The effect of botulinum toxin type A injection into the gastrocnemius muscle on sit-to-stand transfer in children with spastic diplegic cerebral palsy

Abstract

OBJECTIVE: To investigate the benefit of botulinum toxin type A injection into the ankle plantarflexor muscle on sit-to-stand transfer in children with spastic diplegic cerebral palsy. DESIGN: Case-control study. SETTING: Inpatients in a university-affiliated hospital. SUBJECTS: Forty spastic diplegic children aged from 2 to 6 years (18 children with botulinum toxin type A injection into both gastrocnemius muscles as an experimental group and 14 children without injection as a control group). MAIN MEASURES: Sit-to-stand transfer task was evaluated using a motion analyser (Vicon 370 MA with six infrared cameras). The tests were performed twice with a two- week interval. The changes in temporal, kinematic and kinetic parameters were investigated in each group. RESULTS: In the control group there were no significant changes in any of the measured parameters between the tests. In the experimental group, total duration (s) of sit-to-stand transfer was shortened after injection (4.35 +/- 2.49 to 2.89 +/- 1.48, P < 0.05). The maximal angles (degrees) of pelvic and hip joints were reduced (28.88 +/- 5.53 to 26.57 +/- 3.73 and 90.78+8.69 to 87.23 +/- 8.76) and the initial angle of ankle dorsiflexion was increased (4.41 +/- 6.16 to 7.08 +/- 6.09) after injection (P < 0.05). The maximal moments (Nm/kg) of the hip and knee joints (0.44 +/- 0.17 to 0.51 +/- 0.21 and 0.13 +/- 0.05 to 0.18 +/- 0.14) were increased while that of the ankle joint was reduced (0.32 +/- 0.09 to 0.28 +/- 0.10) after injection (P < 0.05). Only the cases with greater reduction of spasticity showed an improvement on kinematic and kinetic parameters. CONCLUSION: Botulinum toxin type A injection into spastic ankle plantarflexors led to better accomplishment of sit-to-stand transfer in children with spastic diplegic cerebral palsy.