Advanced skeletal maturity in ambulatory cerebral palsy patients

Introduction: Both advanced and delayed bone age relative to chronological age have been described in non ambulatory children with moderate to severe cerebral palsy (CP). The purpose of our study was to assess skeletal maturation in an ambulatory CP population and determine the affects of body mass index (BMI), type of CP, and Gross Motor Function Classification System (GMFCS) on skeletal maturity. Methods: A retrospective chart and radiograph review was performed on 51 patients with ambulatory CP. A control group of 50 patients was also analyzed. Age, sex, height, weight, type of CP, and GMFCS were recorded from the chart. The height and weight were used to calculate BMI. Bone age was determined using the Oxford method. Statistical analysis for the data included descriptive statistics with bivariate and multivariate regression analyses. Significance was determined as P < 0.05. Results: There were 26 boys and 25 girls. All CP patients were independent ambulators. The mean chronological age was 7.1 years for boys and 8.6 years for girls. The mean bone age was 9.9 years for boys and 10.6 years for girls. Overall, 48 (94%) of 51 patients had advanced bone age compared with chronological age. Bone age was significantly advanced compared with chronological age for boys (P = 0.033) and showed a trend toward significance in girls (P = 0.079). Bone age was advanced compared with our control population in both sexes. In multivariate analysis, quadriplegic CP type showed a trend toward significance (P = 0.066), and GMFCS III was significantly associated with advanced bone age in boys (P = 0.011). In girls, quadriplegic CP type and BMI of less than 15 were significantly associated with advanced bone age (P < 0.05 in both). Conclusion: Our results demonstrated that most of the ambulatory CP patients had advanced bone age compared with chronological age. Quadriplegic CP type in boys and girls contributed to advanced bone age. GMFCS III and a low BMI also contributed to advanced bone age in boys and girls, respectively. Understanding factors that lead to either delayed or advanced skeletal maturation is important in planning the appropriate timing for orthopaedic surgical intervention.