Lower-limb growth: how predictable are predictions?

Area of Science:

• Orthopedics
• Pediatric Endocrinology
• Growth and Development

Background:

• Lower limb growth follows distinct phases: antenatal (exponential), early childhood (rapid), pre-puberty (stable), and puberty (growth spurt).
• Prediction accuracy increases with age and repeated measurements, with the onset of puberty offering the most reliable data.
• Integrating bone age, Tanner signs, growth velocity, and limb lengths provides the most accurate prediction, moving beyond rigid mathematical models.

Purpose of the Study:

• To clarify existing methods for predicting lower limb growth.
• To propose a simplified approach for calculating final limb length discrepancy.
• To determine the optimal timing for epiphysiodesis.

Main Methods:

• Review of established methods for lower limb growth prediction.
• Development of a simplified calculation for final limb length discrepancy based on age and congenital malformations.
• Analysis of timing principles for epiphysiodesis, considering discrepancy size and skeletal maturity.

Main Results:

• Limb length discrepancy multipliers are age-dependent, decreasing as the child ages.
• Epiphysiodesis timing is critical and should be based on the onset of puberty, with specific recommendations for 2-5 cm discrepancies.
• A 5 cm discrepancy typically requires bilateral femur and tibia epiphysiodesis at puberty onset.

Conclusions:

• A flexible, dynamic approach integrating multiple parameters is superior to rigid calculations for growth prediction.
• Simplified, age-adjusted multipliers can estimate final limb length discrepancy.
• Precise timing of epiphysiodesis, particularly at puberty's onset, is key to correcting limb length differences.