Walking status and spinopelvic parameters in young children with achondroplasia: 10-year follow-up.

PURPOSE: Thoracolumbar kyphosis (TLK) is common in children with achondroplasia and resolves in 90% by 10 years of age. Our purpose was to describe the natural progression of TLK in a cohort of pre-walking children with achondroplasia.

METHODS: A single-center, retrospective review identified 62 children (32 male, 30 female) with achondroplasia. Clinical information and sagittal spinopelvic parameters were collected. The children were divided into positive pelvic tilt (PT) and negative PT. All parents were routinely counseled about unsupported sitting.

RESULTS: Spontaneous resolution rate was 64.5% at 1-year post-walking, 74.2% at 5 years of age, and 88.7% at 10 years of age. None of the children required posterior spinal decompression and fusion for progressive deformity or symptomatic spinal stenosis. At 1-year post-walking, the negative PT group had a higher sacral slope (p = 0.006), higher lumbar lordosis (p < 0.001), and lower pelvic incidence (p < 0.001). This relationship remained constant up to 10 years of age, and there was no association with TLK.

CONCLUSION: In this largest series to date, spontaneous resolution of TLK in children with achondroplasia was 64.5% at 1-year post-walking, 74.2% at 5 years of age, and 88.7% in children followed to 10 years of age. With early identification and regular follow-up with patient education, no patient in this series required treatment or developed symptomatic spinal stenosis. While not predictive of resolution of TLK, the dichotomous presentation of PT in young children with achondroplasia persists at 5 and 10 years of age and reliably predicts the spinopelvic parameters.

LEVEL OF EVIDENCE: III-retrospective comparative study.