Chronological Age Distribution Across Risser+ Stages: A Retrospective Study of 535 Radiographs

Area of Science:

• Pediatric Orthopedics
• Radiology
• Skeletal Biology

Background:

• Accurate skeletal maturity assessment is crucial for pediatric orthopedic treatment decisions, especially for adolescent idiopathic scoliosis (AIS).
• The Risser sign is a standard radiographic indicator, but a modified Risser+ system offers improved characterization of early skeletal maturation.
• Limited data exist on the relationship between chronological age and Risser+ stages.

Purpose of the Study:

• To determine the relationship between chronological age and Risser+ skeletal maturity stages.
• To investigate sex-specific differences in the timing and progression of skeletal maturation.
• To validate the clinical utility of the Risser+ classification.

Main Methods:

• Retrospective analysis of 535 pelvic radiographs from patients aged 8-20 years.
• Skeletal maturity assessed using the Risser+ classification.
• Statistical analysis of age distributions, sex differences, and stage-to-stage progression intervals; inter- and intra-observer reliability assessed.

Main Results:

• Chronological age increased with Risser+ stages (Stage 0: 10.69 years to Stage 5: 15.82 years).
• Females reached Risser+ stages 1-3 significantly earlier than males (p ≤ 0.05).
• Mean stage-to-stage progression was 10.5 months, with excellent Risser+ staging reliability (inter-observer κ = 0.907).

Conclusions:

• Chronological age correlates consistently with Risser+ stages, confirming its clinical utility for skeletal maturity assessment.
• Sex-based maturation differences are most pronounced in early stages, with females maturing faster.
• The Risser+ system, including Risser 0(-) and 0(+) distinction, refines early maturity assessment for AIS management.