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Changes in popliteal angle measurement in infants up to one year of age
Insights
Popliteal and knee extension angles in infants decrease with age, indicating reduced hamstring and capsular tightness. Measurements at birth show the most limitation, resolving by eight months in most healthy infants.
Area of Science:
- Pediatrics
- Orthopedics
- Neuromuscular assessment
Background:
- Assessing infant neuromuscular pathology requires understanding normal developmental changes in joint mobility.
- Hamstring and capsular tightness can indicate underlying neuromuscular conditions.
Purpose of the Study:
- To track changes in the popliteal angle and hip extended knee extension (HEKE) angle in normal infants from one day to 12 months.
- To establish normative data for these angles to aid in diagnosing potential neuromuscular issues.
Main Methods:
- A cohort of 130 normal infants was studied.
- Popliteal and HEKE angles were measured using a 360-degree goniometer.
- Measurements were taken with the hip flexed at 90 degrees and with the hip extended.
Main Results:
- Both popliteal and HEKE angles demonstrated the greatest limitation of knee extension at birth.
- A significant decrease in these angles was observed, with most infants showing no limitation by eight months of age.
- A strong negative correlation exists between infant age and mean popliteal/HEKE angles.
Conclusions:
- Infant knee extension limitations, indicative of hamstring and capsular tightness, naturally decrease with age.
- These findings provide a developmental reference for the popliteal and HEKE angles in healthy infants.
- Reduced joint mobility in infants may warrant further investigation for neuromuscular pathology.
Abstract:
The purpose of this study was to determine trends in the changes of the popliteal angle in 130 normal infants between one day and 12 months of age, for use in assessing infants with possible neuromuscular pathology. Using a 360 degree goniometer, the popliteal angle was measured with the hip held at 90 degree flexion, to indicate hamstring-muscle tightness. Limitation of knee extension was also measured with the hip extended (HEKE angle) to indicate capsular tightness. Both the popliteal and HEKE angle measurements showed greatest limitation of knee extension at birth, which decreased until eight months of age, when most infants showed no limitation. A highly significant negative correlation was found between age and mean popliteal and HEKE angles.