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Normal limits of knee angle in white children--genu varum and genu valgum
1University of Washington School of Medicine, Seattle.
Insights
This study establishes normal knee angles in children, finding that bowlegs are common in infants but abnormal after age two. Knock knees peak around age four, gradually decreasing by age eleven.
Area of Science:
- Pediatric orthopedics
- Human anatomy and physiology
Background:
- Tibiofemoral angle and intermalleolar/intercondylar distances are key indicators of knee alignment in children.
- Understanding normal developmental changes in these parameters is crucial for identifying skeletal abnormalities.
Purpose of the Study:
- To establish the normal range of tibiofemoral angles and intermalleolar (IM) or intercondylar (IC) distances in white children.
- To define the typical progression of knee alignment from infancy through early childhood.
Main Methods:
- Measurement of knee angle and IM/IC distance in 196 white children aged 6 months to 11 years.
- Longitudinal observation of developmental changes in lower limb alignment.
Main Results:
- Children exhibit maximal bowleggedness at 6 months, progressing to neutral knee angles by 18 months.
- Mean knock knee of 8 degrees observed at age 4 years, decreasing to <6 degrees by age 11.
- Normal knock knee up to 12 degrees and IM distance up to 8 cm are acceptable in children aged 2-11 years; bowlegs after age 2 are considered abnormal.
Conclusions:
- Normal tibiofemoral angles demonstrate significant developmental changes in early childhood.
- Early identification of persistent bowlegs after age two is critical for timely orthopedic intervention.
Abstract:
Knee angle and intermalleolar (IM) or intercondylar (IC) distance were measured in 196 white children aged 6 months to 11 years to establish normal limits of tibiofemoral angle. Children were maximally bowlegged at age 6 months and progressed toward approximately neutral knee angles (0 degree) by age 18 months. Greatest mean knock knee of 8 degrees was observed at age 4 years, followed by a gradual decrease to a mean of < 6 degrees at 11 years. Normal children aged 2-11 years had knock knee up to 12 degrees and intermalleolar distance up to 8 cm; the existence of bowlegs after age 2 years was abnormal.