• Long disease duration in rigid post-traumatic thoracolumbar kyphosis is associated with increased lumbar lordosis and accelerated lumbar degeneration.
• The L4/5 segment serves as the primary compensatory segment in lumbar curvature compensation.
• Patients with disease duration >5 years show significantly worse clinical outcomes (higher ODI, lower SRS-22) compared to those with ≤5 years.
• Surgical correction should emphasize restoring lower lumbar curvature to address compensatory changes.