This prospective study provides Level-I evidence that Botox (botulinum toxin A) injections into the adductor longus and medial hamstrings of young children with spastic cerebral palsy, used in combination with part-time use of a hip abduction orthosis, is not effective in preventing hip subluxation in this patient population. This study is reflective of a very welcome change in orthopaedic clinical research, with an increasing number of prospective clinical research studies being reported.
Botox intramuscular injections have been widely used in children with spastic cerebral palsy for well over a decade to temporarily decrease spasticity. It is anticipated that this decrease in spasticity of overactive muscles will allow for potential improvement in function, in part by allowing these and other less spastic muscles to be used more efficiently. The most common lower extremity muscles into which Botox is injected are the hip adductors, the medial and/or lateral hamstrings, and the gastrocnemius-soleus. The Botox injection usually will have a pharmacological effect on the treated muscle for anywhere from three to six months, so injections are commonly repeated every four to six months if the initial injection has been useful and if spasticity has returned to its pre-injection baseline level.
Most parents will want to try any effective nonoperative treatment that may prevent the need for surgery in their child with spastic cerebral palsy. But treatment with Botox can be expensive. In terms of cost in United States dollars in California, the cost to the institution for the Botox injections in the dosage used in this study each six months is approximately $1000 and the charge to the patient is about $2500. What the cost is in Australia, where this study was carried out, was not noted. In addition, the cost of the hip abduction orthosis is substantial. With the data from this study, it would seem inappropriate to offer parents this combined treatment of periodic Botox injections and part-time abduction bracing just to avoid or delay surgical treatment.
The children in this study only wore the hip abduction orthosis during the day for an average of just under six hours, with parents reporting the total amount of time that the child wore the brace. It is important to remember, however, that parental reports may contain overestimations of the actual time of brace wear, as parents want to be thought of as participating fully in the care of their child. The hip abduction orthosis only abducted the hips 15° to 30°, possibly because it is difficult to abduct the hips widely if the child is in a wheelchair during the day. The question arises whether use of a hip abduction orthosis at nighttime in wider abduction would have provided more of a treatment effect than the small nonsignificant difference that was seen with the approach reported here. I have often prescribed the use of a hip abduction orthosis at nighttime to maintain symmetrical wide hip abduction, even though the use of a medication such as diazepam may be needed to somewhat reduce muscle tone and allow sleep.
It should be emphasized that Botox is used to minimize dynamic contractures due to spasticity and is not usually used to improve actual contractures of the muscle-tendon unit. In the clinical trial reported here, the Botox was used to decrease the spasticity of the hip adductors and medial hamstring muscles, but, in combination with the hip abduction brace, was also being used to prevent further fixed contractures of the hip. In 2004, Kay and associates1 in Los Angeles reported on the results of a randomized controlled study of treatment for equinus contracture in children with spastic cerebral palsy with use of either stretching casts alone or Botox injection followed by stretching casts. While the results were equally good for both groups at three months after treatment completion, at the time of the one-year follow-up, the children treated with Botox and casts had a higher rate of recurrence of equinus contracture than did those treated with stretching casts alone, leading these authors to recommend avoiding the use of Botox in conjunction with stretching casts for equinus contractures in these children. Now, in the prospective study by Kerr Graham et al., Botox has once again been found to be ineffective as a clinical treatment.
It is important that this study was published in JBJS, as the majority of studies involving orthopaedic treatment for spastic cerebral palsy are published in journals that are not usually seen by most orthopaedists. Since dislocation of the hip can occur with the hypotonic and dystonic forms of cerebral palsy as well as with the spastic type, it is not too surprising that the temporary reduction of the spasticity of muscles around the hip, as achieved in this study, did not significantly modify the natural course of hip displacement that was seen in the children with more involved disease. The fact that Botox and daytime bracing did not delay early hip subluxation in these children with spastic cerebral palsy suggests the need to consider early soft-tissue or tendon-lengthening surgery around the hip to prevent progressive hip subluxation and dislocation. Given the results of this study, it would appear that clinical recommendations should be limited to careful, periodic clinical examination and radiographic follow-up of the hips, with surgical treatment instituted early once progressive hip subluxation is identified. With preservation of symmetrical abduction of the hips, a more normal hip development can result, potentially decreasing the need for more extensive femoral and pelvic osteotomies at an older age. Preventing hip dislocation and pelvic obliquity should continue to be a goal of orthopaedic management in these young patients, many of whom are either limited walkers or nonwalkers. This report has clearly outlined one means of treatment that no longer should be recommended for the purpose of delaying or avoiding surgery for the treatment of early hip displacement in children with spastic cerebral palsy.
*The author did not receive any outside funding or grants in support of his research for or preparation of this work. Neither he nor a member of his immediate family received payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity. No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, division, center, clinical practice, or other charitable or nonprofit organization with which the author, or a member of his immediate family, is affiliated or associated.
1. Kay RM, Rethlefsen SA, Fern-Buneo A, Wren TA, Skaggs DL. Botulinum toxin as an adjunct to serial casting treatment in children with cerebral palsy. J Bone Joint Surg Am. 2004;86:2377-84.