This study evaluates whether the literature-reported potential predictors can predict the outcome of multilevel botulinum toxin A injections in children who walk with flexed knees. The associations between 11 different predictors and 2 different outcome measures (the Gross Motor Function Measure and knee angle at midstance) at different weeks of follow-up were studied in 46 children with cerebral palsy (age 4-12 years), using regression analysis. Only age was positively associated with change in the Gross Motor Function Measure at 12 weeks, and only ankle angle at midstance was positively associated with change in knee angle at midstance at 48 weeks. Of these, only the former association was found to be clinically relevant.
Conclusion: The majority of potential predictors do not predict the outcome of multilevel botulinum toxin A injections in this patient group. The only relevant significant predictor, with regard to gross motor function, is older age.