Splint: The efficacy of orthotic management in rest in children with cerebral palsy, a randomised controlled trial.

Objectives:

1. To evaluate the efficacy of knee-ankle-foot orthoses (worn in rest) and to evaluate the differences in efficacy between dynamic and static knee-ankle-foot orthoses in preventing a decrease of range of motion to ankle dorsiflexion in children with cerebral palsy (Clinical part);

2. To evaluate the effect of in rest-worn knee-ankle-foot orthosis on muscle morphology in children with cerebral palsy (Morphological part).



Participants:
Children with spastic cerebral palsy (aged 4-12 years) who have been successfully treated in the past for a decreased range of motion (to dorsiflexion) in the ankle.



Setting:
Two departments of rehabilitation medicine in the Netherlands (VU University medical center, Amsterdam and Groot Klimmendaal, Arnhem). Data of a study performed at the department of Neurology of the Washington University, St Louis, USA will be combined with this study and then analysed together. Morphological data will be collected in the Netherlands only.



Design:
A single blind randomised controlled trial will be performed. Three groups will be investigated. Two groups will be treated for muscle shortening (prevention of recurrence of decrease of range of motion) with static or dynamic knee-ankle-foot-orthoses for 1 year and one group will be included as a control group receiving usual care. Measurements will be performed at baseline and at 3, 6, 9 and 12 months after treatment allocation.



Intervention:
One group will be treated with a custom made static knee-ankle-foot orthosis with a fixed ankle angle and one group will be treated with a custom made dynamic knee-ankle-foot orthosis using an ultraflex„¥ ankle power unit (variable ankle angle). Both knee-ankle-foot orthoses have a fixed 0o knee extension. The control group will receive usual care only. All groups continue with their usual therapies.



Main outcome measures:

1. Clinical part: The primary outcome measure will be ankle range of motion to dorsiflexion. The secondary outcome measures will be i) maximal knee extension in stance during gait, ii) ankle dorsiflexion in mid stance during gait and iii) the gross motor function measure;

2. Morphological part: The outcome measures will be morphological parameters like achilles tendon length, muscle belly length, muscle fibre length, muscle physiological cross sectional area length and fibre pennation angle.

It is hypothesised that children who have been treated with a knee-ankle-foot orthosis show an increase or smaller decrease of range of motion to dorsiflexion in time compared to the children in the control group. In addition, it is expected that children wearing the static knee-ankle-foot orthosis show less increase or more decrease in ankle range of motion to dorsiflexion compared to children wearing the dynamic knee-ankle-foot orthosis.
Consequentially, it is expected that children wearing the knee-ankle-foot orthosis show a smaller unfavorable change in or improved knee and ankle angles during gait compared to children in the control group. This is also expected in children wearing the dynamic knee-ankle-foot orthosis compared to the static knee-ankle-foot orthosis.
Lastly, it is expected that children who have been treated with a knee-ankle-foot orthosis show an increase or smaller decline of level of mobility compared to children in the control group. This is also expected in children wearing the dynamic knee-ankle-foot orthosis compared to the static knee-ankle-foot orthosis.


Morphological part: it is hypothesised that the tendon of the MTC and the muscle fibres and PCSA increase in length due to sustained strain. These possible morphological differences are related to the passive ankle moment – ankle angle relationship and to the efficacy of the treatment.

All outcome measures: baseline, 3 months, 6 months, 9 months, 12 months.



Methods:

1. Ankle ROM: dynamometer;

2. Ankle dorsiflexion and knee flexion during gait: videoanalysis;

3. Level of mobility.

1. Group 1: Static knee-ankle-foot orthosis;

2. Group 2: Dynamic knee-ankle-foot orthosis (with ultraflex power unit);

3. Control group: No orthosis.



One group will be treated with a custom made static knee-ankle-foot orthosis with a fixed ankle angle and one group will be treated with a custom made dynamic knee-ankle-foot orthosis using an ultraflex„¥ ankle power unit (variable ankle angle). Both knee-ankle-foot orthoses have a fixed 0o knee extension. Treatment lasts one year. The control group will receive usual care only. All groups continue with their usual therapies.