EMG-Untersuchungen nach Frakturen der unteren Extremität im Kindesalter

Abstract

Length and torsion discrepancies after leg fractures in children are a frequent problem. The consequences for the affected children vary from pain during walking to the necessity of early joint replacement caused by arthrosis. Aim: Surface electromyography - a radiation-free and painless method ideal for follow-up studies in children was investigated to detect posttraumatic deformities after these fractures. Method: 34 children with a mean age of 9.2 years at time of fracture were examined 6.3 years after operation. At first length and torsion of the leg were defined by 2.5D-ultrasound followed by an simultaneous treadmill gait-analysis and detection of surface-EMG of 5 leg-muscles at two different speeds (2,5 m/s and 4 m/s). According to the ultrasound results the children were separated into 4 groups (normal leg-geometry, isolated length-deformity, isolated torsional-deformity, combined length- and torsional-deformity). Parameters of gait-analysis (time of gait cycle, stance and swing-phase) and EMG-activity were compared for each group. Results: Gait-cycle of the fractured leg was almost equal at the fractured leg compared to the non-fractured. At higher speed gait cycle shortened in all groups but remained in physiological range. EMG-activity was elevated at the fractured leg compared to the non-fractured in all groups except from isolated torsional deformity of the leg. At higher speed levels of activity remained constant. Conclusions: Gait parameters showed no differences at the fractured leg. EMG-activity was mostly higher at the fractured leg. There is no coherence between pathologic leg geometry and gait parameters as well as muscle activation.