Cerebral palsy is the most common motor disability in childhood. Orthopedic care depends on the appreciation and the identification of muscle tone abnormalities and how they affect growth and development of the child. Abnormal muscle tone is a common diagnostic feature of cerebral palsy and can include hypotonia or hypertonia. Hypertonia is the most frequent tone abnormality in children with cerebral palsy. This article reviews hypertonia and provides information on discriminating between spasticity, dystonia, and rigidity. Medication and neurosurgical options for the management of hypertonia are presented and compared.
Cerebral palsy is the most common motor disability in childhood. The management of children with cerebral palsy ideally involves a team of professionals, including physical therapists, occupational therapists, physiatrists, developmental pediatricians, and an orthopedic surgeon with clearly identified areas of expertise. The pediatric orthopedic surgeon manages contractures and alignment. Cerebral palsy was first described in 1843 by an orthopedic surgeon named William John Little. Since then, pediatric orthopedic surgeons have contributed to prognosis, management, and development of new treatments that promote improved function in the population with cerebral palsy.
Orthopedic care depends on the appreciation and identification of muscle tone abnormalities on the overlay of the growth and development of the child. Abnormal muscle tone is a diagnostic feature of cerebral palsy. Abnormal tone includes hypotonia and hypertonia. Frequently, both exist in the child. Hypertonia is the most frequent tone abnormality appreciated in the extremities of children with cerebral palsy.
Hypertonia is caused by the upper motor neuron syndrome. The cascade of problems or impairments associated with the upper motor neuron syndrome is divided into negative and positive symptoms ( Fig. 1 ). Hypertonia is one of the positive symptoms and plays an integral role in the formation of deformities in growing children with cerebral palsy ( Fig. 2 ). Although it is not known to what extent hypertonia plays a role in the process of deformity or functional limitations, it is a major factor in reducing range of motion and inhibiting growth of muscle, which disadvantages alignment. Hypertonia and, in particular, spasticity act as a brake on the musculoskeletal system, which increases the work of walking, which in turn inhibits function.