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Blounts Disease

Unit 6 Assignment

October 11, 2011

Kathryn BonvillianJillianne Hart

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Blounts Disease

Description:

Also known as Tibia Vara- it is

the abnormal bone growth of

the tibia at the epiphysis that

results in a bowing of thelower extremities.

Caused by abnormal weight

distribution on the tibia

Usually a result of obesity or

early walking in infants

Usually asymmetric or

unilateral1, but can occur

bilaterally4

Incidence:

Idiopathic cause

May have a genetic link, although aparticular gene has not been identified4

Young children and adolescents

More common in females

More common in African Americans

More common in Africa, the WestIndies, and Finland4

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Main Types

Infantile- most common, early onset- 1-3

years, progressive deformity

Juvenile- later onset >4 years, usually an

infantile case that was not treated earlier, lesscommon

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Signs and Symptoms

Signs

May have abnormal gait

Bowing at the knees

Rotational deformity calledin-toeing4, where lower

extremities start to turn in.

This disease has rapid

progression.

Symptoms4

Generally, children have few

significant symptoms and

do not experience pain fromtheir condition.

Occasionally, children may

experience some discomfort

in the legs near the knees May have some instability

when walking

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Diagnosis and Prognosis

Diagnosis

6 Stage Classification

system1

Physical examination Imaging by a medical

doctor:

Best: Anterioposterior

radiograph of bilateral lowerextremitites

Secondary: an MRI

Prognosis

Good prognosis, if treated

early1,4

If not surgically corrected,could result in5,6,7:

Vascular problems

Malalignment

Fractures wound infection

Progressive deformities

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Impairments and Functioning

Impairments:

Abnormal gait

Leg length discrepancy

Muscle imbalances causedby abnormal alignment1,7

Decreased muscle strength7

Impact on Functioning:

Poor gait

Children may experience

some discomfort in the legsnear the knees4

May have some instability

when walking4

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Treatment4

Observation

Mild bowing

Children under 2 years old

Progression monitored by anorthopedic surgeon

In many cases, it will correctitself over the course of about1 year without any furthertreatment by a doctor

Orthotics

Bowing worsens

Children 2 to 4 years old

Usually fitted with knee anklefoot orthotic (KAFO)

Goal is to gradually guide thegrowth of the legs towards astraighter position of the legs,so that the knees and feet arealigned properly

Monitored by an orthopedicsurgeon through the use ofradiographs and physicalexaminations

Weight management would be beneficial, if it was seen as a possible cause.

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Surgical Treatment4

Severe bowing

Children 3 to 4 years old

Ineffective bracing

Osteotomy A very small wedge of the tibia (shinbone), and sometimes the fibula, is removed in an effort

to realign the lower leg in a straighter position.

Small pins are inserted in order to maintain this realignmen A cast extending from above the knee to the foot is applied.

About 1 month following the operation, the pins are removed and a new cast is applied, whichis generally worn for another 2 to 3 months.

Epiphysiodesis The epiphysis is removed in order to halt the abnormal growth of the tibia and correct its

alignment

External fixation Following an osteotomy, in which a device on the outside of the leg is attached to the leg for a

number of months with small metal bars, which facilitates the proper healing of the newlyaligned tibia.

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Physical Therapy Treatment

Physical therapist will be helpfulin early conservative treatmentsto give exercises and techniquesto promote function.

Activity modification in order tominimize the unnatural stresses

on the lower extremity duringweight-bearing.

Role in rehabilitation aftersurgery to help return the patientto function with strengtheningand gait training.

Ensure that the surrounding softtissues remain flexible as thebone heals, and that musclestrength is maintained8

Attached please find two YouTubevideo of a little boy named Benwho has Blounts disease. He isseen ambulating with orthotics.

Ben Has Blounts

Ben Has Blounts

http://youtu.be/lscBiebTjLshttp://youtu.be/Zw4wLn2nQsQhttp://youtu.be/Zw4wLn2nQsQhttp://youtu.be/lscBiebTjLs

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Role of Imaging

Radiograph

Best source for diagnosis,progression, and healing

Best view: Anterioposterior

radiograph of bilateral lowerextremitites1

Show the abnormal shape ofthe tibia4

Possibly shows the changes inthe epiphysis of the bone justunder the knee4

Allows orthopedic surgeons tomeasure the angles of thedifferent segments of the leg1,4

MRI1

View and evaluate the

growth plate

Can assist in surgicalplanning

Predict development of

Blount disease in patients

with severe physiologicbowing

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Radiograph

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Radiographic Findings: Alignment

General Skeletal Architecture:Developmental deformity of thetibia, often termed tibiavara. There is a disturbance ofgrowth of the medial proximaltibial epiphysis.

General Contour of Bone: Thetibia becomes bowshaped. There is space withinthe epiphyseal line, not fusedwhen compared to other linespresent in radiograph.

Alignment of bones: The tibia islaterally shifted relative to thefemur. Fibula is posterior to thetibia, hence thesuperimposition.

Bone Density

General Bone Density: Normalbetween cortical and cancellousbone.

Textural Abnormalities: Thereseems to be bony growthoccuring at the epiphyseal plates,

but inconsistent fusion isoccurring.

Local Density Changes: There isan increase in the width ofcortical bone on the medial andlateral sides of the tibial shaft on

the left lower extremity.

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Radiographic Findings continued:

Cartilage:

Joint Space Width: Medialtibiofemoral joint space isincreased due to depression ofthe medial condyle/epicondyle.

Subchondral bone: N/A

Epiphyseal Plates: Coursemargins. Increased space withinthe line. Inconsistent fusionwithin the epiphyseal plates.

Sclerosing in small areasindicating bone growth activity.

Soft Tissues:

Muscles: Due to themalalignment of the tibia, themusculature appears to be in animproper position

Fat Pads/lines: N/A

Joint Capsules: Normal

Periosteum: N/A

Miscellaneous: The patientappears to be obese which is acommon factor in patients with apresentation of Blounts disease

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Radiograph Predictor Variables4

Behavior of lesion: Tibia Vara formationsecondary to early walking or obesity inthe pediatric population. Osteoblastic

activity still occurring in the metaphysisand epiphysis.

Bone or Joint involved: Tibia

Locus in bone: The metaphyseal andepiphyseal region of the tibia

Age, Gender, Race: Young children andadolescents. More common in femalesand African Americans.

Margin of Lesion: Wide poorly definedmargins of the epiphyseal line and tibialplateau

Shape of lesion: Tibia becomes in a varusposition with an unfused epiphyseal lineand depressed medial epicondyle

Joint space crossed: The shape of the tibiadisplaces the normal alignment of thetibiofibular joint. The joint becomes more

posterior.

Bony reaction: N/A

Matrix production: N/A

Soft Tissue changes: The radiograph may

display obesity in the patient orhypertrophied muscular in the limbssecondary to compensations of thedeformation.

History of trauma or Surgery: Trauma N/A.Surgery may be indicated for medicaltreatment of this disease.

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Possible impairments based on these

radiographic findings

Biomechanical:

Abnormal anterior andposterior glides of theknee

Abnormalarthrokinematics up anddown the kinetic chain(hip and foot/ankle) as acompensation

Abnormal articulation ofthe tibiofemoral andtibiofibular joints

Physical:

Abnormal gait

Abnormal ligamentouspull

Abnormal muscle pull

Decreased musclestrength

Possible leg length

discrepancy

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MRI

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MRI Findings1

Metaphyseal changes in both the proximal

tibia and the distal femur

Physeal widening is noted in the proximal tibia

medially (arrow).

T1-weighted MR images show abnormal

metaphyseal signal intensity in the distal

femur and proximal tibia (arrowheads).

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Possible impairments based on these MRI

findings

Biomechanical:

Abnormal

arthrokinematics

between the femur and

tibia

Abnormal

arthrokinematics up and

down the kinetic chain

(hip and foot/ankle), as a

compensation

Physical:

Abnormal gait

Abnormal ligamentous

pull Abnormal muscle pull

Decreased muscle

strength

Possible leg lengthdiscrepancy

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Questions

What measurement is used to distinguish

Blounts disease from developmental bowing

(please explain the process)?

What range of degrees is indicative of Blounts

disease?

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References

1. Cheema J, Chrissom L, Harcke T. Radiographic Characteristics of Lower extremity Bowing inChildren. Radiographics. 2003;23, 871-880

2. Blounts Disease. Pubmed Health. National Center for Biotechnology Information, U.S. NationalLibrary of Medicine. 2011. A.D.A.M., Inc. Available at:http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0002551/

3. VCU Health System Pediatric Radiology. Blounts Disease. Available athttp://www.pedsradiology.com/Historyanswer.aspx?qid=38&fid=1

4. Blounts Disease. Columbia Orthopaedics. Available at:http://childrensorthopaedics.com/blountsdisease.html . Accessed October 4, 2011.

5. DeOrio, M.J. Blount Disease Treatment & Management.http://emedicine.medscape.com/article/1250420-treatment#a17 . Updated September 25, 2010.Accessed October 5, 2011.

6. Kaneshiro, Neil. Blount's Disease. Health Guide. Availableat: http://health.nytimes.com/health/guides/disease/blounts-disease/overview.html. AccessedOctober 5, 2011.

7. Wills, Mary. Orthopedic Complications of Childhood Obesity. Pediatric PhysicalTherapy. Availableat: http://www.integrehab.com/library/Childhood_Obesity_and_Orthop_Complications.pdf. Accessed October 5, 2011.

8. Blanco JS and Widmann RF. Limb (Leg) Deformity Reconstruction for the Pediatric Patient.Available at: http://www.hss.edu/conditions_limb-leg-deformity-pediatric-patient.asp . AccessedOctober 11, 2011.

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