Risk factors for the severity of heterotopic ossification in children with cerebral palsy

Heterotopic ossification is a recognized complication following hip reconstruction in children with cerebral palsy (CP). While risk factors for the occurrence of heterotopic ossification have been investigated, factors influencing its severity remain unclear. This study aimed to identify variables associated with heterotopic ossification severity in this population. This retrospective study included children with CP who developed heterotopic ossification following hip reconstruction between 2016 and 2021, with a minimum follow-up of 24 months. Demographic, clinical, and surgical variables were analyzed. Heterotopic ossification severity was classified using a standardized classification system. Univariate and multivariable analyses were performed using a proportional-odds ordinal logistic regression model. A total of 46 hips in 36 patients were analyzed. In univariate analysis, medial capsulotomy showed a tendency toward higher heterotopic ossification severity, although this did not reach statistical significance (P = 0.062). Other variables, including age, sex, Gross Motor Function Classification System level, iliac osteotomy, and postoperative immobilization, were not significantly associated with heterotopic ossification severity. In multivariable analysis, no independent predictors of increased heterotopic ossification severity were identified. No statistically significant predictors of heterotopic ossification severity were identified in this cohort. The findings should be interpreted with caution because of the limited sample size and low statistical power. Further studies with larger populations are required to better define potential risk factors.