till union is evident radiologically

CHEVERON OSTEOTOMY• GREENE

• MODIFICATION OF DOME OSTEOTOMY

• Advantages

Greater Stability

Mininmal changes in leg length.

TECHNIQUE

Fibular osteotomy.

• Tibial osteotomy.

• Osteotomy fixation with pin.

• Long leg bent knee cast .

• Postoperative

DISADVANTAGES

Loss of fixation/ correction

longer period of cast immobilisation

HEMICONDYLAR OSTEOTOMY

• ZAYER

INDICATED –LIGAMENTOUS LAXITY

EXTREME DEPRESSION AND SLOPING OF MEDIAL TIBIAL CONDYLE.

INTRA EPIPHYSEAL OSTEOTOMY

• Stiffert , Johnson ET AL.

• Indication

severe joint instability

To correct intrarticularcomponents of Blount disease

• in addition valgus osteotomyto correct genu vara.

ILIZAROV TECHNIQUE

• Effective in correction of deformity and lengthening if indicated in adolescent patient.

• Allows – adjustment of limb alignment postoperatively.

• Fixation to tibia is achieved by 4 proximal and 4 distal wires that are affixed to rings and tensioned.

COMPLICATIONS

• Common peroneal nerve palsy.

• Compartment Syndrome

• Anterior Tibial Artery Occlusion

• Recurrence

Treatment in breifAGE LANGENSKOILD

STAGETREATMENT

< 2 YEARS STAGE 1 AND 2 OBSERVATTION

2-3 YEARS STAGE 1 AND 2 MODIFIED LOCKED KAFO

3-8 YEARS STAGE 2 TO STAGE 3

OBLIQUE / CHEVERON OSTEOTOMY

9+ YEARS STAGE 4 AND ABOVE

RESECTION OF BONY/ PHYSEAL BAR + OSTEOTOMY + EPIPHYSEAL ELEVATION +/- LATERAL EPIPHYSEAL EPIPHYSEODESIS

REFERENCES

1. Campbells operative orthopaedics volume 2; 12th edition

2. Tachdijian’s pediatric orthopedics volume 2; 4th edition

3. Turek orthopaedic principle and application volume 2 ;4th edition.

THANK YOU!!!!!!!