Purpose of the study: Clinical assessment of the upper limb in the cerebral palsy child remains difficult, and minimally reproducible. Thus many authors use for the upper limb, as for the lower limb, movement analysis to aid in decision making and obtain an objective measurement of postoperative results.

Material and method: Kinematic analysis and EMG were performed with the Vicon system in 27 cerebral palsy children with a spastic upper limb. The patients were compared with data obtained in a control population of 12 children. Eight patients had a second assessment after treatment. The experimental protocol followed the recommendations of the International Society of Biomechanics. The muscles targeted by the treatment were the pronator teres, the flexor carpi ulnaris, and the adductor pollicis (lengthening, transfer, toxin injection).

Results: Significant kinematic anomalies (p< 0.05) found were: excessive homolateral inclination and flexion/extension of the trunk, excessive abduction and external rotation of the arm/trunk, excessive elbow flexion, excessive pronation of the forearm, and flexion and ulnar inclination of the wrist. There was significant improvement postoperatively in the group of treated patients (p< 0.05) regarding the kinematics of the trunk, shoulder and elbow, as well as the EMG behaviour of the biceps/triceps couple despite the fact that the procedure had not affected these muscles or joints.

Discussion: Kinematic and EMG anomalies involving the trunk, shoulder and elbow represent motor strategies compensating for distal anomalies: – recruitment of the biceps allows improved supination, pulls the elbow in flexion. Since the patient cannot extend the elbow to achieve a task, compensation with the trunk increases the amplitude of the flexion-extension movement; – ‘extrinsic’ supination is achieved via an increase in external rotation of the arm in relation to the trunk and homolateral inclination of the trunk.

Conclusion: These observations have therapeutic implications: clinical, kinematic or EMG anomalies involving the trunk, shoulder, and elbow should not be treated per se but reevaluated after treatment of more distal anomalies.