A Pilot Study of the Effect of Botulinum Toxin Type a (Dysport®, Abobotulinum Toxin A) Injection on Changes in Musculotendinous Length and Dynamics of Hamstring Muscles During Gait in Children With Spastic Cerebral Palsy Walking With Excessive Knee Flexion

This is a longitudinal, prospective, and open-label interventional study in a single center. We will investigate the effect of single injection in each patient. This study was designed to establish the clinical evidence for effect of botulinum toxin type a (Dysport, abobotulinum toxin A) injection on changes in musculotendinous length and dynamics of hamstring muscles during gait in children with spastic cerebral palsy walking with excessive knee flexion. Baseline data such as Modified Ashworth scale (MAS), Modified Tardieu scale (MTS), Gross Motor Function Measures (GMFM), and Gross Motor Function Classification System (GMFCS) level will be assessed. Gait analysis will be performed using a computerized gait analysis system (VICON MX-T10 System with 6 infrared cameras, Oxford Metrics Inc., Oxford, UK) to measure the kinematic data (angle of each joint) during the gait cycle. A trained investigator will place 14 reflective markers on the anterior and posterior superior iliac spine, the mid points of the lateral femur, the lateral knee joint axis, the midpoints of the lateral tibia, the lateral malleolus, and the dorsal foot between metatarsal heads 2 and 3. All subjects should walk barefoot at a self-selected speed along an 8-meter path with the markers in place and the motion will be captured with a 100-Hz sampling frequency. Force-plates (AMTI OR 6-5, Advanced Mechanical Technology, Newton, MA, USA) under the path will record ground reaction forces during the walking trials with a 1000-Hz sampling frequency, and joint moments will be expressed as internal moments to counter the ground reaction forces. Data collection will continue until the subject achieved at least 3 'clean' force-plate strikes. Kinematic and kinetic data from successful trials will be used for statistical analysis. Video recording will be done simultaneously from the front, rear, and side, with the 3D gait analysis.