Background: Hip displacement is considered to be common in children with cerebral palsy but the reported incidence and the proposed risk factors vary widely. Knowledge regarding its overall incidence and associated risk factors can facilitate treatment of these children. Methods: An inception cohort was generated from the Victorian Cerebral Palsy Register for the birth years 1990 through 1992, inclusive, and multiple data sources pertaining to the cohort were reviewed during 2004. Gross motor function was assessed for each child and was graded according to the Gross Motor Function Classification System (GMFCS), which is a valid, reliable, five-level ordinal grading system. Hip displacement, defined as a migration percentage of >30%, was measured on an anteroposterior radiograph of the pelvis with use of a reliable technique. Results: A full data set was obtained for 323 (86%) of 374 children in the Register for the birth years 1990 through 1992. The mean duration of follow-up was eleven years and eight months. The incidence of hip displacement for the entire birth cohort was 35%, and it showed a linear relationship with the level of gross motor function. The incidence of hip displacement was 0% for children with GMFCS level I and 90% for those with GMFCS level V. Compared with children with GMFCS level II, those with levels III, IV, and V had significantly higher relative risks of hip displacement (2.7, 4.6, and 5.9, respectively). Conclusions: Hip displacement is common in children with cerebral palsy, with an overall incidence of 35% found in this study. The risk of hip displacement is directly related to gross motor function as graded with the Gross Motor Function Classification System. This information may be important when assessing the risk of hip displacement for an individual child who has cerebral palsy, for counseling parents, and in the design of screening programs and resource allocation. Level of Evidence: Prognostic Level II. See Instructions to Authors for a complete description of levels of evidence.

During the past 25 years, botulinum toxin type A (BoNT-A) has become the most widely used medical intervention in children with cerebral palsy. In this review we consider the gaps in our knowledge in the use of BoNT-A and reasons why muscle morphology and function in children with cerebral palsy are impaired. We review limitations in our knowledge regarding the mechanisms underlying the development of contractures and the difficulty in preventing them. It is clear from this review that injection of BoNT-A in the large muscles of both the upper and lower limbs of children with cerebral palsy will result in a predictable decrease in muscle activity, which is usually reported as a reduction in spasticity, for between 3 and 6 months. These changes are noted by the use of clinical tools such as the Modified Ashworth Scale and the Modified Tardieu Scale. Decreased muscle over-activity usually results in improved range of motion in distal joints. Injection of the gastrocnemius muscle for toe-walking in a child with hemiplegia or diplegia usually has the effect of increasing the passive range of dorsiflexion at the ankle. In our review, we found that this may result in a measurable improvement in gait by the use of observational gait scales or gait analysis, in some children. However, improvements in gait function are not always achieved and are small in magnitude and short lived. We found that some of the differences in outcomes in clinical trials may relate to the use of adjunctive interventions such as serial casting, orthoses, night splints and intensive therapy. We note that the majority of clinical trials of the use of BoNT-A in children with cerebral palsy have focussed on a single injection cycle and this is insufficient to understand the balance between benefit and harm. Most outcomes were reported in terms of changes in muscle tone and there were fewer studies with robust methodology that reported improvements in function. Changes in the domains of activities and participation have rarely been reported in studies to date. There were no clinical reviews to date that consider the findings of studies in human volunteers and in experimental animals and their relevance to clinical protocols. In this review we found that studies in human volunteers and in experimental animals show muscle atrophy after an injection of BoNT-A for at least 12 months. Muscle atrophy was accompanied by loss of contractile elements in muscle and replacement with fat and connective tissue. It is not currently known if these changes, mediated at a molecular level, are reversible. We conclude that there is a need to revise clinical protocols by using BoNT-A more thoughtfully, less frequently and with greatly enhanced monitoring of the effects on injected muscle for both short-term and long-term benefits and harms.

Background: Cerebral palsy is the most common cause of childhood physical disability in developed countries, affecting two children per 1000 live births. Hip displacement affects about one-third of children with cerebral palsy and may result in pain, deformity, and impaired function. The prevention of hip displacement has not been studied in a randomized trial as far as we know. Methods: A randomized, controlled trial was conducted to examine the effect of intramuscular injections of botulinum toxin A combined with use of a variable hip abduction brace on the progression of hip displacement in children with cerebral palsy. The patients in the treatment group received injections of botulinum toxin A to the adductor and hamstring muscles every six months for three years and were prescribed a hip abduction brace to be worn for six hours per day. In the control group, no hip bracing was used nor were injections performed. The primary outcome measure was hip displacement from the acetabulum as determined by serial measurements of the migration percentage. Results: Ninety children with bilateral cerebral palsy and so-called hips at risk (a migration percentage of >10% but <40%) were entered into the study. Fifty-nine patients were boys, and the mean age was three years. Progressive hip displacement, as determined by serial measurements of the migration percentage, was found in both the treatment and control groups. The rate of hip displacement was reduced in the treatment group by 1.4% per year (95% confidence interval, −0.6% to 3.4%; p = 0.16) when weighted for the uncertainty in rates due to the differing numbers of migration percentage measurements per subject. Conclusions: There may be a small treatment benefit for the combined intervention of intramuscular injection of botulinum toxin A and abduction hip bracing in the management of spastic hip displacement in children with cerebral palsy. However, progressive hip displacement continued to occur in the treatment group, and our data do not support recommending this treatment. Level of Evidence: Therapeutic Level I. See Instructions to Authors for a complete description of levels of evidence.

Rt studies or long-term results have been reported, to our knowledge....