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Popliteal angle of low birth weight infants during the first year of life
Toru Kato1, Akihisa Okumura, Fumio Hayakawa
1Department of Pediatrics, Okazaki City Hospital, Okazaki, Aichi, Japan.
Insights
A tight popliteal angle is more common in infants with lower birth weights at 4 months corrected age. This finding highlights the need for serial popliteal angle assessments in low birth weight infants to avoid misdiagnosis of cerebral palsy.
Area of Science:
- Pediatrics
- Neonatology
- Developmental Pediatrics
Background:
- The popliteal angle reflects lower extremity muscle tone in infants.
- Understanding its evolution in low birth weight infants is crucial for early developmental assessment.
Purpose of the Study:
- To investigate the changes in the popliteal angle in low birth weight infants during their first year of life.
- To determine if a tight popliteal angle at early ages is predictive of later neurological conditions.
Main Methods:
- Popliteal angle measured in 204 appropriate-for-date infants at 1, 4, 8, and 12 months corrected age.
- Infants categorized by birth weight: <1000g, 1000-1499g, 1500-1999g, 2000-2499g, and >=2500g.
- Popliteal angle classified as 'tight' (<=120 degrees) or 'wide' (>120 degrees).
Main Results:
- A significantly higher rate of tight popliteal angles was observed in infants with birth weights <2000g compared to those >=2000g at 4 months corrected age.
- Tight popliteal angles were infrequent in all birth weight groups by 8 and 12 months corrected age.
- Physiological muscle tone in lower extremities appears higher in infants <2000g at 4 months.
Conclusions:
- A tight popliteal angle in early infancy may be a transient finding related to birth weight.
- Serial popliteal angle measurements are essential for accurate interpretation in low birth weight infants.
- Avoid premature diagnosis of conditions like spastic cerebral palsy based solely on early popliteal angle findings.
Abstract:
The aim of this study is to clarify the evolutional changes of the popliteal angle in low birth weight infants during the first year of life. The popliteal angle was measured at 1, 4, 8, and 12 months of corrected age on routine physical examination of 204 appropriate-for-date infants who had achieved normal psychomotor development. The popliteal angle was visually determined and categorized into two groups; tight, when it was 120 degrees or less, and wide, when it was more than 120 degrees. The infants were divided into five groups according to their birth weights; Group E, birth weight
