Musculoskeletal aspects of cerebral palsy.

©2003 British Editorial Society of Bone and Joint Surgery doi.10.1302/0301-620X.85B2.14066 $2.00 J Bone Joint Surg [Br] 2003;85-B:157-66. Cerebral palsy is the most common cause of physical disability affecting children in developed countries, with an incidence of 2.0 to 2.5 per 1000 live births.1 It is not a single entity but a heterogeneous collection of clinical syndromes, characterised by abnormal motor patterns and postures. Although in most parts of the world the orthopaedic burden secondary to poliomyelitis and myelomeningocele is declining rapidly, the prevalence of cerebral palsy is static or increasing. It is the most common diagnosis after trauma in most paediatric orthopaedic units and is therefore of enormous strategic importance in terms of allocation of resources, planning and service delivery. The definitions of cerebral palsy have undergone a number of refinements by developmental paediatricians and neurologists. They stress two features. First, cerebral palsy is the result of a lesion in the immature brain, which is nonprogressive; it is a static encephalopathy.2 It is clearly important to differentiate cerebral palsy from progressive neurological conditions from the standpoint of both taxonomy and clinical management. Secondly, cerebral palsy results in a disorder of posture and movement which is permanent but not unchanging.3 To this we would add a third feature, that it results in progressive musculoskeletal pathology in most affected children.4 It is inappropriate to emphasise that the cerebral lesion is static without clearly stating that the musculoskeletal pathology will be progressive. In Little’s original description5 of spastic diplegia, prominence was given to the description of the musculoskeletal deformities. The newborn child with cerebral palsy usually has no deformities or musculoskeletal abnormalities at birth. Scoliosis, dislocation of the hip and fixed contractures develop during the rapid growth of childhood. Cerebral palsy is a useful term which describes a large group of children with motor impairment from many causes and expressed as a wide variety of clinical syndromes. The preferred term is therefore ‘the cerebral palsies’.6 It was formerly considered that most cases of cerebral palsy were the result of obstetric misadventure. Careful epidemiological and brain-imaging studies suggest that it frequently has antenatal antecedents and is often multifactorial. Recent studies also point to an increasing number of specific aetiological factors including intrauterine infections and inherited malformations.1 These investigations will in time lead to both primary prevention and secondary minimisation of cerebral injury. The increase in the incidence of cerebral palsy in preterm infants is because of neonatal intensive care and a rise in multiple births. The rates of cerebral palsy in babies born at term are steady, despite strategies to reduce birth asphyxia. The most important issue in cerebral palsy is the elucidation of the causal pathways from population-based epidemiological studies. This will lead to primary prevention, which in a chronic, incurable condition is clearly the most humane and cost-effective strategy. Cerebral palsy is subdivided according to the movement disorder and its topographical distribution. Spastic and mixed motor disorders account for more than 85% of children on current registers; dyskinetic cerebral palsy is much less common.1,6 The most common topographical syndromes are spastic hemiplegia, spastic diplegia and spastic quadriplegia which is also known as ‘whole-body involvement’.1,3,6