Category: Orthopedics
Keywords: Varus, knee (PubMed Search)
Posted: 5/15/2022 by Brian Corwell, MD
(Updated: 11/27/2024)
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4-year-old patient comes to the ED for an unrelated complaint and you notice that his knees appear to be touching while his ankles remain apart.
Genu Varum or “knock knees” may be caused by Infantile Blount’s disease
-A progressive pathologic condition causing genu varum in children between ages 2 to 5
- Centered at the tibia
-Bilateral in up to 80%
-More common in boys
-Leg length discrepancy
- Articular incongruity
Risk factors: Early walkers (<1 year), overweight, large stature, Hispanic and African American
Results in disruption of normal cartilage growth at the MEDIAL aspect of the proximal tibia while LATERAL growth continues normally
May complain of knee soreness or subjective instability
On physical exam
Focal angulation of the proximal tibia
Lateral thrust during stance phase of walking (brief lateral shift of proximal fibula and tibia)
No tenderness or effusion
Imaging: Plain film shows varus deformity of the proximal tibia with medial beaking (beak like appears of bone) and downward slope of the proximal tibia metaphysis (increased metaphyseal-diaphyseal angle)
https://paleyinstitute.org/wp-content/uploads/blounts1.jpg
Treatment depends upon the age of the child and the severity
Successful in up to 80%
Note: In adolescent variant bracing is ineffective and surgery is only treatment
: Genu varum is normal in children <2 years old and becomes neutral at 14 months
DDX: Physiologic varus, Rickets
