Using the Proximal Femur Maturity Index at Brace Initiation for Adolescent Idiopathic Scoliosis Predicts Curve...

Area of Science:

• Orthopedics
• Radiology
• Pediatric Spine Surgery

Background:

• The Proximal Femur Maturity Index (PFMI) assesses skeletal maturity using existing radiographs, avoiding extra radiation.
• Its relationship with curve progression in adolescent idiopathic scoliosis (AIS) treated with bracing is not well understood.

Purpose of the Study:

• To investigate the link between PFMI at brace initiation and AIS curve progression.
• To determine the predictability of adult curve progression and surgical thresholds based on PFMI grade.

Main Methods:

• A prospective study of 202 AIS patients undergoing bracing.
• Longitudinal data collection on Cobb angle and skeletal maturity (including PFMI).
• Logistic regression to predict progression to ≥40° and ≥50° curves.

Main Results:

• PFMI correlated well with other skeletal maturity indices.
• Pre-brace PFMI grade correlated with progression to ≥40° (r=-0.30) and ≥50° (r=-0.20).
• PFMI grades 2 and 3 at brace initiation for curves ≥30° predicted significant risks of reaching surgical thresholds.

Conclusions:

• PFMI is a valuable tool for predicting curve progression and brace outcomes in AIS.
• Patients with PFMI grade 4 or 5 have a low risk of significant progression.
• Skeletally immature patients (PFMI ≤3) with larger curves (≥30°) have a higher risk despite bracing.