Blount's Disease: Difference between revisions

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== Description  ==
== Description  ==


Blount's disease, also known as tibia vara, is a growth disorder of the tibia (shin bone) that causes the lower leg to angle inward, resembling a bowleg.<br>
Blount's disease, also known as tibia vara, is a developmental growth disorder of the [[tibia]] that causes the lower leg to angle outwards, causing bowing of the leg. It is characterised by progressive multiplanar deformities of the leg caused by disordered endochondral ossification of the proximal medial tibia.  
 
Blount's disease occurs in young children and adolescents. The cause is unknown, but is thought to be due to the effects of weight on the growth plate. The inner part of the [[tibia]], just below the [[knee]], fails to develop normally, causing angulation of the bone. &nbsp;Unlike bowlegs, which tend to straighten as the child develops, Blount's disease is progressive and the condition worsens. It can cause severe bowing of the legs and can affect one or both legs.
 
This condition is more common among children of African ancestry. It is also associated with obesity, short stature, and early walking. There does not appear to be an obvious genetic factor.  


The cause of Blount's disease is assumed to be multifactoral, mostly mechanically due to childhood obesity.<ref name=":0">Sabharwal S. [https://s3.amazonaws.com/academia.edu.documents/41528057/Blount_CCR_JBJS.pdf?response-content-disposition=inline%3B%20filename%3DBlount_CCR_JBJS.pdf&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=ASIATUSBJ6BAI2IGOEXQ%2F20200501%2Fus-east-1%2Fs3%2Faws4_ Blount disease.] Journal of Bone and Joint Surgery 2009;91(7):1758-76.</ref> This can be described by the effects of increased weight on the growth plates. The medial proximal [[tibia]] fails to develop normally, causing angulation of the bone. &nbsp;Unlike bowlegs, which tend to straighten as the child develops, Blount's disease is progressively worsening. It can cause severe bowing and can affect one or both legs.<br>
== Clinically Relevant Anatomy  ==
== Clinically Relevant Anatomy  ==


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== Etiology / Epidemiology ==
== Etiology / Epidemiology ==
The cause of Blount's disease is assumed to be multifactoral, mostly mechanically due to childhood obesity.<ref name=":0">Sabharwal S. [https://s3.amazonaws.com/academia.edu.documents/41528057/Blount_CCR_JBJS.pdf?response-content-disposition=inline%3B%20filename%3DBlount_CCR_JBJS.pdf&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=ASIATUSBJ6BAI2IGOEXQ%2F20200501%2Fus-east-1%2Fs3%2Faws4_ Blount disease.] Journal of Bone and Joint Surgery 2009;91(7):1758-76.</ref>
The following are known epidemiological characteristics of Blount's disease:
* This condition is more common among children of African and Scandanavian ancestry.
* It is associated with obesity, short stature, and early walking.
* There does not appear to be an obvious genetic factor.


== Mechanism of Injury / Pathological Process   ==
== Classification   ==


Blount's disease is catagorised into early-onset if it develops in children under 4 years old, and late-onset, when it develops after the age of 4.<ref name=":0" />
Blount's disease is mostly catagorised into early-onset if it develops in children under 4 years old, and late-onset, when it develops after the age of 4.<ref name=":0" /> The late-onset type can further be classified into juvenile (age 4 - 10) and adolescent (after the age of 10) Blount's disease.<ref>Thompson GH, Carter JR. [https://europepmc.org/article/med/2189629 Late-onset tibia vara (Blount's disease). Current concepts.] Clinical orthopaedics and related research 1990(255):24-35.</ref>


<br>
t. Also, there are comparable histologic findings at the proximal tibial growth plate9-11<br>


== Clinical Presentation  ==
== Clinical Presentation  ==
* Unilateral or bilateral (mostly with early onset) presentation
* Multiplanar deformities of the lower leg includes:<ref name=":0" />
** [[Tibia|Tibial]] varus
** Procurvatum
** Internal torsion
** [[Leg Length Discrepancy|Limb shortening]]
** Distal [[Femur|femoral]] varus (in late-onset)


Multiplanar deformities of the lower leg includes:<ref name=":0" />
* <br>
* [[Tibia|Tibial]] varus
This entity can lead to a progressive deformity with gait deviations, limb-length discrepancy, and premature arthritis of the knee6-8.
* Procurvatum
* Internal torsion
* [[Leg Length Discrepancy|Limb shortening]]
* Distal [[Femur|femoral]] varus (in late-onset)<br>


== Diagnostic Procedures  ==
== Diagnostic Procedures  ==
X-rays is used as the main tool for diagnosis.


add text here relating to diagnostic tests for the condition<br>  
The radiographic changes are divided into 6 progressive stages in early onset Blount's disease.
* X-rays
*
*
* . Langenskiold ¨ 2 described six radiographic stages of progressive changes at the proximal tibial epiphysis and metaphysis in children with early-onset Blount disease (Fig. 3). With advancing age and higher Langenskiold ¨ stageUnilats (V and VI), irreversible physeal changes with permanent inhibition of the medial portion of the tibial growth plate can occur. Although the Langenskiold classification is useful, there ¨ is substantial interobserver variability, especially with regard to the intermediate stages12. Loder and Johnston13 studied the applicability of the Langenskiold classification to a predomi- ¨ nantly nonwhite population (one in which 73% of the patients<br>


== Outcome Measures  ==
== Outcome Measures  ==

Revision as of 16:17, 2 May 2020

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Description[edit | edit source]

Blount's disease, also known as tibia vara, is a developmental growth disorder of the tibia that causes the lower leg to angle outwards, causing bowing of the leg. It is characterised by progressive multiplanar deformities of the leg caused by disordered endochondral ossification of the proximal medial tibia.

The cause of Blount's disease is assumed to be multifactoral, mostly mechanically due to childhood obesity.[1] This can be described by the effects of increased weight on the growth plates. The medial proximal tibia fails to develop normally, causing angulation of the bone.  Unlike bowlegs, which tend to straighten as the child develops, Blount's disease is progressively worsening. It can cause severe bowing and can affect one or both legs.

Clinically Relevant Anatomy[edit | edit source]

add text here relating to clinically relevant anatomy of the condition

Etiology / Epidemiology[edit | edit source]

The following are known epidemiological characteristics of Blount's disease:

  • This condition is more common among children of African and Scandanavian ancestry.
  • It is associated with obesity, short stature, and early walking.
  • There does not appear to be an obvious genetic factor.

Classification[edit | edit source]

Blount's disease is mostly catagorised into early-onset if it develops in children under 4 years old, and late-onset, when it develops after the age of 4.[1] The late-onset type can further be classified into juvenile (age 4 - 10) and adolescent (after the age of 10) Blount's disease.[2]

t. Also, there are comparable histologic findings at the proximal tibial growth plate9-11

Clinical Presentation[edit | edit source]

  • Unilateral or bilateral (mostly with early onset) presentation
  • Multiplanar deformities of the lower leg includes:[1]

This entity can lead to a progressive deformity with gait deviations, limb-length discrepancy, and premature arthritis of the knee6-8.

Diagnostic Procedures[edit | edit source]

X-rays is used as the main tool for diagnosis.

The radiographic changes are divided into 6 progressive stages in early onset Blount's disease.

  • X-rays
  • . Langenskiold ¨ 2 described six radiographic stages of progressive changes at the proximal tibial epiphysis and metaphysis in children with early-onset Blount disease (Fig. 3). With advancing age and higher Langenskiold ¨ stageUnilats (V and VI), irreversible physeal changes with permanent inhibition of the medial portion of the tibial growth plate can occur. Although the Langenskiold classification is useful, there ¨ is substantial interobserver variability, especially with regard to the intermediate stages12. Loder and Johnston13 studied the applicability of the Langenskiold classification to a predomi- ¨ nantly nonwhite population (one in which 73% of the patients

Outcome Measures[edit | edit source]

add links to outcome measures here (see Outcome Measures Database)

Medical management[edit | edit source]

Conservative management[edit | edit source]

Children who develop severe bowing before the age of 3 may be treated with bracing. However, bracing may fail, or bowing may not be detected until the child is older.

Surgical management[edit | edit source]

  • Realignment tibial osteotomy: To be done before the age of 4 to decrease the risk of recurrent lower extremity deformity and to restore leg length where needed.[1]
  • Distraction osteogenesis: For late-onset disease:[1]
    • Aim to achieve multiplanar correction
  • The growth of just the outer half of the tibia can be surgically restricted to allow the child’s natural growth to reverse the bowing process. This much smaller surgery is most effective in children with less severe bowing and significant growth remaining.[1]


Differential Diagnosis[edit | edit source]

add text here relating to the differential diagnosis of this condition


Resources[edit | edit source]

add appropriate resources here

Case Studies[edit | edit source]

add links to case studies here (case studies should be added on new pages using the case study template)

References[edit | edit source]

References will automatically be added here, see adding references tutorial.

  1. 1.0 1.1 1.2 1.3 1.4 1.5 Sabharwal S. Blount disease. Journal of Bone and Joint Surgery 2009;91(7):1758-76.
  2. Thompson GH, Carter JR. Late-onset tibia vara (Blount's disease). Current concepts. Clinical orthopaedics and related research 1990(255):24-35.