NHMRC Early Career Fellowship (Peter Doherty Biomedical): Efficacy of interventions for equinus gait in children with cerebral palsy (2014–2017)
Abstract:
Individuals with spastic cerebral palsy (CP) typically experience muscle weakness, reduced range of motion, and
increased stiffness of affected joints, which contribute to reduced functional capacity. There is increasing awareness that muscle structural and functional adaptations contribute to these deficits.
Equinus deformity is the most prevalent lower limb abnormality in children with spastic CP (>80%) and is caused by calf muscle adaptations in response to spasticity. Initially, equinus is dynamic and can be managed with orthoses, physiotherapy, casting and intramuscular injections of botulinum toxin type-A (BoNT-A). However, BoNT-A and casting may have detrimental effects on the growth of lower limb muscles due to
reduced muscle activation and use. Given that children with spastic CP already exhibit reduced muscle size and weakness, the short-term benefits of BoNT-A may be offset by accelerated long-term structural weakening of muscle. The first part of this fellowship will investigate the efficacy of BoNT-A and casting treatments on calf muscle growth and function in preschool children. The recent International Consensus Statement on the use of BoNT-A for minimising spasticity on the lower limb (Love et al., 2010) highlights the need for research on this important issue.
Even with treatment the equinus deformity often becomes more fixed, producing negative effects on gait, balance and independence in activities
of daily living, which may necessitate surgical correction. One of the commonly performed operations for equinus is gastrocnemius lengthening which allows for an appropriate static ankle range of motion and improved balance and walking ability. However, the effect of surgical interventions on the muscle structure and function is unknown. Determining the impact of gastrocnemius lengthening on muscle and tendon
structure and function will help guide future surgical decision-making in children with spastic CP equinus gait.
