Dynamics of the functional state of the forearm muscles in patients with congenital anomaly of development of the upper limb in conditions of distraction osteosynthesis

Electromyographic examinations of 29 patients at the age of 4-18 years with congenital developmental anomalies of the upper limb have demonstrated that the activation ability of forearm muscles in the limb involved is to greater extent decreased in the developmental disorder of radius. In case of shortening of the forearm not accompanied by defects of its bones the decrease of the ability of forearm muscle voluntary activation is minimal. EMG changes by maximal voluntary tension in patients with ulnar defects stand midway. Numerous low-amplitude EMG patterns of lengthened forearm muscles in patients with upper limb developmental anomalies reflect variety of the processes of adaptation and disadaptation of motor unit peripheral structures under the conditions of distraction osteosynthesis. The recovery of EMG-parameters within the periods of 1 year after treatment in patients with different variants of developmental anomalies also has a wave-like character and represents an oscillatory transitional process.